反应详情

The cyclization of the crude diamine of Step D was carried out with one equivalent of 1,1′-thiocarbonyldiimidazole in refluxing dioxane under nitrogen for one hour. Subsequently, two equivalents of para-toluenesulfonic acid hydrate were added and the mixture was refluxed for 48 hours. The solvent was removed in vacuo and the residue was dissolved in dichloromethane (100 mL). The solution was washed with water, dried over magnesium sulfate, filtered and evaporated. The crude product was purified by flash chromatography (on Merck-60 silica gel) eluting with 10-25% petroleum ether/ethyl acetate. The title compound was obtained as a white solid (4.4 g, 52%), m.p. 116-118° C.

1. temperaturethe mixture was refluxed for 48 hours
2. customThe solvent was removed in vacuo
3. dissolutionthe residue was dissolved in dichloromethane (100 mL)
4. washThe solution was washed with water
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. customevaporated
8. customThe crude product was purified by flash chromatography (on Merck-60 silica gel)
9. washeluting with 10-25% petroleum ether/ethyl acetate