Reactions of muconaldehyde isomers with nucleophiles including tri-O-acetylguanosine: formation of 1,2-disubstituted pyrroles from reactions of the (Z,Z)-isomer with primary amines.

(Z,Z)-Muconaldehyde reacts with primary amines, including valine and lysine (epsilon-amino), to afford N-substituted-2-(oxoethyl)pyrroles, which were reduced with sodium borohydride to the more stable N-substituted-2-(hydroxyethyl)pyrroles. The formation of the pyrrole aldehydes was performed in a variety of solvents including aqueous methanol. With tri-O-acetylguanosine, the putative pyrrole aldehyde derived from reaction at NH2 condenses with N-1 (guanine component) to afford a bicyclic adduct: 4,5-dihydro-5-hydroxy-10-beta-D-tri-O- acetylribosylpyrrolo[1',2':3,4]pyrimido[1,2-a]purin-7(10H)-one (5a). This was hydrolyzed to 4,5-dihydro-5-hydroxy-10-beta-D- ribosylpyrrolo[1',2':3,4]pyrimido[1,2-a]purin-7(10H)-one (5b). The structures of 5a and 5b were primarily based on NMR evidence and comparison with 4,5-dihydro-5-hydroxy-9-methylpyrrolo[1',2':3,4]pyrimido[2,1-b] pyrimidin-7-one (7), obtained from reacting (Z,Z)-muconaldehyde with 2-amino-4-hydroxy-6-methylpyrimidine. (E,Z)-Muconaldehyde also reacted with primary amines to give N-substituted-2-(oxoethyl)pyrroles, whereas (E,E)-muconaldehyde gave bis-imines. The results described are discussed in the context of the carcinogenicity of benzene.