反应详情

4-Isopropyl-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl (1.0 g, 4.8 mmol) was dissolved in dichloromethane (30 mL) and the solution was placed on an ice-bath and brominated according to literature (Tetrahedron 44,10,1988, 2977-2984) in very bad yield. N-Bromosuccinimide (3.45 g, 19.4 mmol) was added slowly at 0° C. and then left overnight at rt. No reaction was observed. An additional 3.45 g of N-bromosuccinimide was added during 8 h, and then the reaction mixture was left at rt for 2 days. Aqueous concentrated Na2CO3 was added and the mixture was extracted with dichloromethane (3×75 mL). The combined organic extracts were dried (MgSO4), filtered and evaporated. The oily residue was purified on a silica gel column with dichloromethane/MeOH (9:1) as eluent. Yield: 196 mg (28%) of 5-bromo-4-isopropyl-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl as an oil.

1. customthe solution was placed on an ice-bath
2. waitthe reaction mixture was left at rt for 2 days
3. extractionthe mixture was extracted with dichloromethane (3×75 mL)
4. dry with materialThe combined organic extracts were dried (MgSO4)
5. filtrationfiltered
6. customevaporated
7. customThe oily residue was purified on a silica gel column with dichloromethane/MeOH (9:1) as eluent