反应详情

9.9 g of 2-methyl-1,3-benzodioxole-5,6-diamine dihydrochloride were suspended in 125 ml of isopropanol. While stirring there was added dropwise thereto a solution of 4.75 g of potassium hydroxide in 40 ml of water and the mixture was stirred at room temperature for an additional 30 minutes. After adding 7.5 g of purified potassium ethylxanthate, the solution was boiled at reflux overnight, then diluted with 125 ml of water and made neutral with a small amount of glacial acetic acid. The cooled suspension was filtered under suction and the crystals were washed well with water. There were obtained 7.5 g (87.4% of theory) of 2-methyl-5H-1,3-dioxolo(4,5-f)benzimidazole-6-thiol with a melting point above 300° C.

1. additionwas added dropwise
2. temperatureat reflux overnight
3. filtrationThe cooled suspension was filtered under suction
4. washthe crystals were washed well with water