Synthesis of phenylacetylene containing 1,2,3-triazole group

Bromination of (E)-1-[4-(2-carboxy-vinyl)phenyl]-[1,2,3]triazole-4-carboxylic acid ethyl ester, which was synthesized in 90% yield by a Huisgen-type [3 + 2]-cycloaddition reaction between 3-(4-azidophenyl) acrylic acid and ethyl propiolate, in CHCl₃ followed by a debrominative decarboxylation reaction with Et₃N in DMF under microwave irradiation condition afforded stereoselective (Z)-1-(4-(2-bromovinyl)phenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester in 94% yield. Treatment of (Z)-1-(4-(2-bromovinyl)phenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester with EtONa in DMF afforded 1-(4-ethynylphenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester in a yield of 90%.     

3-(2-氧代环烷基)丙酸与(R)-2-硫代四氢噻唑-4-羧酸乙酯的反应

３－（２－氧代环烷基）丙酸与（Ｒ）－２－硫代四氢噻唑－４－羧酸乙酯的反应李叶芝,田颜清,黄化民（吉林大学化学,长春,１３００２３）关键词（Ｒ）－２－硫代四氢噻唑－４－羧酸乙酯,Ｎ－３－（２－氧代环烷基）丙酰－２－硫代四氢噻唑－４－羧酸乙酯,环合反应,...     

Synthesis and antibacterial activity of 1-(substituted-benzyl)-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acids and their 6,8-difluoro analogs

Alkylation of 6,7-difluoro-4-hydroxyquinoline-3-carboxylic acid ethyl ester with substituted-benzyl chlorides gave 1-(substituted-benzyl)-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid ethyl esters. Their treatment with piperazine or N-methylpiperazine in pyridine yielded 1-(substituted-benzyl)-6-fluoro-1,4-dihydro-4-oxo-7-(l-piperazinyl)quinoline-3-carboxylic acid ethyl esters which were hydrolyzed with aqueous sodium hydroxide and then acidified with hydrochloric acid afforded the desired 1-(substituted-benzyl)-6-fluoro-1,4-dihydro-4-oxo-7-(1-iperazinyl)quinoline-3-carboxylic acids. The 6,8-difluoro analogs were prepared similarly using 6,7,8-trifluoro-4-hydroxyquinoline-3-carboxylic acid ethyl ester as a starting material. Some of these quinolones demonstrated fairly good antibacterial activities. Among them, 6-fluoro-1-(4-fluorophenylmethyl)-1,4-dihydro-7-(1-iperazinyl)-4-oxoquinoline-3-carboxylic acid ( 7d ) and 6,8-difluoro-1-(3-fluorophenylmethyl)-1,4-dihydro-7-(1-piperazinyl)-4-oxoquinoline-3-carboxylic acid ( 8c ) are two of the best.     

Synthesis of 3-arylsulfonylmethyl-1,2,4-oxadiazole-5-carboxylic acid derivatives

Several new 3-arylsulfonylmethyl-1,2,4-oxadiazole-5-carboxylic acid derivatives have been synthesized. A typical example, 3-[(4-chlorophenylsulfonyl)methyl]-1,2,4-oxadiazole-5-carboxylic acid ethyl ester ( 2c ), was prepared from the reaction of 2-(4-chlorophenylsulfonyl)acetamide oxime ( 1c ) with ethyl oxalyl chloride. The hydrazide derivative ( 3f ) showed antihypertensive activity in rats. Various structural modifications to improve activity are discussed.     

Catalytic reductive cyclization of potassium salt of ethyl ester of o-nitrophenylpyruvic acid

Conclusions In the presence of nickel catalysts, the reductive cyclization of the K salt of the ethyl ester of o-nitro-phenylpyruvic acid gives 2-carbethoxyindole, while 1-hydroxyindole-2-carboxylic acid is obtained in the presence of ruthenium, and a mixture of 2-carbethoxyindole and 1-hydroxy-2-carbethoxyindole in the presence of either platinum or palladium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 661–663, March, 1973.     

1,6- and 1,7-naphthyridines. II. Synthesis from acyclic precursors

A number of 8-hydroxy-6-methyl-1,6-naphthyridin-5(6H)-one-7-carboxylic acid alkyl esters 3 and the isomeric 5-hydroxy-7-methyl-1,7-naphthyridin-8(7H)-one-6-carboxylic acid alkyl esters 4 were synthesized from acyclic precursors obtained starting from quinolinic anhydride 5. Thus, methanolysis of 5 afforded the hemiester 6 which treated with oxalyl chloride and sarcosine ethyl ester gave 3-(N-ethoxycarbonylmethyl-N-methylcarbamoyl)pyridine-2-carboxylic acid methyl ester 8. Compound 8 was cyclized to naphthyridines 3a-e with sodium alkoxides. The isomeric naphthyridines 4a-c were obtained by cyclization of the open intermediary 2-(N-ethoxycarbonylmethyl-N-methylcarbamoyl)pyridine-3-carboxylic acid methyl ester 9 obtained by a route that involves treatment of 5 with sarcosine ethyl ester and esterification with diazomethane. Spectroscopic properties (¹H nmr, uv, ir) of compounds 3 and 4 are discussed and confirmed the proposed structures.     

Thiazolecarboxylic Acid Derivatives. 1. N-Substituted 2-Amino-4-methylthiazole-5-carboxylic Acid Derivatives

Acylation of the ethyl ester and anilide of 2-amino-4-methylthiazole-5-carboxylic acid gave 2-acetyl(arylsulfonyl)amino derivatives. Methylation of acetylaminothiazole and subsequent deacetylation gave 2-methylamino-4-methylthiazole-5-carboxylic acid, which was then converted into esters. The ethyl ester and anilide of thiazole-2-carboxylic acid were used as starting compounds for the synthesis of 2-dimethylaminoformimino- and 2-chlorobenzenesulfonylureido derivatives.     

4-Hydroxy-2-quinolones. 107. Reaction of triethyl methanetricarboxylate with indoline

The first stage of the reaction of triethyl methanetricarboxylate with indoline is the formation of the diethyl ester of 2-(indoline-1-carbonyl)malonic acid, which then, depending on the conditions selected, may be converted into the ethyl ester of 2-(indoline-1-carbonyl)-3-(indolin-1-yl)-3-oxopropionic acid, methanetri-N-(indolin-1-yl)carboxamide, or the ethyl ester or (indolin-1-yl)amide of 1-hydroxy-3-oxo-5,6-dihydro-3H-pyrrolo[3,2,1-ij]quinoline-2-carboxylic acid. __________ Translated From Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1191–1197, August, 2006.     

Synthesis and properties of 3-substituted 2h-1,2,4-benzothiadiazine 1,1-dioxides

The ethyl ester and amides of 2H-1,2,4-benzothiadiazine-3-carboxylic acid 1,1-dioxide were obtained by reaction of 2-aminobenzenesulfonamide with diethyl oxalate or oxamic acid esters in the presence of sodium methoxide. The hydrolysis, animation, and hydrazinolysis of the ester were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 479–483, April, 1976.     

Synthesis of Imidazo[1′,5′:1,2]pyrido[3,4- b ]indole Derivatives

 The reactions of 1,2,3,4-tetrahydro-β-carboline-1-carboxylic acid and its ethyl ester with alkyl and aryl isothiocyanates under mild conditions resulted in the corresponding thiohydantoin-fused tetrahydro-β-carbolines. Treatment of the ethyl ester with isocyanates furnished ethyl 2-alkyl- or arylcarbamoyl-1,2,3,4-tetrahydro-β-carboline-1-carboxylates which were transformed to hydantoin-fused tetrahydro-β-carbolines. The structures of the thiohydantoin compounds, involving two conformers and the presence of keto-enol tautomerism, were determined by NMR spectroscopy.     

Synthesis of Imidazo[1′,5′:1,2]pyrido[3,4-b]indole Derivatives

Summary.  The reactions of 1,2,3,4-tetrahydro-β-carboline-1-carboxylic acid and its ethyl ester with alkyl and aryl isothiocyanates under mild conditions resulted in the corresponding thiohydantoin-fused tetrahydro-β-carbolines. Treatment of the ethyl ester with isocyanates furnished ethyl 2-alkyl- or arylcarbamoyl-1,2,3,4-tetrahydro-β-carboline-1-carboxylates which were transformed to hydantoin-fused tetrahydro-β-carbolines. The structures of the thiohydantoin compounds, involving two conformers and the presence of keto-enol tautomerism, were determined by NMR spectroscopy. Corresponding author. E-mail: fulop@pharma.szote.u-szeged.hu Received February 2, 2002. Accepted (revised) March 4, 2002     

Rearrangements of 4-(2-Aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylic acid diethyl ester

The treatment of 4-(2-aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinecarboxylic acid diethyl ester (III) with refluxing toluene or pyridine afforded 1,2,3,6-tetrahydro-2,4-dimethyl-2,6-methano-1,3-benzodiazocine-5,11-dicarboxylic acid diethyl ester (IV) as the major product. In addition, the following minor products were isolated: 2-methyl-3-quinolinecarboxylic acid ethyl ester (V), 3-(2-aminophenyl)-5-methyl-6-azabicyclo[3,3,1]-hept-1-ene-2,4-dicarboxylic acid diethyl ester (VI), and 5,6-dihydro-2,4-dimethyl-5-oxobenzo[c][2,7]naphthyridine-1-carboxylic acid ethyl ester (VII). In contrast, acidic conditions caused the conversion of III into V in a 95% yield. The formation of the latter appears to involve IV as an intermediate, since IV degraded rapidly in acid to give V in a quantitative yield.     

Oligomerization of indole derivatives with incorporation of thiols

Two molecules of indole derivative, e.g. indole-5-carboxylic acid, reacted with one molecule of thiol, e.g. 1,2-ethanedithiol, in the presence of trifluoroacetic acid to yield adducts such as 3-[2-(2-amino-5-carboxyphenyl)-1-(2-mercaptoethylthio)ethyl]-1Hindole-5-carboxylic acid. Parallel formation of dimers, such as 2,3-dihydro-1H,1'H-2,3'-biindole-5,5'-dicarboxylic acid and trimers, such as 3,3'-[2-(2-amino-5-carboxyphenyl) ethane-1,1-diyl]bis(1H-indole-5-carboxylic acid) of the indole derivatives was also observed. Reaction of a mixture of indole and indole-5-carboxylic acid with 2-phenylethanethiol proceeded in a regioselective way, affording 3-[2-(2-aminophenyl)-1-(phenethylthio)ethyl]-1H-indole-5-carboxylic acid. An additional product of this reaction was 3-[2-(2-aminophenyl)-1-(phenethylthio)ethyl]-2,3-dihydro-1H,1'H-2,3'-biindole-5'-carboxylic acid, which upon standing in DMSO-d6 solution gave 3-[2-(2-aminophenyl)-1-(phenethylthio)ethyl]-1H,1'H-2,3'-biindole-5'-carboxylic acid. Structures of all compounds were elucidated by NMR, and a mechanism for their formation was suggested.     

Synthesis,Structure, and Electrochemical Characteristics of 4-Aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic Acid Nitriles

We have obtained 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles by S-alkylation of the corresponding 2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxylic acid nitrile by iodoacetamide or one-pot multicomponent synthesis methods: condensation of 2-arylidene-acetoacetic acid ethyl ester, 2-cyanothioacetamide, piperidine, and iodoacetamide; acetoacetic acid ethyl ester, 3-aryl-2-cyanothioacrylamide, piperidine, and iodoacetamide; acetoacetic acid ethyl ester, an aromatic aldehyde, 2-cyanothioacetamide, piperidine, and iodoacetamide. We have carried out a comparative analysis of the capability of 2-alkylthio-4-aryl-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles for electrochemical oxidation as a function of the electronic properties of the aryl substituent in the 4 position of the heterocycle and the 2-alkylthio substituent. X-ray diffraction data indicate the existence of a hydrogen bond between the C=O of the 2-carbamoylmethylthio substituent and the NH of the hydrogenated heterocycle, which explains the more facile oxidation of the studied compounds compared with 2-methylthio-substituted 1,4-dihydropyridines.Dedicated to Academician V. Minkin to show our appreciation for his contribution to organic chemistry and his wonderful humanity, remembering his collaboration with his colleagues from Riga.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 416–428, March, 2005.     

Synthesis of novel imidazo[1,2-a][3,1]benzothiazines 4, imidazo[1,2-a]-[1,2,4]benzotriazines 5, and 4H-imidazo[2,3-c]pyrido[2,3-e][1,4]oxazines 6

Starting from the readily available 2-aminobenzhydrols ( 7 ), 3-amino-1,2,4-benzotriazine ( 11 ) and 2-amino-3-pyridinol ( 12 ), novel derivatives of 5-phenyl-5H-imidazo[1,2-a][3,1]benzothiazine-2-carboxylic acid, ethyl ester ( 4 ), imidazo[2,1-c][1,2,4]benzotriazine-2-carboxylic acid, ethyl ester ( 5 ) and 4H-imidazo[2,3-c]pyrido-[2,3-e][1,4]oxazine ( 6 ) were prepared.     

Synthesis and reactions of 8-benzylidene-2-methyl-5,6,7,8-tetrahydroquinoline-3-carboxylic acid arylamides

Arylamides of 8-benzylidene-2-methyl-5,6,7,8-tetrahydroquinoline-3-carboxylic acid were obtained by treating the ethyl ester with dimagnesylamines. An example is given of their conversion to 8-benzylidene-2-styryl-5,6,7,8-tetrahydroquinoline-3-carboxylic acid anilides and subsequent cyclization to 1-oxo-1,2,3,4,6,7,8,9-octa-hydrobenzo[b]-1,6-naphthyridines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 506–508. April, 1986.     

Synthesis of a spirocyclic indoline lactone

Base-promoted cyclization of tert-butyl [2-(benzylideneamino)phenyl]acetate (13a) and subsequent C3-alkylation with allyl bromide affords 3-allyl-2-phenyl-2,3-dihydro-1H-indole-3-carboxylic acid, tert-butyl ester (15b) in high yield as a single diastereomer. This result is contrary to prior publications that describe failed cyclization of an analogous ethyl ester (ethyl [2-(4-methoxybenzylideneamino)phenyl]acetate) under strongly basic conditions. N-Acylation, olefin dihydroxylation, and tert-butyl ester cleavage affords the spirocyclic lactone 18 as a pair of diastereomers. Isolation and characterization of individual diastereomers 18a and 18b are described.     

Isolation and identification of a major impurity in a new bulk drug candidate by preparative LC, ESI-MS(n), LC-MS-MS, and NMR

A simple preparative liquid chromatography (LC) method is developed to isolate a major impurity in a new bulk drug candidate, 6-bromo-4-(carbamidinemethyl)-5-hydroxy-1-methyl-2-(phenylthiomethyl)-1H-indole-3-carboxylic acid ethyl ester hydrochloride monohydrate (carmidole). The carmidole solution for preparation is exposed to daylight before isolation. Based on the electrospray ionization (ESI)-mass spectroscopy (MS(n)) spectral data of the impurity fraction and carmidole, the impurity is preliminarily characterized as 6-bromo-4-(carbamidinemethyl)-5-hydroxy-1-methyl-2-methyl-1H-indole-3-carboxylic acid ethyl ester. LC-MS-MS is used to analyze a carmidole sample. The impurity, lyophilate, is obtained from the fraction of preparative LC, and the impurity standard is synthesized. By comparison of the retention times of high-performance liquid chromatography, ESI-MS(n), and (1)H-nuclear magnetic resonance of the impurity lyophilate with impurity standard and carmidole itself, the structure of the impurity is confirmed and its formation is discussed.     

4-hydroxy-2-quinolones. 96. Synthesis and properties of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid

Alkaline hydrolysis of the ethyl ester of 4-(cyanoethoxycarbonylmethyl)-2-oxo-1,2-dihydroquinoline-3-carboxylic acid is accompanied by decarboxylation with loss of two molecules of CO₂ and leads to 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 887–893, June, 2006.     

Microbial enantioselective ester hydrolysis for the preparation of optically active 4,1-benzoxazepine-3-acetic acid derivatives as squalene synthase inhibitors

Microbial enantioselective ester hydrolysis for the preparation of optically active (3R,5S)-(-)-5-phenyl-4,1-benzoxazepine-3-acetic acid derivatives as potent squalene synthase inhibitors was investigated. Pseudomonas diminuta and Pseudomonas taetrolens hydrolyzed the racemic ethyl ester of the 5-(2-chlorophenyl) analogue to yield the (-)-carboxylic acid with excellent enantiomeric excess (>99% ee). We found that the (-)-enantiomer was an active inhibitor. Bulkiness of the ester moiety did not affect the enantioselectivity but did affect reactivity. The racemic ethyl ester of the 5-(2-methoxyphenyl) analogue, 5-(2,3-dimethoxyphenyl) analogue and 5-(2,4-dimethoxyphenyl) analogue were also hydrolyzed with Pseudomonas taetrolens to afford enantiomerically pure (-)-carboxylic acids in large scale. As another route to (3R,5S)-(-)-7-chloro-5-(2,3-dimethoxyphenyl)-1-neopentyl-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-acetic acid [(-)-1c], the earlier intermediate (-)-2-amino-5-chloro-alpha-(2,3-dimethoxyphenyl)benzyl alcohol [(-)-12] was successfully obtained by asymmetric hydrolysis of (+/-)-5-chloro-alpha-(2,3-dimethoxyphenyl)-2-pivaloylaminobenzyl acetate with Pseudomonas sp. S-13 with >99% ee in kilogram scale followed by alkaline treatment. The product (-)-12 was converted to (-)-1c without racemization.