Molecular structure of trichlorophosphazo compounds from ab initio calculation and chlorine-35 NQR spectroscopy data

The molecular structures of trichlorophosphazo compounds Cl₃P=NR with R = C(CH₃)₃, C(C₂H₅)₃, C(CF₃)₃, CCl(CF₃)₂, CCl₂CF₃, CCl₃, CCl₂CCl₃, and CCl(CCl₃)₂ were analyzed by combined consideration of the results of ab initio MP2/6-31G* calculations and previously measured ³⁵Cl NQR frequencies. The conformational peculiarity of these molecules caused by the relative spatial orientations of the P-Cl and N-C bonds is reflected in the calculated geometric parameters of the Cl₃P=NC fragments and in the pattern of ³⁵Cl quadrupole resonance spectra for PCl₃ groups. For these atomic groups, the ³⁵Cl NQR frequencies were brought in correlation with the charges of the chlorine atoms found by quantum-chemical calculations.     

Reaction of methyl esters of substituted 2-oxochromene-3-carboxylic acids with zinc enolates formed from 1-aryl-2-bromoalkanones

Zinc enolates formed from 1-aryl-2-bromoalkanones react with methyl esters of substituted 2-oxochromene-3-carboxylic acids to give methyl esters of 6-bromo- or 6,8-dibromo-4-(2-aryl-2-oxo-1-R- ethyl)-2-oxochromane-3-carboxylic acids as mixtures of two diastereomers.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1520–1523.Original Russian Text Copyright © 2004 by Shchepin, Korzun, Shurov, Vakhrin, Russkikh.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis of 3-R<Superscript>1</Superscript>-1-R<Superscript>2</Superscript>-1-R<Superscript>3</Superscript>-4a,10b-dihydro-1<Emphasis Type="Italic">H</Emphasis>-chromeno[3,4-<Emphasis Type="Italic">c</Emphasis>]-pyridine-2,4,5-triones by the Reformatskii reaction

The Reformatskii reagents formed from alkyl esters of -bromoacetic, -bromopropanoic, and -bromoisobutyric acids and zinc react with N-arylamides of 2-oxochromene-3-carboxylic acid, yielding 3-R¹-1-R²-1-R³-4a,10b-dihydro-1H-chromeno[3,4-c]pyridine-2,4,5-triones.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1516–1519.Original Russian Text Copyright © 2004 by Shchepin, Fotin, Vakhrin, Shurov.This revised version was published online in April 2005 with a corrected cover date.     

Reactions of zinc enolates derived from 1-Aryl-2-bromo-alkanones with 3-acyl-6-bromochromen-2-ones

Zinc enolates derived from 1-aryl-2-bromoalkanones react with 3-acyl-6-bromochromen-2-ones to give 3-acetyl(benzoyl)-6-bromo-4-(2-aryl-2-oxo-1-R-ethyl)chromen-2-ones as a single diastereoisomer.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1536–1538.Original Russian Text Copyright © 2004 by Shchepin, Korzun, Shurov, Vakhrin.     

Reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with 6,7-dimethoxy-3,4-dihydroisoquinoline. Crystal structure of 1-benzoyl-8,9-dimethoxy-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione

The reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with 6,7-dimethoxy-3,4-dihydroisoquinoline gave 1-benzoyl-2-hydroxy-8,9-dimethoxy-3,5,6,10b-tetrahydropyrrolo[2,1-a]isoquinolin-3-one and its oxidation product,viz., 1-benzoyl-8,9-dimethoxy-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione. The last-mentioned compound was studied by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1845–1848, October, 1997.     

Reformatsky Reaction of Methyl α-Bromoisobutyrate with 2-Oxo-2H-benzo[f]chromene-3-carboxylic Acid Esters and N-Benzylamide

Reformatsky reagent derived from methyl -bromoisobutyrate reacts with methyl and ethyl 2-oxo-2H-benzo[f]chromene-3-carboxylates and N-benzyl-2-oxo-2H-benzo[f]chromene-3-carboxamide to afford the corresponding derivatives of 4-(1-methyl-1-methoxycarbonylethyl)-2-oxo-3,4-dihydro-2H-benzo[f]chromene-3-carboxylic acid as a single stereoisomer.     

Reaction of the Reformatskii reagent obtained from bromotetrahydrofuran-2-one with 2-oxochromene-3-carboxylic or 3-oxo-3<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">f</Emphasis>]chromene-2-carboxylic acid derivatives

The Reformatskii reagent obtained from 3-bromotetrahydrofuran-2-one reacts with alkyl esters of 6-bromo- and 6,8-dibromo-2-oxochromene-3-carboxylic acid or alkyl esters and N-benzylamide of 3-oxo-3H-benzo[f]chromene-2-carboxylic acid to form alkyl esters of 6-bromo- and 6,8-dibromo-2-oxo-4-(2-oxotetrahydrofuran-3-yl)chroman-3-carboxylic acid or alkyl esters and N-benzylamide of 2,3- dihydro-3-oxo-1-(2-oxotetrahdrofuran-3-yl)-1H-benzo[f]chromene-2-carboxylic acid as a mixture of two diastereomers.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1513–1515.Original Russian Text Copyright © 2004 by Shchepin, Fotin, Shurov.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and crystal structure of ethyl 1-benzyl-2-hydroxy-5-methyl-3-oxo-2-phenacyl-2,3-dihydropyrrole-4-carboxylate

Reaction of 5-phenyl-2,3-dihydro-2,3-furandione with ethyl 3-benzylamino-2-butenoate, resulting in ethyl 1-benzyl-2-hydroxy-5-methyl-3-oxo-2-phenacyl-2,3-dihydropyrrole-4-carboxylate and benzylamide ofN-benzoylpyruvic acid, was studied. The structure of the pyrrole derivative was confirmed by X-ray analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1552–1555, August, 1995.