Stereochemistry of the bacteriochlorophyll-e homologues

Abstract

Using proton n.m.r. spectroscopy, reversed-phase h.p.l.c., and synthetic interconversion into methyl bacteriopheophorbides-c(3), the chirality of the 2-(1-hydroxyethyl) in methyl bacteriopheophorbides-e(and hence the bacteriochlorophylls-e) from Chlorobium phaeobacteroides is shown to be 95%(R) and 5%(S) for the [4-Et,5-Et] homologue, 40%(R) and 60%(S) for the [Prⁿ,Et] compound, and approximately 1%(R) and 99%(S) for the [Buⁱ,Et] homologue.