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.     

Reaction of thiazolidinethiones with hydrazine hydrate

Thiazolidinethiones react with hydrazine hydrate to give bicyclic compounds with a bridge sulfur atom. The bicyclic structure of the reaction products is confirmed by data from¹H NMR and IR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 171–172, January, 1998.     

Reaction of tetracyanocyclopropyl ketones with hydrazine hydrate

The reaction of 2,2,3,3-tetracyanocyclopropyl ketones with hydrazine involved the addition at the carbonyl and cyano groups and resulted in the formation of previously unknown polycyclic systems whose common feature was the presence in the structure of a pyridazine ring. In the general case 3-substituted 6-amino-8-oxo-4,5,7-tptriazatricyclo[4.3.0.0^2.9]-non-3-ene-1,9-dicarbonitriles were obtained. The reaction with 3-pivaloylcyclopropane-1,1,2,2-tetracarbonitrile took another route with the opening of the three-membered ring and the formation of 3-amino-7a-tert-butyl-6-oxo-5,6,7,7a-tetrahydro-4aH-pyrrolo[2,3-c]pyridazine-4,5-dicarbonitrile.     

New synthesis of 2-trifluoromethyl-2,3-dihydro-1H-quinolin-4-ones

N-(1-Ethoxy-2,2,2-trifluoroethyl)anilines 2a-2f, prepared from trifluoroacetaldehyde ethyl hemiacetal and aniline, readily reacted with diethyl malonate in the presence of sodium hydride, giving substituted products 5a-5f in high yields. Compounds 5a-5f subjected to hydrolysis and decarboxylation under specified conditions yielded the 4,4,4-trifluorobutyric acids 6a-6e or 7. Direct ring-closure of 6a-6e with polyphosphoric acid gave 2-trifluoromethyl-2,3-dihydro-1H-quinolin-4-ones 9a-9e.     

Synthesis of 6-hetaryl-5,5-dialkyl-3,3-dimethyl-tetrahydropyran-2,4-diones by Reformatsky Reaction

Zinc enolates derived from ethyl 4-bromo-2,2,4-trimethyl-3-oxopentanoate and 4-bromo-4- ethyl-2,2-dimethyl-3-oxohexanoate react with 2-furan-, 2-thiophene-, 1-(3-nitrophenyl)-2-pyrrole-, 1-acyl-3-indole-, and 2-pyridinecarbaldehydes to give the corresponding 6-hetaryl-5,5-dialkyl-3,3-dimethyltetrahydropyran-2,4-diones.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1549–1551.Original Russian Text Copyright © 2004 by Shchepin, Korzun, Sazhneva.     

Reaction of 5,5-dialkyl-2-halo-6-hydroxy-5,6-dihydro-1H-pyridine-3,4,4-tricarbonitriles with Morpholine

5,5-Dialkyl-2-halo-6-hydroxy-5,6-dihydro-1H-pyridine-3,4,4-tricarbonitriles reacted with morpholine in aprotic solvent to give the corresponding 3,3-dialkyl-4,5-dicyano-6-halo-2-morpholino-1,2,3,4-tetrahydropyridine-4-carboxamides, while analogous reaction in amphiprotic solvent resulted in the formation of 8,8-dialkyl-3-halo-6-oxo-2,7-diazabicyclo[3.2.1]oct-3-ene-4,5-dicarbonitriles.     

Reaction of 5,5-dialkyl-2-halo-6-hydroxy-5,6-dihydro-1H-pyridine-3,4,4-tricarbonitriles with alcohols

Russian Journal of Organic Chemistry -     

Synthesis of substituted bis(3,3-dialkyl-3,4-dihydro-1-isoquinolyl)methanes

Symmetrical and non-symmetrical substituted bis(3,4-dihydro-1-isoquinolyl)methanes were synthesized by fusion of substituted 1-methylthio-3,4-dihydroisoquinolines with 1-methyl-3,4-dihydroisoquinolines and by the Ritter reaction of 1,1-dialkyl-2-arylethanols with 1-cyanomethylidene-1,2,3,4-tetrahydroisoquinoline or malononitrile.     

Reaction of 2,3-dihydro-4-phenyl-1H-1,5-benzodiazepinethione-2 with acetylhydrazine

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, p. 1430, October, 1991.     

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.     

Dealkylation with hydrazine hydrate

Cleavage of one alkyl group occurs in the reaction of 4-amino-3,5-di(alkylthio)-1,2,4-triazoles with hydrazine hydrate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1708–1710, December, 1973.     

类Mannich反应合成2,5-二苯基-3,3-二取代-2,3-二氢-1,4,2-氧氮磷杂环戊烯-2-氧化物

本文报道了以苯甲酰胺,醛(或酮)苯基二氯化膦为原料进行的Mannich反应,其产物经部分水解合成了α-(N-苯甲酰氨基)二取代甲基苯基膦酸(Ⅰ),此化合物脱水关环得2,5-二苯基-3,3-二取代-2,3-二氢-1,4,2-氧氮磷杂环戊烯-2-氧化物(Ⅱ).经¹HNMR及元素分析证明了Ⅰ和Ⅱ的结构,并对反应机理进行了探讨。     

A simple synthesis of 4-amino-6-methyl-1,1,1-trifluoro(trichloro)hepta-3,5-dien-2-ones and 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyridone

Treatment of 2,2-dimethyl-6-trifluoro(trichloro)methyl-2,3-dihydro-4-pyrones with ammonia gives 4-amino-1,1,1-trifluoro(trichloro)-6-methylhepta-3,5-dien-2-ones. Under similar conditions 1,1,1-trifluoro-2-hydroxy-6-methylhepta-2,5-dien-4-one and 6-chloro-1, 1,1-trifluoro-2-hydroxy-6-methylhept-2-en-4-one cyclize into 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyridone. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2263–2265, December, 1997.