Chelate synthesis of 8-diaminomethylene-5,6,7,8-tetrahydroquinazoline-7-one derivatives

A scheme for synthesizing 5,6,7,8-tetrahydroquinazoline systems from ketene aminal1 via its diphenylboron chelate2 has been suggested. The interaction ofp-toluamidine with the condensation product of the chelate with dimethylformamide dimethylacetal results in the formation of 8-(N-benzoyldiaminomethylene)-2-p-tolyl-5,6,7,8-tetrahydroquinazoline-7-one, which is easily debenzoylated by sodium ethoxide. 8-Diaminomethylene-5,6,7,8-tetrahydroquinazolinone derivatives can be used for the preparation of boron chelate complexes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 888–890, May, 1994.     

A novel one-pot pseudo-five-component synthesis of 4,5,6,7-tetrahydro-1H-1,4-diazepine-5-carboxamide derivatives

A novel one-pot pseudo-five-component synthesis of 4,5,6,7-tetrahydro-1 H-1,4-diazepine-5-carboxamide derivatives starting from simple and readily available inputs including 2,3-diaminomaleonitrile, a cyclic or acyclic ketone, an isocyanide, and water in the presence of a catalytic amount of p-toluenesulfonic acid in aqueous medium at ambient temperature in high yields is described.     

Efficient synthesis of 4-phosphinoyl-4,5,6,7-tetrahydro-2H-indazol-3-ylamines

We described in this paper an efficient synthesis of variously substituted 4-phosphinoyl-4,5,6,7-tetrahydro-2H-indazol-3-ylamines involving nucleophilic addition of hydrazine on β-ketothioamides as key-step.     

Chelate synthesis of 2,2′-bipyridin-4-one

A method for the synthesis of 2,2′-bipyridin-4-one from 4-amino-4-(2-pyridyl)-but-3-en-2-onevia its diphenylboron, chelates was proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2071–2073, November, 1997.     

One-pot synthesis of some 2H-Pyran-2-one derivatives

A one-pot synthesis of various 2H-pyran-2-one derivatives 5–19 starting from methyl ketones 1 , N,N-dimethylformamide dimethyl acetal and N-acylglycines 3 in acetic anhydride is described.     

One-pot synthesis of N-substituted 2-methyl-4,5,6,7-tetrahydroindole derivatives

We describe the preliminary results of one-pot syntheses of various N-substituted 2-methyl-4,5,6,7-tetrahydroindole derivatives from 2-(2-bromoallyl)cyclohexanone and the corresponding primary amines in good yields. Aliphatic amines were directly converted to tetrahydroindoles, whereas aromatic amines needed an extra base treatment step to complete the transformation.     

A convenient synthesis and structural analysis of novel 4,5,6,7-tetrahydro-1H-indazoles

A new series of t-4-aryl-3,c-6-dihydroxy-6-methyl-4,5,6,7-tetrahydro-1H-indazole-r-5-carboxylic acid isopropyl esters has been synthesized by adopting a conventional method from cyclic β-keto esters. ¹H, ¹³C NMR, and IR spectra for all the compounds were investigated. HMBC, HSQC, COSY, and NOESY spectra of the representative compounds were studied. The stereochemistry of a six-membered ring of the fused indazoles resembled that of keto esters. From the HMBC correlations the indazole structure was confirmed as 1H-indazole.     

Heterocyclic Rearrangement of 4,5,6,7-Tetrahydro-6,6-dimethyl-benzo[c][1,2,5]oxadiazol-4-one (Z)-Arylhydrazones into Corresponding 2-Aryl-4,5,6,7-tetrahydro-2H-benzo[d][1,2,3]triazol-4-one Oximes

The thermal base-catalysed and photochemical transformation (Boulton-Katritzky rearrangement) of the title tetrahydrobenzo[c][1,2,5]oxadiazoles to tetrahydro-2H-benzo[d][1,2,3]triazoles is studied. Attempts to induce analogous rearrangement in tetrahydro-2H-benzo[d][1,2,3]triazol-4-one arylhydrazones or oximes failed. Some CNDO/2 calculation are also carried out.     

Synthesis and Biological Activity of 4-Aryl-3,6-dihydroxy-6-methyl-4,5,6,7-tetrahydro-2H-indazole-5-carboxamides

Russian Journal of General Chemistry - The reaction of 2-aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxamides with hydrazine hydrate in ethanol gave...     

1,3,4,5-四氢-7-烷氧基-2H-1-苯并氮杂(卓)-2-酮的合成及生物活性

合成了一系列1,3,4,5-四氢-7-烷氧基-2H-1-苯并氮杂(卓)-2-酮衍生物.采用最大电惊厥实验测定化合物的抗惊厥活性,其中的1,3,4,5-四氢-7-丁氧基-2H-1-苯并氮杂(卓)-2-酮(4b)具有较强的抗惊厥活性,ED_(50)为52.8 mg/kg,TD_(50)为246.2mg/kg,PI为4.7.     

Structure of the Product of the Beckmann Rearrangement, 2-Methyl-4,5,6,7-Tetrahydrobenzothiazol-7-one Oxime

Russian Journal of General Chemistry -     

New method for synthesis of 3-pyrrolin-2-one derivatives

We propose a method for synthesis of derivatives of pyrrolinone by reaction of the methyl ester of 3-substituted 2-oxo-3-pentonoic acid with primary amines or acetylhydrazine.Institute of Organic Chemistry, National Academy of Sciences of the Armenian Republic, Yerevan 375094. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1345–1350, October, 1994. Original article submitted July 4, 1994.     

A convenient one-pot synthesis of 2-(trifluoromethyl)-3,4,7,8-tetrahydro-2H-chromen-5(6H)-one derivatives and their further transformations

The trifluoromethyl containing heterocycles, 2-hydroxy-4-aryl-3-(thien-2-oyl)-2-(trifluoromethyl)-3,4,7,8-tetrahydro-2H-chromen-5(6H)-one derivatives 4, were synthesized via a one-pot three-component reaction of aldehyde 1 with 1,3-cyclohexanedione 2 and 4,4,4-trifluoro-1-(thien-2-yl)butane-1,3-dione 3 in the presence of a catalytic amount of Et₃N. The effect of bases and solvents on the reaction efficiency and yield was briefly investigated. Treatment of 4 with an excess amount of NH₄OAc in ethanol afforded 2-trifluoromethyl-1H-quinolin-5-one derivatives 5. Refluxing of 4 with TsOH in CHCl₃ gave the corresponding dehydrated products 8.