Lawesson's reagent → 7-bromo-3-methyl-4,5-dihydro-1H-benzo[b][1,4]diazepine-2(3H)-thione

A solution of 7-bromo-3-methyl-4,5-dihydro-1H-benzo[b][1,4]diazepin-2(3H)-one (1.8 g, 7.1 mmol) and Lawesson's reagent (4.2 g, 10.4 mmol) in tetrahydrofuran (50 mL) was heated at 80° C. for 12 hours. The mixture was concentrated in vacuo. To the residue was added water (50 mL), extracted with ethyl acetate (50 mL×3). The combined layers were washed with brine (50 mL). The organic phase was dried over anhydrous sodium sulfate, filtered and concentrated to give a crude product, which was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=5:1) to afford 7-bromo-3-methyl-4,5-dihydro-1H-benzo[b][1,4]diazepine-2(3H)-thione (1.5 g, 79%).

1. concentrationThe mixture was concentrated in vacuo
2. additionTo the residue was added water (50 mL)
3. extractionextracted with ethyl acetate (50 mL×3)
4. washThe combined layers were washed with brine (50 mL)
5. dry with materialThe organic phase was dried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customto give a crude product, which
9. customwas purified by column chromatography (silica gel, petroleum ether/ethyl acetate=5:1)

ORD record

ord-310b4cb803804dbdbc80bd9333ac6a69

Source dataset

uspto-grants-2016_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09422292B2