Process for the preparation of 9-deoxo-8a-aza-(8a-alkyl)-8a-homoerythromycin a derivatives from 9-deoxo-9(z)-hydroxyiminoerythromycin a

Abstract From the Canadian patent

The invention provides a process for the preparation of 9-deoxo-8a-aza-8a-homoerythromycin A (see formula V) , and of its 8a-alkylated derivatives from 9-deoxo-9(Z)--hydroxyiminoerythromycin A via a stereospecific Beckmann rearrangement in a , reaction mixture using pyridine as main solvent resulting in imidate , intermediates , which are not isolated from said mixture and which are employed directly in a reduction stage using a sufficient amount of borohydride after extraction of , the , pyridine with a hydrocarbon which is miscible with the latter and in which said imidates , are insoluble. The compound V can be directly N-alkylated at the 8a-position using an , aldehyde without …