Hydrochloric Acid → Benzyl 4-methylidenepyrazolidine-1-carboxylate

Participants

Reaction Steps

To a solution of crude 4-methylenepyrazolidine-1,2-dicarboxylic acid 1-benzyl ester 2-tert-butyl ester, 8, (30 g) in methanol (300 ml.) is added thionyl chloride dropwise at 0° C. The reaction is warmed to room temperature and stirred an additional 18 hours. Concentration of the reaction in vacuo affords a yellow oil which crystallizes upon standing to provide 23 g (97% yield) of the desired product as the HCl salt.

Provenance & Evidence