2-Carbethoxymethyl-4H-3,1-benzoxazin-4-one. 4. Reaction with anilines

In a solution of DMF, 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one reacts with primarily aromatic amines basically with the formation of the corresponding 2-carbethoxymetlzyl-3-arylquinazolin-4(3H)-ones. Possible mechanisms of these chemical transformations are reported and discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 225–228, February, 1994. Original article submitted June 28, 1993.     

Quantum-chemical Investigations of Pyrimidinones-4. 1. Tautomerism of 2-Oxopyrimidinones-4

Semiempirical quantum-chemical calculations have been carried out of the molecules of 2-oxopyrimidinones-4. The geometry and electronic structures and the stabilities of the tautomeric forms have been analyzed.     

Fluorination of 4-nitroisoxazoline salts. Synthesis of 4-fluoro-4-nitroisoxazolines and 4-fluoroisoxazoles

Methods for the synthesis of hitherto unknown 4-fluoro-4-nitroisoxazolines by fluorination of 4-nitroisoxazoline salts with FClO₃ in MeOH and 4-fluoroisoxazoles by treatment of fluoronitroisoxazolines bearing the hydrogen atom bound to the C(5) atom of the isoxazole ring with MeONa in MeOH were developed.     

A variant of the bruylants reaction. Synthesis of 4-heteroaryl-4-anilinopiperidines.

Imines can be generated in situ from -aminonitriles and efficiently trapped by a variety of lithiated heterocycles. This variation of the Bruylants reaction has proven to be a general method for the synthesis of -heteroaryl secondary amines.     

The ethynyl carbocation. 4. Reaction of 4-phenylethynylpyrylium salts with c-nucleophiles

The reaction of 4-phenylethynylpyrilium salts with indoles leads to indolylvinylpyrilium derivatives through attack of the -carbon atom of the triple bond and subsequent intramolecular transfer of a proton from C(in3) of the indole ring to the sp-hybridized carbon atom of the allene group. The structure of 2,6-diphenyl-4-[2-phenyl-2-((-methylindolyl)vinyl]pyriliumperchloratewasdeterminedunequivocallybyx-ray diffraction analysis and the most likely reaction scheme was indicated. The bond length distribution in the pyrilium cation indicates significant delocalization of positive charge.For communication 3, see [1]Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1316–1324, October, 1992.     

2-Carbethoxymethyl-4H-3,1-benzoxazin-4-one. 3. Condensation of o-phenylenediamive

3-(2-Benzimidazolyl)-4-hydroxy-2-quinolone was unexpectedly obtained as the principal reaction product on fusion of 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one with o-phenylenediamine. A possible mechanism of its formation is presented.For Communication 2 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–241, February, 1992.     

4. Kolloide Systeme

Colloid and Polymer Science -     

4. Biologisches Material

Analytical and Bioanalytical Chemistry -