Modifications of lincomycin involving the carbohydrate portion. Part IV. (7S)-7-alkoxy-7-deoxy-analogues
Abstract
Modifications of the antibiotic lincomycin have been synthesised in which the 7(R)-hydroxy-group of the parent has been replaced by a series of 7(S)-alkoxy-substituents. These substituents were introduced by the ready acid-catalysed alcoholysis of the 6,7-acetylepimine (XI) or its 2,3,4-tri-O-acetyl ester (XXI), derived from the carbohydrate portion of the antibiotic. Hydrazinolysis yielded the free amino-sugars, and condensation with 1-methyl-trans-4-propyl-L-proline gave the lincomycin analogues. The (7S)-7-deoxy-7-methoxy-analogue shows significantly enhanced antibacterial activity, but this activity diminishes as larger alkoxy-substituents are introduced.