Synthesis and properties of substituted 2-methylene-hydrazono-2,3-dihydro-3-benzo[<Emphasis Type="Italic">b</Emphasis>]furanones

The reaction of 2,3-dihydro-2,3-benzo[b]furandione with the triphenylphosphazines of diazo compounds leads to substituted 2-methylenehydrazono-2,3-dihydro-3-benzo[b]furanones, which are hydrolyzed in an acidic medium to the substituted methylenehydrazides of o-hydroxyphenylglyoxalic acid and react with amines to form the products of addition at the activated CH=N bond of the side chain or 2-hydrazono-2,3-dihydro-3-benzo[b]furanone respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 817–822, June, 2007.     

Chemistry of Diazopolycarbonyl Compounds: VIII. Synthesis of Nitrogen-containing Heterocycles via Transformations of Substituted 2-diazopentane-1,3,5-triones

Ethyl 5-aryl-2-diazo-3,5-dioxopentanoates and 1,5-diaryl-2-diazopentane-1,3,5-triones are partially enolized in solutions. By O-methylation of enol forms of diazo esters with diazomethane ethyl 5-aryl-2-diazo-5-methoxy-3-oxopent-4-enoates were prepared. Concurrently with the O-methylation the diazo esters undergo heterocyclization into 3,5-disubstituted 4-hydroxypyrazoles which under the reaction condition suffer O- and N-methylation by excess diazomethane. 3,5-Diaroyl-4-hydroxypyrazoles were also obtained from diazopentanetriones but here triethylamine served as the cyclization reagent.     

Decyclization of 5-Aryl-4-methyl-2,3-dihydrofuran-2,3-diones by the Action of Nucleophiles

Ring cleavage in 4-methyl-5-phenyl-2,3-dihydrofuran-2,3-dione by the action of methanol and in 5-aryl-4-methyl-2,3-dihydrofuran-2,3-diones by the action of aniline and N-methylaniline results in formation of, respectively, methyl 3-methyl-4-phenyl-2,4-dioxobutanoate and 4-aryl-3-methyl-2,4-dioxobutananilides. The reaction mechanism was studied by ¹H NMR spectroscopy.     

Synthesis and molecular structure of 3-(2-aryl-2-oxoethyl)-3-methoxy-2-oxo-2,3-dihydroimidazo-[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridine hydrochlorides

Reactions between 2-pyridylamides of Z-4-aryl-2-hydroxy-4-oxobut-2-enoic acids with diazomethane have been used to synthesize 3-(2-aryl-2-oxoethyl)-3-methoxy-2-oxo-2,3-dihydroimidazo[1,2-a]pyridines, which form hydrochlorides with hydrochloric acid. The structure of the latter has been demonstrated by XRD for the hydrochloride of 3-methoxy-2-oxo-3-(2-phenyl-2-oxoethyl)-2,3-dihydroimidazo[1,2-a]pyridine. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 464–468, 2007.     

Synthesis, Structure, and Chemical Properties of N-Substituted 2(3)-Imino-2,3-dihydrofuran-3(2)-ones. (Review)

Published data on the synthesis, structure, and chemical properties of N-substituted 2(3)-imino-2,3-dihydrofuran-3(2)-ones to 2002 are reviewed     

Chemistry of Diazopolycarbonyl Compounds: IX. Synthesis of 6-Aryl-3-acyl-4-hydroxypyridazines by Heterocyclization of 1,5-Disubstituted 2-Diazo-1,3,5-pentanetriones

5-Aryl-2-diazo-1,3,5-pentanetriones undergo intramolecular cyclization by the action of triphenylphosphine to give triphenylphosphine oxide and substituted 6-aryl-3-acyl-4-hydroxypyridazines.     

Cyclization of 4,4-dinitrobutenoic acid esters to 3-nitroisoxazoline N-oxides

Chemistry of Heterocyclic Compounds -     

Synthesis and Intramolecular Cyclization of N-Substituted 2-Amino-4-aryl-4-oxo-2-butenoic Acids

Treating 4-aryl-2,4-dioxobutanoic acids with aromatic amines, 4-aminoantipyrine, and benzophenone hydrazone furnished N-substituted 2-amino-4-aryl-4-oxo-2-butenoic acids that existed in solutions in enaminoketone and iminoketone forms. The acids obtained underwent in the presence of acetic anhydride cyclization into N-substituted 5-aryl-3-imino-3H-furan-2-ones.