反应详情

Acetyl chloride (460 mg, 5.84 mmol) was added dropwise with ice cooling to a solution of 5-amino-2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran (100g, 4.87 mmol) and triethylamine (640 mg, 6.33 mmol) in tetrahydrofuran (20 ml). After the addition was completed, the mixture was stirred for 4 hours. Water was added to the reaction mixture and the mixture was extracted with chloroform. The extract was washed with saturated sodium bicarbonate solution and saturated saline, dried and concentrated. The residue was purified by column chromatography on silica gel. (chloroform-methanol, 97:3) to obtain the desired compound (920 mg, yield: 76.4%). A part of it was recrystallized from dichloromethane-isopropyl ether, m.p. 190° C. (dichloromethane-isopropyl ether).

1. additionAfter the addition
2. extractionthe mixture was extracted with chloroform
3. washThe extract was washed with saturated sodium bicarbonate solution and saturated saline
4. customdried
5. concentrationconcentrated
6. customThe residue was purified by column chromatography on silica gel