反応 #657314

反応方程式

2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine

bromine

sodium thiosulfate

→

3-bromo-2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine

溶媒

chloroform

chloroform

反応条件

後処理

1. 1
   その他the phases are separated
2. 2
   洗浄the organic phase is washed with water
3. 3
   乾燥dried over sodium sulfate
4. 4
   その他The volatiles are evaporated
5. 5
   ろ過the crude product is purified by filtration over silica using
6. 6
   workup.ADDITIONa 1:1 mixture of ethyl acetate/cyclohexane as eluent
7. 7
   その他After evaporation of the solvent 7.0 g (90%) of 3-bromo-2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine
8. 8
   その他are obtained as solid

実験手順

To a solution of 2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine (6.3 g, 0.031 mol) in 60 mL chloroform is added a solution of bromine (1 eq, 5.03 g, 0.031 mol) in 40 mL chloroform over a period of 25 min at room temperature. The resulting suspension is stirred for 4 h at room temperature. Thereafter the reaction mixture is treated with aqueous sodium thiosulfate, the phases are separated and the organic phase is washed with water and dried over sodium sulfate. The volatiles are evaporated and the crude product is purified by filtration over silica using a 1:1 mixture of ethyl acetate/cyclohexane as eluent. After evaporation of the solvent 7.0 g (90%) of 3-bromo-2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine are obtained as solid.

出典