Process for the preparation of ivermectin

摘要

Prepn. of 22,23-dihydro-avermectin comprises selective catalytic hydrogenation of avermectin B1a and/or B1b. The catalyst is a rhodium complex cpd. which is prepd. by (a) reaction of a rhodium salt, a hydrazine (or a hydrazine salt) and a tertiary phosphine, or (b) reaction of a rhodium-phosphine complex with a hydrazine (or a hydrazine salt).