反应详情

336.0 g of potassium t-butoxy was suspended in 2 liters of toluene. Under cooling on ice, 2 liters of 196.0 g of 2'-hyroxy-4',6'-dimethoxyacetophenone and 72.0 ml carbon disulfide in toluene were added dropwise to said suspension. The mixture was stirred for 20 hours at room temperature, and 7 liters of water was added for extraction of a toluene layer. This toluene solution was adjusted to pH 4-5 by addition of 800 ml of 10% sulfuric acid (aq.) and was then stirred for 5 hours at room temperature. The solution was allowed to stand overnight. The resulting yellow crystals were collected by filtration under reduced pressure, sufficiently washed with water and dried at 50° C. for 3 days under reduced pressure, thus giving rise to 160.0 g crude 4-hydroxy-5,7-dimethoxychromene-2-thion.

1. additionwere added dropwise
2. stirringwas then stirred for 5 hours at room temperature
3. waitto stand overnight
4. filtrationThe resulting yellow crystals were collected by filtration under reduced pressure
5. washsufficiently washed with water
6. customdried at 50° C. for 3 days under reduced pressure