Synthesis and exchange reactions of 5-alkyl-2-oxo-6-thioxo-1,2,3,6-hexahydropyrimidine-4-carboxylic acids

An improved preparation of 2-oxo-6-thioxo-1,2,3,6-hexahydropyrimidine-4-carboxylic acid 3, a potent inhibitor of dihydroorotase is presented. Trans-5-alkyl-2-oxo-6-thioxohexahydropyrimidine-4-carboxylic acids 12a-c were synthesised via the thiation of the p-methoxybenzyl esters of 5-alkyldihydroorotic acids with Lawesson's reagent followed by subsequent de-protection. The corresponding cisisomers were prepared by reduction of 5-alkyl-6-thioxoorotic acids with zinc in acetic acid. The stability and exchange reactions of 12a-c under physiological conditions were investigated by ultra-violet and ¹H nmr spectroscopy. The attempted synthesis of 16 , a fused cyclopentyl derivative of 3 is also presented.     

Synthesis and interconversion of 6-aroyl-4-oxohexanoie acids and 5-aryl-2-furanpropionic acids. Antiinflammatory agents

A series of 6-aroyl-4-oxohexanoic acids ( 2 ) was prepared for intermediate use by acid-catalyzed solvolysis of substituted 3-(2-furyl)acrylophenones ( 1 ). This reaction occasionally gave 5-aryl-2-furanpropionic acids ( 3 ) instead of, or in addition to, the desired diketones ( 2 ). Equilibrium between 2 and 3 was observed in the case where Ar is m-nitrophenyl. A rationalization for the formation of 3 is offered, and published reports with which our results differ are discussed. Diketones ( 2 ) were cyclized to furans ( 3 ) and antiinflammatory screening data are reported for the latter.     

Synthesis of diethyl 6-aryl-2-oxo-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates

Reaction of diethyl oxalylacetate sodium salt with aromatic aldehydes and urea led to the formation of diethyl 6-aryl-2-oxo-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates.     

Synthesis and antimicrobial activity of 6-aryl-3,4-dimethyl-N-phenyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides

Three-component reaction of acetoacetanilide, aromatic aldehydes, and N-methylurea afforded 6-aryl-3,4-dimethyl-N-phenyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides. IR, ¹H NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis data confirmed the structure of the compounds obtained. Antimicrobial activity of these compounds was investigated.     

Synthesis of methyl esters of 6-dialkylamino-2-(carbethoxy)-methylthiopyrimidine-4-carboxylic acids

A preparative method is proposed for the synthesis of methylesters of 6-dialkylamino-2-(carbethoxy)methylthiopyrimidine-4-carboxylic acids form the butyl ester of orotic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 818–821, June, 1986.     

Improved preparation and structural investigation of 4-aryl-4-oxo-2-hydroxy-2-butenoic acids and methyl esters

A simple and efficient oxalylation of aryl methyl ketones was accomplished with dimethyl oxalate in the presence of sodium methoxide. The unpreviously reported sodium ketoenolate esters were isolated and gently hydrolyzed into the ketoenol esters in good yields. Alternatively the sodium ketoenolate esters hydrolysis could also be conducted to directly afford the ketoenol acids, which represent one of the most promising class of HIV-1 integrase inhibitors. Advantages over previously reported procedures were better yields and simplicity of the purification protocol.     

Synthesis of 2-substituted 7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids

2-Substituted 7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids were synthesized by reaction of acyl- and aroylpyruvic acids with 3-amino-5,5-dimethylcyclohex-2-en-1-one. A plausible mechanism of their formation was proposed on the basis of ab initio quantum-chemical calculations.     

Three-component synthesis of 6-aryl-4-methyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-(N-aryl)carboxamides

A three-component synthesis using acetoacetanilides and a mixture of an aromatic aldehyde and urea yields 6-aryl-4-methyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-(N-aryl)carboxamides.     

Synthesis of 1-aryl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acids and esters

Ethyl 1-aryl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylates 2 were prepared by the condensation of arylhydrazines with ethyl 3-ethoxy-2-(trifluoroacetyl)-2-propenoate (1a) at low temperature. The corresponding acids were also synthesized. X-ray diffraction analysis of an amide derivative 4 verified the position of the trifluoromethyl group on the pyrazole ring.     

Synthesis of cis-5-aryl-4-aroyl-1,3-dioxolanes

The reaction of trans-3-aryl-2-aroyloxiranes containing electron-acceptor substituents in the aryl group with acetone under acid-catalysis conditions gives the corresponding cis-1,3-dioxolanes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1315–1317, October, 1984.     

Synthesis and characterization of Boc-protected 4-amino- and 5-amino-pyrrole-2-carboxylic acid methyl esters

Syntheses of Boc-protected 4-amino- and 5-amino-pyrrole-2-carboxylic acid methyl esters have been achieved and the structures of these compounds have been fully characterized by detailed NMR studies.     

Synthesis of 6-aryl- and 5-aroylcomanic acids from 5-aroyl-2-carbethoxy-4-pyrones via a deformylative rearrangement and ring-opening/ring-closure sequence

The reaction of 1-aryl-2-(dimethylaminomethylene)butane-1,3-diones with diethyl oxalate in the presence of sodium hydride in THF gave ethyl 5-aroyl-4-oxo-4H-pyran-2-carboxylates, from which 4-oxo-6-aryl-4H-pyran-2-carboxylic acids (6-arylcomanic acids) were obtained in high yields via acid-catalyzed deformylative rearrangement. 5-Aroyl-4-oxo-4H-pyran-2-carboxylic acids (5-aroylcomanic acids) were prepared via а ring-opening/ring-closure sequence by the reaction of 5-aroyl-2-carbethoxy-4-pyrones with piperidine and subsequent basic hydrolysis and acidification.     

2-aryl-5-arylsulfanyl-1,3-oxazole-4-carboxylic acids and their derivatives

A convenient preparative procedure has been developed for the synthesis of previously unknown 2-aryl-5-arylsulfanyl-1,3-oxazole-4-carboxylic acids and their functional derivatives from accessible multicenter substrates of the general formula Cl₂C=C(NHCOR)C(O)OMe. The products turned out to be suitable for various subsequent transformations. Some oxazole-4-carboxylic acid hydrazide derivatives containing a substituted oxazol-5-yl fragment at the N² atom in the hydrazine moiety underwent recyclization on heating in acetic acid; as a result, one oxazole ring was converted into 1,3,4-oxadiazole.     

Synthesis of 1-Aminocarbonylmethyl-5-aryl-4-aroyl-3-hydroxy-3-pyrroline-2-ones

Russian Journal of General Chemistry - A series of new 1-aminocarbonylmethyl-5-aryl-4-aroyl-3-hydroxy-3-pyrrolin-2-ones has been synthesized through a three-component reaction of aroylpyruvic acid...     

Synthesis of methyl esters of 5-amino-4-(substituted amino)-2-methylthio-7H-pyrrolo[2,3d]-pyrimidine-6-carboxylic acids

The optimum route for the synthesis of methyl esters of N-[(4-substituted amino)-5-cyano-2-methylthiopyrimidin-6-yl]amino acids (which are starting materials for preparing the methyl esters of the corresponding 5-amino-4-(substituted amino)pyrrolo[2,3-d]pyrimidine-6-carboxylic acids) is via subsequent reactions of 4,6-dichloro-2-methylthiopyrimidine-5-carbonitrile with amines and methyl glycinate. In some examples, the reaction of methyl N-(4-chloro-2-methylthio-6-pyrimidinyl)aminoacetate with amines occurs to give the corresponding acid amides. The previously unknown synthesized derivatives of pyrimidin-6-yl amino acids and 4,5-diaminopyrrolo[2,3-d]pyrimidine- 6-carboxylic acids possess fungicidal properties.Vilnius University, Vilnius 2006, Lithuania. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No 7, pp. 955–961, July, 2000.     

Synthesis of some schiff bases of 3-aroyl-6-aryl-4-hydroxy-2H-pyran-2-ones

Summary The reaction of 3-aroyl-6-aryl-4-hydroxy-2H-pyran-2-ones (Ar=p-tolyl, 1,1-biphenyl-4-yl or thienyl) with aniline and substitutedo-phenylenediamine (R=H, CH₃ or Cl) yields a series of new Schiff bases2a–f in 51–72% yield. Bromination of1a gave the 5-bromo derivative1c, while the compounds1a,1b,2b,2e, and2f were converted into 2,6-diaryl-4H-pyran-4-ones3a–c. All products have been fully characterized.

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Synthese von Schiff'schen Basen von 3-Aroyl-6-aryl-4-hydroxy-2H-pyran-2-onen

Zusammenfassung Die Reaktion von 3-Aroyl-6-aryl-4-hydroxy-2H-pyran-2-onen (Ar=p-Tolyl, 1,1-Biphenyl-4-yl oder Thienyl) mit Anilin und substituierteno-Phenylendiaminen liefert neue Schiff'sche Basen2a–f/bd in 51–72% Ausbeute. Bromierung von1a gab das 5-Bromderivate1c, während die Verbindungen1a,1b,2b,2e und2f in 2,6-Diaryl-4H-pyran-4-onen3a–c übergeführt wurden. Alle Produkte wurden voll charakterisiert.

     

Synthesis of 5-aryl-2-alkoxyfuranes from 1-aroyl-2,2-dichlorocyclopropanes

The reaction of 1-aroyl-2,2-dichlorocyclopropanes with a mixture of potassium tertbutylate and potassium methylate (or ethylate) in tert-butyl alcohol gives 5-aryl-2-methoxy (or ethoxy) furanes in good yield.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1603–1605, December, 1984.     

Reaction of methyl esters of substituted 2-oxochromene-3-carboxylic acids with zinc enolates formed from 1-aryl-2-bromoalkanones

Zinc enolates formed from 1-aryl-2-bromoalkanones react with methyl esters of substituted 2-oxochromene-3-carboxylic acids to give methyl esters of 6-bromo- or 6,8-dibromo-4-(2-aryl-2-oxo-1-R- ethyl)-2-oxochromane-3-carboxylic acids as mixtures of two diastereomers.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1520–1523.Original Russian Text Copyright © 2004 by Shchepin, Korzun, Shurov, Vakhrin, Russkikh.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and thermal decomposition of 3-aroyl-4-aryl-2-pyrazolines

Summary 3-Aroyl-4-aryl-2-pyrazolines (21–40) have been synthesized by the reaction of ,-unsaturated ketones (1–20) with diazomethane. These 2-pyrazolines gave -methyl-,-unsaturated ketones (41–46) on thermal denitrogenation.Dedicated to Prof. Dr.F. Sauter on the occasion of his 65^th birthday     

Synthesis,stereochemistry, and isomeric transformations of 4-aryl-5-aroyl-2-methylthio-2-imidazolines

The corresponding 4-aryl-5-aroyl-2-methylthio-2-imidazolines were obtained by the reaction of complexes of cis- and trans-3-aroylaziridines and boron trifluoride with methyl thiocyanate. It is shown on the basis of spectral data that the aziridine ring is opened regiospecifically at the C(₂) atom and stereospecifically with inversion of the configuration.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1484–1488, November, 1988.