The constitution of primycin. Part I. Characterisation, functional groups, and degradation to the secoprimycins

Abstract

Primycin, the antibiotic agent produced by S. primycini, has been found to be the sulphate of a monoalkylated guanidine. The molecule contains six C-methyl groups, two ethylenic linkages, and probably between 12 and 15 hydroxy-groups. The presence of a (–)-D-arabinose unit has been demonstrated.

Hydrolysis of primycin with concentrated alkali gives, together with hexanoic acid and other unidentified substances, a long-chain polyhydroxylated amino-acid (2a). This has been acetylated, esterified, and then cleaved by ozonolysis to give three fragments. These were isolated as their borohydride reduction products, the secoprimycins. Evidence is provided which establishes secoprimycin A as 2-butyl-3,7,11,15,16-pentahydroxy-4-methylheptadecanoic acid, B as an arabinosyl derivative of heptadecane-1,2,3,5,7,9,11,16-octaol, the position of the arabinosyl group being undetermined, and C as N-(4,6,8-trihydroxy-5,7-dimethyloctyl)acetamide. By using borodeuteride as the reducing agent, the positions of the original ethylenic linkages in the secoprimycins were established.