反应详情

10.5 mL of trifluoroacetic acid was added under ice cooling to a 25 mL chloroform solution of 3.50 g of the compound obtained in step 1-2b, after which the reaction mixture was stirred for 3 hours at room temperature. The solvent was then distilled off under reduced pressure, which gave 7.27 g of residue (yellow oily substance). This compound was used in the following reaction without being purified.

1. distillationThe solvent was then distilled off under reduced pressure, which