反应详情

To a solution composed of 8.82 g (31.7 mmol) of (3,4-dihydro-6-methoxy-2,5,7,8-tetramethyl-2H-benzopyran-2-yl)acetic acid, 5.66 g of thionyl chloride and 20 ml of benzene was added 2 drops of N,N-dimethylformamide, and the mixture was refluxed for 2 hours. Low-boiling substances were distilled off from the reaction mixture under reduced pressure. The residue was dissolved in 20 ml of dioxane and the solution was added dropwise to a solution composed of 65 millimoles of guanidine, 7.5 ml of ethanol and 25 ml of dioxane at room temperature. Thereafter, the resultant mixture was stirred at room temperature for 1 hour and so obtained reaction mixture was poured into water and extracted with diethyl ether. The ether extract was washed with a saturated aqueous solution of sodium chloride and then dried over anhydrous sodium sulfate. Low-boiling substances were distilled off under reduced pressure. The residue was purified by silica gel column chromatography and recrystallized from methylene chloride/diethyl ether/n-hexane to give 5.1 g of N-(3,4-dihydro-6-methoxy-2,5,7,8-tetramethyl-2H-benzopyran-2-yl)-acetylguanidine [Compound (1)], which shows the following physical characteristics.

1. temperaturethe mixture was refluxed for 2 hours
2. distillationLow-boiling substances were distilled off from the reaction mixture under reduced pressure
3. dissolutionThe residue was dissolved in 20 ml of dioxane
4. additionthe solution was added dropwise to a solution
5. customso obtained reaction mixture
6. extractionextracted with diethyl ether
7. extractionThe ether extract
8. washwas washed with a saturated aqueous solution of sodium chloride
9. dry with materialdried over anhydrous sodium sulfate
10. distillationwere distilled off under reduced pressure
11. customThe residue was purified by silica gel column chromatography
12. customrecrystallized from methylene chloride/diethyl ether/n-hexane