Pfizer Handbook of Microbial Metabolites 690 



PA-114A. E-129B may be identical with PA-114B, but 

 different from staphylomycin S : ^^^ 



770a Ostreogrycin B, (E-129B) C45H-4O9NS, colorless prisms from 

 methanol with solvation, colorless needles from toluene, 

 m.p. 266-268°, [aW -66.8° (c 0.5 in methanol). 



CH--CH^CH3 



N-Me-p- / ^O 



Dimethylamino- 



phenylalanine L-Pro 



N 



CH, 



-N C^^ \ / 



Streptomyces ostreogriseiis 



This structure differs from staphylomycin only by sub- 

 stitution of p-dimethylamino-N-methylphenylalanine for 

 N-methylphenylalanine. 



A similar structure has been proposed for mikamycin B, 

 the only difference being a hydroxyl group in the /^-posi- 



'-" F. W. Eastwood, B. K. Snell and Alexander Todd, /. Chem. Soc, 

 2286 (1960). 



