Hydrochloric Acid → 4-Amino-3-bromobenzthioamide

A stirred solution of 4-amino-3-bromobenzonitile (6.92 g, 35.1 mmol) and diethyl dithiophosphate (17.7 mL 105 mmol, 3 eq.) in absolute ethanol (160 mL) at 0° C. was perfused with hydrogen chloride gas at a moderate rate for 30 minutes. The resulting reaction mixture was stirred at room temperature for 12 hours, and then solvent was removed via evaporation under reduced pressure. The residue was suspended in a saturated solution of sodium hydrogen carbonate (25 mL), and this aqueous mixture was extracted with ethyl acetate (3×25 mL). The organic extracts were combined, dried (MgSO4), and evaporated under reduced pressure. The residue was chromatographed using silica gel (approximately 300 g) and elution with an acetone gradient in methylene chloride [1:50 to 1:20] to afford the title compound (1.02 g, 25%) as an amorphous yellow solid: 1H NMR (DMSO-d6) δ 9.41 (br s, NH), 9.13 (br s, NH), 8.11 (d, J=2.1 Hz, 1H), 7.78 (dd, J=2.1 and 8.6 Hz, 1H), 6.72 (d, J=8.7 Hz, 1H), 6.03 (s, 2NH); TLC: RBf =0.15[1% diethyl ether in methylene chloride].

1. customThe resulting reaction mixture
2. customsolvent was removed via evaporation under reduced pressure
3. extractionthis aqueous mixture was extracted with ethyl acetate (3×25 mL)
4. dry with materialdried (MgSO4)
5. customevaporated under reduced pressure
6. customThe residue was chromatographed
7. washsilica gel (approximately 300 g) and elution with an acetone gradient in methylene chloride [1:50 to 1:20]

ORD record

ord-b959dc04283b47179ba59edf5e32215c

Source dataset

uspto-grants-1998_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05717102