IMIDAZOPYRIDINE DERIVATIVES AS ACID PUMP ANTAGONISTS

This invention relates to newly identified imidazopyridine compounds, to the use of such compounds in therapy and to their production.

The gastric H ⁺ /K ⁺ ATPase, or proton pump, is responsible for gastric acid secretion from the acid secreting parietal cells of the stomach. The H ⁺ /K ⁺ ATPase actively transports protons and K ⁺ ions in opposite directions in a non-electrogenic manner, coupled to the hydrolysis of ATP. Under physiological conditions, this generates and maintains a proton gradient in excess of a million- fold across the luminal membrane of the gastric parietal cell.

Gastric acid is one of the major risk factors for gastrointestinal disease and specific inhibitors of the gastric H ⁺ /K ⁺ ATPase are currently used for clinical treatments and control of hyperacidity. Such inhibitors can be classified into two groups, the first of which are the irreversible inhibitors such as omeprazole, which are termed proton pump inhibitors or PPIs. This class of compounds are weak bases which accumulate in the acidic canaliculi of active parietal cells where they rapidly form cationic tetracyclic sulphenamides. The sulphenamide then binds irreversibly to the lumenal surface of the H ⁺ /K ⁺ ATPase and inhibits its activity. In patients with gastro-oesophageal reflux disease (GERD), PPIs are currently the treatment of choice. However, the majority of patients treated with PPIs, histamine H2 receptor antagonists or prokinetic agents continue to experience frequent heartburn and nocturnal acid breakthough, suggesting that current therapies may not always achieve sufficient control of acid production. Currently available PPIs may take 3-5 days to achieve maximal acid inhibition due to the fact that they require activation within the acidic canaliculus and thus target only actively secreting parietal cells. A proportion of the pumps therefore remains un-inhibited after each dose, and repeated daily dosing is required to reach a steady- state of inhibition. The second group of H ⁺ /K ⁺ ATPase inhibitors are the reversible inhibitors, which are described as acid pump antagonists (APAs) or potassium-competitive acid blockers (p-CABs). In contrast to the currently available PPIs, the reversible, K ⁺ competitive APAs do not require activation in an acidic environment and block acid secretion in a direct manner by binding at or near the potassium binding site, resulting in a very rapid onset of action compared to PPIs. It is also expected that APAs will afford improvements in control of acid secretion over an extended period.

Accordingly the present invention provides a compound of formula (I)

(I)

wherein X is NH, NR7 or O; Rl is H, C _M alkyl, CH ₂ CN, CH ₂ NH ₂ , C _3-6 cycloalkyl, C _3-6 cycloalkylCi _-4 alkyl, Ci- ₄ alkoxy, C _2-6 alkenyl, C _2-6 alkenyloxyCi _-4 alkyl, C _2-6 alkynyl, hydroxyCi _-4 alkyl, Ci- ₄ alkoxyCi- ₄ alkyl, fluoroCi _-4 alkyl, C _2-6 alkynyloxyCi. ₄ alkyl, or NR8R9, where each of R8 and R9, which may be the same or different, are H or Q^alkyl or, together with the nitrogen to which they are attached, form a 5- or 6- membered heterocyclic group containing 0 to 3 further heteroatoms selected from N, O and S;

R2 is Ci^alkyl, NH ₂ , C _3-6 cycloalkyl, Cs^cycloalkylC _M alkyl, Ci _-4 alkoxy, C _2-6 alkenyl, hydroxyCi _-4 alkyl, Ci _-4 alkoxyCi _-4 alkyl, hydroxyCi _-4 alkoxyCi _-4 alkyl, cyanoCi _-4 alkyl, R3 is H or C _M alkyl;

R4 and R5, which may be the same or different, are H, Ci _-4 alkyl, OH, halogen, Ci- ₄ alkoxy, NR14R15 where each of R14 and Rl 5, which may be the same or different, are H or C, _-4 alkyl, NHCONRIORI 1 or OCONRlORl 1 where each of RlO and Rl 1, which may be the same or different, are H or Ci _-4 alkyl or, together with the nitrogen to which they are attached, form a 5- or 6- membered heterocyclic group containing 0 to 3 further heteroatoms selected from N, O and S; or R3 and R4 together with the interconnecting atoms form a 5- or 6- membered carbocyclic group or a heterocyclic group containing 1 heteroatom selected from N, O and S, which carbocyclic or heterocyclic group is optionally substituted with one group selected from Ci _-4 alkyl, OH, OCi _-4 alkyl, halogen and NR16R17 where each of Rl 6 and Rl 7, which may be the same or different, are H or Ci _-4 alkyl; R6 is H, C^ancyl, halogen, OH, NHCO ₂ C i _-4 alkyl, NR18R19 where each of R18 and Rl 9, which may be the same or different, are H or Ci _-4 alkyl; R7 is Ci _-4 alkyl; or R4 and R7 together with the interconnecting atoms form a 5- to 7- membered heterocyclic group containing 0 or 1 further heteroatoms selected from N, O and S, which heterocyclic group is optionally substituted with one group selected from Ci-

₄ alkyl, OH, OC _M alkyl, halogen and NR20R21 where each of R20 and R21, λ may be the same or different, are H or C _1-4 alkyl; and

Het is an optionally substituted 4 to 7- membered non-aromatic heterocyclyl containing 1 to 3 heteroatoms selected from N, O and S; or a pharmaceutically acceptable salt thereof.

Examples of Het include pyrrolidinyl, pyrrolidin-2-on-yl, dioxolanyl, imidazolinyl, imidazolidin-2-on-yl, oxazolidinyl, oxazolidin-2-on-yl, pyrazol piperazinyl, ketopiperazinyl, diketopiperazinyl, piperidinyl, piperidin-2-on-y] morpholinyl, thiomorpholinyl, morpholin-2-on-yl or isothiazolidinyl.

The Het group may be attached to the imidazopyridine core through e carbon atom or a heteroatom of the Het ring. For example if the Het group is pyrrolidinone group, the bond to the imidazopyridine core may be through ei carbon atom (C-linked) or a nitrogen atom (N-linked) on the pyrrolidinone H Optional substituents for the carbocyclyl and heterocyclyl groups are i from halogen, hydroxy, oxo, cyano, nitro, (Ci _-4 )alkyl, (C _1-4 )alkoxy, hydroxy( ₄ )alkyl, hydroxy(Ci _-4 )alkoxy, halo(Ci _-4 )alkyl, halo(Ci _-4 )alkoxy, aryl(Ci _-4 )alkc ₄ )alkylthio, (Ci-^aIkOXy(Ci _-4 )alkyl, (C _3-6 )cycloalkyl(C _1-4 )alkoxy, (Ci _-4 )alkan ₄ )alkylsulfonyl, (Ci _-4 )alkylsulfonyl(Ci _-4 )alkyl, arylsul arylsulfonyloxy, aryloxysulfonyl, arylsulfonyl(Ci _-4 )alkyl, (Ci _-4 )alkylsulfonan ₄ )alkyl, (Ci _-4 )alkylamido(Ci _-4 )alkyl, arylsulfonamido, arylcarboxamido, arylsulfonamido(C _{\ -4} )alkyl, arylcarboxamido(C i _-4 )alkyl, arylaminosulfonyl, arylaminocarbonyl, aroyl, aroyl(Ci _-4 )alkyl, or aryl(Ci _-4 )alkanoyl group; a gro NR22R23, CO ₂ R22, CONR22R23, where each of R22 and R23, which may 1 same or different, are H, Ci _-4 alkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl, or together form an optionally substituted 5- or 6- memberec heterocyclic group containing a further heteroatom selected from N, O or S.

When the compound contains an alkyl group, whether alone or formii a larger group, e.g. alkoxy or alkylthio, the alkyl group may be straight chain branched or cyclic, or combinations thereof.

In one embodiment Het is pyrrolidinon-yl, imidazolidinyl, piperidin-2 imidazolidin-2-on-yl, morpholin-2-on-yl, or hydroxy-2-pyrrolidinon-yl.

In a further embodiment Het is piperidin-2-on-yl or imidazolidinonyl.

In one embodiment the optional substituents on the Het group are (Ci or hydroxy.

In a further embodiment as optional substituents on the He are methyl or ethyl.

In one embodiment X is NH or O.

In a further embodiment X is NH. In a further embodiment X is O.

In one embodiment Rl and R2 are both methyl.

In one embodiment R3 is H.

In one embodiment R4 and R5 are not both H.

In a further embodiment R4 and R5 are both methyl, or R4 is methyl and R5 is ethyl.

In one embodiment R6 is H.

In one embodiment X is NH, Rl and R2 are both methyl, R3 is H, R4 and R5 are both methyl and R6 is H.

In one embodiment X is O, Rl and R2 are both methyl, R3 is H, R4 and R5 are both methyl and R6 is H.

When used herein, halogens include fluoro, chloro, bromo and iodo.

When used herein the term aryl means a 5- to 6- membered aromatic ring for example phenyl, or a 7 to 12 membered bicyclic ring system where at least one of the rings is aromatic for example naphthyl.

It is to be understood that the present invention covers all combinations of particularised groups and substituents described herein above.

It will be appreciated that compounds of formula (I) may exist as R or S enantiomers. The present invention includes within its scope all such isomers, including mixtures. Where additional chiral centres are present in compounds of formula (I), the present invention includes within its scope all possible diastereoisomers, including mixtures thereof. The different isomeric forms may be separated or resolved one from the other by conventional methods, or any given isomer may be obtained by conventional synthetic methods or by stereospecific or asymmetric syntheses. The invention also extends to any tautomeric forms and mixtures thereof.

It will be understood that the invention includes pharmaceutically acceptable derivatives of compounds of formula (I) and that these are included within the scope of the invention.

Particular compounds according to the invention include those mentioned in the examples and their pharmaceutically acceptable derivatives.

As used herein "pharmaceutically acceptable derivative" includes any pharmaceutically acceptable salt, ester or salt of such ester of a compound of formula (I) which, upon administration to the recipient is capable of providing (directly or indirectly) a compound of formula (I) or an active metabolite or residue thereof.

It will be appreciated that for use in medicine the salts of the compounds of formula (I) should be pharmaceutically acceptable. Suitable pharmaceutically acceptable salts will be apparent to those skilled in the art. Pharmaceutically acceptable salts include those described by Berge, Bighley and Monkhouse,

J.Pharm.Sci. (1977) 66, ppl-19. Such pharmaceutically acceptable salts include acid addition salts formed with inorganic acids e.g. hydrochloric, hydrobromic, sulphuric, nitric or phosphoric acid; and organic acids e.g. succinic, maleic, acetic, fumaric, citric, tartaric, benzoic, p-toluenesulfonic, methanesulfonic or naphthalenesulfonic acid. Other salts e.g. oxalates or formates, may be used, for example in the isolation of compounds of formula (I) and are included within the scope of this invention. Also included within the scope of the invention are solvates and hydrates of compounds of formula (I).

Certain of the compounds of formula (I) may form acid addition salts or more equivalents of the acid. The present invention includes within its sec possible stoichiometric and non-stoichiometric forms.

The compounds of formula (I) may be prepared in crystalline or non- crystalline form and, if crystalline, may optionally be solvated, eg. as the hyd This invention includes within its scope stoichiometric solvates (eg. hydrates as compounds containing variable amounts of solvent (eg. water).

The subject invention also includes isotopically-labeled compounds w identical to those recited in formula (I) and following, but for the fact that om atoms are replaced by an atom having an atomic mass or mass number diffeπ the atomic mass or mass number most commonly found in nature. Examples isotopes that can be incorporated into compounds of the invention include isc hydrogen, carbon, nitrogen, oxygen, fluorine, iodine and chlorine such as 3H 14C, 18F, 1231, 1251. Compounds of the present invention and pharmaceutically acceptable said compounds that contain the aforementioned isotopes and/or other isotop other atoms are within the scope of the present invention. Isotopically-labele compounds of the present invention, for example those into which radioactiv isotopes such as 3H or 14C have been incorporated, are useful in drug and/or tissue distribution assays. Tritiated, ie. 3H, and carbon- 14, ie. 14C, isotopes particularly preferred for their ease of preparation and detectability. 11C and isotopes are particularly useful in PET (positron emission tomography).

Since the compounds of formula (I) are intended for use in pharmacei compositions it will readily be understood that they are each preferably provi substantially pure form, for example at least 60% pure, more suitably at least pure and preferably at least 85%, especially at least 98% pure (% are on a we weight basis). Impure preparations of the compounds may be used for prepai more pure forms used in the pharmaceutical compositions.

According to a further aspect of the present invention there is provide process for the preparation of compounds of formula (I) and derivatives there following schemes detail some synthetic routes to compounds of the inventio following schemes reactive groups can be protected with protecting groups a deprotected according to well established techniques.

Scheme 1 - Synthesis of JV-linked 6-(hetero)cyclyls via metal-mediated co reactions with a 6-halo compound

Thus, compounds of the invention for which X is NH can be synthesised as o in Scheme 1. Step 1 typically comprises reacting a diamino-halopyridine der with the appropriate haloketone in an appropriate solvent such as N- methylpyrrolidinone (NMP) under microwave conditions at an appropriate temperature such as 18O ⁰ C for an appropriate time such as Ih. Alternatively, can be effected by heating at reflux in ethanol, or by heating at a suitable tem in NMP. Step 2 consists of reacting the 8-amino-6-haloimidazopyridine with appropriate benzyl halide such as the benzyl chloride in the presence of a bas sodium carbonate in a suitable solvent such as dimethylformamide (DMF) fo suitable time such as 3 - 16h. Additives such as potassium iodide may be use step 3, an appropriate metal-mediated coupling of a heterocyclyl group can b For example, Ullman-type couplings can be used, in which the 6-halo compo be reacted in the presence of copper (I) iodide and a base such as potassium c in a suitable solvent such as dioxane at a suitable temperature such as reflux 1 suitable time such as 3 days. Alternatively, the reaction can be conducted un microwave conditions in a suitable solvent such as DMF or NMP at suitable temperatures up to 195 ⁰ C. Additives such as r used, and the base can alternatively be potassium phosphate. Alternatively th coupling may be performed in the presence of an appropriate palladium catal as tris(dibenzylideneacetone)dipalladium(0) and a phosphine ligand such as ^L bis(diphenylphosphino)-9,9-dimethyl-xanthene, in the presence of a suitable such as cesium carbonate in a suitable solvent system such as dioxane at a su temperature such as reflux for a suitable time such as 5 hours. This reaction, may alternatively be conducted under microwave conditions.

Alternatively, compounds of the invention wherein X is NH can be generated according to Scheme 2:

Scheme 2: Alternative approach to generation of compounds for which X=NH.

Typically, In step 1, an appropriate metal-mediated coupling of a heterocyclyl group can be used. For example, Ullman-type couplings can be used, in which the 6-halo compound can be reacted in the presence of copper (I) iodide and a base such as potassium carbonate in a suitable solvent such as dioxane at a suitable temperature such as reflux for a suitable time such as 3 days. Alternatively, the reaction can be conducted under microwave conditions in a suitable solvent such as DMF or NMP at suitable temperatures up to 195 ⁰ C. Additives such as trans 1,2-diaminocyclohexane may be used, and the base can alternatively be potassium phosphate. Alternatively the coupling may be performed in the presence of an appropriate palladium catalyst such as tris(dibenzylideneacetone)dipalladium(0) and a phosphine ligand such as 4,5- bis(diphenylphosphino)-9,9-dimethyl-xanthene, in the presence of a suitable base such as cesium carbonate in a suitable solvent system such as dioxane at a suitable temperature such as reflux for a suitable time such as 5 hours. This reaction, also, may alternatively be conducted under microwave conditions. Step 2 typically consists of reacting the product of step 1 with an appropriate benzyl halide such as the benzyl bromide in the presence of a base such as sodium carbonate in a suitable solvent such as DMF for a suitable time such as 3h. Additives such as potassium iodide may be used.

Compounds of the invention for which X is O can be synthesised according to steps 1 to 3 of scheme 3:

Scheme 3. Route to C8 O-linked compounds:

Step 1 typically comprises the use of an appropriate ketone such as alpha- alpha-bromo ketone, in the presence of a suitable solvent such as NMP, at temperature such as between 160°C and 180°C in the presence of microwave typically comprises the use of the appropriate benzylic alkoxide (generated t of an appropriate base such as sodium hydride , in the presence of a suitab such as DMF at a suitable temperature such as 0 ⁰ C to room temperatui presence of a suitable solvent such as DMF at an appropriate temperatun between 60°C and 9O ⁰ C. Step 3 typically comprises the use of the at heterocyclyl derivative in the presence of an appropriate catalyst such as c iodide and a base such as potassium carbonate in the presence of a suitabl such as NMP or DMF at a suitable temperature such as between 150 ⁰ C and the presence of microwaves.

Alternatively, compounds of the invention for which X is O can be generated according to steps 4 and 5 of scheme 3. Thus, when the groups R4, R5, R3 o facilitate removal of the O-benzyl group, for example when R4, R5, R3 are F (in this scheme) is OMe, the product of step 3 can be subjected to steps 4 and

provide alternative C8-modified analogues. Typically step 4 consists of treat an acid such as trifluoroacetic acid in a suitable solvent such as dichlorometh suitable temperature such as room temperature. Typically step 5 consists of 1 with a suitable base such as sodium hydride in a suitable solvent such as DM followed by reacting with the appropriate benzylhalide, such as a benzylbron suitable temperature such as room temperature for an appropriate time, such ,

It will be understood by those skilled in the art that certain compound invention can be converted into other compounds of the invention according standard chemical methods.

The starting materials for use in Schemes 1 to 3 are commercially ava known in the literature or can be prepared by known methods.

The compounds of formula (I) may be prepared singly or as compoun libraries comprising at least 2, e.g. 5 to 1000, preferably 10 to 100 compound formula (I). Compound libraries may be prepared by a combinatorial 'split ai approach or by multiple parallel synthesis using either solution phase or solic chemistry, by procedures known to those skilled in the art.

Thus according to a further aspect of the invention there is provided a compound library comprising at least 2 compounds of formula (I), or pharmaceutically acceptable derivatives thereof.

Pharmaceutically acceptable salts may be prepared conventionally by with the appropriate acid or acid derivative.

The compounds of formula (I) and their pharmaceutically acceptable derivatives are useful for the treatment of diseases or disorders where an acid antagonist (APA) is required such as gastrointestinal diseases or disorders, fc example those associated with hyperacidity. The compounds of the inventioi particularly useful for the treatment or prophylaxis of inflammatory gastroint diseases and diseases associated with an imbalance in gastric acid such as ga: duodenal ulcer, gastritis, gastro-oesophageal reflux disease (GERD), and ZoI Ellison Syndrome or diseases and disorders where gastric antisecretory effeci desirable for example in patients with gastrinomas and acute upper gastrointe bleeding.

The invention also provides a method of treating or preventing diseas disorders where an antagonist of a human acid pump is required, for example diseases and disorders mentioned hereinabove, which comprises administerir subject in need thereof an effective amount of a compound of formula (I), or pharmaceutically acceptable derivative thereof.

The invention also provides a compound of formula (I), or a pharmac acceptable derivative thereof, for use in the treatment or prophylaxis of disea disorders where an antagonist of a human acid pump is required, for example diseases and disorders mentioned hereinabove.

The invention also provides the use of a compound of formula (I), or pharmaceutically acceptable derivative thereof, in the manufacture of a medi<

for the treatment or prophylaxis of diseases or disorders where an antagonist of a human acid pump is required, for example those diseases and disorders mentioned hereinabove.

The invention also provides the use of a compound of formula (I), or a pharmaceutically acceptable derivative thereof, in the manufacture of a medicament for the treatment or prophylaxis of diseases or disorders where an antagonist of a human acid pump is required such as inflammatory gastrointestinal diseases and diseases associated with an imbalance in gastric acid such as gastric or duodenal ulcer, gastritis, gastro-oesophageal reflux disease (GERD), and Zoller-Ellison Syndrome or diseases and disorders where gastric antisecretory effect is desirable for example in patients with gastrinomas and acute upper gastrointestinal bleeding.

For use in therapy the compounds of the invention are usually administered as a pharmaceutical composition. The invention also provides a pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically acceptable derivative thereof, and a pharmaceutically acceptable carrier.

The compounds of formula (I) and their pharmaceutically acceptable derivatives may be administered by any convenient method, e.g. by oral, parenteral, buccal, sublingual, nasal, rectal or transdermal administration, and the pharmaceutical compositions adapted accordingly. The compounds of formula (I) and their pharmaceutically acceptable derivatives which are active when given orally can be formulated as liquids or solids, e.g. as syrups, suspensions, emulsions, tablets, capsules or lozenges.

A liquid formulation will generally consist of a suspension or solution of the active ingredient in a suitable liquid carrier(s) e.g. an aqueous solvent such as water, ethanol or glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring and/or colouring agent.

A composition in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations, such as magnesium stearate, starch, lactose, sucrose and cellulose.

A composition in the form of a capsule can be prepared using routine encapsulation procedures, e.g. pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), e.g. aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule.

Typical parenteral compositions consist of a solution or suspension of the active ingredient in a sterile aqueous carrier or parenterally acceptable oil, e.g. polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration.

Compositions for nasal administration may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations typically comprise a solution

or fine suspension of the active ingredient in a pharmaceutically acceptable a or non-aqueous solvent and are usually presented in single or multidose quan sterile form in a sealed container which can take the form of a cartridge or re: use with an atomising device. Alternatively the sealed container may be a di; dispensing device such as a single dose nasal inhaler or an aerosol dispenser with a metering valve. Where the dosage form comprises an aerosol dispensi contain a propellant which can be a compressed gas e.g. air, or an organic pπ such as a fluorochlorohydrocarbon or hydrofluorocarbon. Aerosol dosage fo also take the form of pump-atomisers. Compositions suitable for buccal or sublingual administration include lozenges and pastilles where the active ingredient is formulated with a carriei sugar and acacia, tragacanth, or gelatin and glycerin.

Compositions for rectal administration are conveniently in the form o suppositories containing a conventional suppository base such as cocoa butte Compositions suitable for transdermal administration include ointmer and patches.

Preferably the composition is in unit dose form such as a tablet, capsii ampoule.

The dose of the compound of formula (I), or a pharmaceutically accej derivative thereof, used in the treatment or prophylaxis of the abovementione disorders or diseases will vary in the usual way with the particular disorder o: being treated, the weight of the subject and other similar factors. However, a general rule, suitable unit doses may be 0.05 to 1000 mg, more suitably 0.05 mg. Unit doses may be administered more than once a day for example two i times a day, so that the total daily dosage is in the range of about 0.01 to 100 and such therapy may extend for a number of weeks or months. In the case c pharmaceutically acceptable derivatives the above figures are calculated as tl compound of formula (I).

No toxicological effects are indicated/expected when a compound of (I) is administered in the above mentioned dosage range.

All publications, including but not limited to patents and patent applic cited in this specification are herein incorporated by reference as if each indύ publication were specifically and individually indicated to be incorporated bj reference herein as though fully set forth. The following Examples illustrate the preparation of pharmacological compounds of the invention.

Description 1. 1,1-DimethylethyI 4-(8-{[(2,6-dimethylphenyl)methyl]ami dimethylimidazo[l,2-α]pyridin-6-yl)-l-piperazinecarboxylate

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- fl]pyridin-8-amine (200 mg, 0.558 mmol; WO 98/37080), 1,1-dimethylethyl 1- piperazinecarboxylate (153 mg, 0.84 mmol), 2-dicyclohexylphosphino-2'-(N,N- dimethylamino)biphenyl (33 mg, 0.083 mmol), tris(dibenzylideneacetone)dipalladium(0) (25 mg, 0.028 mmol) and sodium tert- butoxide (107 mg, 1.12 mmol) in dioxane (4 mL) was heated in an Initiator™ Microwave Synthesizer at 120°C for 1 hour. The cooled mixture was partitioned between ethyl acetate and water. The organic phase was washed with water, then brine, dried (MgSO ₄ ) and evaporated. Purification by chromatography on silica gel (ethyl acetate/hexane) gave the title compound as a yellow gum. MS (ES+ve): [M+H] ⁺ at m/z 464 (C ₂₇ H ₃₇ N ₅ O ₂ requires [M+H] ⁺ at m/z 464).

Description 2 l-(8-Amino-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2(lH)-py ridinone

A mixture containing 6-bromo-2,3-dimethylimidazo[l,2-α]pyridin-8-amine (6 g, 25 mmol; WO 98/37080), 2-hydroxypyridine (4.75 g, 50 mmol), potassium carbonate (6.9 g, 50 mmol), copper (I) iodide (0.95 g, 5 mmol) and N-methylpyrrolidinone (50 mL) was stirred at 195 ⁰ C for 8 hours. The mixture was filtered through celite, washing with ethyl acetate and water, and then immobilised on SCX resin which were washed with methanol. The mixture was eluted with 2N NH ₃ /MeOH and solvent removed in vacuo. The mixture was purified on silica eluting with a 0-20% methanol in ethyl acetate gradient to give, upon evaporation, the title compound as a brown solid. 2.4g. MS (ES+ve): [M+H] ⁺ at m/z 255 (Ci ₄ Hi ₄ N ₄ O requires [M+H] ⁺ at m/z 255).

Description 3. l-(8-Amino-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2-piperi dinone

10% Palladium on carbon (10 mg) was added to a solution of l-(8-amino-2,3 dimethylimidazo[l,2-α]pyridin-6-yl)-2(lH)-pyridinone (90.5 mg, 0.356 mmc Description 2) in ethanol (20 mL), then the mixture was shaken under hydroj psi) for 16 hours. The mixture was filtered through a celite pad and the solve evaporated to give the title compound. MS (ES+ve): [M+η] ⁺ at m/z 259 (Ci- requires [M+H] ⁺ at m/z 259).

Description 4. 6,8-Dibromo-2,3-dimethylimidazo[l,2-α]pyridine

A mixture of 2-amino-3,5-dibromopyridine (5.45 g, 21.6 mmol), 3-bromo-2- (3.64 g, 24.1 mmol) and iV-methylpyrrolidinone (11 mL) was heated in an In Microwave Synthesizer at 180°C for 1 hour. After cooling, methanol (10 ml added and the mixture poured into ethyl acetate and aqueous sodium bicarbo The mixture was filtered, the filtrate layers were separated and the aqueous 1; extracted with ethyl acetate. The combined organic extracts were washed tw water, then brine, dried (MgSO ₄ ) and evaporated. Purification by chromatog silica gel (ethyl acetate/toluene) gave the title compound. MS (ES+ve): [M+ m/z 303 (C ₉ H ₈ ⁷⁹ Br ₂ N ₂ requires [M+H] ⁺ at m/z 303).

Description 5.

6-Bromo-2,3-dimethyl-8-({ [4-(methyloxy)phenyI] methyl} oxy)imidazo [ 1 ,: α]pyridine

Sodium hydride (80 mg of a 60% dispersion in mineral oil; 2.0 mmol) was a stirring solution of [4-(methyloxy)phenyl]methanol (250 μL; 2.0 mmol) in di

dimethylformamide (3 mL) and the mixture stirred under argon for 90 minutf Dibromo-2,3-dimethylimidazo[l,2-α]pyridine (300 mg, 1.0 mmol; Descriptic added and the resulting mixture was heated at 90°C under argon for 18 hours The mixture was applied to an Isolute® SCX cartridge and eluted with metha followed by 2M NH ₃ in methanol. The basic fractions were combined and ev under reduced pressure. The residue was purified by column chromatograph> eluting with 2-1 n-pentane - ethyl acetate and then ethyl acetate to afford the compound as a pale yellow solid (200 mg). ¹ H NMR (CDCl ₃ ) δ 2.35 (3H, s), (3H, s), 3.81 (3H, s), 5.22 (2H, s), 6.54 (H, s), 6.90 (2H, m), 7.41 (2H, m), 7.:

Description 6. l-[2,3-Dimethyl-8-({[4-(methyloxy)phenyl]methyI}oxy)imidazo[ l,2-fl]pyr yl]-2(l//)-pyridinone

A mixture of 6-bromo-2,3-dimethyl-8-( {[4-(methyloxy)phenyl]methyl} oxy)imidazo[l,2-α]pyridine (90 mg, 0.25 mmol. Description 5), 2(lH)-pyridi mg, 0.5 mmol), potassium carbonate (69 mg, 0.5 mmol) and copper (I) iodid( 0.05 mmol) in dry dimethylformamide (3 mL) was heated in an Initiator™ Microwave Synthesizer at 150°C for 4 hours. The mixture was filtered throuj and the pad washed with ethyl acetate. The filtrate was evaporated under redi pressure and the residue applied to an Isolute® SCX cartridge and eluted wit] methanol followed by 2M NH ₃ in methanol. The basic fractions were combir evaporated under reduced pressure. This residue was purified by column chromatography on silica eluting with ethyl acetate and then 3 - 97 2M NH ₃ methanol - dichloromethane to afford the title compound as a pale yellow gu mg) MS (ES+ve): [M+H] ⁺ at m/z 376 (C ₂₂ H ₂ iN ₃ O ₃ requires [M+H] ⁺ at m/z 3'

Description 7. l-(8-Hydroxy-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2(lH)- pyridinone

Trifluoroacetic acid (5 mL) was added to solution of l-[2,3-dimethyl-8-({[4- (methyloxy)phenyl]methyl}oxy)imidazo[l,2-α]pyridin-6-yl]-2( lH)-pyridinoi mg, 1.19 mmol; Description 6) in dichloromethane (5 mL) and the mixture st room temperature for 3 hours. The mixture was purified on an Isolute® SCX and eluted with methanol followed by 2M NH ₃ in methanol. The basic fractk combined and evaporated under reduced pressure. This residue was triturated diethyl ether and the title compound obtained by filtration as a buff powder (. MS (ES+ve): [M+H] ⁺ at m/z 256 (Ci ₄ Hi ₃ N ₃ O ₂ requires [M+H] ⁺ at m/z 256).

Description 8. l-{2,3-Dimethyl-8-[(3-methyl-2-buten-l-yl)oxy]imidazo[l,2-α ]pyridin-6-j

Sodium hydride (33 mg of a 60% dispersion in mineral iol, 0.82 mmol) was ; a solution of l-(8-hydroxy-2,3-dimethylimidazo[l,2-fl]pyridin-6-yl)-2(lH)- p (200 mg, 0.78 mmol; Description 7) in dimethylformamide (4 mL) and the m stirred for 1 hour. 4-Bromo-2-methyl-2-butene (95 μl, 0.82 mmol) was added mixture allowed to react at room temperature for 16 hours. The mixture was ; to an Isolute® SCX cartridge and eluted with methanol followed by 2M NH ₃ methanol. The basic fractions were combined and evaporated under reduced This residue was purified by column chromatography on silica eluting with 3 NH ₃ in methanol - dichloromethane to afford the title compound as a colourl (87 mg) MS (ES+ve): [M+H] ⁺ at m/z 324 (Ci ₉ H ₂ iN ₃ O ₂ requires [M+H] ⁺ at m

Description 9. l-(8-Hydroxy-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2-pipe ridinone

A solution of l-{2,3-dimethyl-8-[(3-methyl-2-buten-l-yl)oxy]imidazo[l,2-α ] 6-yl}-2(lH)-pyridinone (67 mg, 0.21 mmol, Description 8) in ethanol (3 mL] hydrogenated at room temperature and pressure over a 50% wet paste of 10^ palladium on carbon (10 mg) for 18 hours. The catalyst was removed by filtr, through celite and the filtrate evaporated under reduced pressure to afford the

compound as a colourless powder (55 mg) MS (ES+ve): [M+H] ⁺ at m/z 260 (Ci ₄ H _n N ₃ O ₂ requires [M+H] ⁺ at m/z 260).

Description 10. (4S)-l-[2,3-Dimethyl-8-({[4-(methyloxy)phenyl]methyl}oxy)imi dazo[l,2- 2-pyrrolidinone

A mixture of 6-bromo-2,3-dimethyl-8-( {[4-(methyloxy)phenyl]methyl} oxy)imidazo[l,2-α]pyridine (500 mg, 1.38 mmol;. Description 5), (S) 4-hydroxy- pyrrolidin-2-one (279 mg, 2.76 mmol), potassium carbonate (666 mg, 4.83 mmol) and copper(I) iodide (76 mg, 0.4 mmol) along with racemic-trans-N,N'- dimethylcyclohexane-l,2-diamine (56 mg, 0.4 mmol) in dry dimethylformamide (10 mL) was heated in an Initiator™ Microwave Synthesizer in 2 equal vessels at 120°C for 4 hours. The cooled mixture was applied to an Isolute® SCX cartridge and washed with methanol followed by elution with 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure. This residue was purified by column chromatography on silica eluting with a 0-10% methanol in ethyl acetate gradient to afford the title compound MS (ES+ve): [M+H] ⁺ at m/z 382 (C ₂₎ H ₂₃ N ₃ O ₄ requires [M+H] ⁺ at m/z 382)

Description 11 (45)-4-Hydroxy-l-(8-hydroxy-2,3-dimethylimidazo[l,2-α]pyrid in-6-yl)-2-

Trifluoroacetic acid (0.5 mL) was added to solution of (4S)-l-[2,3-dimethyl-8-({[4- (methyloxy)phenyl]methyl}oxy)imidazo[l,2-α]pyridin-6-yl]-4- hydroxy-2- pyrrolidinone(155 mg, 0.41 mmol; Description 10) in dichloromethane (10 mL) and the mixture stirred at room temperature for 15 minutes. The mixture was purified on an Isolute® SCX cartridge and eluted with methanol followed by 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure

to yield the title compound. MS (ES+ve): [M+H] ⁺ at m/z 262 (C ₁₃ Hi ₅ N ₃ O ₃ requires [M+H] ⁺ at m/z 262).

Description 12 4-[2,3-Dimethyl-8-({ [4-(methyloxy)phenyl] methyI}oxy)imidazo[l,2-α]pyridin-6-

A mixture of 6-bromo-2,3-dimethyl-8-({[4-(methyloxy)phenyl]methyl} oxy)imidazo[l,2-α]pyridine (589 mg, 1.63 mmol; Description 5), 3-moφholinone (330 mg, 3.27 mmol; US 3308121), cesium carbonate (1.86 g, 5.7 mmol), copper(I) iodide (89 mg, 0.47 mmol) and λζN'-dimethylethylenediamine (42 mg, 0.47 mmol) in N-methylpyrrolidinone (10 mL) was heated in an Initiator™ Microwave Synthesizer at 120°C for 18 hours. The mixture was applied to an Isolute® SCX cartridge and washed with methanol followed by elution with 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure. This residue was purified by column chromatography on silica eluting with a 50-100% ethyl acetate in hexane gradient to afford the title compound. MS (ES+ve): [M+H] ⁺ at m/z 382 (C ₂ ]H ₂₃ N ₃ O ₄ requires [M+H] ⁺ at m/z 382).

Description 13

4-(8-hydroxy-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-3-m orpholinone

OH

Trifluoroacetic acid (1.0 mL) was added to a solution of 4-[2,3-dimethyl-8-({[4- (methyloxy)phenyl]methyl} oxy)imidazo[ 1 ,2-α]pyridin-6-yl]-3-morpholinone (300 mg, 0.79 mmol; Description 12) in dichloromethane (15 mL) and the mixture stirred at room temperature for 105 minutes. The mixture was purified on an Isolute® SCX cartridge and washed with methanol followed by elution with 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure to yield the title compound; MS (ES+ve): [M+H] ⁺ at m/z 262 (Ci ₃ Hi ₅ N ₃ O ₃ requires [M+H] ⁺ at m/z 262).

Description 14

1 ,1 -Dimethylethyl (6-bromo-2,3-dimethyiimidazo [1 ,2-α] pyridin-8-yl)carl

To a solution of 6-bromo-2,3-dimethylimidazo[l,2-α]pyridin-8-amine (450 n mmol, WO 98/37080) in tetrahydrofuran (16 niL) was added sodium bis(trimethylsilyl)amide (4.3 mL, 4.30 mmol, 1.0M solution in tetrahydrofun mixture was stirred at room temperature for 10 minutes and then a solution o butyldicarbonate (490 mg, 2.24 mmol) in tetrahydofuran (4 mL) was added, stirring for 2 hours, the reaction mixture was quenched with aqueous ammon chloride solution and the product extracted into ethyl acetate, dried (MgSO ₄ ) solvent evaporated. The crude product was purified by chromatography on s (ethyl acetate/hexane) to give the title compound.

Description 15 1,1-Dimethylethyl [2,3-dimethyl-6-(2-oxo-l-pyrrolidinyl)imidazo[l,2-α]p yl]carbamate

To a solution of 1,1 -dimethylethyl (6-bromo-2,3-dimethylimidazo[l,2-α]pyr] yl)carbamate (100 mg, 0.30 mmol; Description 14) in dioxane (4 mL) was ac pyrrolidinone (23 uL, 0.30 mmol), potassium carbonate (194 mg, 1.40 mmol iodide (23 mg, 0.12 mmol) and N, N '-dimethylethyl enediamine (13uL, 0.12 r The mixture was heated to reflux for 16 hours and then cooled to room temp The reaction was then diluted with ethyl acetate and water. After separation layers, the aqueous phase was re-extracted with ethyl acetate and then the co organic layers were dried (MgSO ₄ ) and the solvent evaporated. The crude pi was purified by chromatography on silica gel (ethyl acetate/hexane) to give t compound. MS (ES+ve): [M+H] ⁺ at m/z 345 (C] ₈ H ₂₄ N ₄ O ₃ requires [M+H] ⁺ 345).

Description 16 l-(8-Amino-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2-pyrrol idinone

Trifluoroacetic acid (1 mL) was added to a solution of 1,1-dimethylethyl [2,3- dimethyl-6-(2-oxo-l-pyrrolidinyl)imidazo[l,2-α]pyridin-8-yl ]carbamate (30 mg, 0.09 mmol; Description 15) in dichloromethane (3 mL) at 0 ⁰ C. The reaction mixture was allowed to warm to room temperature and stirred for a further 4 hours. The mixture was diluted with dichloromethane and aqueous sodium hydrogen carbonate solution. After separation of the layers, the aqueous phase was further extracted with dichloromethane. The combined organic layers were dried (MgSO ₄ ) and the solvent evaporated to give the title compound; MS (ES+ve): [M+H] ⁺ at m/z 245 (Ci ₃ Hi ₆ N ₄ O requires [M+H] ⁺ at m/z 245).

Example 1 l-(8-{[(2,6-DimethylphenyI)methyl]amino}-2,3-dimethylimidazo [l,2-α]pyridin-6- ydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- α]pyridin-8-amine (50 mg, 0.140 mmol; WO 98/37080), 2-pyrrolidinone (24 mg, 0.279 mmol), tris(dibenzylideneacetone)dipalladium (6 mg, 0.007 mmol), 4,5- bis(diphenylphosphino)-9,9-dimethyl-xanthene (12 mg, 0.0209 mmol), cesium carbonate (68 mg, 0.209 mmol) and dioxane (2 mL) was heated under reflux under argon for 24 h. The cooled mixture was partitioned between ethyl acetate and water. The organic phase was washed with water, dried (MgSO ₄ ) and evaporated. Purification by chromatography on silica gel (ethyl acetate/hexane) gave the free base of the title compound. This was dissolved in dichloromethane (2 mL), and then IM HCl in diethyl ether (1 mL) was added. After stirring for 2 h, the solvents were evaporated. The residue was dissolved in water and freeze dried to give the title compound as a solid; MS (ES+ve): [M+H] ⁺ at m/z 363 (C ₂₄ H ₂₅ N ₃ requires [M+H] ⁺ at m/z 363).

Example 2 l-(8-{[(2,6-dimethylphenyl)methyl]amino}-2,3-dimethylimidazo |l,2-αlpyridin-6- yl)-2-imidazolidinone hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[l ,2- α]pyridin-8-amine (400 mg, 1.117 mmol; WO 98/37080), 2-imidazolidinone (576 mg, 6.704 mmol), tris(dibenzylideneacetone) dipalladium (51 mg, 0.056 mmol), 4,5- bis(diphenylphosphino)-9,9-dimethyl-xanthene (97 mg, 0.168 mmol), cesium carbonate (545 mg, 1.676 mmol) and dioxane (24 mL) was heated under reflux under argon for 5 hours. The cooled mixture was partitioned between ethyl acetate and water. The organic phase was washed with water, dried (MgSO ₄ ) and evaporated. Purification by chromatography on silica gel (ethyl acetate/hexane) gave the free base of the title compound which was triturated with diethyl ether. This was dissolved in dichloromethane (2 mL), and then IM HCl in diethyl ether (1 mL) was added. After stirring for 3 hours, the solvents were evaporated to give the title compound as a yellow solid; MS (ES+ve): [M+H] ⁺ at m/z 364 (C ₂₄ H ₂₅ N ₃ requires [M+H] ⁺ at m/z 364).

Example 3. iV-[(2,6-Dimethylphenyl)methyl]-2,3-diinethyl-6-(4-morpholin yl)imidazo[l,2- α]pyridin-8-amine hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- α]pyridin-8-amine (100 mg, 0.279 mmol; WO 98/37080), morpholine (0.0486 mL, 0.556 mmol), 2-dicyclohexylphosphino-2'-(λζN-dimethylamino)biphenyl (16.7 mg, 0.042 mmol), tris(dibenzylideneacetone)dipalladium(0) (12.7 mg, 0.014 mmol) and sodium tert-butoxide (53.7 mg, 0.56 mmol) in dioxane (1.5 mL) was heated in an Initiator™ Microwave Synthesizer at 12O ⁰ C for 40 minutes. The cooled mixture was partitioned between ethyl acetate and water. The organic phase was washed with water, then brine, dried (MgSO ₄ ) and evaporated. The residue was purified by chromatography on silica gel (ethyl acetate). The product was dissolved in methanol (3 mL), water (1 mL) and 2N HCl (0.3 mL) were added. After stirring for 5 minutes,

the mixture was evaporated to give the title compound as a buff solid. MS (1 [M+H] ⁺ at m/z 365 (C ₂₂ H ₂₈ N ₄ O requires [M+H] ⁺ at m/z 365).

Example 4. λ4(2,6-Dimethylphenyl)methyI]-2,3-dimethyl-6-(l-piperidinyl )imidazo[ α]pyridin-8-amine hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo α]pyridin-8-amine (100 mg, 0.279 mmol; WO 98/37080), piperidine (0.0553 mmol), 2-dicyclohexylphosphino-2'-(7V,N-dimethylamino)biphenyl (16.7 mg mmol), tris(dibenzylideneacetone)dipalladium(0) (12.7 mg, 0.014 mmol) and tert-butoxide (53.7 mg, 0.56 mmol) in dioxane (1.5 mL) was heated in an Ini Microwave Synthesizer at 120°C for 1 hour. The cooled mixture was partitk between ethyl acetate and water. The organic phase was washed with water, brine, dried (MgSO ₄ ) and evaporated. The residue was purified by chromato on silica gel (ethyl acetate/hexane). The product was dissolved in methanol ( water (1 mL) and 2N HCl (0.3 mL) were added. After stirring for 5 minutes, mixture was evaporated to give the title compound as a buff solid. MS (ES+ ¹ [M+H] ⁺ at m/z 363 (C ₂₃ H ₃₀ N ₄ requires [M+H] ⁺ at m/z 363).

Example 5.

7V-[(2,6-Dimethylphenyl)methyl]-2,3-dimethyl-6-(l-piperaz inyl)imidazo[] α]pyridin-8-amine hydrochloride

To a solution of 1,1-dimethylethyl 4-(8-{[(2,6-dimethylphenyl)methyl]amino dimethylimidazo[l,2-α]pyridin-6-yl)-l-piperazinecarboxylate (64 mg, 0.138 i

Description 1) in dichloromethane (15 mL), cooled in an ice bath, was added trifluoroacetic acid (0.5 mL). The mixture was stirred in the ice bath for 1 ho allowed to warm to room temperature and stirred for a further 2 hours. Tolue

added and the mixture was evaporated to dryness, a further portion of toluene was added and evaporated. The residue was dissolved in methanol and applied to an Isolute® SCX cartridge, elution with methanol, then IM NH ₃ in methanol gave, after evaporation, the product as the free base. This was dissolved in methanol/water/2N HCl (3 :45 :0.5 mL) and then loaded onto a 1 Og tC 18 Sep-Pak® cartridge and eluted with a gradient up to methanol/water/2N HCl (40:60:0.5) to give the title compound as a buff solid. MS (ES+ve): [M+H] ⁺ at m/z 364 (C ₂₂ H ₂₉ N ₅ requires [M+H] ⁺ at m/z 364).

Example 6. l-(8-{|(2,6-Dimethylphenyl)methyl]amino}-2,3-dimethyHmidazo[ l,2-α]pyridin-6- yl)-2-piperidinone hydrochloride

To a solution of l-(8-amino-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2-piperi dinone (81.2 mg, 0.314 mmol; Description 3) in dimethylformamide (4 mL) was added sodium carbonate (83 mg, 0.783 mmol) and 2,6-dimethylbenzyl bromide (78 mg, 0.392 mmol). The mixture was stirred at room temperature for 20 hours, and then partitioned between ethyl acetate and water. The organic phase was washed with water, then brine, dried (MgSO ₄ ) and evaporated. The residue was purified by chromatography on silica gel (ethyl acetate/methanol). The product was dissolved in methanol (3 mL), water (1 mL) and 2N HCl (0.2 mL) were added. After stirring for 5 minutes, the solution was evaporated to give the title compound as a buff solid. MS (ES+ve): [M+H] ⁺ at m/z 311 (C ₂₃ H ₂₈ N ₄ O requires [M+H] ⁺ at m/z 377).

Example 7.

1 -(8-{ [(2,6-Dimethylphenyl)methyl] amino}-2,3-dimethylimidazo [1 ,2-α] py ridin-6- yl)-3-methyl-2-imidazolidinone hydrochloride

To a solution of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[l ,2- α]pyridin-8-amine (370 mg, 1.03 mmol; WO 98/37080) in dioxane (22 mL) was added l-methyl-2-imidazolidinone (620 mg, 6.20 mmol), cesium carbonate (504 mg, 1.55 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethyl-xanthene (90 mg, 0.16 mmol). After degassing the reaction mixture with argon, tris(dibenzylideneacetone)dipalladium (47 mg, 0.052 mmol) was added and the mixture heated to reflux for 5 hours. After cooling to room temperature, the dioxane was evaporated at reduced pressure. The residue was diluted with ethyl acetate, washed with water, dried (MgSO ₄ ) and the solvent evaporated. The crude product was purified by chromatography on silica gel (ethyl acetate/hexane). The product was dissolved in dichloromethane (2 mL) and then IMHCl in diethyl ether (1 mL) was added. After stirring for 5 minutes, the solvents were evaporated to yield the title compound. MS (ES+ve): [M+H] ⁺ at m/z 378 (C ₂₂ H ₂₇ N ₅ O requires [M+H] ⁺ at m/z 378).

Example 8. l-(8-{[(2,6-DimethyIphenyl)methyl]oxy}-2,3-dimethylimidazo[l ,2-α]pyridin-6-yl)-

2-piperidinone

Sodium hydride (9 mg of a 60% dispersion in mineral iol, 0.21 mmol) was added to a solution of l-(8-hydroxy-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2(l//) -pyridinone (55 mg, 0.21 mmol; Description 9) in dimethylformamide (3 mL) and the mixture stirred for 1 hour. 2-(Chloromethyl)-l,3-dirnethylbenzene (29 mg, 0.21 mmol) was added and the mixture allowed to react at room temperature for 18 hours. The mixture was applied to an Isolute® SCX cartridge and eluted with methanol followed by 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure. This residue was purified by column chromatography on silica eluting with 3 - 97 2M NH ₃ in methanol - dichloromethane to afford the title compound as a colourless powder; MS (ES+ve): [M+H] ⁺ at m/z 378 (C ₂₃ H ₂₇ N ₃ O ₂ requires [M+H] ⁺ at m/z 378).

Example 9. iV-[(2,6-dimethylphenyl)methyl]-6-[c/s-3,5-(iimethyl-l-piper azinyl]-2,3- dimethylimidazo[l,2-α]pyridin-8-amine hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- α]pyridin-8-amine (30 mg, 0.0837 mmol; WO 98/37080), cw-2,6-dimethylpiperazine (14.3 mg, 0.126 mmol), 2-dicyclohexylphosphino-2'-(N,N-dimethylamino)biphenyl (5 mg, 0.0126 mmol), tris(dibenzylideneacetone)dipalladium(0) (3.8 mg, 0.0042 mmol) and sodium tert-butoxide (16.1 mg, 0.167 mmol) in dioxane (0.5 mL) was heated in an Initiator™ Microwave Synthesizer at 120°C for 20 minutes. The reaction was repeated on a 2-fold scale, except that microwave heating was conducted for 30 minutes. The cooled reaction mixtures were combined and partitioned between ethyl acetate and dilute ammonium hydroxide. The aqueous phase was extracted with ethyl acetate and the combined organic phases were washed with water and then evaporated. The residue was dissolved in methanol/water/2ν HCl (3:45:0.5 mL) and then loaded onto a 1Og tC18 Sep-Pak® cartridge and eluted with a gradient up to methanol/water/2N HCl (60:40:0.5) to give the title compound as a buff solid. MS (ES+ve): [M+H] ⁺ at m/z 392 (C ₂₄ H ₃₃ N ₅ requires [M+H] ⁺ at m/z 392).

Example 10.

λ ^r -[(2,6-Dimethylphenyl)methyl]-6-(l,l-dioxido-2-isothiazolidi nyl)-2,3- dimethylimidazo[l,2-α]pyridin-8-amine hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- α]pyridin-8-amine (100 mg, 0.28 mmol; WO 98/37080), isothiazolidine 1,1 -dioxide (67 mg, 0.56 mmol; WO 04/050619), copper(I) iodide (16 mg, 0.083 mmol), potassium carbonate (138 mg, 1.0 mmol) and N,N'-dimethylethylenediamine (7.4 mg, 0.083mmol) in dioxane (2 mL) was heated in an Initiator™ Microwave Synthesizer at 14O ⁰ C for 12 hours. The cooled mixture was applied to an Isolute® SCX cartridge. Elution with methanol, followed by water, then methanol then IM NH ₃ in methanol gave, after evaporation, the product which was further purified by chromatography on

silica gel. Elution with dichloromethane/methanol (0 to 10%) gave a pale yellow solid which was dissolved in dichloromethane (2 mL), Ethereal HCl (IM; LOmL) was added and the solvent evaporated. The residue was triturated under ether (1 mL) and filtered to give the title compound as a colourless solid; MS (ES+ve): [M+H] ⁺ at m/z 399 (C _2I H ₂₆ N ₄ O ₂ S requires [M+H] ⁺ at m/z 399).

Example 11

4-(8-{[(2,6-Dimethylphenyl)methyl|amino}-2,3-dimethylimid azo[l,2-α]pyridin-6- yl)-3-morpholinone hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- α]pyridin-8-amine (100 mg, 0.28 mmol; WO 98/37080), 3-morpholinone (56 mg, 0.56 mmol; US 3308121), copper(I) iodide (16 mg, 0.083 mmol), potassium carbonate (138 mg, 1.0 mmol) and λζN'-dimethylethylenediamine (7.4 mg, 0.083mmol) in dioxane (2 mL) was heated in an Initiator™ Microwave Synthesizer at 140°C for 12 hours. The cooled mixture was applied to an Isolute® SCX cartridge. Elution with methanol, followed by water, then methanol then IM NH ₃ in methanol gave, after evaporation, the product which was further purified by chromatography on silica gel. Elution with dichloromethane/methanol (0 to 10%) gave a pale yellow solid which was dissolved in methanol (2 mL), Ethereal HCl (IM; 0.3ml) was added and the solvent evaporated to give the title compound as a pale yellow solid; MS (ES+ve): [M+H] ⁺ at m/z 379 (C ₂₂ H ₂₆ N ₄ O ₂ requires [M+H] ⁺ at m/z 379).

Example 12 (4S)-l-(8-{[(2,6-dimethylphenyl)methyl]amino}-2,3-dimethylim idazo[l,2- -2-pyrrolidinone hydrochloride

A mixture of 6-bromo-7V-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[ 1 ,2- α]pyridin-8-amine (200 mg, 0.558 mmol; WO 98/37080), (45)-4-hydroxy-2-

pyrrolidinone (112 mg, 1.12 mmol), copper(I) iodide (32 mg, 0.167 mmol), potassium carbonate (276 mg, 2.0 mmol) and N.N'-dimethylethylenediamine (15 mg, 0.167 mmol) in dioxane (2 mL) was heated in an Initiator™ Microwave Synthesizer at 140°C for 14 hours. The cooled mixture was applied to an Isolute® SCX cartridge. Elution with methanol, followed by water, then methanol then IM NH ₃ in methanol gave, after evaporation, the product which was further purified by chromatography on silica gel. Elution with dichloromethane/methanol (0 to 10%) gave a pale yellow solid which was dissolved in methanol (2 mL), Ethereal HCl (IM; 0.5ml) was added and the solvent evaporated to give the title compound as a brick-red coloured solid. MS (ES+ve): [M+H] ⁺ at m/z 379 (C ₂₂ H ₂₆ N ₄ O ₂ requires [M+H] ⁺ at m/z 379).

Example 13

(4R)-l-(8-{[(2,6-dimethylphenyl)methyl]amino}-2,3-dimethy limidazo[l,2- α]pyridin-6-yl)-4-hydroxy-2-pyrroIidinone hydrochloride

A mixture of 6-bromo-N-[(2,6-dimethylphenyl)methyl]-2,3-dimethylimidazo[l ,2- α]pyridin-8-amine (200 mg, 0.558 mmol; WO 98/37080), (4λ)-4-hydroxy-2- pyrrolidinone (112 mg, 1.12 mmol), copper(I) iodide (32 mg, 0.167 mmol), potassium carbonate (276 mg, 2.0 mmol) and N.iV'-dimethylethylenediamine (15 mg, 0.167 mmol) in dioxane (2 mL) was heated in an Initiator™ Microwave Synthesizer at 140°C for 14 hours. The cooled mixture was applied to an Isolute® SCX cartridge. Elution with methanol, followed by water, then methanol then IM NH ₃ in methanol gave, after evaporation, the product which was further purified by chromatography on silica gel. Elution with dichloromethane/methanol (0 to 10%) gave a pale yellow solid which was dissolved in methanol (2 mL), Ethereal HCl (IM; 0.5ml) was added and the solvent evaporated to give the title compound as a brick-red coloured solid. MS (ES+ve): [M+H] ⁺ at m/z 379 (C ₂₂ H ₂₆ N ₄ O ₂ requires [M+H] ⁺ at m/z 379).

Example 14 (4S)-l-(8-{[(2,6-Dimethylphenyl)methyl]oxy}-2,3-dimethylimid azo[l,2-α]pyridin- 6-yl)-4-hydroxy-2-pyrrolidinone hydrochloride

A mixture of potassium carbonate (52 mg, 0.38 mmol), (4S)-4-hydroxy-l-(8-hydroxy- 2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2-pyrrolidinone (66 mg, 0.25 mmol; Description 11) and 2,6-dimethylbenzyl bromide (60 mg, 0.3 mmol) in dimethylformamide (2 mL) was stirred under argon at ambient temperature for 3 hours. The mixture was applied to an Isolute® SCX cartridge and eluted with methanol followed by 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure. This residue was purified by column chromatography on silica eluting with a hexane to ethyl acetate to 10% methanol in ethyl acetate gradient to afford the free base of the title compound after evaporation under reduced pressure. This was dissolved in dichloromethane (2 mL), and then IM HCl in diethyl ether (0.3 mL) was added. The solvents were evaporated, to give the title compound; MS (ES+ve): [M+H] ⁺ at m/z 380 (C ₂₂ H ₂₅ N ₃ O ₃ requires [M+H] ⁺ at m/z 380).

Example 15

4-(8-{[(2,6-dimethylphenyl)methyl]oxy}-2,3-dimethylimidaz o[l,2-α]pyridiii-6-yl)- ochloride

A mixture of potassium carbonate (143 mg, 1.04 mmol), 4-(8-hydroxy-2,3- dimethylimidazo[l,2-α]pyridin-6-yl)-3-morpholinone (180 mg, 0.69 mmol; Description 13) and 2,6-dimethylbenzyl bromide (165 mg, 0.83 mmol) in dimethylformamide (5 mL) was stirred under argon at ambient temperature overnight. The mixture was applied to an Isolute® SCX cartridge and washed with methanol followed by elution with 2M NH ₃ in methanol. The basic fractions were combined and evaporated under reduced pressure. This residue was purified by column chromatography on silica eluting with a hexane to ethyl acetate gradient, evaporated under reduced pressure and dissolved in dichloromethane (2 mL). 1.0M ethereal HCl was added (0.5 mL) and the solution evaporated under reduced pressure to yield the

title compound; MS (ES+ve): [M+H] ⁺ at m/z 380 (C ₂₂ H ₂₅ N ₃ O ₃ requires [M+H] ⁺ at m/z 380).

Example 16 l-(8-{[(2-Ethyl-6-methylphenyl)methyl]amino}-2,3-dimethylimi dazo[l,2- a] pyridin-6-yl)-2-pyrrolidinone hydrochloride

To a solution of l-(8-amino-2,3-dimethylimidazo[l,2-α]pyridin-6-yl)-2-pyrrol idinone (14 mg, 0.057 mmol; Description 16) in dimethylformamide (2 mL) was added 2- (bromomethyl)-l-ethyl-3-methylbenzene (14 mg, 0.066 mmol) and sodium carbonate (22 mg, 0.208 mmol). The reaction mixture was stirred at room temperature for 16 hours and then treated with a further portion of 2-(bromomethyl)-l-ethyl-3- methylbenzene (8 mg, 0.038 mmol). The mixture was stirred for 60 hours and then neutralised by addition of 2M hydrochloric acid. The mixture was loaded onto an Isolute® SCX cartridge, eluting with methanol, then 2M NH ₃ in methanol. After evaporation of the basic fractions, the crude product was further purified by chromatography on silica gel (ethyl acetate/hexane). The product was dissolved in dichloromethane (3 mL) and then IMHCl in diethyl ether (1 mL) was added. After stirring for 1 hour, the solvents were evaporated to give the title compound. MS (ES+ve): [M+H] ⁺ at m/z 311 (C ₂₃ H ₂₈ N ₄ O requires [M+H] ⁺ at m/z 377).

Example 17 - Preparation of H+/K+ ATPase

The H+/K+ ATPase assay was based on Hongo et al (1990) Jpn J Pharmacol. 52.295-

305 "Purification and characterization of (H+,K+ )-ATPase from hog gastric mucosa" Preparation of H+/K+ ATPase

Fresh porcine stomachs were obtained and washed with 0.9% NaCl. The surface mucus was removed by vigorously wiping; the fundic mucosa was then removed from the underlying muscular layer and suspended in a chilled 0.25M sucrose solution. Homogenization was carried out with polytron setting 5 for 3 minutes and the homogenate was centrifugated at 8,000 rpm for 15 minutes. The supernatants after filtration over stainless gauze were then centrifugated at 13,000 rpm for 15 minutes. The resulting supernatants were recentrifuged using rotor type 70 Ti at 31,000 rpm for 1 hour to obtain the crude microsomal sediment (FO). The crude microsomes were suspended in the 0.25M sucrose solution. The resuspended microsomes (4 mL, 11 mg/mL) were layered on a single step gradient made from 5 mL of 7% (w/v) Ficoll in the 0.25 sucrose solution and centrifugated using rotor type 41 Ti at 30,000 rpm for 40 minutes. The light membrane (FB) appeared at the interface of the 7% Ficoll, and the

heavy membrane (FS) appeared in the form of a sediment. FB was collected ; diluted to 10-fold with the 0.25M sucrose solution and then centrifugated usi: type 41 Ti at 31,000 rpm for 1 hour.

The resulting sediments were resuspended in the 0.25M sucrose solution by 1 of a loose-fitting motor-driven, Telfon pestle rotating at 1 ,000 rpm in a homo and refrigerated overnight for the final purification.

The resuspended microsomes (8 mL/ 3.5 mg/mL) were furthermore layered c 5 mL of 7% (w/v) Ficoll in the 0.25M sucrose solution and centrifuged using type 41 at 30,000 rpm for 40 minutes. The heavy membrane (FBS), appearing in the form of a sediment, was then resuspended in the 0.25M sucrose solution and centrifugated using rotor type 37,500 rpm for 2 hours. The pellet was resuspended in 0.25M sucrose solution and stored at -80°C ur

Alternatively the protein can be prepared in the following procedure:

1. 4 pig stomachs obtained fresh from abattoir.

2. Stomachs excised and washed thoroughly with cold water, then shipt saturated in phosphate buffered saline solution (PBS). 3. All subsequent operations are performed at 4°C; the harvesting oi from the stomachs should be performed within a cold room (steps 2-i

4. Fundic regions are removed and rinsed twice in ice-cold PBS.

5. The mucosa is peeled away from the stomach wall using a scalpel (i off relatively easily and stay intact). 6. Liberally apply ice-cold saturated NaCl to the surface, leaving the upside-down in the NaCl solution. Leave to soak around 15 minutes.

7. After soaking vigorously wipe the mucosae with paper towels to r< mucus and loose surface cells

8. Using a spoon, scrape the mucosa away from the underlying conned from all 4 stomachs, and put it in 80OmL of 0.25M sucrose containi

Cocktail protease inhibitors, ImM EDTA, ImM EGTA pH 7.4.

9. Using scissors, roughly homogenize the tissue as much as possible.

10. Dounce homogenize the suspension using a tight- fitting Te homogenizer (e.g. 50 mL volume) with 6 strokes at maximum rpm. 11. Centrifuge the homogenate for 45 minutes at 2O ₅ OOOg in a Beckr rotor at 4°C. Chill the tubes and rotor beforehand in the cold room all subsequent centrifugation steps). 12. Decant off the supernatant from this spin and centrifuge further for 4 at 10O ₅ OOOg in a Beckman JA30.5 rotor. 13. Resuspend the pellets in a total of 17ImL of 0.25M sucrose containi

Cocktail protease inhibitors : dounce homogenize as above. Keep o pool in one vessel.

14. Prepare discontinuous (step) gradients in tubes for a Beckman JS2 (swing out type), consisting of 15mL of 7% Ficoll (w/w) overlaid on 34% (w/v) sucrose. Load carefully 16mL of sample on the top.

15. Being careful not to disturb the tubes, centrifuge them for 2h at 100 JA24.38 rotor.

16. After centrifugation, There should be a clearly visible cloudy regi Ficoll/0.25M sucrose interface. Collect this using a 1 mL Gilson pi not to take sucrose - the material will be in the Ficoll and you shoul to harvest it all without disturbing the interface. Keep on ice 17. Pool all the samples together in one tube. Fill with 0.25M sue centrifuge for 45 minutes at 100,00Og in a Beckman JA30.5 rotor carefully the supernatant and resuspend the pellet in approximately niM Pipes/Tris pH 7.4.

18. Transfer the material to a round bottom flask and shell-freeze (rotat an angle in a bath of methanol and cardice, to form a thin "shell" material on inside of flask). Lyophilize immediately overnight.

19. Re-suspend the lyophilized material in a minimum volume of Pipes freeze aliquots down at -80°C.

Example 18 - H+/K+ ATPase assay

The H+/K+ ATPase activity was determined by spectrophotometric quantific enzymatic inorganic phosphate release from ATP. Concentration response ci experiments were carried out from a starting concentration of test compound! lOOμM with serial half log units dilution to 3nM. One full curve contains 8 \ duplicate. a) for determination of total ATPase activity lμL of the test compound was preincubated in 80μL incubation assay buffer (37.5mM Bis-Tris acetate, pHf MgCl ₂ , 1OmM KCl ) and H+/K+ ATPase enzyme from example 17 (lOμL oi μg/mLmL) at 37°C for 15 minutes. b) for non-specific ATPase activity lμL of the test compound was preincuba 80μl control assay buffer (37.5mM Bis-Tris acetate, pH5.5, 4mM MgCl ₂ ) am ATPase enzyme from example 17 (lOμL of 0.25 μg/mLmL) at 37°C for 15 n The reaction was initiated by adding 10 μL of 1 mM ATP to (a) and (b) and 1 incubating at 37°C for 60 minutes.

Malachite green buffer was added 100 μL/well and absorbance was read at 6 Specific H+/K+ ATPase activity is the total ATPase activity (in the presence 1OmM KCl: reaction (a)) minus the basal, non-specific, ATPase activity (in t absence of KCl: reaction (b)).

Alternatively, the assay can be performed with the following slightly modifk procedure:

Concentration response curve experiments were carried out from a starting concentration of test compounds of lOOμM with serial 4-fold dilutions. Oi curve contains 11 points in duplicate. a) for determination of total ATPase activity O.lμL of the test compound was preincubated in lOμL incubation assay buffer (2OmM PIPES, pH6.0, ImM N 1OmM KCl ) and H+/K+ ATPase enzyme from example 17 (final assay cone 0.25μg/mL) at 37°C for 15 minutes. b) for non-specific ATPase activity 0.1 μl of the test compound was preincub lOμl control assay buffer (2OmM PIPES, pH6.0, ImM MgCl ₂ ) and H+/K+ A

enzyme from example 17 (final assay concentration 0.25μg/mL) at 37°C for minutes.

The reaction was initiated by adding 10 μL of 0.2mM ATP to (a) and (b) and incubating at 37°C for 60 minutes. Malachite green buffer was added 30 μl/well and absorbance was read at 63C Specific H+/K+ ATPase activity is the total ATPase activity (in the presence 1OmM KCl: reaction (a)) minus the basal, non-specific, ATPase activity (in t absence of KCl: reaction (b)).

All compounds tested in one or other of the two methods described above ha of <5uM.