The Action of Hydrazines upon \u27Thiazolidine-4-carboxylic Acids I. Preparation of D-Penicillamine from D-Benzylpenilloic Acid

In the reaction of phenylhydrazine with n-benzylpenilloic acids (Ia or Ila) n-penicillamine was obtained in high yield and purity. The lack of reactivity of N-acyl derivatives (Ib or Ub) with phenylhydrazine indicated that the above reaction proceeded through the open chain imine tautomer of Ia or Ila (IV). The epim~risation of n-benzylpenilloic acid (Ia and Ha) in aprotic solvents was studied by using PMR spectroscopy