Propylhygric acid

Lincomycin is produced by Streptomyces lincolnensis var. lincolnensis in a number of culture media (Mason et al., 1962). It is active against a wide variety of primarily gram positive bacteria. Lincomycin was shown to have the structure in Fig. 1 by Hoeksema et aL (1964). The antibiotic contains two C9 fragments joined by an amidic linkage. One is ra> 5-l-methyl-4-propyl-L prohne which will be referred to as propylhygric acid (PHA). The other is methyl 6 amino-6,8-di-deoxy-1 -thio-D- ry Aro-a-D-galacto-octop5n anoside [methyl a-thiolincosaminide (MTL)] (Fig. 1). 

A first step in the degradation of hncomycin is the cleavage of the antibiotic by hydrazine to methyl a-thiohncosaminide (MTL) and the hydrazide of propyl-hygric acid. Acid hydrolysis of the hydrazide affords crystalhne propylhygric acid (PHA). 

Both the —N—CH3 and —C—CH3 groups of propylhygric acid are derived from methionine. 

The carboxyl group and carbons 2 and 3 of propylhygric acid appear to originate from a three-carbon unit, probably pyruvate. 

The foUowing biosynthetic scheme is proposed for the biosynthesis of the propylhygric acid moiety of hncomycin ... 

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