Thionyl Chloride → 5-Bromo-6-fluorobenzo[c][1,2,5]thiadiazole
Reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([NH2:10])[C:5]([NH2:9])=[CH:6][C:7]=1[F:8].[S:11](Cl)(Cl)=O>C(Cl)(Cl)Cl.C(OCC)(=O)C>[Br:1][C:2]1[C:7]([F:8])=[CH:6][C:5]2=[N:9][S:11][N:10]=[C:4]2[CH:3]=1Participants
5
Reactant 2
Product 1
Reagents, catalysts & solvents 2
Procedure
4-Bromo-5-fluorobenzene-1,2-diamine (500 mg, 2.4 mmol) was dissolved in 20 mL chloroform, treated in portions with thionyl chloride (580 mg, 4.9 mmol) and heated to reflux for 20 h. After cooling the mixture was diluted with 60 mL ethyl acetate, washed with 15 mL water, 15 mL saturated NaCl, dried (Na2SO4) and concentrated under vacuum. The material was chromatographed on silica with a 0-30% ethyl acetate-hexane gradient to give the title compound as a white solid (425 mg, 76%): mp 79-82° C.; 1H NMR (400 MHz, CDCl3) δ 8.33 (d, J=6.7 Hz, 1H), 7.72 (d, J=8.3 Hz, 1H); 19F NMR (376 MHz, CDCl3) δ −102.91; EIMS m/z 232.