反应详情

10.2 g of 4-methyl-1,2,3,4-tetrahydro-β-carbolin-3-carboxylic acid ethyl ester is dissolved/suspended in 300 ml xylene and the mixture is boiled for 10 minutes in a Dean-Stark apparatus to remove moisture. After cooling to 100°-110° C., 2.1 mole equivalents of sulphur are added and the mixture is boiled under reflux for 5 hours. The progress of the reaction is followed by DC. Subsequently, the xylene is evaporated in vacuo. The remainder is dissolved in chloroform and purified by chromatography (chloroform-ethanol radient) on silica to remove non-reacted sulphur. 4-Methyl-β-carbolin-3-carboxylic acid ethyl ester having a melting point of 235°-239° C. is obtained in a yield of 72%.

1. customto remove moisture
2. temperatureAfter cooling to 100°-110° C.
3. addition2.1 mole equivalents of sulphur are added
4. temperatureunder reflux for 5 hours
5. customSubsequently, the xylene is evaporated in vacuo
6. dissolutionThe remainder is dissolved in chloroform
7. custompurified by chromatography (chloroform-ethanol radient) on silica
8. customto remove non-reacted sulphur