Triethylamine → 5,6-Dichloro-2,1,3-benzothiadiazole

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Reaction Steps

To a solution of 4,5-dichlorobenzene-1,2-diamine (3.0 g, 0.017 mol) and triethylamine (9.45 mL, 0.068 mol) in dichloromethane (120 mL) was added SOCl2 (4.92 mL, 0.068 mol) dropwise at room temperature. The resulting reaction mixture was heated to reflux for 20 h. 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 dark solid as the crude compound. The crude compound was purified by flash column chromatography (silica gel, CHCl3) to afford 5,6-dichlorobenzo[1,2,5]thiadiazole as an off-white crystalline solid (2.35 g, 68% yield). 1H NMR (CDCl3 500 MHz): δ: 8.19 (t, 2H, J=8.5 Hz). 13C NMR (CDCl3, 500 MHz): δ 153.07, 135.28, 121.51. Anal. calcd. for (C6H2Cl2N2S): C, 35.14; H, 0.98; N, 13.66. Found: C, 35.08; H, 1.01; H, 13.56. m.p: 108-110° C.

Provenance & Evidence