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-Eintrag

ord-2b963be2827845c39bb55a6429131886

Quelldatensatz

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08916580B2