Cleavage and reactions of some NH-BOC protected 1-aminopyrroles: a new one-pot route to pyrrolo[1,2-b][1,2,4]triazines together with spectroscopic and X-ray studies

Abstract

1-NH-BOC protected 1,2-diaminopyrroles have been converted by one-pot cleavage of the protecting group and subsequent reaction of the compounds obtained with 1,2-dicarbonyl compounds into highly substituted pyrrolo[1,2-b][1,2,4]triazines. Structural assignments to the regioisomers arising from the reaction with phenylglyoxal have been made on the basis of NMR spectral evidence. An X-ray crystal structure analysis of 6-ethoxycarbonyl-7-methyl-3-phenyl-5-piperidin-1-ylcarbonylpyrrolo[1,2- b][1,2,4]triazine has been carried out in order to confirm unambiguously the structure assignment.