Reacción #657314

Ecuación de reacción

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

Disolventes

chloroform

chloroform

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrothe phases are separated
2. 2
   Lavadothe organic phase is washed with water
3. 3
   Secadodried over sodium sulfate
4. 4
   OtroThe volatiles are evaporated
5. 5
   Filtraciónthe crude product is purified by filtration over silica using
6. 6
   workup.ADDITIONa 1:1 mixture of ethyl acetate/cyclohexane as eluent
7. 7
   OtroAfter 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
   Otroare obtained as solid

Procedimiento

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.

Fuente