Hydrochloric Acid → 2-Sulfanylidene-2,3-dihydro-1,3-benzothiazole-6-carbonitrile

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Reaction Steps

To a solution of 4-amino-3-chlorobenzonitrile (12.2 g, 80.2 mmol) from Step 1 of this Example in DMF (60 mL) was added potassium O-ethyl carbonodithioate (28.9 g, 180.7 mmol) at rt. The mixture was refluxed for 4 h. After cooling to rt, the reaction mixture was poured into ice water and acidified with 2N aq HCl. The tan solids were collected and dried in vacuum oven overnight. Then the solids were refluxed with 500 mL of CHCl3 for 10 min. After cooling to rt, the mixture was treated with 200 mL of hexanes and sonicated for 20 min. The pale brown solid was collected by filtration to give 2-mercaptobenzo[d]thiazole-6-carbonitrile (12.9 g, 84%). 1H NMR (300 MHz, DMSO-d6) δ 14.16 (br s, 1H), 8.23 (d, J=0.9 Hz, 1H), 7.83 (dd, J=1.3, 8.5 Hz, 1H), 7.31-7.51 (m, 1H).

Provenance & Evidence