Water → 6-Chloro-7-methoxy-2-methylchroman-4-one

反応式

[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([OH:8])=[CH:4][C:3]=1[O:9][CH3:10].[C:11](O)(=[O:15])/[CH:12]=[CH:13]/[CH3:14].O>CS(O)(=O)=O>[Cl:1][C:2]1[CH:7]=[C:6]2[C:5](=[CH:4][C:3]=1[O:9][CH3:10])[O:8][CH:13]([CH3:14])[CH2:12][C:11]2=[O:15]

参加物

反応条件

温度: 23 °C

実験手順

A solution of 1.0 g (6.3 mmol) 4-chloro-3-methoxyphenol and 5.4 g (6.3 mmol) crotonic acid in 15 ml methane sulfonic acid was heated at 95° C. under nitrogen for 20 hours. The reaction was cooled to 23° C., poured onto 150 ml ice and water and extracted with 100 ml ethyl acetate. The ethyl acetate extract was successively washed with 100 ml water, 2×100 ml 1N sodium hydroxide and 100 ml brine, dried over magnesium sulfate and concentrated in vacuo to a purple crystalline solid. This was purified by flash chromatography on 150 cc silica gel using chloroform as eluant to give the product as a yellow crystalline solid, 1.1 g (78%); m.p. 96°-100° C.