反应详情

Trifluoroacetic acid (27.4 ml) was added to a stirred, chilled (ice-methanol bath) solution of 2-(4-chloro-6-fluoro-1-hydroxy-1-indanyl)acetic acid (12.5 g, 0.05 mol) in dichloromethane (200 ml). After 1.5 h, the mixture was concentrated in vacuo. Dichloromethane was added to the residue and the mixture was concentrated in vacuo to give 10.6 g of crude (E)-2-(4-chloro-6-fluoro-1-indanylidene)acetic acid. Chromatography of a 1.0 g sample on silica gel with ethyl acetate:hexanes (1:1) as eluent gave 0.32 g of (E)-2-(4-chloro-6-fluoro-1-indanylidene)acetic acid as a white solid: mp 229°-230° C.

1. concentrationthe mixture was concentrated in vacuo
2. additionDichloromethane was added to the residue
3. concentrationthe mixture was concentrated in vacuo