Syntheses of 23-C-alkylidene, and 23-N-containing derivatives of 5-O-mycaminosyltylonolide.

Several derivatives of 5-O-mycaminosyltylonolide substituted at C-23 have been prepared; these are 23-deoxy-23-C-methylene (3), 23-deoxy-23-C-(methoxycarbonylmethylene) (5), 23-deoxy-23-C-(ethoxycarbonylmethylene) (7), and 23-deoxy-23-C-(butoxycarbonylmethylene) (9), 23-deoxy-23-C-[(2E)-3-(ethoxycarbonyl)-2-propenylene] (11), and 23-deoxy-23-(dimethylaminoimino) (13), and 14-de(hydroxymethyl)-14-nitrile (16) derivatives. The key steps in these syntheses are the reactions of 2',4'-di-O-acetyl-3-O-tert-butyldimethylsilyl-23-deoxy-23-oxo-5-O- mycaminosyltylonolide diethyl acetal (1) with several Wittig reagents, 1,1-dimethylhydrazine and hydroxylamine. Antibacterial activities of these compounds are also described.