Reaction of 3,3-dialkyl-6-trifluoromethyl-2,3-dihydro-4-pyrones with hydrazine hydrate

3,3-Dialkyl-2,3-dihydro-6-trifluoromethyl-4-pyrones react with hydrazine hydrate to give 2-hydrazino-2-trifluoromethyl-4-tetrahydropyrone hydrazones. When heated, the latter are transformed into 3(5)-(2-hydroxyethyl)-5(3)-trifluoromethylpyrazoles, while their treatment with HCl in ether leads to 3,3-dialkyl-2,3-dihydro-6-trifluoromethyl-4-pyrone azines.     

A rapid and diverse construction of 6-substituted-5,6-dihydro-4-hydroxy-2-pyrones through double Reformatsky reaction

A rapid and diverse synthesis of biologically important 6-substituted-5,6-dihydro-4-hydroxy-2-pyrones through a double Reformatsky reaction of aldehydes to δ-hydroxy-β-ketoesters followed by lactonization is described. Due to the high functional group tolerance and reaction site discrimination between aldehyde, nitrile, and ester groups in the substrate, the protocol can provide the dihydropyrones with bromo, nitro, carboxylic acid, and β-ketoester groups, which are suitable for the further derivatizations. Furthermore, the protocol has been successfully applied to the rapid total synthesis of naturally occurring Yangonin.     

Synthesis and stereochemistry of 3-hydroxy-6-perfluoroalkyl-2, 3-dihydro-4-pyrones

The reaction of a number of aliphatic and alicyclic acetloxiranes with perfluoroalkanoic acid esters was studied. It is shown that substituted 3-hydroxy-6-perfluoroalkyl-2,3-dihydro-4-pyrones are formed. The reverse reaction scheme, including the formation of an intermediate -diketone and cyclization of its enol form to a dihydropyrone, was confirmed in the case of the condensation of 3-methyl-2,3-epoxycyclohexanone with ethyl trifluoroacetate. The stereochemistry of the reaction products, which exist in a half-chair confirmation with a pseudoequatorial hydroxyl group, was examined by means of PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 897–900, July, 1978.     

Synthesis of isomerically pure 3-(5-trifluoromethyl-1,2,3-triazol-4-yl)cinnamic acid derivatives via the reaction of 4-aryl-6-trifluoromethyl-2-pyrones with sodium azide

Treatment of 4-aryl-6-trifluoromethyl-2-pyrones with sodium azide in DMSO afforded the corresponding (Z)-3-(5-trifluoromethyl-1,2,3-triazol-4-yl)cinnamic acids in good yields. Similarly, 4-aryl-3-carbethoxy-6-trifluoromethyl-2-pyrones smoothly reacted with sodium azide in acetonitrile to produce (E)-2-ethoxycarbonyl-3-(5-trifluoromethyl-1,2,3-triazol-4-yl)cinnamic acids in high yields, whereas their reactions in ethanol, accompanied by a configurational change, gave the thermodynamically more stable (Z)-2-ethoxycarbonyl-3-(5-trifluoromethyl-1,2,3-triazol-4-yl)cinnamic acids.     

Reactions of regioisomeric 3,3-dimethyl- and 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyrones with N-nucleophiles

Reactions of 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyrone with ethylenediamine, hydrazine, or hydroxylamine yield 5-methyl-7-trifluoromethyl-2,3-dihydro-1H-1,4-diazepine, 3(5)-(2-hydroxy-2-methylpropyl)-5(3)-trifluoromethylpyrazole, and 5-hydroxy-3-(2-hydroxy-2-methylpropyl)-5-triflouromethyl-Δ², respectively. The same compounds were obtained from 2-amino-1,1,1-trifluoro-6-hydroxy-6-methylhept-2(Z)-en-4-one and 2-hydroxy-6, 6-dimethyl-2-trifluoromethyltetrahydro-4-pyrone.     

Interaction of 2-aryl-6-hydroxy-5,6-tetra-methyl-enepiperidine-3,3,4,4-tetracarbonitriles and 2-aryl-5,6-tetramethylene-3,3,4-tricyano-2,3,4,5-tetrahydropyridine-4-carboxamides with ammonia

The interaction of 2-aryl-6-hydroxy-5,6-tetramethylenepiperidine-3,3,4,4-tetracarbonitriles and 2-aryl-5,6-tetramethylene-3,3,4-tricyano-2,3,4,5-tetrahydropyridine-4-carboxamides with ammonia results in the formation of 5-aryl-1,7-tetramethylene-3-imino-4,8-dicyano-2,6-diazabicyclo[2.2.2]octane-8-carboxamides. In solvents, these latter compounds are converted to 3-amino-6-oxo-1,8-tetramethylene-2,7-diazabicyclo-[3.2.1]octa-3-ene-4,5-dicarbonitrile and 2-amino-3-cyano-5,6-tetramethylenepyridine-4-carboxamide. I. N. Ul'yanov Chubash State University, Cheboksary 428015. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 533–541, April, 1997.     

Synthesis of 2,4-disubstituted N-acyl-5,6-dihydro-2-pyridones

A simple two-step procedure converts 2-substituted N-acyl-2,3-dihydro-4-pyridones to 2,4-disubstituted N-acyl-5,6-dihydro-2-pyridones.     

Synthesis and fungicidal activity of new 4-hydroxy-6-trifluoromethyl-2-phenylindoles

Starting from 1,3-dinitro-5-trifluoromethylbenzene, a pioneering synthesis and dimethylaminomethylation of new 2-aryl- 4-hydroxy-6-trifluoromethylindoles have been performed. The study of fungicidal activity has revealed the effect of dimethylaminomethyl group position on fungitoxic properties.     

Synthesis of 6-arylazo-substituted 5-hydroxy-2-hydroxymethyl-4-pyridones and related compounds

5-Hydroxy-2-hydroxymethyl-4-pyridone ( 1 ) and 5-hydroxy-2-hydroxymethyl-1-methyl-4-pyridone ( 2 ) reacted with arenediazonium salts to give 6-arylazo-substituted compounds 3a-d and 4a-d , respectively. Compounds 3a-d were methylated with diazomethane to afford 6-arylazo-2-hydroxymethyl-4,5-dimethoxypyridines 5a-d .     

Reaction of 1-chloroalkylheterocumulenes with diphenylguanidine. Synthesis and IR spectra of 2-aryl-2-trifluoromethyl-4-oxo-6-imino- and 2-aryl-2-trifluoromethyl-4,6-diiminoperhydro-1,3,5-triazines

1-Chloro-1-aryl-2,2,2-trifluoroethylheterocumulenes (isocyanates and carbodiimides) undergo regioselective cyclization with diphenylguanidine to give 2-aryl-2-trifluoromethyl-4-oxo-6-imino- and 2-aryl-2-trifluoromethyl-4,6-diiminoperhydro-1,3,5-triazines. An IR study of the 4-oxo-1,3,5-triazine derivatives showed a tendency for the formation of intermolecular aggregates or intramolecular hydrogen bonding, while a similar study of the 4-imino-1,3,5-triazine derivatives revealed that these compounds tend to undergo prototropic isomerization in the moiety.Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 252660 Kiev, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 706–710, May, 1997.     

5，6－二取代－3，4－二氢－2－吡啶酮的N－烷基化反应

由四个５，６－二取代－３，４－二氢－２－吡啶酮经烷基化反应合成了九个未见文献报道的Ｎ－取代５，６－二取代－３，４－二氢－２－吡啶酮，并确定了它们的结构。     

Synthesis of 3, 4, 6-triaryl-2-pyrones

A preparative method was worked out for the synthesis of 3,4,6-triaryl-2-pyrones by 1,3-dipolar cycloaddition of selenium arylacylmethylides to diphenylcyclopropenone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1478, November, 1977.     

Synthesis of N-substituted 3-hydroxy-2-methyl-4-pyridones and -pyridonimines

Carbohydrates with 1,4 glycosidic bonds like maltose, lactose, dextrin or starch react with primary amines as well as amino acids or proteins to give i.e. 3-hydroxy-2-methyl-4-pyridones 5 and 3-hydroxy-2-methyl-4-pyridonimines 7. A generally applicable synthesis of compounds of this type is described. The pyridones 5 and pyridonimines 7 are strongly complexing agents. Molybdenum-derivatives, for instance, are suitable as fairly stable oxidation catalysts.     

Synthesis of 2-aryl-4-hydroxy-5-thio substituted 1,3-thiazin-6-ones via sulfenylation of 2-aryl-4-hydroxy-[1,3]thiazin-6-ones with sulfenyl chlorides

A series of 2-aryl-4-hydroxy-5-thio substituted 1,3-thiazin-6-ones were synthesized for human immunodeficiency virus-1 protease inhibition. These compounds were synthesized by the treatment of 4-hydroxy-5-thio substituted-1,3-thiazin-6-ones with the corresponding sulfenyl chlorides. The products were obtained in good isolated yields, inspite of the presence of bulkyl substitutents at the ortho position of phenyl sulfenyl chloride portion.