反应详情

2 ml (18.6 mmol) of 3-methylbutyraldehyde were dissolved in 15 ml of dioxane. 40.4 ml (18.6 mmol) of a solution 2% v/v of bromine in dioxane was dropped therein at 0° C. The mixture was maintained at room temperature under stirring for 2 hours, then 2.83 g (37.2 mmol) of thiourea and 5 ml of ethanol were added. After 6 hours at room temperature the solution was evaporated to dryness, the residue was dissolved in methylene chloride and the product extracted with 1M hydrochloric acid; the aqueous layer was made basic by using 30% ammonium hydrate and extracted again with methylene chloride. The organic phase was dried over sodium sulfate and evaporated under vacuum. The residue was chromatographed on a silica gel column, eluting with cyclohexane-ethylacetate to give 1.1 g (42% yield) of the title compound.

1. customat 0° C
2. customAfter 6 hours at room temperature the solution was evaporated to dryness
3. dissolutionthe residue was dissolved in methylene chloride
4. extractionthe product extracted with 1M hydrochloric acid
5. extractionextracted again with methylene chloride
6. dry with materialThe organic phase was dried over sodium sulfate
7. customevaporated under vacuum
8. customThe residue was chromatographed on a silica gel column
9. washeluting with cyclohexane-ethylacetate