L-Tartaric acid → methyl (2S)-1-[(1S)-1-phenylethyl]azetidine-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of methyl N-[(S)-methylbenzyl]azetidine-2-carboxylate (29.91 g, the ratio: 2S isomer/2R isomer=52/48) in methyl tert-butyl ether was added dropwise to a solution of L-tartaric acid (16.55 g) in methanol (20.26 g) under reflux. Further, 21.43 g of methanol was added and the obtained homogeneous solution was cooled to 29° C. A small amount of the crystals obtained in Example 6 was fed as seed crystals to initiate crystallization. Then, after cooled to 5° C., crystals were collected by filtration, washed with methyl tert-butyl ether and dried in vacuo to give tartaric acid salt of methyl N-[(S)-methylbenzyl]azetidine-2-(S)-carboxylate (25.36 g, yield: 48%, 91% d.e.).

Provenance & Evidence