Effect of metal ions in organic synthesis. Part XIV. A mild,simple, and convenient method for the synthesis of 1-(arylamino)pyrrole derivatives by copper(II) ion-catalyzed reaction of (arylazo)alkenes and 1,3-dicarbonyl compounds

A mild, simple and convenient method for the synthesis of some 1-(arylamino)pyrrole derivatives by copper(II) ion-catalyzed reaction of (arylazo)alkenes and 1, 3-dicarbonyl compounds is reported. These reactions take place under magnetic stirring at room temperature, do not require a strong acid or base, nor expensive or difficultly available reagents, nor even complicated procedures. The synthesis seems to be successfully applicable to different (arylazo)alkenes, 1, 3-diketones and ß-ketoesters, and frequently occurs with good yields.     

Access to new 2-oxofuro[2,3-b]pyrroles and 2-methylenepyrroles through the reaction of 1,2-diaza-1,3-butadienes and gamma-ketoesters

New and interesting 2-oxofuro[2,3-b]pyrroles and 19-methyl-15-oxa-20-azatricyclo[12.3.3.0(1,14)]icos-18-en-18-carboxylates have been obtained in good yields by the one-pot reaction, in basic medium, of 1,2-diaza-1,3-butadienes with diethyl or dimethyl acetylsuccinate or methyl 2-(1,3-dioxo-2-cyclotetradecyl)acetate, respectively, under mild conditions. Treatment of the same starting materials with diethyl 2-acetylglutarate, in acidic medium, afforded unknown 2-methylenepyrrole derivatives in high yields. Novel 4-(3-oxopropyl)-2,5-dimethyl-1H-pyrrole-3-carboxylates also have been achieved by reacting 1,2-diaza-1,3-butadienes with ethyl or methyl 4-acetyl-5-oxo-hexanoate.     

Base-catalyzed hydrogen-deuterium exchange in some 5-substituted benzothiazoles and in thiazolo-[4,5-c]pyridine. effect of substituents and polar effects of the aza group

The rates of base-catalyzed hydrogen-deuterium exchange at C-2 in some 5-substituted benzothiazoles and in thiazolo[4,5-c]pyridine were studied. Transmission through the thiazole ring of the effects of substituents in the benzothiazoles and of the polar effects of the aza group in the thiazolopyridine, was assessed from these data.     

Reduction of N-acyl,N′-tosylhydrazines with diborane : A simple,convenient procedure for the conversion of the carboxylic to the methyl group

Aliphatic tosylhydrazides upon treatment with diborane followed by alkaline hydrolysis yield aliphatic hydrocarbons. Aromatic hydrocarbons are produced when aromatic tosylhydrazides undergo heating in presence of diborane and are subsequently oxidated by KIO₄. A discussion on the structures of intermediate products is reported.