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-a06530950c6e46f28dbbb3cdd255b661

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08263606B2