反应详情

A solution of intermediate 19a (55 mg, 0.138 mmol) in 4 mL 1:1 TFA/CH2Cl2 with 2 drops water was stirred at rt for 12 h. The mixture was concentrated in vacuo, then coevaporated with CCl4 to afford 50 mg of intermediate 19b (quantitative), which was used without further purification in the following step.

1. concentrationThe mixture was concentrated in vacuo