N-bromobutanimide → 7-Bromo-5-fluoro-2,3-dihydro-1,4-benzodioxine

A solution of 5-fluoro-2,3-dihydrobenzo[b][1,4]dioxine (1.54 g, 10.0 mmol) and 1-bromopyrrolidine-2,5-dione (1.8 g, 10 mmol) in methanol (20 mL) was heated at reflux for 0.5 h, allowed to cool to ambient temperature and concentrated in vacuo. The residue was taken up in dichloromethane (50 mL) and washed with water (50 mL). The organic phase was dried over magnesium sulfate, filtered and concentrated in vacuo. Purification of the residue by column chromatography eluted with a 0% to 30% gradient of ethyl acetate in hexanes afforded 7-bromo-5-fluoro-2,3-dihydrobenzo[b][1,4]dioxine (2.04 g, 87%) as a colorless solid: MS (ES+) m/z 233.6 (M+1).

1. temperatureat reflux for 0.5 h
2. concentrationconcentrated in vacuo
3. washwashed with water (50 mL)
4. dry with materialThe organic phase was dried over magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customPurification of the residue by column chromatography
8. washeluted with a 0% to 30% gradient of ethyl acetate in hexanes

ORD record

ord-3e10c0ba6a494923a8a9e16ffe3855c6

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08415370B2