Dicyclohexylcarbodiimide → (1R,4R)-3-Benzoyl-4-[(R)-alpha-methyl-p-hydroxybenzylcarbamoyl]-1-oxothiazolidine

Participants

Reaction Conditions

Reaction Steps

9.47 g (69.11 mmole) of (R)-α-methyl-p-hydroxybenzylamine (prepared as described in Preparation 13), 10.58 g (69.11 mmole) of N-hydroxybenzotriazole monohydrate and 14.26 g (69.11 mmole) of dicyclohexylcarbodiimide were added in that order to a solution of 17.50 g (69.11 mmole) of (1R,4R)-3-benzoyl-1-oxo-thiazolidine-4-carboxylic acid (prepared as described in Preparation 10) in 100 ml of dimethylformamide cooled at 5° C., and the mixture was stirred at a temperature between 3° and 6° C. for 30 minutes and then at room temperature for a further 4 hours. At the end of this time, the reaction mixture was filtered and the insolubles were washed with 100 ml of hot dimethylformamide. The filtrate and the washings were combined and concentrated by evaporation under reduced pressure to leave crystals. These crystals were recrystallized from methanol to give 19.21 g (74.6%) of the title compound in the form of colorless needles melting at 233°-234° C.

Provenance & Evidence