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US 5,399,717 AGranted
Glycosidation route to 4"-epi-methylamino-4"-deoxyavermectin B.sub.1
AssigneeMerck & Co., Inc.
InventorsRaymond Cvetovich, Mallory F. Loewe
Life of this patent
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Abstract
A stereocontrolled glycosidation with thiophenyl 4-(N-allyloxycarbonyl)-epi-methylamino-4-deoxyoleandrose and 5-O-allyloxycarbonyl avermectin B.sub.1 monosaccharide using N-iodosuccinimide produces exclusively the .alpha.-anomer of a precursor of 4"-epi-methylamino-4"-deoxyavermectin B.sub.1 in 90% yield. Deprotection and crystallization as the benzoic acid salt yields 4"-epi-methylamino-4"-deoxyavermectin B.sub.1 (emamectin benzoate), a potent insecticide.
Claims4
A process comprising the step of reacting the compound of the following structure:
- ##STR7## with a compound of the following structure:
- ##STR8## where the combination of X and Y is either H, SPh, or SPh and H, respectively;
- or mixture thereof;
- in a polar, aprotic organic solvent, in the presence of a proton acceptor agent and an iodine-containing condensing agent selected from the group consisting of iodine or N-iodosuccinimide, at a temperature in the region of -15.degree. to 100.degree. C., for a sufficient time to form the compound of the following structure:
- ##STR9##
2 more elements
Dependencies are inferred from the claim text.