| abstract |
(57) [Summary] (Modified) [PROBLEMS] To provide an advantageous synthetic intermediate such as octahydroindole-2-carboxylic acid useful as an angiotensin converting enzyme inhibitor. Formula I (In the formula, n = 1, 2 or 3, and R is (C 1 to C 17 ) -acyl and R 1 is (C 1 -C 6 ) -alkyl, another carboxyl protecting group, etc.) is treated with Raney nickel in a suitable solvent to give a compound of formula IV (Wherein R 3 and R 4 are hydrogen or have the same definition as defined above for R in formula I), and then, if appropriate, by hydrolysis or transesterification to give R 4 Formula I showing the same definition as above for R in Formula I A process for preparing a compound of formula IV, which is converted to an ester of V. |