The biosynthesis of phenols. Part XVIII. Carbon-14 labelling in rings C and D of oxytetracycline incorporating [2-14C]acetic acid

Abstract

The radioactivity of carbon atoms at positions 6 and 11 of [¹⁴C]oxytetracycline, isolated from cultures containing [2-¹⁴C]acetic acid, has been compared with the averages for positions (7,9, and 10a) and (6a, 8, and 10) respectively. The close agreement of the measured radioactivities indicates that carbon atoms 6 and 11 in ring C and all those of ring D arise from incorporation of acetic acid in accordance with the polyketide hypothesis. An improved procedure was developed for the isolation of bromopicrin from the oxidation of nitrated phenols.