The singlet oxygen oxidation of chlorpromazine and some phenothiazine derivatives. Products and reaction mechanisms.
A kinetic and product study of the reactions of chlorpromazine 1, N-methylphenothiazine 2, and N-ethylphenothiazine 3 with singlet oxygen was carried out in MeOH and MeCN. 1 undergoes exclusive side-chain cleavage, whereas the reactions of 2 and 3, in MeOH, afforded only the corresponding sulfoxides. A mechanism for the reaction of 1 is proposed where the first step involves an interaction between singlet oxygen and the side-chain dimethylamino nitrogen. This explains why no side-chain cleavage is observed for 2 and 3.
Baciocchi
Enrico
E
Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Rome, Italy. enrico.baciocchi@uniroma1.it
Del Giacco
Tiziana
T
Lanzalunga
Osvaldo
O
Lapi
Andrea
A
Raponi
Daniele
D
D002746:Chlorpromazine / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D010640:Phenothiazines / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry*
D010640:Phenothiazines; D026082:Singlet Oxygen; D002746:Chlorpromazine