Phosphorus tribromide → 1-(2-bromoethyl)-5-(bromomethyl)-3-nitro-1H-pyrazole

To as solution of (1-(2-bromoethyl)-3-nitro-1H-pyrazol-5-yl)methanol (482 mg, 1.93 mmol) in chloroform (20 mL) was cooled to 0° C. was added phosphorus tribromide (522 mg, 0.18 mL, 1.93 mmol) drop wise via syringe. The resulting solution was warmed to room temperature and stirred for 1 h. The resulting solution was cooled to 0° C. and diluted with dichloromethane (50 ml). The resulting solution was made basic (pH 8.5) with saturated aqueous sodium bicarbonate was (20 mL). The layers were separated, and the aqueous layer was extracted with dichloromethane (3×20 mL). The combined organic layers were washed with brine (30 mL), dried over magnesium sulfate. The resulting mixture was filtered and concentrated in vacuo to give 1-(2-bromoethyl)-5-(bromomethyl)-3-nitro-1H-pyrazole (469 mg, 78%) as a yellow solid.

1. temperatureThe resulting solution was cooled to 0° C.
2. customThe layers were separated
3. extractionthe aqueous layer was extracted with dichloromethane (3×20 mL)
4. washThe combined organic layers were washed with brine (30 mL)
5. dry with materialdried over magnesium sulfate
6. filtrationThe resulting mixture was filtered
7. concentrationconcentrated in vacuo

ORD record

ord-02891554ff904e038004ebd00bc5c2b2

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08940741B2