4-Methylmorpholine → n-Tert-butoxycarbonyl-(r)-(-)thiazolidine-4-carboxylic acid-n-methoxy-n-methyl amide

Participants

Reaction Steps

To a solution in DMF (10 mL) of N-tert-butoxycarbonyl-(R)-(−)thiazolidine-4-carboxylic acid (777 mg, 3.33 mmol), prepared as in Example 164A, 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (602 mg, 3.69 mmol), and ethyl dimethylaminopropyl carbodiimide hydrochloride (709 mg, 3.70 mmol) was added N,O-dimethylhydroxylamine hydrochloride (357 mg, 3.66 mmol) and 4-methylmorpholine (0.44 mL, 4.01 mmol) and the reaction mixture was stirred overnight at ambient temperature. The reaction mixture was diluted with ethyl acetate and extracted with aqueous 1M H3PO4 (2×), saturated aqueous NaHCO3 (2×), and brine. The organic phase was dried over Na2SO4, filtered, and concentrated in vacuo. Chromatography on silica gel (2:1 hexane-ethyl acetate) gave N-tert-butoxycarbonyl-(R)-(−)thiazolidine-4-carboxylic acid-N-methoxy-N-methyl amide (605 mg) as a thick yellow oil.

Provenance & Evidence