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Abstract

The reduction of toluenesulphonyl-L-pyrrolidonecarboxamide (II) and the corresponding anilide (III) with lithium borohydride yields the amide and anilide of N-toluenesulphonyl-δ-hydroxy-L-α-aminovaleric acid (IV and V), respectively. Cyclisation of these compounds leads to the corresponding derivatives of toluenesulphonyl-L-proline which have been converted to L-proline. These reactions represent the first direct chemical conversion of L-glutamic acid to L-proline.