反应详情

In a nitrogen atmosphere, 10 ml (138 mmol.) of thionyl chloride was added to 1.00 g (4.71 mmol.) of 2,3,4-trimethoxybenzoic acid. The mixture was refluxed under heating for 2 hours. The solvent was distilled off under reduced pressure. To the residue was added 10 ml of dry benzene, and the mixture was placed under reduced pressure to distill off benzene. This procedure was repeated once. To the residue was dropwise added at room temperature a solution of 0.88 g (4.74 mmol., purity 95%) of methyl 1-piperazinecarbodithioate in 12 ml of dichloromethane. In the course of the addition, 0.48 g (4.74 mmol.) of triethylamine was added to the mixture. The resulting mixture was then stirred overnight. The reaction mixture was washed successively with 1-N hydrochloric acid and a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, and placed under pressure to distill off the solvent. The residue was crystallized from acetone. The crystals were collected by filtration. The filtrate was concentrated, and additional crystals were further precipitated from the concentrated filtrate by addition of a small amount of ethanol. These crystalline portions were combined to give 0.90 g of the desired compound as a white crystalline product, m.p. 149°-150° C. (decomp.), yield 51.6%.

1. temperatureThe mixture was refluxed
2. temperatureunder heating for 2 hours
3. distillationThe solvent was distilled off under reduced pressure
4. additionTo the residue was added 10 ml of dry benzene
5. distillationto distill off benzene
6. additionwas added to the mixture
7. washThe reaction mixture was washed successively with 1-N hydrochloric acid
8. dry with materiala saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate
9. distillationto distill off the solvent
10. customThe residue was crystallized from acetone
11. filtrationThe crystals were collected by filtration
12. concentrationThe filtrate was concentrated
13. customadditional crystals were further precipitated from the concentrated filtrate by addition of a small amount of ethanol