Methanol → 7-Ethyl-3-hydroxy-2-(3,4,5-trihydroxyphenyl)-4H-1-benzopyran-4-one

Participants

Reaction Steps

To a stirring solution of 26 (0.504 g, 1.4.mmol) in dichloromethane (50 ml) under Ar at 0° C. was added boron tribromide in dichloromethane (1.0M, 10 ml, 10 mmol, 7 equ). The mixture was warmed to room temperature and then stirred for 21 hours. The reaction was then cooled to 10° C. and methanol (10 ml) added. The reaction was heated to reflux for 3 hours, then concentrated in vacuo to give an orange solid. Water (50 ml) was added and stirred for two hours then left to stand overnight then 9c (0.313 g, 70%) was collected as a black solid.

Provenance & Evidence