Abstract
Fatty acid obtained by the saponification of fats in diphterial bacteria, named by Chargaff as diphtheric acid, is an unsatuated acid, C35H68O2, m.p. 35-36°, which is catalytically reduced to dihydrodiphtheric acid, C35H70O2, m.p. 95° (anilide, m.p. 73°). Oxidation of diphtheric acid by KMnO4 gives dihydroxydiphtheric acid, C35H70O4, m.p. 46°, which is further oxidized by sulfuric acid and sodium bichromate to cerotic acid, m.p. 78°, and 8-keto-nonic acid, m.p. 40.5° (semicarbazone, m.p. 134.5°), the latter being identified by synthesis. Cleavage of this acid must be at a point where two OH radicals are situated next to each other which were oxidized, i.e. oxidative cleavage of the double bond in diphtheric acid. It follows, therefore, that the structure of diphtheric acid can be shown by CH3-(CH2)24-CH=C-(CH2)6-COOH.
