Chemical transformation of 1,2-oxazinochlorin derivatives; synthesis and X-ray crystal structure of a novel porphyrinporphyrin dimer with a condensed cyclohexane ring

Base-assisted ring opening in 1,2-oxazinochlorin derivatives led selectively to the corresponding /neso-cyanohydroxychlorin derivatives. The latter could then undergo acid-mediated carbocation formation followed by nucleophilic treatment to give different products, depending on the nature of the nucleophile reagent. Treatment of (E)- and/or (Z)-2-ethylidene-3-hydi-oxy-5-cyano3,7,8,12,13,17,18-heptaethylchlorin nickel complex with a mixture of 5% trifluoroacetic acid and dichloromethane yielded a novel type porphyrin-porphyrin dimer with a condensed cyclohexane ring in an almost quantitative yield. The structure of this dimer was determined by single crystal X-ray analysis. Copyright (c) 2007 Society of Porphyrins & Phthalocyanines.