Dicyclohexylcarbodiimide → HCID 9932935, compound

Participants

Reaction Steps

(2R,4R)-tert-Butyl 3-(2-tert-butoxycarbonylamino)-2-(2-fluorophenyl)-thiazolidine-4-carboxylate can be prepared in the following manner: a solution of 18.2 g of N,N'-dicyclohexylcarbodiimide in 75 cm3 of anhydrous acetonitrile is added over 30 minutes to a solution of 25.0 g of (2RS,4R)-tert-butyl 2-(2-fluorophenyl)thiazolidine-4-carboxylate and of 15.5 g of 2-tert-butoxycarbonylaminoacetic acid in 150 cm3 of anhydrous acetonitrile, maintained at a temperature close to 0° C. The reaction mixture is stirred for 16 hours at a temperature close to 25° C. The insoluble product is separated off by filtration, washed with 3 times 20 cm3 of acetonitrile, and the filtrate is concentrated to dryness at reduced pressure at 40° C. The crude product obtained is purified by chromatography on silica [eluent: ethyl acetatecyclohexane (30-70 by volume)]. The fractions containing the expected product are combined and concentrated to dryness at reduced pressure at 40° C. 25.0 g of (2R,4R)-tert-butyl 3-(2-tert-butoxycarbonylaminoacetyl)-2-(2-fluorophenyl)thiazolidine-4-carboxylate are thus obtained in the form of an oil, which is employed as it is in the subsequent syntheses.

Provenance & Evidence