Borane → 6-bromo-8-fluoro-5-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazine

An ice cold mixture of 6-bromo-8-fluoro-5-methyl-2H-benzo[b][1,4]oxazin-3(4H)-one (510 mg, 1.961 mmol) in Tetrahydrofuran (THF) (8 mL) was treated with borane 1M in THF (2.94 mL, 2.94 mmol) (1.5 eq) and then stirred at ambient temperature for 150 minutes. The mixture was cooled to 0° C. and then quenched slowly with 1N NaOH (5 mL×10). The mixture was extracted with ethyl acetate, washed with 1N NaOH, dried over sodium sulfate, filtered and then concentrated to afford 6-bromo-8-fluoro-5-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazine (450 mg) as a light brown solid which was used without further purification. 1H NMR (400 MHz, CHLOROFORM-d) d=6.77 (d, J=10.1 Hz, 1 H), 4.28-4.25 (m, 2 H), 3.77 (br. s., 1 H), 3.52 (m, 2 H), 2.16 (s, 3 H); LC/MS (m/z) ES+=245.99 (M+1).

1. temperatureThe mixture was cooled to 0° C.
2. customquenched slowly with 1N NaOH (5 mL×10)
3. extractionThe mixture was extracted with ethyl acetate
4. washwashed with 1N NaOH
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated

ORD record

ord-43ee0bab69bd4c768253ff05d6a64669

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08609653B2