Reactions of 1,2-diaza-1,3-butadienes with propargyl alcohol as an approach to novel bi-heterocyclic systems.

Here we describe the reaction of 1,2-diaza-1,3-dienes and propargyl alcohol furnishing α-(prop-2-yn-1-yloxy)hydrazones that are converted into novel alkyl-1-oxa-7,8-diazaspiro[4.4]nona-3,8-dien-6-ones, by means of 2,3-Wittig rearrangement under very mild conditions. The same α-(prop-2-yn-1-yloxy)hydrazones, treated with benzyl azides furnish the corresponding α-[(1,2,3-triazol-4-yl)methoxy]hydrazones, via Cu(ii)-catalyzed 1,3-dipolar cycloaddition. Their subsequent base-promoted cyclization produces interesting pyrazolone-triazole derivatives. The impact of this work can be ascribable to the attractiveness of the bi-heterocyclic systems obtained and to the ease of the synthetic methodologies proposed.

Synthesis of biphenylyltetrazole derivatives of 1-aminopyrroles as angiotensin II antagonists.

Based on preliminary molecular modelling study, the synthesis of two different classes of biphenylyltetrazole derivatives of 1-aminopyrroles, as potentially active non-peptide angiotensin II (AII) antagonists, is reported. Some NH-Boc protected l-aminopyrroles were deprotected, N-acylated, N-alkylated with 5-[4'-bromomethyl-1,1'-biphenyl-2-yl]-1-triphenylmethyl-1H-tetrazo le, and then detritylated to give the first class of title compounds. Other 1-NH-Boc protected 1,2-diaminopyrroles were regioselectively subjected to the 1-alkylation with 5-[4'-bromomethyl-1,1'-biphenyl-2-yl]-1-triphenylmethyl-1H-tetrazo le, to the acylation of the amino group at 2-position of the pyrrole ring, and then to the detritylation process to yield the second class of title compounds.