反应详情

A mixture of (3,5-Di-t-butyl-4-hydroxyphenyl)ethanone (EXAMPLE 58, 800 mg) in ether (15 ml) and chloroform (10 ml) is cooled to 0° and then treated in a dropwise manner with a mixture containing 0. 17 ml of bromine dissolved in 5 ml of chloroform. The reaction mixture is allowed to warm to 20°-25° and stirred for 1 hr. Standard work-up gives the crude product (1.21 g) which is chromatographed on 180 g of silica gel. The column is packed and eluted with chloroform. An initial fraction of 200 ml is collected, followed by 7 ml fractions. Based on their TLC homogeneity, fractions 36-65 are combined and concentrated. Recrystallization from hexane gives the title compound, mp 105°-106°; IR (mineral oil) 3590, 2955, 2925, 2871, 2856, 1685, 1594, 1581, 1466, 1459, 1451, 1438, 1426, 1366, 1328, 1302, 1282, 1242, 1194, 1153, 1139, 1121, 860 and 615 cm-1 ; NMR (CDCl3 ; TMS) 7.88, 5.85, 4.40 and 1.47δ; CMR (CDCl3 ; TMS) 190.6, 159.0, 135.9, 126.8, 125.6, 34.2, 30.6 and 29.9δ; MS (m/z) M+ found=327, other ions at m/z 326, 311,233, 219, 203, 189, 175, 115, 101, 87, 57 and 40.

1. temperatureis cooled to 0°
2. additiontreated in a dropwise manner with a mixture
3. additioncontaining 0
4. temperatureto warm to 20°-25°
5. customStandard work-up gives the crude product (1.21 g) which
6. customis chromatographed on 180 g of silica gel
7. washeluted with chloroform
8. customAn initial fraction of 200 ml is collected
9. concentrationconcentrated
10. customRecrystallization from hexane