4,7-Dibromo-2,1,3-benzothiadiazole → 3,6-Dibromobenzene-1,2-diamine

Temperature

30 °C

NaBH4 (26 g, 680 mmol, 10 equiv) was added portionwise (2 h) to a vigorously stirred suspension of 4,7-dibromo-benzo[1,2,5]thiadiazole (Step 1.7) (20 g, 68.0 mmol) in EtOH (400 mL), under a nitrogen atmosphere and keeping the internal temperature below 15° C. The reaction mixture was allowed to warm to 30° C., stirred for 1 h, cooled to 5° C., quenched by addition of H2O (50 mL), and concentrated. The residue was diluted with Et2O/H2O. The resulting suspension was filtered and the filtrate extracted with Et2O. The organic phase was washed with H2O and brine, dried (Na2SO4), filtered and concentrated. The residue was triturated in hexane to provide 12 g of the title compound as a white solid: ESI-MS: 262.9/264.9/266.9 [M−H]−; tR=4.20 min (System 1).

1. customthe internal temperature below 15° C
2. temperaturecooled to 5° C.
3. customquenched by addition of H2O (50 mL)
4. concentrationconcentrated
5. additionThe residue was diluted with Et2O/H2O
6. filtrationThe resulting suspension was filtered
7. extractionthe filtrate extracted with Et2O
8. washThe organic phase was washed with H2O and brine
9. dry with materialdried (Na2SO4)
10. filtrationfiltered
11. concentrationconcentrated
12. customThe residue was triturated in hexane

ORD record

ord-52494ee422464adcbc510367089c2322

Source dataset

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08536175B2