Porpholactams and chlorolactams: replacement of a beta,beta '-double bond in meso-tetraphenyl-porphyrin and -chlorin by a lactam moiety

Reaction of meso-tetraphenylporpholactone with hydrazine converts the lactone moiety to an N-aminolactam. It also reduces the opposite pyrrolic moiety of both the starting material and the N-aminolactam, generating chlorin-like chlorolactone and N-aminochlorolactam, respectively. Reductive N-N cleavage of the N-aminoporpholactam generates the parent porpholactam.