Abstract: The invention relates to manufacturing process for a halide or an organic sulfonate of N-carbobenzyl-L-glutamic acid-.alpha.-cholinester in high purification, which is useful as e.g. hypotensive drug. According to the prior art, undesired .gamma.-form byproduct is inevitably formed to be mingled with said .alpha.-form objective compound of which separation is difficult. It has been found that when using N-carbobenzyloxy-.gamma.-tert. butyl-L-glutamic acid-dicyclohexyl-ammonium salt readily available in high purification as starting material, reacting N, N-dimethyl-aminoethylchloride therewith to form N-carbobenzyloxy-.gamma.-tert. butyl-L-glutamic acid-.alpha.-dimethylaminoethyl ester which is quaternerized to form N-carbobenzyloxy-.gamma.-tert. butyl-L-glutamic acid-.alpha.-cholinester salt, which is subjected to mild salt treatment, the objective compound can be obtained in high purification.