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AssigneesDainippon Sumitomo Pharma Co., Ltd., Katayama Seiyokusyo Co., Ltd.
InventorsTakashi Inagaki, Yoshikazu Yamakawa
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The present invention provides with a process of preparing an optically active succinimide derivative, which is a key intermediate for production of ranirestat. A compound (3) is easily prepared by treating the derivative of succinic acid diester of the formula (2): wherein R1 is an amino group protected with a group removed by hydrogenolysis or a tert-butoxycarbonylamino group and R2 is an ethyl group optionally substituted with one or two methyl group(s) at α-position, provided that R2 is not a tert-butyl group when R1 is a tert-butoxycarbonylamino group; with alkali metal alkoxide and the compound (3) can be an important intermediate for production of ranirestat.
A succinic acid diester derivative of the formula (1):
A succinic acid diester derivative of the formula (2):
A process for preparing a compound of the formula (1b) which is a compound of the formula (1) wherein R3 is a cyano group, comprising a step in which a compound of the formula (5) below:
A process for preparing a compound (2), comprising a step in which a compound (1b) which is a compound of the formula (1) wherein R3 is a cyano group, is reacted under the presence of a base and hydrogen peroxide, and a step in which a product of the said step is recrystallized from acetone.
Dependencies are inferred from the claim text.