Yield:25654-51-7 74%

Reaction Conditions:

with hydrogenchloride;sodium hydroxide;sodium chloride in toluene;

Steps:

R.1.1 Synthesis of (2R,2S)-1-benzyloxycarbonylazetidine-2-carboxylic acid (Reference Compound No. 1-1):

Reference Example 1-1 Synthesis of (2R,2S)-1-benzyloxycarbonylazetidine-2-carboxylic acid (Reference Compound No. 1-1): To 60 ml of a 1 N sodium hydroxide solution containing 5.05 g (56 mmol) of (2R,2S)-azetidine-2-carboxylic acid synthesised in accordance with the method described in Agr. Biol. Chem vol 37 (No. 3) 649 (1973), 45 ml of a 32% toluene solution of benzyloxycarbonyl chloride and 60 ml of a 1 N sodium hydroxide solution were added dropwise at the same time under an ice-cooled condition. The reaction mixture was stirred overnight at room temperature and then washed with ether twice. The reaction mixture was made acid (pH= 1 - 2) by the addition of concentrated hydrochloric acid thereto and extracted with ethyl acetate twice. The resultant organic extract layer was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, and concentrated under reduced pressure, whereby 9.8 g of the captioned Reference Compound No. 1-1 was obtained in a yield of 74%.

References:

EP520336,1992,A2