Strucral Formulæ of the Chlorophylls

Abstract

SOMEWHAT more than a year ago, a structural formula for chlorophyll-a was suggested¹ in which a carbomethoxy residue was placed in the ß-position of one pyrrole ring. This seemed necessary as a monomethyl ester (phæopurpurin 7) was obtained as one of the products of an oxidative hydrolysis (‘phase test’) and the position of the methoxyl group in this phæopurpurin was clearly established. We have now found that the purest samples of the phæophorbides of the ‘a’ series do not yield any phæopurpurin 7. Under special conditions of oxidative hydrolysis, a monomethyl compound can be isolated (as the sole product) and the carbomethoxy group in this substance can be shown to be part of the side chain attached to the bridge (the so-called γ-position). This finding is in accord with the position of the methoxyl group in Fischer's formula for chlorophyll-a.