1-Hydroxybenzotriazole → Tak-778

Participants

Reaction Conditions

Reaction Steps

A solution of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.39 g) in dichloromethane (7 ml) was added drop by drop to a solution of (2R,4S)-(-)-1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepine-2-carboxylic acid (0.47 g) as obtained in Reference Example 2 (0.41 g) and diethyl 4-aminobenzylphosphonate (0.41 g) in N,N-dimethylformamide (DMF) (7 ml) at 0° C., followed by the addition of 1-hydroxybenzotriazole (HOBt) (0.28 g). After being stirred at 0° C. for 1 hour and at room temperature (25° C.) for 15 hours, the mixture was poured over water and extracted with ethyl acetate. The ethyl acetate layer was washed with water and dried (MgSO4), after which the solvent was distilled off. The residual crystal was collected by filtration, and recrystallized from ethyl-hexane acetate and methanol-hexane to yield compound A (0.37 g, 44%) in the form of a colorless prism.

Provenance & Evidence