N(OC(C)(C)C)=O.N[C:9]1[S:10][C:11]2[CH:17]=[C:16]([C:18]([F:21])([F:20])[F:19])[CH:15]=[CH:14][C:12]=2[N:13]=1.[ClH:22]>C(#N)C.[Cu]>[Cl:22][C:9]1[S:10][C:11]2[CH:17]=[C:16]([C:18]([F:21])([F:20])[F:19])[CH:15]=[CH:14][C:12]=2[N:13]=1In a three-necked flask fitted with a condenser, a suspension of copper II chloride (370 mg, 2.75 mmol) in acetonitrile (5 mL) was treated with tert-butyl nitrite (0.41 mL, 3.44 mmol) and stirred at rt for 10 minutes. A solution of 2-amino-6-trifluoromethylbenzthiazole (500 mg, 2.29 mmol) in acetonitrile (1 mL) was then added dropwise. The mixture was heated at 65° C. for 30 minutes, then cooled and diluted with an excess of 1 N aqueous hydrochloric acid solution. The mixture was extracted with ethyl acetate. The organic phase was separated, dried (MgSO4), and concentrated under reduced pressure. An orange semi-solid (501 mg, 92%) was obtained and used without further purification. 1H NMR (300 MHz, CDCl3) δ 8.10–8.05 (m, 2 H), 7.74 (d, 1 H); LC-MS m/z 238.2 (MH+), ret. time 3.76 min TLC Rf=0.50 (9:1 hexanes/ethyl acetate).
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