تفاعل #657314

معادلة التفاعل

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

المذيبات

chloroform

chloroform

ظروف التفاعل

المعالجة

1. 1
   أخرىthe phases are separated
2. 2
   غسيلthe organic phase is washed with water
3. 3
   تجفيفdried over sodium sulfate
4. 4
   أخرىThe volatiles are evaporated
5. 5
   ترشيحthe crude product is purified by filtration over silica using
6. 6
   workup.ADDITIONa 1:1 mixture of ethyl acetate/cyclohexane as eluent
7. 7
   أخرىAfter 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
   أخرىare obtained as solid

الإجراء التجريبي

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.

المصدر