FIELD OF THE INVENTION
[0001] The present invention relates to novel substituted azetidine dihydrothienopyridines
with phosphodiesterase inhibitory activity, and to their use in therapy, and to pharmaceutical
compositions comprising the compounds and to methods of treating diseases with the
compounds.
BACKGROUND OF THE INVENTION
[0002] Phosphodiesterases are enzymes that catalyse the hydrolysis of cyclic AMP and/or
cyclic GMP in cells to 5-AMP and 5-GMP, respectively, and as such they are critical
to cellular regulation of cAMP or cGMP levels. Of the 11 phosphodiesterases identified
so far, phosphodiesterase (PDE) 4, PDE7 and PDE8 are selective for cAMP. PDE4 is the
most important modulator of cAMP expressed in immune and inflammatory cells such as
neutrophils, macrophages and T-lymphocytes. As cAMP is a key second messenger in the
modulation of inflammatory responses, PDE4 has been found to regulate inflammatory
responses of inflammatory cells by modulating proinflammatory cytokines such as TNF-α,
IL-2, IFN-γ, GM-CSF and LTB4. Inhibition of PDE4 has therefore become an attractive
target for the therapy of inflammatory diseases such as asthma, chronic obstructive
pulmonary disease (COPD), rheumatoid arthritis, atopic dermatitis, psoriasis, inflammatory
bowel disease such as Crohn's disease etc. (
M.D. Houslay et al., Drug Discovery Today 10 (22), 2005, pp. 1503-1519). As atopic dermatitis (AD) patients have increased PDE-activity, PDE4-inhibition
would also appear to be a viable treatment of AD (
Journal of Investigative Dermatology (1986), 87(3), 372-6).
[0003] The PDE4 gene family consists at least of four genes, A, B, C and D, which have a
high degree of homology (
V. Boswell Smith and D. Spina, Curr. Opinion Investig. Drugs 6(11), 2006, pp. 1136-1141). The four PDE4 isoforms are differentially expressed in different tissues and cell
types. Thus, PDE4B is predominantly expressed in monocytes and neutrophils, but not
in cortex and epithelial cells, while PDE4D is expressed in lung, cortex, cerebellum
and T-cells (
C. Kroegel and M. Foerster, Exp. Opinion Investig. Drugs 16(1), 2007, pp. 109-124).
[0004] Numerous PDE4 inhibitors have been studied for their therapeutic effect on inflammatory
diseases, primarily asthma and COPD.
[0008] WO 2014/124860 discloses PDE4 inhibitors for the treatment of diabetes mellitus.
WO 2011/124525 describes combinations comprising a PDE4 inhibitor and an EP4 antagonist for the
treatment of respiratory illnesses.
WO 2010/097334 discloses combinations comprising a PDE4 inhibitor and a non-steroidal anti-inflammatory
drug.
[0009] There is a continuous need for developing novel PDE4 inhibitors which have a more
favourable therapeutic window, i.e. fewer adverse effects, while retaining their therapeutic
effect.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide novel substituted azetidine dihydrothienopyridines.
In one aspect the present invention relates to PDE4 inhibitors that could be useful
as therapeutic agents for diseases mediated by PDE4, including dermal diseases or
conditions, inflammatory allergic diseases, autoimmune diseases; acute or chronic
cutaneous wound disorders, and the like.
[0011] The compounds of the present invention could have favourable oral bioavailability,
solubility, absorption and metabolic stability. They could also have a favourable
safety profile making them better tolerated than other PDE4 inhibitors.
[0012] The compounds of the present invention could have low clearance in human liver microsomes
thus making them suitable for oral use.
[0013] The compounds of the present invention could have an improved window over nausea
and emesis side effect, relative to other PDE4 inhibitors, thus allowing them to be
dosed at higher multiples of their PDE4 potencies for greater therapeutic effect.
[0014] The present invention is defined by the claims. In one aspect the invention provides
a compound of general formula (I)

wherein
R1 is selected from the group consisting of phenyl, 6 membered heteroaryl, phenoxy and
6 membered heteroaryloxy; all of which are optionally substituted with one or more
substituents independently selected from R3; and
R2 is selected from the group consisting of (C3-C7)cycloalkyl, bridged (C3-C7)cycloalkyl and (4-7 membered) heterocycloalkyl; all of which are optionally substituted
with one or more substituents independently selected from R4; and
R3 is selected from the group consisting of halogen, -CN, (C1-C4)alkyl, halo(C1-C4)alkyl, hydroxy(C1-C4)alkyl and (C3-C6)cycloalkyl; and
R4 is selected from the group consisting of fluoro, -CN, -OH, (C1-C4)alkyl, halo(C1-C4)alkyl, hydroxy(C1-C4)alkyl, -ORx, -S(O)2Rx, -S(O)2NRaRb, -C(O)Rx, -C(O)(ORx), and - C(O)NRaRb; and
Rx is selected from the group consisting of (C1-C4)alkyl and (C3-C6)cycloalkyl; and
Ra and Rb are independently selected from the group consisting of hydrogen, (C1-C4)alkyl and (C3-C6)cycloalkyl; and
S∗ represents a chiral sulfur atom with (R) stereochemistry; and
pharmaceutically acceptable salts, enantiomers, mixtures of enantiomers, diastereomers,
mixtures of diastereomers, hydrates and solvates thereof.
[0015] In another aspect, the invention provides pharmaceutical compositions comprising
a compound of the invention as defined above together with a pharmaceutically acceptable
vehicle or excipient or pharmaceutically acceptable carrier(s), optionally together
with one or more other therapeutically active compound(s).
[0016] Also disclosed is the use of a compound of the invention, for the manufacture of
pharmaceutical compositions for the prophylaxis, treatment, prevention or amelioration
of a disease, disorder or condition responsive to PDE4 inhibitory activity.
[0017] Also described is a method for treatment, prevention or alleviation of diseases,
disorders or conditions responsive to PDE4 inhibitory activity, and which method comprises
the step of administering to a living animal body a therapeutically effective amount
of the compound of the invention.
[0018] Other objects of the invention will be apparent to the person skilled in the art
from the following detailed description and examples.
DETAILED DESCRIPTION OF THE INVENTION
Definitions of the invention
[0019] As used throughout the present specification and appended claims, the following terms
have the indicated meaning:
The term "alkyl" is intended to indicate a radical obtained when one hydrogen atom
is removed from a branched or linear hydrocarbon. Said alkyl comprises 1-6, such as
1-4, such as 1-3, such as 2-3 or such as 1-2 carbon atoms. The term includes the subclasses
normal alkyl (n-alkyl), secondary and tertiary alkyl, such as methyl, ethyl, n-propyl,
isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl,
n-hexyl and isohexyl.
[0020] The terms "alkyloxy" and "alkoxy" are intended to indicate a radical of the formula
-OR', wherein R' is alkyl as indicated herein, wherein the alkyl group is appended
to the parent molecular moiety through an oxygen atom, e.g. methoxy (-OCH
3), ethoxy (-OCH
2CH
3), n-propoxy, isopropoxy, butoxy, tert-butoxy, and the like.
[0021] The term "hydroxyalkyl" is intended to indicate an alkyl group as defined above substituted
with one or more hydroxy, e.g. hydroxymethyl, hydroxyethyl, or hydroxypropyl.
[0022] The term "halogen" is intended to indicate a substituent from the 7
th main group of the periodic table, such as fluoro, chloro and bromo, preferably fluoro.
[0023] The term "haloalkyl" is intended to indicate an alkyl group as defined herein substituted
with one or more halogen atoms as defined herein, e.g. fluoro or chloro, such as fluoromethyl,
difluoromethyl or trifluoromethyl.
[0024] The terms "haloalkyloxy" and "haloalkoxy" are intended to indicate a haloalkyl group
as defined herein which is appended to the parent molecular moiety through an oxygen
atom, such as difluoromethoxy or trifluoromethoxy.
[0025] The term "cycloalkyl" is intended to indicate a saturated cycloalkane hydrocarbon
radical, as described herein. Said cycloalkyl comprises 3-7 carbon atoms, such as
3-6 carbon atoms, such as 3-5 carbon atoms or such as 3-4 carbon atoms, e.g. cyclopropyl,
cyclobutyl, cyclopentyl, cyclohexyl, or cycloheptyl.
[0026] The term "bridged cycloalkyl" is intended to indicate a saturated carbocyclic ring
having the indicated number of carbon atoms and containing one or two carbon bridges.
Representative examples include, but are not limited to, norbornyl, nortricyclyl,
and bicyclo[1.1.1]pentyl.
[0027] The term "heteroaryl" is intended to indicate radicals of monocyclic heteroaromatic
rings comprising 5- or 6-membered ring which contains from 1-5 carbon atoms and from
1-4 heteroatoms selected from O, N, or S. The heteroaryl radical may be connected
to the parent molecular moiety through a carbon atom or a nitrogen atom contained
anywhere within the heteroaryl group. Representative examples of (5-6) membered heteroaryl
groups include, but are not limited to, furanyl, imidazolyl, isothiazolyl, isoxazolyl,
oxadiazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl,
tetrazolyl, thiadiazolyl, thiazolyl, thienyl, and triazolyl.
[0028] The term "6 membered heteroaryl" is intended to indicate radicals of monocyclic heteroaromatic
rings, comprising a 6-membered ring, i.e. having a ring size of 6 atoms, which contain
from 1-5 carbon atoms and from 1-5 heteroatoms, such as 1 heteroatom, such as 1-2
heteroatoms, such as 1-3 heteroatoms, such as 1-4 heteroatoms, where the heteroatom
is N. Representative examples of 6 membered heteroaryl groups include, but are not
limited to pyrazinyl, pyridazinyl, pyridyl, pyrimidinyl, and triazinyl.
[0029] The term "heteroaryloxy" as used herein refers to the radical heteroaryl-O-, where
"heteroaryl" is as described above. Representative examples of 6 membered heteroaryloxy
groups include, but are not limited to pyrazinyloxy, pyridazinyloxy, pyridyloxy, pyrimidinyloxy,
and triazinyloxy.
[0030] The term "hydrocarbon radical" is intended to indicate a radical containing only
hydrogen and carbon atoms, it may contain one or more double and/or triple carbon-carbon
bonds, and it may comprise cyclic moieties in combination with branched or linear
moieties. Said hydrocarbon comprises 1-6 carbon atoms, and preferably comprises 1-5,
e.g. 1-4, e.g. 1-3, e.g. 1-2 carbon atoms. The term includes alkyl, cycloalkyl and
aryl, as indicated herein.
[0031] In some instances, the number of carbon atoms in a hydrocarbon radical (e.g. alkyl,
cycloalkyl and aryl) is indicated by the prefix "(C
a-C
b)", wherein a is the minimum number and b is the maximum number of carbons in the
hydrocarbon radical. Thus, for example (C
1-C
4)alkyl is intended to indicate an alkyl radical comprising from 1 to 4 carbon atoms,
and (C
3-C
6)cycloalkyl is intended to indicate a cycloalkyl radical comprising from 3 to 6 carbon
ring atoms.
[0032] The term "oxo" is intended to indicate an oxygen atom which is connected to the parent
molecular moiety via a double bond (=O).
[0033] The group "CN" is intended to represent cyano.
[0034] The group "OH" is intended to represent hydroxy.
[0035] The group "C(O)" is intended to represent a carbonyl group (C=O).
[0036] The group "S(O)
2" is intended to represent a sulfonyl group (S(=O)
2).
[0037] If substituents are described as being independently selected from a group, each
substituent is selected independent of the other. Each substituent may therefore be
identical or different from the other substituent(s).
[0038] The term "optionally substituted" means "unsubstituted or substituted", and therefore
the general formulas described herein encompass compounds containing the specified
optional substituent(s) as well as compounds that do not contain the optional substituent(s).
[0039] The term "pharmaceutically acceptable salt" is intended to indicate salts prepared
by reacting a compound of formula (I), which comprise a basic moiety, with a suitable
inorganic or organic acid, such as hydrochloric, hydrobromic, hydroiodic, sulfuric,
nitric, phosphoric, formic, acetic, 2,2-dichloroacetic, adipic, ascorbic, L-aspartic,
L-glutamic, galactaric, lactic, maleic, L-malic, phthalic, citric, propionic, benzoic,
glutaric, gluconic, D-glucuronic, methanesulfonic, salicylic, succinic, malonic, tartaric,
benzenesulfonic, ethane-1,2-disulfonic, 2-hydroxy ethanesulfonic acid, toluenesulfonic,
sulfamic, fumaric and ethylenediaminetetraacetic acid. Pharmaceutically acceptable
salts of compounds of formula (I) comprising an acidic moiety may also be prepared
by reaction with a suitable base such as sodium hydroxide, potassium hydroxide, magnesium
hydroxide, calcium hydroxide, silver hydroxide, ammonia or the like, or suitable non-toxic
amines, such as lower alkylamines, hydroxy-lower alkylamines, cycloalkylamines, or
benzylamines, or L-arginine or L-lysine. Further examples of pharmaceutical acceptable
salts are listed in
Berge, S.M.; J. Pharm. Sci.; (1977), 66(1), 1-19.
[0040] The term "solvate" is intended to indicate a species formed by interaction between
a compound, e.g. a compound of formula (I), and a solvent, e.g. alcohol, glycerol
or water, wherein said species are in a crystalline form. When water is the solvent,
said species is referred to as a hydrate.
[0041] The term "protic solvent" is intended to indicate a solvent which has an acidic hydrogen,
such as water, or such as alcohols, e.g. methanol, ethanol or isopropanol.
[0042] The term "aprotic solvent" is intended to indicate a solvent which does not have
an acidic hydrogen, such as for example dichloromethane, acetonitrile, dimethylformamide,
dimethyl sulfoxide or acetone.
[0043] The term "treatment" as used herein means the management and care of a patient for
the purpose of combating a disease, disorder or condition. The term is intended to
include the delaying of the progression of the disease, disorder or condition, the
amelioration, alleviation or relief of symptoms and complications, and/or the cure
or elimination of the disease, disorder or condition. The term may also include prevention
of the condition, wherein prevention is to be understood as the management and care
of a patient for the purpose of combating the disease, condition or disorder and includes
the administration of the active compounds to prevent the onset of the symptoms or
complications. Nonetheless, prophylactic (preventive) and therapeutic (curative) treatments
are two separate aspects.
[0044] The terms "disease", "condition" and "disorder" as used herein are used interchangeably
to specify a state of a patient which is not the normal physiological state of man.
[0045] The term "medicament" as used herein means a pharmaceutical composition suitable
for administration of the pharmaceutically active compound to a patient.
[0046] The term "pharmaceutically acceptable" as used herein means suited for normal pharmaceutical
applications, i.e. giving rise to no adverse events in patients etc.
Embodiments of the invention
[0047] In one aspect the invention provides a compound of general formula (I)

wherein
R1 is selected from the group consisting of phenyl, 6 membered heteroaryl, phenoxy and
6 membered heteroaryloxy; all of which are optionally substituted with one or more
substituents independently selected from R3; and
R2 is selected from the group consisting of (C3-C7)cycloalkyl, bridged (C3-C7)cycloalkyl and (4-7 membered) heterocycloalkyl; all of which are optionally substituted
with one or more substituents independently selected from R4; and
R3 is selected from the group consisting of halogen, -CN, (C1-C4)alkyl, halo(C1-C4)alkyl, hydroxy(C1-C4)alkyl and (C3-C6)cycloalkyl; and
R4 is selected from the group consisting of fluoro, -CN, -OH, (C1-C4)alkyl, halo(C1-C4)alkyl, hydroxy(C1-C4)alkyl, -ORx, -S(O)2Rx, -S(O)2NRaRb, -C(O)Rx, -C(O)(ORx), and - C(O)NRaRb; and
Rx is selected from the group consisting of (C1-C4)alkyl and (C3-C6)cycloalkyl; and
Ra and Rb are independently selected from the group consisting of hydrogen, (C1-C4)alkyl and (C3-C6)cycloalkyl; and
S∗ represents a chiral sulfur atom with (R) stereochemistry; and
pharmaceutically acceptable salts, enantiomers, mixtures of enantiomers, diastereomers,
mixtures of diastereomers, hydrates and solvates thereof.
[0048] In another embodiment of the present invention, R
1 is phenyl or phenoxy, optionally substituted with one of R
3.
[0049] In another embodiment of the present invention, R
3 is fluoro.
[0050] In another embodiment of the present invention, R
2 is piperidinyl, pyrrolidinyl or tetrahydropyranyl, all of which are optionally substituted
with one or more substituents independently selected from R
4.
[0051] In another embodiment of the present invention, R
2 is piperidinyl or pyrrolidinyl, both of which are independently substituted with
one of -C(O)R
x or -C(O)(OR
x), and R
x is methyl.
[0052] In another embodiment of the present invention, R
2 is tetrahydropyranyl.
[0053] In another embodiment the invention provides a compound selected from the following:
(1R)-5-(3-(4-Fluorophenyl)azetidin-1-yl)-7-((tetrahydro-2H-pyran-4-yl)amino)-2,3-dihydrothieno[3,2-b]pyridine
1-oxide;
Methyl (3R)-3-[[(1R)-5-[3-(4-fluorophenyl)azetidin-1-yl]-1-oxido-2,3-dihydrothieno-[3,2-b]pyridin-7-yl]amino]piperidine-1-carboxylate;
Methyl (3R)-3-[[(1R)-5-(3-(4-phenylazetidin-1-yl)-1-oxido-2,3-dihydrothieno[3,2-b]pyridin-7-yl]amino]piperidine-1-carboxylate;
(1R)-5-(3-(4-Fluorophenoxy)azetidin-1-yl)-7-((tetrahydro-2H-pyran-4-yl)amino)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide;
Methyl (3S)-3-[[(1R)-5-[3-(4-fluorophenoxy)azetidin-1-yl]-1-oxido-2,3-dihydrothieno[3,2-b]pyridine-7-yl]amino]pyrolidine-1-carboxylate;
1-[(3S)-3-[[(1R)-5-[3-(4-Fluorophenoxy)azetidin-1-yl]-1-oxido-2,3-dihydrothieno[3,2-b]pyridin-7-yl]amino]pyrrolidin-1-yl]ethenone;
(1R)-5-(3-Phenylazetidin-1-yl)-7-((tetrahydro-2H-pyran-4-yl)amino)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide;
or a pharmaceutically acceptable salt, enantiomer, mixture of enantiomers, diastereomer,
mixture of diastereomers, hydrate and solvate thereof.
[0054] The compounds of the invention may be obtained in crystalline form either directly
by concentration from an organic solvent or by crystallisation or re-crystallisation
from an organic solvent or mixture of said solvent and a co-solvent that may be organic
or inorganic, such as water. The crystals may be isolated in essentially solvent-free
form or as a solvate, such as a hydrate. The invention covers all crystalline forms,
such as polymorphs and pseudopolymorphs, and also mixtures thereof.
[0055] The compounds of the invention may or may not comprise asymmetrically substituted
(chiral) carbon atoms which give rise to the existence of isomeric forms, e.g. enantiomers
and possibly diastereomers. The present invention relates to all such isomers, either
in optically pure form or as mixtures thereof (e.g. racemic mixtures or partially
purified optical mixtures). Pure stereoisomeric forms of the compounds and the intermediates
of this invention may be obtained by the application of procedures known in the art.
The various isomeric forms may be separated by physical separation methods such as
selective crystallization and chromatographic techniques, e.g. high pressure liquid
chromatography using chiral stationary phases. Enantiomers may be separated from each
other by selective crystallization of their diastereomeric salts which may be formed
with optically active amines or with optically active acids. Optically purified compounds
may subsequently be liberated from said purified diastereomeric salts. Enantiomers
may also be resolved by the formation of diastereomeric derivatives. Alternatively,
enantiomers may be separated by chromatographic techniques using chiral stationary
phases. Pure stereoisomeric forms may also be derived from the corresponding pure
stereoisomeric forms of the appropriate starting materials, provided that the reaction
occurs stereoselectively or stereospecifically. If a specific stereoisomer is desired,
said compound will be synthesized by stereoselective or stereospecific methods of
preparation. These methods will advantageously employ chiral pure starting materials.
Furthermore, when a double bond or a fully or partially saturated ring system is present
in the molecule geometric isomers may be formed. It is intended that any geometric
isomer, as separated, pure or partially purified geometric isomers or mixtures thereof
are included within the scope of the invention.
[0056] The present invention is intended to include all isotopes of atoms occurring in the
present compounds. Isotopes include those atoms having the same atomic number but
different mass numbers. By way of general example and without limitation, isotopes
of hydrogen include deuterium and tritium. Isotopes of carbon include
13C and
14C. Isotopically-labelled compounds of the invention can generally be prepared by conventional
techniques known to those skilled in the art or by processes analogous to those described
herein, using an appropriate isotopically-labelled reagent in place of the non-labelled
reagent otherwise employed.
Medical use
[0057] As the Compounds of the invention could exhibit PDE4 inhibitory activity, the Compounds
could be useful as therapeutic agents for inflammatory allergic diseases such as bronchial
asthma, COPD, allergic rhinitis, and nephritis; autoimmune diseases such as rheumatoid
arthritis, multiple sclerosis, Crohn's disease ulcerative colitis, vitiligo, lupus,
systemic lupus erythematosus, and discoid lupus erythematosus; acute or chronic cutaneous
wound disorders; diseases of the central nervous system such as depression, amnesia,
and dementia; organopathy associated with ischemic reflux caused by cardiac failure,
shock, and cerebrovascular diseases, and the like; insulin-resistant diabetes; wounds,
and the like.
[0058] In one embodiment, the Compounds of the present invention are considered useful for
the treatment, prevention or alleviation of dermal diseases or conditions.
[0059] In another embodiment, the Compounds of the present invention are considered useful
for the treatment, prevention or alleviation of dermal diseases or conditions selected
from the group consisting of proliferative and inflammatory skin disorders, dermatitis,
atopic dermatitis, seborrheic dermatitis, contact dermatitis, including irritative
contact dermatitis and allergic contact dermatitis, hand dermatitis, psoriasis, psoriasis
vulgaris, inverse psoriasis, psoriatic arthritis, spondyloarthritis, epidermal inflammation,
alopecia, alopecia areata, rosacea, skin atrophy, steroid induced skin atrophy, photo
skin ageing, SAPHO syndrome, (synovitis, acne, pustulosis, hyperostosis and osteitis),
acne vulgaris, hidradenitis suppurativa, urticaria, pruritis, and eczema.
[0060] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of atopic dermatitis.
[0061] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of psoriasis, psoriasis vulgaris, inverse psoriasis
or psoriatic arthritis.
[0062] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of psoriasis.
[0063] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of alopecia areata.
[0064] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of acne.
[0065] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of pruritis.
[0066] In another embodiment, the Compounds of the present invention are considered useful
for the treatment or alleviation of eczema.
[0067] Compounds of the invention, optionally in combination with other active compounds,
could be useful for the treatment of dermal diseases or conditions, in particular
for the treatment of proliferative and inflammatory skin disorders, dermatitis, atopic
dermatitis, seborrheic dermatitis, contact dermatitis, including irritative contact
dermatitis and allergic contact dermatitis, hand dermatitis, psoriasis, psoriasis
vulgaris, inverse psoriasis, psoriatic arthritis, spondyloarthritis, epidermal inflammation,
alopecia, alopecia areata, rosacea, skin atrophy, steroid induced skin atrophy, photo
skin ageing, SAPHO syndrome, (synovitis, acne, pustulosis, hyperostosis and osteitis),
acne vulgaris, hidradenitis suppurativa, urticaria, pruritis, and eczema.
[0068] Besides being useful for human treatment, the compounds of the present invention
could also be useful for veterinary treatment of animals including mammals such as
horses, cattle, sheep, pigs, dogs, and cats.
Pharmaceutical Compositions of the invention
[0069] For use in therapy, compounds of the present invention are typically in the form
of a pharmaceutical composition. The invention therefore relates to a pharmaceutical
composition comprising a compound of formula (I), optionally together with one or
more other therapeutically active compound(s), together with a pharmaceutically acceptable
excipient or vehicle. The excipient must be "acceptable" in the sense of being compatible
with the other ingredients of the composition and not deleterious to the recipient
thereof.
[0070] Conveniently, the active ingredient comprises from 0.0001-50 % by weight of the formulation.
[0071] In the form of a dosage unit, the compound could be administered one or more times
a day at appropriate intervals, always depending, however, on the condition of the
patient, and in accordance with the prescription made by the medical practitioner.
Conveniently, a dosage unit of a formulation contain between 0.001 mg and 1000 mg,
preferably between 0.01 mg and 250 mg, such as 0.1-100 mg of a compound of formula
(I).
[0072] A suitable dosage of the compound of the invention will depend, inter alia, on the
age and condition of the patient, the severity of the disease to be treated and other
factors well known to the practising physician. The compound could be administered
either orally, parenterally or topically according to different dosing schedules,
e.g. daily or with weekly intervals. In general a single dose will be in the range
from 0.001 to 10 mg/kg body weight, e.g. in the range from 0.01 to 5 mg/kg body weight.
The compound could be administered as a bolus (i.e. the entire daily dose is administered
at once) or in divided doses two or more times a day.
[0073] In the context of topical treatment it could be more appropriate to refer to a "usage
unit", which denotes unitary, i.e. a single dose which is capable of being administered
to a patient, and which could be readily handled and packed, remaining as a physically
and chemically stable unit dose comprising either the active material as such or a
mixture of it with solid or liquid pharmaceutical diluents or carriers. A "usage unit"
is capable of being administered topically to a patient in an application per square
centimetre of the skin of from 0.1 mg to 50 mg and preferably from 0.2 mg to 5 mg
of the final formulation in question.
[0074] It is also envisaged that in certain treatment regimes, administration with longer
intervals, e.g. every other day, every week, or even with longer intervals could be
beneficial.
[0076] The administration of a compound of the present invention with one or more other
active compounds could be either concomitantly or sequentially.
[0077] The formulations include e.g. those in a form suitable for oral (including sustained
or timed release), rectal, parenteral (including subcutaneous, intraperitoneal, intramuscular,
intraarticular and intravenous), transdermal, ophthalmic, topical, dermal, nasal or
buccal administration.
[0078] The formulations may conveniently be presented in dosage unit form and may be prepared
by but not restricted to any of the methods well known in the art of pharmacy, e.g.
as disclosed in
Remington, The Science and Practice of Pharmacy, 21 ed., 2005. All methods include the step of bringing the active ingredient into association
with the carrier, which constitutes one or more accessory ingredients. In general,
the formulations are prepared by uniformly and intimately bringing the active ingredient
into association with a liquid carrier, semisolid carrier or a finely divided solid
carrier or combinations of these, and then, if necessary, shaping the product into
the desired formulation.
[0079] For oral administration, including sustained or timed release, the compound of formula
(I) could typically be present in an amount of from 0.001 to 20% by weight of the
composition, such as 0.01% to about 10 %.
[0080] Formulations of the present invention suitable for oral and buccal administration
could be in the form of discrete units as capsules, sachets, tablets, chewing gum
or lozenges, each containing a predetermined amount of the active ingredient; in the
form of a powder, granules or pellets; in the form of a solution or a suspension in
an aqueous liquid or non-aqueous liquid, such as ethanol or glycerol; or in the form
of a gel, a nano- or microemulsion, an oil-in-water emulsion, a water-in-oil emulsion
or other dispensing systems. The oils may be edible oils, such as but not restricted
to e.g. cottonseed oil, sesame oil, coconut oil or peanut oil. Suitable dispersing
or suspending agents for aqueous suspensions include synthetic or natural surfactants
and viscosifying agents such as but not restricted to tragacanth, alginate, acacia,
dextran, sodium carboxymethylcellulose, gelatin, methylcellulose, hydroxypropylmethylcellulose,
hydroxypropylcellulose, carbomers, polyvinylpyrrolidone, polysorbates, and sorbitan
fatty acid esters. The active ingredients could also be administered in the form of
a bolus, electuary or paste.
[0081] A tablet may be made by compressing, moulding or freeze drying the active ingredient
optionally with one or more accessory ingredients. Compressed tablets may be prepared
by compressing, in a suitable machine, the active ingredient(s) in a free-flowing
form such as a powder or granules, optionally mixed by a binder and/or filler, such
as e.g. lactose, glucose, mannitol starch, gelatine, acacia gum, tragacanth gum, sodium
alginate, calcium phosphates, microcrystalline cellulose, carboxymethylcellulose,
methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, ethylcellulose,
hydroxyethylcellulose, polyethylene glycol, waxes or the like; a lubricant such as
e.g. sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate,
sodium chloride or the like; a disintegrating agent such as e.g. starch, methylcellulose,
agar, bentonite, croscarmellose sodium, sodium starch glycollate, crospovidone or
the like or a dispersing agent, such as polysorbate 80. Moulded tablets may be made
by moulding, in a suitable machine, a mixture of the powdered active ingredient and
suitable carrier moistened with an inert liquid diluent. Freeze dried tablets may
be formed in a freeze-dryer from a solution of the drug substance. A suitable filler
can be included.
[0082] Formulations for rectal administration may be in the form of suppositories in which
the compound of the present invention is admixed with low melting point, water soluble
or insoluble solids such as cocoa butter, hydrogenated vegetable oils, polyethylene
glycol or fatty acids esters of polyethylene glycols, while elixirs may be prepared
using myristyl palmitate.
[0083] Formulations suitable for parenteral administration conveniently comprise a sterile
oily or aqueous preparation of the active ingredients, which is preferably isotonic
with the blood of the recipient, e.g. isotonic saline, isotonic glucose solution or
buffer solution. Furthermore, the formulation may contain co-solvent, solubilising
agent and/or complexation agents. The formulation may be conveniently sterilised by
for instance filtration through a bacteria retaining filter, addition of sterilising
agent to the formulation, irradiation of the formulation or heating of the formulation.
Liposomal formulations as disclosed in e.g.
Encyclopedia of Pharmaceutical Technology, vol.9, 1994, are also suitable for parenteral administration.
[0084] Alternatively, the compounds of formula (I) could be presented as a sterile, solid
preparation, e.g. a freeze-dried powder, which is readily dissolved in a sterile solvent
immediately prior to use.
[0085] Transdermal formulations may be in the form of a plaster, patch, microneedles, liposomal
or nanoparticulate delivery systems or other cutaneous formulations applied to the
skin.
[0086] Formulations suitable for ophthalmic administration may be in the form of a sterile
aqueous preparation of the active ingredients, which may be in micro-crystalline form,
for example, in the form of an aqueous microcrystalline suspension. Liposomal formulations
or biodegradable polymer systems e.g. as disclosed in
Encyclopedia of Pharmaceutical Technology, vol.2, 1989, may also be used to present the active ingredient for ophthalmic administration.
[0087] Formulations suitable for topical, such as dermal, intradermal or ophthalmic administration
include liquid or semi-solid preparations such as liniments, lotions, gels, applicants,
sprays, foams, film forming systems, microneedles, micro- or nano-emulsions, oil-in-water
or water-in-oil emulsions such as creams, ointments or pastes; or solutions or suspensions
such as drops. Compositions for ophthalmic treatment may additionally contain cyclodextrin.
[0088] For topical administration, the compound of formula (I) could typically be present
in an amount of from 0.001 to 20% by weight of the composition, such as 0.01% to about
10 %, but could also be present in an amount of up to about 100% of the composition.
[0089] Formulations suitable for nasal or buccal administration include powder, self-propelling
and spray formulations, such as aerosols and atomisers. Such formulations are disclosed
in greater detail in e.g.
Modern Pharmaceutics, 2nd ed., G.S. Banker and C.T. Rhodes (Eds.), page 427-432, Marcel
Dekker, New York;
Modern Pharmaceutics, 3th ed., G.S. Banker and C.T. Rhodes (Eds.), page 618-619 and
718-721, Marcel Dekker, New York and
Encyclopedia of Pharmaceutical Technology, vol. 10, J. Swarbrick and J.C. Boylan (Eds),
page 191-221, Marcel Dekker, New York.
[0090] In addition to the aforementioned ingredients, the formulations of a compound of
formula (I) may include one or more additional ingredients such as diluents, buffers,
flavouring agents, colourants, surface active agents, thickeners, penetration enhancing
agents, solubility enhancing agents, preservatives, e.g. methyl hydroxybenzoate (including
anti-oxidants), emulsifying agents and the like.
[0091] When the active ingredient is administered in the form of salts with pharmaceutically
acceptable non-toxic acids or bases, preferred salts are for instance easily watersoluble
or slightly soluble in water, in order to obtain a particular and appropriate rate
of absorption.
[0092] The pharmaceutical composition may additionally comprise one or more other active
components conventionally used in the treatment of dermal disease or conditions, e.g.
selected from the group consisting of glucocorticoids, vitamin D and vitamin D analogues,
antihistamines, platelet activating factor (PAF) antagonists, anticholinergic agents,
methylxanthines, β-adrenergic agents, COX-2 inhibitors, JAK inhibitors, other PDE
inhibitors, salicylates, indomethacin, flufenamate, naproxen, timegadine, gold salts,
penicillamine, serum cholesterol lowering agents, retinoids, zinc salts, salicylazosulfapyridine
and calcineurin inhibitors.
METHODS OF PREPARATION
[0093] The compounds of the present invention can be prepared in a number of ways well known
to those skilled in the art of synthesis. The compounds of the invention could for
example be prepared using the reactions and techniques outlined below together with
methods known in the art of synthetic organic chemistry, or variations thereof as
appreciated by those skilled in the art. Preferred methods include, but are not limited
to, those described below. The reactions are carried out in solvents appropriate to
the reagents and materials employed and suitable for the transformations being effected.
Also, in the synthetic methods described below, it is to be understood that all proposed
reaction conditions, including choice of solvent, reaction atmosphere, reaction temperature,
duration of experiment and work-up procedures, are chosen to be conditions of standard
for that reaction, which should be readily recognized by one skilled in the art. Not
all compounds falling into a given class may be compatible with some of the reaction
conditions required in some of the methods described. Such restrictions to the substituents
which are compatible with the reaction conditions will be readily apparent to one
skilled in the art and alternative methods can be used.
[0095] Starting materials are either known or commercially available compounds, or may be
prepared by routine synthetic methods well known to a person skilled in the art. Unless
otherwise noted, reagents and solvents were used as received from commercial suppliers.
Proton nuclear magnetic resonance spectra were obtained on a Bruker AVANCE 400 spectrometer
at 400 MHz, and Bruker AVANCE 500 spectrometer at 500 MHz. Tetramethylsilane was used
as an internal standard for proton spectra. The value of a multiplet, either defined
doublet (d), triplet (t), quartet (q) or (m) at the approximate midpoint is given
unless a range is quoted. (br) indicates a broad peak, whilst (s) indicates a singlet.
Thin layer chromatography was performed using Merck 6OF254 silica-gel TLC plates.
Visualisation of TLC plates was performed using UV light (254 nm). Mass spectra were
obtained on a Shimadzu LCMS-2010EV spectrometer using electrospray ionization (ESI)
and/or atmospheric-pressure chemical ionization (APCI).
[0096] The following abbreviations have been used throughout:
- ABPR
- automated back pressure regulator
- BINAP
- 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl
- dba
- dibenzylideneacetone
- DCM
- dichloromethane
- DMSO
- dimethylsulfoxide
- EtOAc
- ethyl acetate
- EtOH
- ethanol
- HPLC
- high-performance liquid chromatograph
- KOtBu
- potassium tert-butoxide
- LCMS
- liquid chromatography-mass spectrometry
- Me
- methyl
- MeCN
- acetonitrile
- MeOH
- methanol
- MHz
- megahertz
- MTBE
- methyl tert-butyl ether
- NaOMe
- sodium methoxide
- NMR
- nuclear magnetic resonance
- ppm
- parts per million
- SFC
- supercritical fluid chromatography
- TLC
- thin layer chromatography
General Methods
[0097] Compounds of the invention may be prepared according to the following non-limiting
general methods and examples:

[0098] 5,7-Dichloro-2,3-dihydrothieno[3,2-b]pyridine can be prepared, as shown in Scheme
1, by the methods described in Preparations 1 to 5.

[0099] Compounds of general formula (Int1) can be prepared, as shown in Scheme 2, by reaction
of 5,7-dichloro-2,3-dihydrothieno[3,2-b]pyridine (Preparation 5) with amines of general
formula (Int4), which are either commercially available or can readily be synthesised
by methods known to those skilled in the art.

[0100] Typical reaction conditions involve reacting a solution of 5,7-dichloro-2,3-dihydrothieno[3,2-b]pyridine
(Preparation 5) in a suitable solvent, or solvent mixture, such as 1,4-dioxane, with
an amine of formula (Int4) in the presence of a palladium catalyst and an inorganic
or organic base, such as potassium
tbutoxide, potassium carbonate or caesium carbonate. A suitable palladium catalyst
is Pd
2(dba)
3 in the presence of BINAP and a suitable base is potassium
tbutoxide, as exemplified in Preparation 6.
[0101] Sulfoxides of general formula (Int2) can be prepared, as shown in Scheme 2, by reaction
of compounds of general formula (Int1) with a suitable oxidising agent in an appropriate
solvent, optionally in the presence of a chiral catalyst. For example, a solution
of compounds of general formula (Int1) in EtOH/water can be oxidised by treatment
with NaIO
4, at a temperature between 0°C and room temperature as outlined in Preparation 9.
Sulfoxides of general formula (Int2) can be prepared as single enantiomers or, alternatively,
as mixtures of enantiomers which are then separated by methods known to those skilled
in the art. Alternatively it may be preferable to take compounds forward as mixtures
of enantiomers and separate the enantiomers at a later stage, as described in Example
1.
[0102] Compounds of general formula (I) can be prepared, as shown in Scheme 2, by reaction
of compounds of general formula (Int2) with amines of general formula R
2NH
2, which are commercially available or can readily be synthesised by methods known
to those skilled in the art. Typical reaction conditions involve reacting a solution
of a compound of general formula (Int2) in a suitable solvent, or solvent mixture,
such as 1,4-dioxane, with an amine of formula R
2NH
2 in the presence of a palladium catalyst and an inorganic or organic base, such as
potassium
tbutoxide, potassium carbonate or caesium carbonate. A suitable palladium catalyst
is palladium acetate in the presence of BINAP and a suitable base is caesium carbonate,
as exemplified in Example 1. The compounds of general formula (I) may initially be
synthesised as mixtures of enantiomers, which are then separated by methods known
to those skilled in the art.
[0103] Alternatively, compounds of general formula (Int3) can be prepared, as shown in Scheme
2, by reaction of compounds of general formula (Int1) with amines of general formula
R
2NH
2, which are commercially available or can readily be synthesised by methods known
to those skilled in the art. Typical reaction conditions involve reacting a solution
of a compound of general formula (Int1) in a suitable solvent, or solvent mixture,
such as 1,4-dioxane, with an amine of formula R
2NH
2 in the presence of a palladium catalyst and an inorganic or organic base, such as
potassium
tbutoxide, potassium carbonate or caesium carbonate. A suitable palladium catalyst
is Pd
2(dba)
3 in the presence of BINAP and a suitable base is potassium
tbutoxide, as exemplified in Preparation 12.
[0104] Compounds of general formula (I) can then be prepared, as shown in Scheme 2, by reaction
of compounds of general formula (Int3) with a suitable oxidising agent in an appropriate
solvent, optionally in the presence of a chiral catalyst. For example, a solution
of compounds of general formula (Int3) in EtOH/water can be oxidised by treatment
with NaIO
4, at a temperature between 0°C and room temperature as outlined in Example 7.

[0105] The sulfoxide of formula (Int5) can be prepared, as shown in Scheme 3, by reaction
of 5,7-dichloro-2,3-dihydrothieno[3,2-b]pyridine (Preparation 5) with a suitable oxidising
agent in an appropriate solvent, optionally in the presence of a chiral catalyst.
For example, a solution of 5,7-dichloro-2,3-dihydrothieno[3,2-b]pyridine (Preparation
5) in EtOH/water can be oxidised by treatment with NaIO
4, at a temperature between 0°C and room temperature.
[0106] Compounds of general formula (Int2) can be prepared, as shown in Scheme 3, by reaction
of the sulfoxide (Int5) with amines of general formula (Int4), which are either commercially
available or can readily be synthesised by methods known to those skilled in the art.
Typical reaction conditions involve reacting the sulfoxide (Int5) and the appropriate
amine of formula (Int3) in a suitable protic, or polar aprotic, solvent at a temperature
between room temperature and the boiling point of the solvent, in the presence of
an added organic or inorganic base.
[0107] Alternatively, a compound of general formula (Int2) can be prepared from the sulfoxide
(Int5) by reaction with an amine of general formula (Int4) in a suitable solvent,
or solvent mixture, such as 1,4-dioxane, in the presence of a palladium catalyst and
a suitable inorganic or organic base, such as potassium
tbutoxide, potassium carbonate or caesium carbonate.
PREPARATIONS AND EXAMPLES
Preparation 1
[0108] Methyl 3-amino-4,5-dihydrothiophene-2-carboxylate

[0109] Acrylonitrile (76.2 mL, 1.13 mol) was added to a stirred solution of NaOMe (61.0
g, 1.13 mol ) and methyl 2-sulfanylacetate (86 mL, 0.943 mol) in MeOH (600 mL) at
0°C. The reaction mixture was stirred for 2 days at room temperature. The reaction
mass was cooled to 0°C and quenched with aq. citric acid solution (1000 mL). The reaction
mass was then extracted with EtOAc and the organic layer was washed with water. The
resultant organic layer was dried over Na
2SO
4 and concentrated under reduced pressure to give the crude product. MTBE was added
to the crude product and the resultant solid was filtered to afford the title compound
as a solid.
1H NMR (CDCl
3, 500 MHz):
δ (ppm) 7.12 - 7.04 (m, 2H), 3.57 (s, 3H), 2.98 - 2.88 (m, 2H), 2.85 - 2.76 (m, 2H);
LCMS (ESI):
m/
z 160 [M+H]
+; 99%; RT = 1.40 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 2
[0110] Methyl 3-(3-methoxy-3-oxopropanamido)-4,5-dihydrothiophene-2-carboxylate

[0111] KHCO
3 (118.6 g, 1.18 mol) was added to a stirred solution of the compound of Preparation
1 (42.0 g, 264.2 mmol) in DCM (500 mL) at 0°C. After stirring for 5 minutes a solution
of methyl malonyl chloride (42.6 mL, 396.2 mmol) in DCM (150 mL) was added slowly
to it at 0°C. The reaction mixture was stirred for 2 hours at room temperature. After
completion of the reaction the solids were filtered off and the filtrate was concentrated
under vacuum to afford the crude product. MTBE (65 mL) was added to the crude mass
and the resultant suspension was filtered to afford the title compound as a solid.
The compound was used in the next step without further purification.
1H NMR (CDCl
3, 400 MHz):
δ (ppm) 11.08 - 10.98 (m, 1H), 3.81 (d, J=6.6 Hz, 6H), 3.63 (t, J=8.6 Hz, 2H), 3.44
(s, 2H), 3.18 (t, J=8.7 Hz, 2H); LCMS (ESI):
m/
z 260 [M+H]
+; 97%; RT = 1.85 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 3
[0112] Methyl 7-chloro-5-oxo-2,3,4,5-tetrahydrothieno[3,2-b]pyridine-6-carboxylate

[0113] A solution of the compound of Preparation 2 (42.0 g, 174 mmol) and 30% NaOMe in MeOH
(193 mL, 1.04 mol) was stirred at 70°C for 1 hour. After consumption of all starting
material (by TLC) the reaction mass was cooled to 0°C and an aq. solution of citric
acid was added to it to give a pH of approximately 4. The resulting precipitate was
filtered and washed with cold water to afford the pure title compound as a solid.
1H NMR (DMSO-d6, 400 MHz):
δ (ppm) 13.20 - 13.14 (m, 1H), 12.08 - 11.98 (m, 1H), 3.80 (s, 3H), 3.36 - 3.32 (m,
2H), 3.19 - 3.08 (m, 2H); LCMS (ESI):
m/
z 228 [M+H]
+; 99%; RT = 1.29 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 4
[0114] 2,3-Dihydrothieno[3,2-b]pyridine-5,7-diol

[0115] A mixture of the compound of Preparation 3 (2.20 g, 9.69 mmol) and 2M NaOH (46 mL,
92 mmol) was heated at reflux for 3 hours. The reaction mixture was cooled to 0°C
and an aq. solution of citric acid was added to it to achieve a pH of approximately
7. The resulting precipitate was filtered, washed with cold water and dried under
reduced pressure to afford the title compound.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 11.33 - 11.00 (m, 1H), 11.52 - 10.81 (m, 1H), 5.48 - 5.38 (m, 1H), 3.25 - 3.20
(m, 2H), 3.09 - 2.95 (m, 2H); LCMS (ESI):
m/
z 170 [M+H]
+; 98%; RT = 1.42 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 5
[0116] 5,7-Dichloro-2,3-dihydrothieno[3,2-b]pyridine

[0117] N,N-dimethyl aniline (10.1 mL, 79.8 mmol) was added slowly at 0°C to a stirred solution
of the compound of Preparation 4 (3.0 g, 17.8 mmol) in POCl
3 (6.76 mL, 72.8 mmol) and the reaction mixture was stirred at 155°C in sealed tube
for 16 hours. The reaction mixture was then cooled to room temperature and poured
into ice cold water. The mixture was extracted with EtOAc (2 x 100 mL) and the combined
organic layers were washed with brine, dried over anhydrous Na
2SO
4 and concentrated under reduced pressure. The crude product was purified by silica
gel (100-200 mesh) column chromatography (5-15% EtOAc in pet ether as eluent) to afford
the title compound as a solid.
1H NMR (CDCl
3, 400 MHz):
δ (ppm) 7.12 (s, 1H), 3.67 - 3.17 (m, 4H); LCMS (ESI):
m/
z 206 [M+H]
+; 88%; RT = 2.10 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 6
[0118] 7-Chloro-5-(3-(4-fluorophenyl)azetidin-1-yl)-2,3-dihydrothieno[3,2-b]pyridine

[0119] KO
tBu (3.90 g, 35.0 mmol) was added to a stirred solution of the compound of Preparation
5 (2.4 g, 11.7 mmol) and 3-(4-fluorophenyl)azetidine (2.19 g, 11.7 mmol) in 1,4-dioxane
(23 mL). After stirring for 5 min, Pd
2(dba)
3 (1.06 g, 1.16 mmol) and BINAP (720 mg, 1.16 mmol) were added. The reaction mixture
was heated for 2 hours at 70°C then cooled to room temperature and filtered through
a celite pad, washing with EtOAc. The filtrate was concentrated under reduced pressure
to give the crude product which was subjected to flash chromatography using 20% EtOAc
in hexane as eluent to afford the pure title compound as a solid.
1H NMR (DMSO-d6, 400 MHz):
δ (ppm) 7.52 - 7.38 (m, 2H), 7.25 - 7.14 (m, 2H), 6.38 (s, 1H), 4.31 (t,
J=8.0 Hz, 2H), 3.99 - 3.90 (m, 1H), 3.89 - 3.82 (m, 2H), 3.38 - 3.34 (m, 2H), 3.29
- 3.22 (m, 2H); LCMS (ESI):
m/
Z 320[M+H]
+; 99%; RT = 2.01 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 7
[0120] 7-Chloro-5-(3-phenylazetidin-1-yl)-2,3-dihydrothieno[3,2-b]pyridine

[0121] The title compound was prepared using the same method as Preparation 6, starting
from the compound of Preparation 5 and 3-phenylazetidine. The product was obtained
as a solid.
1H NMR (DMSO-d6, 400 MHz):
δ (ppm) 7.38 - 7.28 (m, 4H), 7.28 - 7.18 (m, 1H), 6.38 (s, 1H), 4.32 (t, J=7.9 Hz,
2H), 3.97 - 3.90 (m, 1H), 3.90 - 3.86 (m, 2H), 3.38 - 3.33 (m, 2H), 3.29 - 3.22 (m,
2H); LCMS (ESI):
m/
z 303 [M+H]
+; 92%; RT = 2.73 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 8
[0122] 7-Chloro-5-(3-(4-fluorophenoxy)azetidin-1-yl)-2,3-dihydrothieno[3,2-b]pyridine

[0123] The title compound was prepared using the same method as Preparation 6, starting
from the compound of Preparation 5 and 3-(4-fluorophenoxy)azetidine. The product was
obtained as a solid.
1H NMR (CDCl
3, 400 MHz):
δ (ppm) 7.05 - 6.94 (m, 2H), 6.79 - 6.60 (m, 2H), 6.14 (s, 1H), 5.12 - 4.97 (m, 1H),
4.42 - 4.25 (m, 2H), 4.09 - 3.91 (m, 2H),3.36-3.32(m, 2H),3.26-3.23(m, 2H);LCMS (ESI):
m/
z 337 [M+H]
+; 93%; RT = 2.43 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 9
[0124] 7-Chloro-5-(3-(4-fluorophenyl)azetidin-1-yl)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide

[0125] NaIO
4 (2.1 g, 9.96 mmol) was added to a stirred solution of the compound of Preparation
6 (2.9 g, 9.06 mmol) in EtOH/H
2O (6.0 mL, 1:1 ratio) and the reaction was stirred at room temperature for 16h. After
completion of the reaction (monitored by TLC) the reaction mass was diluted with EtOAc
and the organic layer was separated, dried over Na
2SO
4 and concentrated under reduced pressure to afford the title compound as a solid which
was used without further purification. LCMS (ESI):
m/
z 337 [M+H]
+; 76%; RT = 2.01 min; (AQUITY UPLC BEH C18 column, 0.1% FA in water with MeCN).
Preparation 10
[0126] 7-Chloro-5-(3-phenylazetidin-1-yl)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide

[0127] According to the method of Preparation 9, the compound of Preparation 7 was reacted
to give the title compound as a solid. LCMS (ESI):
m/
z 319 [M+1]
+; 93%; RT = 1.90 min; (AQUITY UPLC BEH C18 column, 0.1% FA in water with MeCN).
Preparation 11
[0128] 7-Chloro-5-(3-(4-fluorobenzyl)azetidin-1-yl)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide

[0129] According to the method of Preparation 9, the compound of Preparation 8 was reacted
to give the title compound as a solid.
1H NMR (CDCl
3, 400 MHz):
δ (ppm) 7.09 - 6.86 (m, 2H), 6.79 - 6.58 (m, 2H), 6.20 (s, 1H), 5.15 -5.01 (m, 1H),
4.55 - 4.36 (m, 2H), 4.22 - 4.11 (m, 2H), 3.96 - 3.76 (m, 1H), 3.36 - 3.07 (m, 3H)LCMS
(ESI):
m/
z353 [M+H]
+; 98%; RT = 1.75 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN).
Preparation 12
[0130] 5-(3-Phenylazetidin-1-yl)-N-(tetrahydro-2H-pyran-4-yl)-2,3-dihydrothieno[3,2-b]pyridin-7-amine

[0131] The title compound was prepared, as a solid, according to the method of Example 1
using the compound of Preparation 7 and tetrahydropyran-4-amine. LCMS (ESI):
m/
z 368 [M+H]
+; 83%; RT = 1.93 min; (AQUITY UPLC BEH C18 column, 0.1% FA in water with MeCN).
Example 1
[0132] (1R)-5-(3-(4-Fluorophenyl)azetidin-1-yl)-7-((tetrahydro-2H-pyran-4-yl)amino)-2,3-dihydrothieno[3,2-b]pyridine
1-oxide

[0133] Cs
2CO
3 (8.1 g, 25.0 mmol) and BINAP (518 mg, 0.83 mmol) were added to a stirred solution
of the compound of Preparation 9 (2.8 g, 8.33 mmol) and tetrahydropyran-4-amine (1.2
g, 12.5 mmol) in 1,4-dioxane (30 mL), followed by palladium acetate (186 mg, 0.83
mmol). The reaction mixture was heated for 16 hours at 100°C. The reaction mixture
was cooled to room temperature and filtered through a celite pad, washing with EtOAc.
The filtrate was concentrated under reduced pressure to afford the crude product.
Purification by flash chromatography using 3% MeOH/DCM as eluent gave the racemic
product (1.6 g, 50%). Further purification was then carried out by chiral SFC using
a (R,R) WHELK-01 column and methanol as co-solvent. The solvent was removed in vacuo
to afford the title compound as a solid.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.44 - 7.36 (m, 2H), 7.18 (t, J=8.9 Hz, 2H), 6.40 (d, J=8.2 Hz, 1H), 5.44 (s,
1H), 4.40-4.32 (m, 2H), 3.98 - 3.81 (m, 5H), 3.73 - 3.63 (m, 1H), 3.52 - 3.35 (m,
3H), 3.27 - 3.21 (m, 1H), 3.05-2.95 (m, 1H), 2.93 - 2.86 (m, 1H), 1.92 - 1.85 (m,
2H), 1.64 - 1.51 (m, 2H); LCMS (ESI):
m/
z 402 [M+H]
+; 99%; RT = 1.64 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC~99% SFC METHOD: Injection volume: 14 µl, Co-Solvent: Methanol,
Column: (R,R)WHELK-01(4.6
∗250) mm,5u, Temperature:30°C, Flow:4, Pressure: 100, RT:5.39 min.
Example 2
[0134] Methyl (3R)-3-[[(1R)-5-[3-(4-fluorophenyl)azetidin-1-yl]-1-oxido-2,3-dihydrothieno-[3,2-b]pyridin-7-yl]amino]piperidine-1-carboxylate

[0135] The title compound was prepared in the same manner as the compound of Example 1 using
the compound of Preparation 9 and methyl (3R)-3-aminopiperidine-1-carboxylate. Final
purification was by chiral SFC using a Chiralpak AD-H column and methanol as co-solvent.
The solvent was removed in vacuo to afford the title compound as a solid.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.46 - 7.35 (m, 2H), 7.23 - 7.13 (m, 2H), 6.45 - 6.35 (m, 1H), 5.55 -5.43 (m,
1H), 4.41 - 4.32 (m, 2H), 4.12 - 3.80 (m, 5H), 3.58 (s, 3H), 3.50 - 3.41 (m, 2H),
3.30 - 3.25 (m, 1H), 3.08 - 2.95 (m, 1H), 3.01 - 2.85 (m, 1H), 2.83 - 2.63 (m, 2H),
2.05 - 1.88 (m, 1H), 1.71 - 1.56 (m, 2H), 1.54 - 1.43 (m, 1H); LCMS (ESI):
m/
z 459 [M+H]
+; 99%; RT = 1.40 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC ~99% SFC METHOD: Column: Chiralpak AD-H (4.6
∗250) mm,5u, Co-solvent: 0.5% DEA in Methanol, Total flow: 4 g/mn , % Co-solvent: 40%,
Temperature:30°C, ABPR: 100 bar, RT: 2.16 min.
Example 3
[0136] Methyl (3R)-3-[[(1R)-5-(3-(4-phenylazetidin-1-yl)-1-oxido-2,3-dihydrothieno[3,2-b]pyridin-7-yl]amino]piperidine-1-carboxylate

[0137] The title compound was prepared in the same manner as the compound of Example 1 using
the compound of Preparation 10 and methyl (3R)-3-aminopiperidine-1-carboxylate. Final
purification was by chiral SFC using a Chiralpak AD-H column and methanol as co-solvent.
The solvent was removed in vacuo to afford the title compound as a solid.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.40 - 7.33 (m, 4H), 7.30 -7.22 (m, 1H), 6.45-6.37 (m, 1H), 5.55 - 5.43 (m,
1H), 4.43 - 4.33 (m, 2H), 4.09 - 3.80 (m, 5H), 3.58 (s, 3H), 3.51 - 3.42 (m, 2H),
3.31 - 3.24 (m, 1H), 3.06 - 2.95 (m, 1H), 3.05 - 2.95 (m, 1H), 2.85 - 2.62 (m, 2H),
2.01 - 1.90 (m, 1H), 1.72 - 1.58 (m, 2H), 1.53 - 1.44 (m, 1H); LCMS (ESI):
m/
z 441 [M+H]
+; 99%; RT = 1.39 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC ~98% SFC METHOD: Column: CHIRALCEL OD-H (4.6
∗250) mm 5u, Co-solvent: 0.5% DEA in Methanol, Total flow: 4 g/mn , % Co-solvent: 40%,
Temperature:30°C, ABPR: 100 bar, RT: 4.47 min.
Example 4
[0138] (1R)-5-(3-(4-Fluorophenoxy)azetidin-1-yl)-7-((tetrahydro-2H-pyran-4-yl)amino)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide

[0139] The title compound was prepared in the same manner as the compound of Example 1 using
the compound of Preparation 11 and tetrahydropyran-4-amine. Final purification was
by chiral SFC using a Chiralpak IC column and methanol as co-solvent. The solvent
was removed in vacuo to afford the title compound as a solid.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.19 - 7.05 (m, 2H), 6.94 - 6.84 (m, 2H), 6.39 (d,
J=8.2 Hz, 1H), 5.46 (s, 1H), 5.16 - 5.06 (m, 1H), 4.49 - 4.38 (m, 2H), 3.96 - 3.80
(m, 4H), 3.73 - 3.62 (m, 1H), 3.49 - 3.37 (m, 3H), 3.28 - 3.23 (m, 1H), 3.05 - 2.94
(m, 1H), 2.92 - 2.86 (m, 1H), 1.85 - 1.74 (m, 2H), 1.63 - 1.51 (m, 2H); LCMS (ESI):
m/
z 418 [M+H]
+; 99%; RT = 1.64 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC ~99% SFC METHOD: Column: Chiralpak AS-H (4.6
∗250) mm 5u, Co-solvent: 0.5% DEA in Methanol, Total flow: 4 g/mn , % Co-solvent: 40%,
Temperature:30°C, Outlet Pressure: 100 bar, RT: 2.18 min.
Example 5
[0140] Methyl (3S)-3-[[(1R)-5-[3-(4-fluorophenoxy)azetidin-1-yl]-1-oxido-2,3-dihydrothieno[3,2-b]pyridine-7-yl]amino]pyrrolidine-1-carboxylate

[0141] The title compound was prepared in the same manner as the compound of Example 1 using
the compound of Preparation 11 and methyl (3S)-3-aminopyrrolidine-1-carboxylate. Final
purification was by chiral SFC using a Chiralpak AD-H column and methanol as co-solvent.
The solvent was removed in vacuo to afford the title compound as a solid.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.17 - 7.10 (m, 2H), 6.95 - 6.87 (m, 2H), 6.90 - 6.80 (m, 1H), 5.44 (s, 1H),
5.17 - 5.05 (m, 1H), 4.48 - 4.38 (m, 2H), 4.25 - 4.15 (m, 1H), 3.89 (td, J=3.2, 9.3
Hz, 2H), 3.65 - 3.58 (m, 2H), 3.62-3.54 (m, 2H), 3.53 - 3.40 (m, 2H), 3.37 - 3.34
(m, 1H), 3.27 - 3.20 (m, 2H), 3.05 - 2.95 (m, 1H), 2.93 - 2.86 (m, 1H), 2.30 -2.08
(m, 1H), 2.01 - 1.89 (m, 1H); LCMS (ESI):
m/
z 461 [M+H]
+; 96%; RT = 1.70 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC ~99% SFC METHOD: Column: Chiralpak AS-H (4.6
∗250) mm 5u, Co-solvent: 0.5% DEA in Methanol, Total flow : 3 g/mn , % Co-solvent:
40%, Back pressure: 1002, RT: 4.02 min.
Example 6
[0142] 1-[(3S)-3-[[(1R)-5-[3-(4-Fluorophenoxy)azetidin-1-yl]-1-oxido-2,3-dihydrothieno[3,2-b]pyridin-7-yl]amino]pyrrolidin-1-yl]ethanone

[0143] The title compound was prepared in the same manner as the compound of Example 1 using
the compound of Preparation 11 and 1-[(3S)-3-aminopyrrolidin-1-yl]ethanone. Final
purification was by chiral SFC using a Chiralpak AD-H column and methanol as co-solvent.
The solvent was removed in vacuo to afford the title compound.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.14 - 7.04 (m, 2H), 6.93 - 6.86 (m, 2H), 6.40 - 6.32 (m, 1H), 5.50 - 5.42
(m, 1H), 5.15 - 5.06 (m, 1H), 4.50 - 4.39 (m, 2H), 4.33 - 4.19 (m, 1H), 3.98 - 3.89
(m, 2H), 3.86 - 3.63 (m, 1H), 3.61 - 3.41 (m, 3H), 3.40 - 3.21 (m, 3H), 2.90 - 2.86
(m, 1H), 2.26 - 2.10 (m, 1H), 2.08 - 1.84 (m, 4H) ; LCMS (ESI):
m/
z 445 [M+H]
+; 99%; RT = 1.60 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC ~99% SFC METHOD: Column: Chiralpak AS-H (4.6
∗250) mm 5u, Co-solvent: 0.5% DEA in Methanol, Total flow: 4 g/mn , % Co-solvent: 40%,
Temperature:30°C, Outlet Pressure: 100 bar, RT: 3.72 min.
Example 7
[0144] (1R)-5-(3-Phenylazetidin-1-yl)-7-((tetrahydro-2H-pyran-4-yl)amino)-2,3-dihydrothieno[3,2-b]pyridine-1-oxide

[0145] According to the method of Preparation 9 the compound of Preparation 12 was reacted
with NaIO
4 to give racemic title compound. Final purification was by chiral SFC using a Chiralcel
OJ-H column and methanol as co-solvent. The solvent was removed in vacuo to afford
the title compound as a solid.
1H NMR (DMSO-d6, 500 MHz):
δ (ppm) 7.38 - 7.32 (m, 4H), 7.29 -7.25 (m, 1H), 6.48 - 6.38 (m, 1H), 5.45 (s, 1H),
4.41 - 4.33 (m, 2H), 3.96 - 3.91 (m, 3H), 3.90 - 3.83 (m, 2H), 3.72 - 3.63 (m, 1H),
3.50 - 3.35 (m, 3H), 3.28 - 3.22 (m, 1H), 3.03 - 2.94 (m, 1H), 2.93 - 2.86 (m, 1H),
1.90 - 1.78 (m, 2H), 1.63 - 1.51 (m, 2H) ; LCMS (ESI):
m/
z 384 [M+H]
+; 97%; RT = 1.60 min; (AQUITY UPLC BEH C18 column, 0.1% FORMIC ACID in water with
MeCN) and Chiral HPLC ~97% SFC METHOD: Column: CHIRALCEL OJ-H (4.6
∗250) mm 5u, Co-solvent: 0.5% DEA in Methanol, Total flow: 4 g/mn ,% Co-solvent: 40%,
Temperature:30°C, ABPR: 100 bar, RT: 2.07 min.
PDE4 assay
[0146] The human PDE4D catalytic domain (UniProt no. Q08499 [S380-L740]) was incubated with
a mixture of non-labelled cAMP (cyclic adenosine monophosphate) and fluorescein amidite
(FAM) conjugated cAMP and titrated test or reference compound. Following brief incubation
the enzymatic reaction was stopped by addition of binding buffer containing nanoparticles
with immobilized trivalent metal ions capable of binding 1) AMP phospho groups and
2) terbium (Tb) donor fluorophores. Subsequent excitation of the Tb donor triggers
time-resolved FRET to adjacent FAM acceptor molecules resulting in light emission.
In the presence of a PDE4 inhibitor, AMP generation was reduced resulting in a lower
fluorescence signal. The cAMP phosphodiester is not bound by the detection system.
[0147] The results were calculated as the molar concentrations resulting in 50% inhibition
of the substrate cleavage compared to controls samples, and are expressed as IC
50 (nM).
[0148] PDE4 IC
50 ranges:
| ∗ |
indicates that IC50 values are > 50 nM and < 150 nM |
| ∗∗ |
indicates that IC50 values are > 10 and < 50 nM |
| ∗∗∗ |
indicates that IC50 values are < 10 nM |
TNF-α release
[0149] Human peripheral blood mononuclear cells (PBMC) were isolated from buffy coats. The
blood is mixed with saline at a ratio of 1:1, and the PBMC were isolated using Lymphoprep
tubesTM (Nycomed, Norway). The PBMC were suspended in RPMI1640 with 0.5% human serum
albumin, pen/strep and 2 mM L-glutamine at a concentration of 5 x 105 c/ml. The cells
were pre-incubated for 30 minutes with the test compounds in 96 well tissue culture
plates and stimulated for 18 hours with lipopolysaccharide 1 mg/ml (Sigma). TNF-α
concentration in the supernatants was measured using homogeneous time-resolved fluorescence
resonance (TR-FRET). The assay is quantified by measuring fluorescence at 665 nm (proportional
to TNF-α concentration) and 620 nm (control).
[0150] Results were expressed as IC
50 values calculated from inhibition curves using as positive controls the secretion
in LPS stimulated wells and as negative controls the secretion in unstimulated cells.
[0151] TNF-α IC
50 ranges:
| ∗ |
indicates that IC50 values are > 50 nM and < 150 nM |
| ∗∗ |
indicates that IC50 values are > 10 and < 50 nM |
| ∗∗∗ |
indicates that IC50 values are < 10 nM |
[0152] The results are shown in Table 1 below.
Table 1
| Example |
PDE4 IC50 range |
TNF-α IC50 range |
| 1 |
∗∗ |
∗∗∗ |
| 2 |
∗∗∗ |
∗∗∗ |
| 3 |
∗∗∗ |
∗∗∗ |
| 4 |
∗∗ |
∗∗ |
| 5 |
∗ |
∗ |
| 6 |
∗∗∗ |
∗∗ |
| 7 |
∗∗ |
∗∗ |