BACKGROUND ART Nuclear factor kappa B (NF-KB) belongs to a family of closely related homo-and hetero-dimeric transcription factor complexes composed of various combinations of the Rel/NF-oB family of polypeptides. NF-KB and related family members are involved in the regulation of more than 50 genes relating to immune and inflammatory responses ((Barnes PJ, Karin M, N. Engl. J. Med. 336,1066- 1071 (1997)) and (Baeuerle PA, Baichwal VR, Adv. Immunol. 65,111-137 (1997)).

The development of a novel compound having effective anti-inflammatory actions based on a specific and selective inhibitory activity to NF-KB has been desired.

The present inventor has found that 2-amino-4,6-disubstituted nicotinic acid ester analogs are useful for intermediate of the novel compound. Synthetic method of 2- amino-4,6-disubstituted nicotinic acid ester analogs shown by the following Scheme 1 is disclosed in W. Nagai et al., J Heterocycl. Chem., 33 (1), 123 (1996), but it was prepared as a byproduct and the yield was very low. Furthermore, the substituents in the position 4 and 6 was limited to those shown in Scheme 1.

Scheme 1

DISCLOSURE OF INVENTION The object of this invention is to provide the synthetic method which can prepare 2- amino-4,6-disubstituted nicotinic acid ester analogs with various substituents and salts thereof in one pot, and in good yield.

As a result of extensive studies on chemical modification of source materials, the present inventor have found that 2-amino-4, 6-disubstituted nicotinic acid ester analogs can be prepared in one pot, and in good yield by using tertiary alkyl cyanoacetate.

Furthermore, various substituent groups, e. g. alkyl-groups and aryl groups can be introduced in the position 4 and the position 6 of the ester analog by the method of present invention. The present invention has been accomplished based on these findings.

This invention is to provide a process for producing 2-amino-4,6-disubstituted nicotinic acid ester analogs and salts thereof, comprising the reaction shown by the following Scheme 2.

Scheme 2 1 R2 C02R3 ammonium , ll r salt Ar O H O CN (II) (III) R2 R Ar N NH2 (IV)

wherein Ar is an aryl or heteroaryl group, and optionally substituted by one or more substituents; preferably, the optional substituent is not amino substituted alkyl, alkyl amino substituted alkyl or acidic group, Rl is hydrogen, halogen, or C1-6alkyl ; R2 is optionally substituted aryl, heteroaryl, alkyl or alkenyl ; preferably, the optional substituent is not amino substituted alkyl, alkyl amino substituted alkyl or acidic group, is is-CRRR, wherein R21, R22 and R23 are each independently Cl-6 alkyl or aryl.

The acidic group is e. g. phenolic-OH,-COOH, or-S03H. Alkanoylamino and alkokycarbonylamino groups are not included in the acidic groups. The acidic groups are not preferable for the reaction of Scheme 2, but can be used in protected form. The protecting group of the acidic group is not limited and may be any groups that can be used and known to those skilled in the art, e. g. benzyl, benzyloxy, methoxybenzyl methoxybenzyloxy or trimethylsilyl.

Preferred compounds of Scheme 2 are those wherein: Ar is phenyl, 2-pyridil, 3-pyridil, 4-pyridil, 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 1- naphthyl, 2-naphthyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl or 8-quinolyl and optionally substituted by one or more substituents, wherein the optional substituents are each independently hydrogen, Cl-6 alkyl, halogen, Cl l2 alkoxy, cyano, nitro, C1-6 alkylsulfonylamino, C1-6 alkoxy- carbonyl, di C1-6 alkylamino, Cl-6 alkylcarbonylamino,-S- (CH2) n-Ru or -O-(CH2) n-R) wherein n represents an integer selected from 0 to 6, and Rll is C2-6 alkenyl, benzoyl, diphenylmethyl, di (Cl-6 alkyl) amino, C1-6 alkanoyl, Cl-6 alkoxycarbonyl, or an optionally substituted 3 to 10 membered saturated or unsaturated ring having 0 to 3 heteroatoms selected from the group consisting of S, O and N as heteroatoms; Rl is hydrogen, halogen, or C1-6alkyl ;

R2 is optionally substituted phenyl or styryl; wherein the optional substituents are each independently hydrogen, halogen, C1-6 alkoxy, di C1-6 alkylamino, C1-6 alkanoylamino, C1-6 alkyl(hydroxy C1-6 alkyl) amino, C1-6 alkyl (benzyl) amino, morpholino, Cl-6 alkylsulfonylamino, optionally substituted piperidino, optionally substituted pyrrolidino, piperidino-C1-6alkylene-oxy, -CO-NHR51, or-NH-COR51, wherein Il represents piperidino-C1_6 alkylene, carboxy-C1-6alkylene, C1-6 alkyl, C1-6 alkoxy, CI-6 alkoxy-CI-6 alkylene, oxotetra- hydrofuryl, oxopyrrolidinyl,-CH (OH) RS',-Ci-6 alkylene-Rsib, wherein la is caxboxy-C1_6 alkylene or CI-6 alkoxycarbonyl-CI-6 alkylene, Ruz is optionally substituted piperidino, optionally substi- tuted piperazino, optionally substituted amino, -CH (NH2)-carboxy ; N-protected amino-C1-6 alkylene, or 5 to 8 membered saturated ring having 0 to 3 N as heteroatoms and the N atom is protected, wherein the protecting groups of the N atom are not limited and may be any groups that can be used and known to those skilled in the art;

-CR31R32R33, wherein R31 is hydrogen or Cl-6 alkyl, R32 is hydrogen, a 5 to 8 membered saturated ring having 0 to 3 atoms selected from the group consisting of S, O and N as heteroatoms, or optionally substituted C1-6 alkyl, and R33 is hydrogen, amino, C1-6 alkoxycarbonylamino, C2-6 alkenyloxy- carbonylamino, benzyloxycarbonylamino or R32 and R33 may form, together with the adjacent carbon atom, an optionally substituted or optionally benzene fused 5 to 8 membered saturated ring having 0 to 3 heteroatoms selected from the group consisting of N, O and S as heteroatoms; R3 is a-CR2lR22R23 wherein R2l, R22 and R23 are each independently C1-6alkyl or phenyl.

More preferred compounds of Scheme 2 are those wherein: Ar is phenyl, 2-pyridil, 3-pyridil, 4-pyridil, 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 1- naphthyl, 2-naphthyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl or 8-quinolyl and optionally substituted by one or more substituents,

wherein the optional substituents are each independently hydrogen, C1-6 alkyl, halogen, C1-12 alkoxy, cyano, nitro, C1-6 alkylsulfonylamino, Cl-6 alkoxy- carbonyl, di C1-6 alkylamino, Cl 6 alkylcarbonylamino,-S-(CH2) n-RIl, or -O-(CH2)n-R11, wherein n represents an integer selected from 0 to 6, and R11 is C2-6 alkenyl, benzoyl, diphenylmethyl, di (C1-6 alkyl) amino, C1-6 alkanoyl, C1-6 alkoxycarbonyl, optionally substituted 3 to 10 membered saturated or unsaturated ring having 0 to 3 heteroatoms selected from the group consisting of S, O and N as heteroatoms, which ring is optionally substituted by one or more substituents selected from the group consisting of C1-6 alkyl, C1-6 alkoxy, halogen, CI-6 alkoxycarbonyl, CI-6 alkyl- sulfonyl, halogen substituted alkyl, nitro, cyano, hydroxy, phenyl, amino, C1-6 alkylamino, C3-8 cycloalkylamino, benzyl- amino, carbamoyl,-O-C1-6 alkylene-phenyl, and-O-phenyl ; Rl is hydrogen, halogen, or C1-6alkyl ; R2 is optionally substituted phenyl or styryl; wherein the optional substituents are each independently hydrogen, halogen, amino, C1-6 alkoxy, di C1-6 alkylamino, C1-6 alkanoylamino, C1-6 alkyl- (hydroxy C1-6 alkyl)amino, C1-6 alkyl (benzyl) amino, morpholino, C1-6 alkyl- sulfonylamino, optionally substituted piperidino, optionally substituted pyrrolidino, piperidino-C1-6 alkylene-oxy, -CO-NHR51, or-NH-COR51, wherein

R51 represents piperidino-C1-6 alkylene, carboxy-C1-6 alkylene, C1-6 alkyl, C1-6 alkoxy, CI-6 alkoxy-CI-6 alkylene, oxotetrahydro- furyl, oxopyrrolidinyl,-CH (OH)R51a, -C1-6 alkylene-R51b, wherein R51a is carboxy-C1-6 alkylene or CI-6 alkoxycarbonyl-Cl-6 alkylene, R5lb is -NHR51b-1 (wherein R51b-1 represents hydrogen, C1-6 alkyl, -C1-6 alkylene-O-C1-6 alkyl, hydroxy-C1-6 alkylene, piperidino-C1_6 alkylene),-CH (NH2)-COOH, pyrroline,-N (Ci-6 alkyl) Reib-2 (wherein R51b-2 represents C1-6 alkyl or ethylpyrrolidine), piperidino optionally substituted by carboxy or Ci-6 alkoxycarbonyl, piperazino fused with cyclohexane, piperazino optionally substituted by Ci-6 alkyl, benzyl, hydroxy-C1-6 alkylene, C1-6 alklyl-carbonyl, cyclo- hexane, benzodioxane-Cz 6 alkylene, or furyl-carbonyl, N-protected amino-C1-6 alkylene, N-protected 2-piperidyl, N- protected 3-piperidyl or N-protected 4-piperidyl, wherein the protecting groups of the N atom are not limited and may be any groups that can be used and known to those skilled in the art;

-CR31R32R33, wherein Ruz is hydrogen or C1-6 alkyl, R32 is hydrogen; C1-6 alkyl optionally substituted by hydroxy, amino, phenyl, C1-6 alkoxyphenyl, halophenyl or aminophenyl ; or a 5 to 8 membered saturated ring having 0 to 3 atoms selected from the group consisting of S, O and N as heteroatoms, and R33 is hydrogen, amino, C1-6 alkoxycarbonylamino, C2-6 alkenyloxy- carbonylamino, or benzyloxycarbonylamino or R32 and R33 may form, together with the adjacent carbon atom, an optionally substituted 5 to 8 membered saturated ring having 0 to 3 heteroatoms selected from the group consisting of N, O and S as heteroatoms, which ring is optionally be substituted by one or more substituents selected from the group consisting of C1-6 alkyl, C1-6 alkoxy, Cl-6 alkoxycarbonyl, Cl-6 alkylsulfonyl, halogen substituted alkyl, nitro, cyano, hydroxy, phenyl, amino, Cl-6 alkylamino, C3-8 cyclo- alkylamino, benzylamino, carbamoyl,-O-C1-6 alkylene-phenyl,-O- phenyl, phenyl-CI-6 alkyl, di C1-6 alkylamino, and piperidino-Cl-6 alkylcarbonyl, or said ring may be fused with a benzene ring; R3 is t-butyl, 1,1-dimetylpropyl or trityl group.

Still more preferred compound of Scheme 2 are those wherein:

Ar is phenyl, and optionally substituted by one substituent, wherein the optional substituent is hydrogen, C1-12 alkoxy, or -O-C1-6 alkylene- R11, wherein Rll is vinyl, diphenylmethyl, C1-6 alkanoyl, optionally substituted C5-lo aryl, or optionally substituted 5 to 10 membered heteroaryl, optionally substituted 3 to 8 membered cycloalkyl optionally interrupted by O atom, or a 5 to 8 membered saturated heterocyclic ring interrupted by NH and/or O ; Rl is hydrogen; is optionally substituted phenyl or styryl; wherein the optional substituents are each independently hydrogen, halogen, amino, C1-6 alkoxy, di C1-6 alkylamino, Cl-6 alkanoylamino, Cl-6 alkyl- (hydroxy Cl-6 alkyl) amino, C1-6 alkyl (benzyl) amino, morpholino, Cl 6 alkylsulfonylamino, optionally substituted piperidino, optionally substituted pyrrolidino, piperidino-C1-6 alkylene-oxy, -CO-NHR51, or-NH-COR51, wherein Ruz represents piperidino-C1-6 alkylene, carboxy-C1_s alkylene, C1-6 alkyl, Cl-6 alkoxy, Cl-6 alkoxy-Cl-6 alkylene, oxotetra- hydrofuryl, oxopyrrolidinyl,-CH (OH) R51a, -C1-6 alkylene-R51b, wherein

la is carboxy-C1_6 alkylene or CI-6 alkoxycarbonyl-Cl-6 alkylene, Rslb is -NHR51b-1 (wherein R51b-1 represents hydrogen, Cl-6 alkyl, -C1-6 alkylene-O-C1-6 alkyl, hydroxy-C1-6 alkylene, piperidino-C1-6 alkylene),-CH (NH2)-COOH, pyrroline,-N (Cl-6 alkyl) R51b-2 (wherein R51b-2 represents C1-6 alkyl or ethylpyrrolidine), piperidino optionally substituted by carboxy or C1-6 alkoxycarbonyl, piperazino fused with cyclohexane, or piperazino optionally substituted by C1-6 alkyl, benzyl, hydroxy-C1-6 alkylene, C1-6 alklyl-carbonyl, cyclo- hexane, benzodioxane-C1-6 alkylene, or furyl-carbonyl, N-protected amino-C1-6 alkylene, N-protected 2-piperidyl, N-protected 3-piperidyl or N-protected 4-piperidyl, wherein the protecting groups of the N atom are not limited and may be any groups that can be used and known to those skilled in the art; -CR31R32R33, wherein R31 is hydrogen or C1-6alkyl, R32 is hydrogen, or C1-6 alkyl optionally substituted by hydroxy, amino, phenyl, C1-6 alkoxyphenyl, halophenyl, or aminophenyl, and

R33 is hydrogen, amino, or benzyloxycarbonylamino; or R32 and R33 may form optionally substituted Cs-g cycloalkyl optionally interrupted by NH, wherein said substituent is Cl 6 alkyl, phenyl-CI 6 alkyl, amino, Cl-6 alkylamino, benzylamino, di C1-6 alkylamino, carbamoyl, CI-6 alkoxycarbonyl, piperidino-Cz 6 alkylcarbonyl, or C1-6 alkylsulfonyl, and said ring may be fused with a benzene ring; R3 is t-butyl group.

The protecting groups of the N atom is preferably alkoxycarbonyl or benzyl- oxycarbonyl.

The term"aryl"used herein means aromatic moiety having 5 to 10 carbon atoms with one to two rings.

The term"heteroaryl"used herein means aromatic moiety having 2 to 9 carbon atoms with one to two rings and at least one heteroatom selected from the group consisting of oxygen, nitrogen and sulfur.

The term "C1-12 alkoxy"used herein means-O-straight or branched alkyl having 1 to 12 carbon atoms.

The-CR31R32R33 group is preferably di-substituted alkyl group (i. e. one of R31, R32 and R33 is hydrogen) or tri-substituted alkyl group, because the yield of the reaction is better than mono-substituted alkyl group.

The ammonium salt in the Scheme 2 is, for example, ammonium acetate, ammonium chloride, ammonium benzoate, ammonium succinate, preferably ammonium acetate.

Typical salts of the compound shown by the formula (IV) include salts prepared by reaction of the compound of the present invention with a mineral or organic acid.

Such salts are known as acid addition salts.

Acids to form acid addition salts include inorganic acids such as, without limitation, sulfuric acid, phosphoric acid, and the like, and organic acids, such as, without limitation, p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromo- phenylsulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, acetic acid, hydrochloric acid, hydrobromic acid, hydroiodic acid and the like.

Examples of such salts are sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, chloride, bromide, iodide, acetate, propionate, decanoate, caprylate, acrylate, formate, isobutyrate, caproate, heptanoate, propiolate, oxalate, malonate, succinate, suberate, sevacate, fumarate, maleate, butyne-1, 4-dioate, hexyne-1, 6-dioate, benzoate, chlorobenzoate, methoxybenzoate, phthalate, sulfonate, xylenesulfonate, phenylacetate, phenylpropionate, phenylbutyrate, citrate, lactate, y-hydroxybutyrate, glycollate, tartarate, methanesulfonate, propanesulfonate, naphthalene-1-sulfonate, naphthalene-2-sulfonate, mandelate, and the like salts of the compound of formula (IV). The preferred acid addition salts are those formed with mineral acids, such as, without limitation, hydrochloric acid, and hydrobromic acid, and those formed with organic acids, such as without limitation, maleic acid and methanesulfonic acid. BEST MODE FOR CARRYING OUT THE INVENTION The compound (IV)

wherein Ar, Ri, R and R3 are the same as defined, or a salt thereof, can be prepared, by the reaction of Scheme 2.

The compound of the formula (I) in which Ar and Ri are the same as defined above, are reacted with an aldehyde of the formula Ra-CHO (II), a nitrile of the formula R3OCO-CH2CN (III) and an ammonium salt such as ammonium acetate.

This reaction can be carried out without a solvent or in a solvent including, for instance, ethers, such as dioxane, and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene and xylene; nitriles such as acetonitrile; amides such as dimethylformamide (DMF) and dimethylacetamide; sulfoxides such as dimethyl sulfoxide, and others, or mixture thereof.

The reaction temperature can be optionally set depending on the compounds to be reacted. The reaction temperature is usually, but not limited to, about 50°C to 200°C. The reaction may be conducted for, usually, 30 minutes to 48 hours and preferably 1 to 24 hours.

The compounds of the general formula (I), (II) and (III) can be commercially available, or can be prepared by the use of known techniques.

EXAMPLES The present invention will be described in detail below in the form of examples, but they should by no means be construed as defining the metes and bounds of the present invention.

In the examples below, all quantitative data, if not stated otherwise, relate to percentages by weight.

Melting points'are uncorrected.'H NMR spectra were recorded using either Bruker DRX-300 (300MHz for IH) or 500 Bruker UltraShieldTM (500MHz for 1H) spectro- meter in CDC13 or DMSO-d6. Chemical shifts are reported in parts per million (ppm) with tetramethylsilane (TMS) as an internal standard at zero ppm. Coupling constant (J) are given in hertz and the abbreviations s, d, t, q, and m refer to singlet, doublet, triplet, quartet and multiplet, respectively. The abbreviation"br"refer to"broad".

Mass spectroscopy data were recorded on a FINNIGAN MAT 95. TLC was performed on a precoated silica gel plate (Merck silica gel 60 F-254). Silica gel (WAKO-gel C-200 (75-150, um)) was used for all column chromatography separa- tions. All chemicals were reagent grade and were purchased from Sigma-Aldrich, Wako pure chemical industries, Ltd., Tokyo kasei kogyo co. Ltd., Arch cooporation. Preparing method of starting compounds: [Starting compound 1A] (Starting compound 1A)

A mixture of 2'-hydroxyacetophenone (68 g, 0.50 mol), benzylbromide (94 g, 0.55 mol) and potassium carbonate (103 g, 0.75 mol) in acetone (1000 mL) was stirred at reflux, and the stirring was continued overnight. After cooled to room temperature, the mixture was concentrated under reduced pressure. The residue was diluted with water, and extracted with ethyl acetate. The separated organic phase was washed with brine, dried over MgS04, filtered and concentrated under reduced pressure. The crude product was purified by distillation under reduced pressure to give 1- [2- (benzyloxy) phenyl] ethanone as a colorless oil. (100 g, yield; 88%) [Starting compound 1B] (Starting compound 1B) In a same manner as the method to prepare starting compound 1A, except that benzylbromide was replaced with methoxybenzylchloride, methoxybenzylaceto- phenone was prepared.

[Starting compound 1C] To a stirred solution of 1- (2, 6-dihydroxyphenyl) ethanone (50.0 g, 328 mmol) in acetone (1000 mL) were added potassium carbonate (227 g, 1643 mmol) and (bromomethyl) cyclopropane (35.1 mL, 361 mmol). The mixture was stirred at 50°C for 2 days. The reaction mixture was filtrated on Celite, and then the filtrate was concentrated under reduced pressure. The residue was diluted with water and extracted with ethyl acetate. The separated organic phase was washed with water and brine, dried over MgS04, filtered and concentrated under reduced pressure. The residue was suspended in hexane. Then the suspension was stirred at 80°C for 30 min. The solution was filtered and the filtrate was allowed to cool to room temperature. The resulting white solid was collected by filtration, washed with hexane, and dried under reduced pressure to give 1-{2-[(cyclopropylmethyl) oxy] 4- hydroxyphenyl} ethanone as a pale yellow solid (56.3 g, yield; 83%).

(Starting compound 1C) To a stirred solution of 1-{2-[(cyclopropylmethyl) oxy]-6-hydroxyphenyl} ethanone (56.3 g, 272 mmol) in acetone (1000 mL) were added potassium carbonate (188 g, 1364 mmol), 4-methoxybenzyl chloride (40.9 mL, 300 mmol) and tetrabutyl- ammonium iodide (20.2 g, 54.6 mmol). The mixture was stirred at reflux overnight.

The reaction mixture was allowed to cool to room temperature, filtered on Celite, and then the filtrate was concentrated under reduced pressure. The residue was diluted with water and extracted with ethyl acetate. The separated organic phase was washed with brine, dried over MgS04, filtered and concentrated under reduced

pressure. Then the resulting white solid was recrystallized from ethanol, collected by filtration, washed with ethanol, and dried under reduced pressure to give 1- {2- (cyclopropylmethoxy)-6- [ (4-methoxybenzyl) oxy] phenyl} ethanone as a white solid (79.2 g, yield; 89%).

[Starting compound 2A] (1) To a cooled (0°C), stirred solution of 3-piperidinecarboxylic acid (100.000 g, 774.233 mmol) in dioxane (400 ml) were added 2N NaOH (400 ml, 800 mmol) and di-tert-butyl dicarbonate (168.978 g, 774.233 mmol). The mixture was stirred at 0°C-room temperature for 12 hrs. The mixture was concentrated in vacuo. The residue was diluted with water and acidified (pH 3-4) with aqueous 1N HC1 solution. The resulting solid was collected by filtration. The white solid was dissolved in ethyl acetate/water and the organic layer was separated.

The organic layer so obtained was dried over Na2SO4, filtered, and concentrated. The resulting solid was suspended in hexane and collected by filtration to give 1- (tert-butoxycarbonyl)-3-piperidine carboxylic acid as a white powder. (156 g, yield; 88%)

(2) To a stirred solution of 1- (tert-butoxycarbonyl)-3-piperidine carboxylic acid (7.000 g, 30.531 mmol) in dichloromethane (200 ml) was added triethylamine (4.681 ml, 33.584 mmol). After cooled to 0°C, benzotriazole-1-yl-oxy-tris- pyrrolidino-phosphonium hexafluorophosphate (15.885 g, 30.531 mmol), N, O- dimethylhydroxyamine (3.276 g, 33.584 mmol) and triethylamine (4.255 ml, 30.531 mmol), successively. The mixture was stirred at room temperature for 12 hrs. The reaction mixture was diluted with dichloromethane and washed with an aqueous 1N HC1 solution, saturated aqueous NaHCO3 solution, and brine, successively. The organic layer was dried over Na2SO4, filtered, and concentrated. The resulting residue was purified by silica gel column (chloroform/ethyl acetate = 10/1-9/1) to give tert-butyl 3-{[methoxy- (methyl) amino] carbonyl}-l-piperidine-carboxylate as a white solid. (8. 050 g, yield ; 96%) (Starting compound 2A) (3) To a cooled (-15°C), stirred suspension of lithium aluminum hydride (4.355 g, 114.743 mmol) in diethyl ether (SOOml) was added tert-butyl 3- { [methoxy- (methyl) amino] carbonyl}-l-piperidine-carboxylate (25.000 g, 91.795 mmol) in THF (150 ml) dropwise for 30 min. The reaction was quenched with aqueous 1N potassium hydrogen sulfate (300 ml). Then the resulting product was extracted with diethyl ether and ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and concentrated. The residue (tert-butyl 3-formyl- 1-piperidine carboxylate) was used for the next steps without further purification. (22.56 g, yield; about 100%) [Starting compound 2B]

(1) To a cooled and stirred solution of nipecotinic acid (3.0 g, 23.3 mmol) in 1,4- dioxane (12 ml) was added 2N NaOH (24.0 ml, 48.0 mmol). Then benzyl chloroformate (3.96 g, 23.2 mmol) in 1,4-dioxane (12 ml) was added dropwise at 0°C. The reaction mixture was stirred at 0°C-room temperature for 3hrs. The mixture was concentrated in vacuo. The residue was diluted with water and acidified with 1H HC1 (pH 3-4). The mixture was extracted with AcOEt, and the organic layer was washed with brine, dried over Na2S04, filtered, and evaporated. The white solid was washed with hexane to give 1- [ (benzyloxy) carbonyl]-3-piperidinecarboxylic acid as a white solid (4.4 g, yield; 71%).

(2) To a cooled (-15°C to-20°C) and stirred solution of 1- [ (benzyloxy) carbonyl]- 3-piperidinecarboxylic acid (4.0 g, 15.2 mmol) in dry THF (50 ml) was added methylmorpholine (2 ml). A solution of isobutyl chloroformate (2.28 g, 16.7 mmol) in THF (10 ml) was added to the mixture dropwise at-15°C to -20°C, and stirred for 20 minutes. After methylmorpholine (2 ml) in THF

(20 ml) was added to the mixture, N, O-dimethylhydroxylamine hydrochloride (1.63 g, 16.7 mmol) was added at-15°C to-20°C. The reaction mixture was allowed to warm to room temperature, and then stirred for 16 hrs. The reaction mixture was concentrated in vacuo and partitioned between EtOAc and water. The separated organic layer was washed with 1N HC1, sat. NaHC03, and brine, successively. The organic layer was then dried over Na2S04, filtered, and concentrated to give benzyl 3- { [methoxy (methyl)- amino] carbonyl}-l-piperidinecarboxylate as a colorless oil (4.7 g, yield; about 100%).

(Starting compound 2B) (3) To a cooled (-78°C) suspension of lithium aluminum hydride (0.70 g, 18.4 mmol) in dry THF (100 ml) was added the solution of benzyl 3- { [meth- oxy (methyl) amino] carbonyl}-l-piperidinecarboxylate (4.5 g, 14.7 mmol) in THF (30ml) dropwise under an Argon atmosphere. The reaction mixture was stirred at-78°C for 45 min. The reaction was quenched with 0. 5N KHS04 (130 ml). The resulting product was extracted with ether. The extracts were dried over MgS04, filtered, and concentrated in vacuo to give benzyl 3- formyl-l-piperidinecarboxylate as a colorless oil (0.54 g, yield; 82%). Example 1: 2-amino-6-r2- (benzyloxy) phenyl]-4- [1- (tert-butoxycarbonyl)-3- piperidinyllnicotinate

A mixture of 1- [2- (benzyloxy) phenyl] ethanone (3.50 g, 15.47 mmol) (starting com- pound 1A), tert-butyl 3-formyl-1-piperidinecarboxylate (3.30 g, 15.47 mmol) (Starting compound 2A), tert-butyl cyanoacetate (2.18 g, 15.47 mmol), ammonium acetate (3.58 g, 46.40 mmol) and 1,2-dimethoxyethane (17 mL) was heated at reflux for 3.5 hrs. After cooled to room temperature, the mixture was concentrated under reduced pressure, and the residue was partitioned between ethyl acetate and water.

The separated organic phase was washed with brine, dried over Na2S04, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (hexane: ethyl acetate, 4: 1) to give tert-butyl 2-amino- 6- [2- (benzyloxy) phenyl]-4- [1- (tert-butoxycarbonyl)-3-piperidinyl] nicotinate (1.89 g, yield; 22%): LCMS (ES) mle 560 (M + H) + ; IH NMR (500 MHz, CDC13) 8 1.13 (1H, ddd, J = 3.8,12.6,25.2 Hz), 1.42 (1H, br), 1.44 (9H, s), 1.58 (9H, s), 1.62-1.71 (1H, m), 1.77-1.83 (1H, m), 2.34 (1H, br), 2.44 (1H, br), 3.14 (1H, br), 3.91 (1H,

br), 4.11 (1H, br), 5.06 (2H, s), 5.62 (2H, s), 7.06-7.10 (2H, m), 7.15 (1H, s), 7.29- 7.31 (1H, m), 7.34-7.37 (3H, m), 7.41-7.43 (2H, m), 7.85 (1H, dd, J = 1. 9,7.9 Hz).

Example 2: tert-butyl 2-amino-4- {1-[(benzyloxy ! carbonyl]-3-piperidinyl}-6- {2- j (4-methoxybenzyl) oxy] phenyl} nicotinate

A mixture of 1- {2- [ (4-methoxybenzyl) oxy] phenyl} ethanone (14.2 g, 55.4 mmol) (starting compound 1B), benzyl 3-formyl-1-piperidinecarboxylate (13.7 g, 55.4 mmol) (starting compound 2B), tert-butyl cyanoacetate (7.8 g, 55.4 mmol), and ammonium acetate (9.8 g, 166.1 mmol) and 1,2-dimethoxyethane (60 mL) was stirred at reflux for 3.5 hrs. After cooled to room temperature, the mixture was partitioned between ethyl acetate and water. The separated organic phase was washed with water and brine, dried over MgS04, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel

(ethyl acetate: hexane, 1: 2) to give tert-butyl 2-amino-4-{1-[(benzyloxy) carbonyl]-3- piperidinyl}-6-{2-[(4-methoxybenzyl)oxy]phenyl}nicotinate as a pale yellow oil (4.89 g, yield; 14%): LCMS (ES) mle 624 (M + H) + ; IH NMR (300 MHz, CDC13) 8 1.13 (1H, ddd, J = 3.8,12.4,25.0 Hz), 1.32-1.85 (3H, m), 1.51 (9H, s), 2.28-2.37 (1H, m), 2.51 (1H, br), 3.09-3.19 (1H, m), 3.74 (3H, s), 3.95-4.27 (2H, br), 4.95 (2H, s), 5.05-5.18 (2H, m), 5.62 (2H, s), 6.82-6.92 (2H, m), 7.04-7.10 (2H, m), 7.17 (1H, s), 7.20-7.39 (8H, m), 7.89 (1H, dd, J = 1. 9,7.9 Hz).

Example 3 : tert-butyl 2-amino-4-[1-(tert-butoxycarbonyl)-3-piperidinyl]-6-{2-(cy- clopropylmethoxy)-6-r (4-methoxybenzyl) oxylphenyl} nicotinate

A mixture of 1- {2- (cyclopropylmethoxy)-6- [ (4-methoxybenzyl) oxy] phenyl} ethanone (10.00 g, 30.638 mmol) (starting compound 1C), tert-butyl 3-formyl-1- piperidinecarboxylate (13.069 g, 61.275 mmol) (Starting compound 2A), tert-

butylcyanoacetate (8.650 g, 61.275 mmol), and ammonium acetate (6.902 g, 91.913 mmol) and 1,4-dioxane (10 mL) was stirred at 90°C overnight. After cooled to room temperature, the reaction mixture was diluted with ethyl acetate (100 mL).

To the mixture was added chloranil (1.507 g, 6.128 mmol), and stirred at room temperature. After being stirred for 1. 5hrs, the mixture was partitioned between ethyl acetate and water. The organic phase was washed with water and brine, dried over MgS04, filtered, and then concentrated under reduced pressure. The resulting residue was purified by column chromatography on Silica gel (hexane: ethyl acetate, 2: 1) to give tert-butyl 2-amino-4- [l- (-butoxycarbonyl)-3-piperidinyl]-6- {2- (cyclopropylmetlioxy)-6- [ (4-methoxybenzyl) oxy] phenyl} nicotinate as a pale brown form (4.9 g, 24 %): LCMS (ES) mle 660 (M + H) + ; IH NMR (500 MHz, CDC13) 8 0.18-0.23 (2H, m), 0.45-0.52 (2H, m), 1.07-1.15 (1H, m), 1.43 (9H, s), 1.41- 1.56 (1H, m), 1.62 (9H, s), 1.70-1.80 (2H, m), 1.96-2.02 (1H, m), 2.59-2.83 (2H, br), 3.25-3.33 (1H, m), 3.76-3.81 (2H, m), 3.77 (3H, s), 4.15 (2H, br), 4.97 (2H, s), 5.64 (2H, s), 6.59 (1H, d, J = 7.9 Hz), 6.63 (1H, s), 6.65 (1H, d, J = 8.2 Hz), 6.82 (2H, d, J = 8.8 Hz), 7.18-7.22 (3H, m). Example 4: tert-butyl 2-amino-6-[2-(benzyloxy)phenyl]-4-{1-[(tert-butoxycarbonyl)- amino]-2-phenylethyllnicotinate

A mixture of 1- [2- (benzyloxy) phenyl] ethanone (3.000 g, 13.258 mmol) (starting compound 1A), N-tert-butoxycarbonyl-phenylalaninal (3 ; 305 g, 13.258 mmol), tert- butyl cyanoacetate (1.872 g, 13.258 mmol), ammonium acetate (3.066 g, 39.774 mmol) and 1,2-dimethoxyethane (5.0 mL) was heated at reflux for 6 hrs.

After cooled to room temperature, the mixture was extracted with ethyl acetate and saturated NaHCO3 solution. The separated organic phase was washed with water and brine successively, dried over Na2S04, filtered and concentrated under reduced pressure. The residue was triturated with diisopropyl ether to give tert-butyl 2- <BR> <BR> amino-6- [2- (benzyloxy) phenyl]-4- {1- [(tert-butoxycarbonyl) amino]-2-phenylethyl}- 1, 4-dihydro-3-pyridinecarboxylate as a pale yellow solid, which was then dissolved in methylene chloride (20.0 mL). To the mixture was added chloranil (0.543 g, 2.208 mmol), and the stirring was continued for 1 hr. The precipitates were filtered off, and the filtrate was concentrated under reduced pressure. The residue was extracted with ethyl acetate and 10% aqueous NaHCO3 solution. The separated

organic phase was washed with water and brine successively, dried over Na2S04, filtered and concentrated under reduced pressure. The crude product was crystallized from ethanol to give tert-butyl 2-amino-6-[2-(benzyloxy) phenyl]-4-{1-[(tert-butoxy- carbonyl) amino]-2-phenylethyl} nicotinate as a pale yellow solid (0.972 g, yield; 13%): LCMS (ES) mle 626 (M + H) + ; IH NMR (500 MHz, DMSO-d6) 8 1.23 (9H, s), 1.53 (9H, s), 2.71-2.84 (2H, m), 3.63 (3H, s), 5.05 (1H, d, J = 11.7 Hz), 5.13 (1H, d, J = 11.7 Hz), 5.33 (1H, br), 6.16 (2H, s), 6.86 (2H, d, J = 8.8 Hz), 7.02-7.05 (lH, m), 7.17-7.30 (6H, m), 7.32 (1H, s), 7.35-7.39 (1H, m), 7.43 (2H, d, J = 8. 8 Hz), 7.57 (1H, d, J= 7. 6 Hz).

Other 2-amino-4,6-disubstituted nicotinic acid ester analogs could be prepared by the similar procedure.

INDUSTRIAL APPLICABILITY The novel synthetic method of 2-amino-4, 6-disubstituted nicotinic acid ester analogs is provided by this invention.

By using tertiary alkyl cyanoacetate, the synthetic method of this invention affords the target compound in one pot, and in good yield. Furthermore, the method is useful for a derivation of various analogs of the ester, e. g. alkyl substituted and aryl substituted analogs.

2-amino-4,6-disubstituted nicotinic acid ester analogs, and salts thereof would be useful template for biologically active compounds, e. g. pyridine derivatives which inhibit IKB kinase ß (IKK-P or IKK-beta) activity, thus inhibit nuclear factor kappa B (NF-KB) activity, and can be used for the prophylaxis and treatment of diseases associated with NF-KB activity, in particular for the treatment of inflammatory diseases.