Triethylamine → 5,6-difluorobenzo[c][1,2,5]thiadiazole

Participants

Reaction Steps

To a solution of 4,5-difluorobenzene-1,2-diamine (2.0 g, 0.014 mol) and triethylamine (7.8 mL, 0.056 mol) in dichloromethane (80 mL) was added SOCl2 (4.04 mL, 0.055 mol) dropwise at room temperature. The resulting reaction mixture was heated to reflux overnight. The reaction mixture was then allowed to cool to room temperature, and quenched with water carefully. The resulting mixture was extracted with dichloromethane, dried over Na2SO4 and concentrated on a rotary evaporator to give a white solid as the crude compound. The crude product was purified by flash column chromatography (silica gel, hexanes) to afford 5,6-difluorobenzo[1,2,5]thiadiazole as a white crystalline solid (1.4 g, 58% yield). 1H NMR (CDCl3 500 MHz): δ: 7.76 (t, 2H, J=8.5 Hz). 13C NMR (CDCl3, 500 MHz): δ 154.94, 154.78, 152.86, 152.70, 150.89, 150.85, 150.81, 106.26, 106.21, 106.14, 106.09. Anal. calcd. for (C6H2F2N2S): C, 41.86; H, 1.17; N, 16.27. Found: C, 41.41; H, 1.22; H, 15.87. m.p: 64-65° C.

Provenance & Evidence