4-Hydroxy-2-quinolones 132. Synthesis, chemical, and biological properties of 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids 2-nitrobenzylidenehydrazides

1-R-4-Hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids 2-nitrobenzylidenehydrazides are reduced to the corresponding quinoline-3-carboxamides by zinc in glacial acetic acid but in refluxing triethylphosphite they are converted to the symmetrical N,N′-di(4-hydroxy-2-oxo-1,2-dihydro-3-quinolinoyl)hydrazines. A study of the antitubercular activity of the synthetic compounds has been carried out. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1687–1692, November, 2007.     

4-hydroxy-2-quinolones. 202*. Synthesis, chemical and biological properties of 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkylamides

In continuation of the search for potential analgesics amongst 4-hydroxyquinol-2-one derivatives we have proposed and carried out a preparative method of synthesis of 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkylamides. It has been shown that bromination of 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid allylamide using an equivalent of molecular bromine occurs with a conventional addition of the halogen to the allyl double bond and not with halocyclization. The results of the study of the analgesic properties of the compounds prepared are presented.     

4-Hydroxy-2-quinolones. 168*. Synthesis,chemical and antitubercular properties of 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid pyrazin-2-ylamides

1-R-4-Hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid pyrazin-2-ylamides have been synthesized as potential antitubercular agents. In contrast to pyrimidin-2-ylamides the compounds prepared are brominated by molecular bromine in glacial acetic acid at position 6 of the quinolone ring rather than in the amide part of the molecule. The 1-N-allyl derivative behaves similarly but undergoes halocyclization to give 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-a]quinoline-4-carboxylic acid pyrazin-2-ylamide. A comparative analysis of the antimycobacterial properties of the synthesized compounds and their isomeric pyrimidin-2-ylamides has been carried out.     

4-hydroxy-2-quinolones. 153*. Synthesis of hetarylamides of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid

4-Methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid hetarylamides can be prepared by two fundamentally different routes with allowance made for the thermal stability of the starting hetarylamines. * For Communication 152 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 426–432, March, 2009.     

4-hydroxy-2-quinolones. 191.* synthesis,tautomerism and biological activity of benzimidazol-2-ylamides of 1-r-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids

A series of benzimidazol-2-ylamides of 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids was prepared in a search for biologically active compounds. These compounds exist in the crystal exclusively in the amide form, while in solution amide↔imide tautomerism is observed. The results of a study of the antithyroid and antituberculosis activities of these compounds are given.     

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.     

4-Hydroxy-2-quinolones 150*. Efficient synthesis,structure, and biological activities of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkyl amides

A simple and efficient method for preparing 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkyl amides is proposed. The results of a study of the diuretic activity of the compounds synthesized are reported. *For communication 149 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1841-1848, December, 2008.     

4-hydroxy-2-quinolones. 110. Bromination of 1-r-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides

1-R-4-Hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides have been prepared. It has been shown experimentally that these compounds are brominated by molecular bromine in glacial acetic acid at position 4 of the anilide fragment. The antitubercular properties of the compounds synthesized are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1508–1516, October, 2006.     

4-Hydroxy-2-quinolones. 154*. Pyrimidin- 2-ylamides of 1-r-4-hydroxy-2-oxo-1,2-dihydro- quinoline-3-carboxylic acids. synthesis,structure, and properties

The synthesis of a series of 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids pyrimidin-2-ylamides has been carried out with the aim of subsequent microbiological investigation. In acetic acid it was found that these compounds are brominated by 1 equivalent of bromine at position 5 of the pyrimidine ring. The only exception is the 1-allyl derivative which undergoes heterocyclization under these conditions to give 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-a]quinoline-4-carboxylic acid pyrimidin-2-ylamide. The results of a study of the antitubercular activity of the synthesized compounds are presented.     

4-Hydroxy-2-quinolones. 111. Simple synthesis of 1-substituted 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acids

A preparative method of obtaining 1-substituted 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acids is proposed. Features of their spatial structure have been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 69–74, January, 2007.     

4-Hydroxy-2-quinolones 171*. Synthesis,isomerism, and antitubercular activity of 1-R-4-hydroxy-2-oxo-1,2-dihydro-quinoline-3-carboxylic acid alkylidenehydrazides

Alkylidenehydrazides have been synthesized by the reaction of 1-R-4-hydroxy-2-oxo-1,2-dihydro-quinoline-3-carboxylic acid hydrazides with lower dialkyl ketones in order to reveal a structure-antitubercular activity relationship. It was shown by ¹H NMR spectroscopy that hydrazones obtained from the unsymmetrical ketone – methyl ethyl ketone – exist primarily in the E-isomer form. It was found that the presence of two aliphatic substituents in the alkylidene fragment of the compounds investigated leads to a marked lowering of antimicobacterial properties.     

4-Hydroxy-2-quinolones. 97. Simple synthesis of the esters of 4-halo-substituted 2-oxo-1,2-dihydroquinoline-3-carboxylic acids

Short term treatment of 3-ethoxycarbonyl-4-morpholino-2-oxo-1,2-dihydroquinoline with aqueous solutions of hydrohalogen acids leads to the formation of the ethyl esters of 4-halo-substituted 2-oxo-1,2-dihydroquinoline-3-carboxylic acids. Hydrolysis in HF is possible on extended boiling only to the 4-hydroxy derivative. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1022–1025, July, 2006.     

4-Hydroxy-2-quinolones. 180*. Synthesis,chemical reactions,and analgesic activity of 1-allyl-4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkylamides

A targeted synthesis was carried out of a series of 1-allyl-4-hydroxy-6,7-dimethoxy-2-oxo-1,2-di-hydroquinoline-3-carboxylic acid alkylamides which show interest for biological study as potential analgesics. It was found that, in the presence of one equivalent of bromine, the compounds indicated undergo halocyclization to the corresponding 2-bromomethyl-7,8-dimethoxy-5-oxo-1,2-dihydro-5H-oxa-zolo[3,2-a]quinoline-4-carboxylic acid alkylamides. However, with an excess of bromine the reaction occurs somewhat differently and concludes with the formation of complexes of bromine with 4-alkyl-carbamoyl-2-bromomethyl-5-hydroxy-7,8-dimethoxy-1,2-dihydrooxazolo[3,2-a]quinolinium ditri- bromides. According to the results of pharmacological screening there are found compounds within the substances discovered with high analgesic activity.     

4-hydroxy-2-quinolones. 43. Thermolysis of ethyl esters of 1-R-2-oxo-4-hydroxy-quinoline-3-carboxylic acids

Ethyl esters of 1-R-2-oxo-4-hydroxyquinoline-3-carboxylic acids under thermolysis conditions are converted to 5,9-di-R-6,7,8-trioxodiquinolino[3,4-b;3,4-e]-4H-pyrans. One of the synthesized compounds was studied by X-ray diffraction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 516–522, April, 2000.     

4-Hydroxy-2-quinolones. 3. Synthesis and physicochemical properties of 1-R-3-carbethoxy-4-hydroxy-2-quinolones

1-R-3-Carbethoxy-4-hydroxy-2-quinolones were synthesized by intramolecular cyclization of N-R-2-carbalkoxymalonanilic acids by the Dieckmann reaction. The possibility and advantages of conducting this reaction in aqueous medium were demonstrated. The mutually perpendicular orientation of the heterocyclic and aryl fragments was demonstrated for the 1-phenyl derivative by ESR spectroscopy.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 636–639, May, 1992.     

4-Hydroxy-2-quinolones 130. The reactivity of ethyl 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylates

The high reactivity of ethyl 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylates is governed by the simultaneous presence of the 4-OH and 2-C=O groups in the pyridine part of the molecule. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1503–1508, October, 2007.