4-Hydroxy-2-quinolones 141. Synthesis and structure of 5R-3-hydroxy-1,5-dihydropyrazolo[4,3-<Emphasis Type="Italic">c</Emphasis>]quinolin-4-ones

Treatment of 1R-4-chloro-3-ethoxycarbonyl-2-oxo-1,2-dihydroquinolines with p-toluenesulfonylhydrazide in refluxing ethanol and in the presence of triethylamine gives the 3-hydroxy-5R-1,5-dihydropyrazolo[4,3-c]quinolin-4-ones. The possible mechanism of formation, features of the steric structure of the synthesized compounds, and their NMR and mass spectra are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 233–238, February, 2008.     

4-Hydroxy-2-quinolones. 92. Reaction of 1-R-4-chloro-3-ethoxycarbonyl-2-oxo-1,2-dihydroquinolines with anilines

A preparative method is proposed and the synthesis of 4-arylamino-2-oxo-1,2-dihydroquinolines has been effected. An X-ray structural investigation of 4-(4-chlorophenylamino)-2-oxo-1-propyl-1,2-dihydroquinoline-3-carboxylic acid has been carried out enabling the ease of decarboxylating such compounds to be substantiated. Results are given of a study of the anti-inflammatory activity of the synthesized compounds. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 386–395, March, 2006.     

4-hydroxy-2-quinolones. 109. Alkylation of 4-substituted ethyl 2-oxo-1,2-dihydro-quinoline-3-carboxylates

The alkylation of the ethyl esters of 4-methyl, 4-chloro-, and 4-amino substituted 2-oxo-1,2-dihydroquinoline-3-carboxylic acid by ethyl iodide in the system DMF/K₂CO₃ has been studied. Features of the structure of the starting compounds and their effect on the ratio of the N-and O-alkyl products formed are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1502–1507, October, 2006.     

4-Hydroxy-2-quinolones 127. Simple method for exchanging chlorine for hydroxyl in 1-R-4-chloro-3-ethoxycarbonyl-2-oxo-1,2-dihydroquinolines

Treatment of ethyl 1-R-4-chloro-2-oxo-1,2-dihydroquinoline-3-carboxylates with sodium nitrite in DMSO is a convenient method for their conversion to the corresponding 4-hydroxy derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1359–1364, September, 2007.     

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 145. <Emphasis Type="Italic">p</Emphasis>-Toluenesulfonylhydrazide as a tosylating agent

The reaction of ethyl 4-chloro-1-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylate with p-toluene-sulfonylhydrazide in anhydrous solvents in the presence of triethylamine results in the tosylation of position 4 of the quinolone. Features of the steric structure of the tosyl-substituted compound are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 847–852, June, 2008.     

4-Hydroxy-2-quinolones 120. Synthesis and structure of ethyl 2-hydroxy-4-oxo-4H-pyrido-[1,2-a]pyrimidine-3-carboxylate

An improved method for the preparation and purification of ethyl 2-hydroxy-4-oxo-4H-pyrido[1,2-a]-pyrimidine-3-carboxylates is proposed. According to ¹H and ¹³C NMR spectroscopic data the synthesized compounds exist in DMSO solution in the 2-hydroxy-4-oxo form while in the crystal (at least for the case of the unsubstituted derivative) X-ray analysis shows that it occurs in the bipolar 2,4-dioxo form. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 864–876, June, 2007.     

4-Hydroxy-2-quinolones. 152*. 3-acetyl-4-hydroxy-2-oxo-1,2-dihydroquinoline and its biologically active derivatives

A synthesis and study of the spatial structure of 3-acetyl-4-hydroxy-2-oxo-1,2-dihydroquinoline have been carried. 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids [1-(4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)ethylidene]hydrazides were prepared from this compound by two routes. A comparative analysis of the antitubercular properties of the synthesized compounds and of the closely structurally related N,N′-di(1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carbonyl)hydrazines has been performed. *For Communication 151 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 214–222, February, 2009.     

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 131. Bromination of 3-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline

The bromination of 3-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline by molecular bromine is accompanied by the closure of a five membered furan ring and gives the corresponding 2-bromomethyl-3,9-dihydro-2H-furo[2,3-b]quinolin-4-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1677–1686, November, 2007.     

4-Hydroxy-2-quinolones 140. Synthesis and diuretic activity of arylalkylamides of 4-methyl-2-oxo-1,2-dihydro-quinoline-3-carboxylic acid

The interaction of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid with thionyl chloride in oxygen-containing solvents leads to the formation of a significant amount of colored side products, consequently it was proposed the reaction be carried out in carbon tetrachloride. The synthesis of a series of amides was effected by the amidation of the obtained acid chloride with appropriate primary arylalkylamines. Results are presented of a study of the effect of the synthesized compounds on the urine-excreting function of the kidney. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 78–87, January, 2008.     

4-Hydroxy-2-quinolinones 128. Bromination of N-allyl-4-hydroxy-2-oxo-1,2-dihydroquinolines and pyridines unsubstituted in position 3

Bromination of N-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline and N-allyl-5-ethoxycarbonyl-4-hydroxy-6-methyl-2-oxo-1,2-dihydropyridine is accompanied not only by closing of a five membered oxazole ring but also by a second bromination of the 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-a]-derivatives formed at position 4. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1365–1373, September, 2007.     

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 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 142. 4-Methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides as potential diuretics

A large series of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides has been prepared as potential diuretic agents. The effect of all of the synthesized compounds on the urinary function of the kidney has been investigated. The appearance of a “structure — diuretic activity” relationship is discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–245, February, 2008.     

4-Hydroxy-2-quinolones 139. Synthesis,structure, and antiviral activity of N-R-amides of 2-hydroxy-4-oxo-4H-pyrido[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine-3-carboxylic acids

Dialkylaminoalkylamides of 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acids have been obtained as potential antiviral agents. The special features of the spatial structure of one example of the synthesized compounds have been studied. Results are given of the investigation of cytotoxicity and antiviral activity in relation to type 1 herpes virus and coronavirus. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–77, January, 2008.     

4-Hydroxy-2-quinolones 143. Synthesis,structure, and spectroscopic characteristics of ethyl 2-hydroxy-4-oxo-4H-pyrazino[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine-3-carboxylate

Condensation of aminopyrazine with triethyl methanetricarboxylate gave ethyl 2-hydroxy-4-oxo-4H-pyrazino[1,2-a]pyrimidine-3-carboxylate. According to X-ray analytical data the compound exists in the 2-hydroxy-4-oxo form in the crystal. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 411–419, March, 2008.     

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 144. Alkyl-, arylalkyl-, and arylamides of 2-hydroxy-4-oxo-4H-pyrido[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine-3-carboxylic acid and their diuretic properties

Alkyl-, arylalkyl-, and arylamides of 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acid were prepared with a view to establishing a structure-biological activity relationship. A comparative analysis has been made of their diuretic properties and those of the structurally similar 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxamides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 718–729, May, 2008.     

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.