Syntheses relevant to vitamin B12 biosynthesis: synthesis of sirohydrochlorin and of its octamethyl ester
Abstract
Sirohydrochlorin is an isobacterichlorin isolated (a) as the metal-free prosthetic group of sulphite reductase and (b) as the aromatised form of the di-C-methylated intermediate on the biosynthetic pathway to vitamin B12; the synthesis is described of the natural enantiomer of sirohydrochlorin and also of its octamethyl ester using a mild photochemical route.