SYNTHESIS OF ( S )-PROLINE DERIVATIVES WITH AN ALKYLATED N-BENZYL SUBSTITUENT. BENZYLATION OF ( S )-INDOLINE-2-CARBOXYLIC ACID
The synthesis is reported of (S)-proline derivatives which contain a 2,4,6-trimethyl-, 4-tert-butyl-, or pentamethylbenzyl substituent on the nitrogen atom. Under similar conditions the benzylation of indoline-2-carboxylic acid was unsuccessful. Treatment of indoline-2-carboxylic acid with benzyl chloride in the presence of KOH in dimethylacetamide gave the benzyl ester of N-benzylindoline-2-carboxylic acid which is unstable on light. Author: A. N. Popkov. English Translation in Chemistry of Heterocyclic Compounds , 2000, 36 (5), pp 544-547 http://link.springer.com/article/10.1007/BF02290842