Benzo(d)thiazol-2-amine → (2E)-N-(1,3-benzothiazol-2-yl)-2-(3-chloro-4-methylsulfonylphenyl)-2-(2-methylpropoxyimino)acetamide

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Reaction Steps

(E)-(3-chloro-4-methanesulfonyl-phenyl)-isobutoxyimino-acetic acid (prepared as in Example 24, 104 mg, 0.31 mmol), 2-aminobenzothiazole (47 mg, 0.31 mmol) and N,N-diisopropylethylamine (163 μL, 0.94 mmol) were combined in methylene chloride (1.5 mL) and cooled in an ice bath. O-(7-Azabenzotriazole-1-yl)-N,N,N′N′-tetramethyluronium hexafluoro-phosphate (119 mg, 0.31 mmol) was added and the ice bath was removed. After stirring 2 h, the reaction mixture was evaporated in vacuo. The residue was treated with saturated aqueous sodium bicarbonate solution (1 mL) and extracted with chloroform (2×3 mL). The combined organic phases were dried over sodium sulfate and evaporated in vacuo. The residue was purified by flash column chromatography (Merck silica gel 60, 40-63 μm; 30% ethyl acetate/hexanes) to afford (E)-N-benzothiazol-2-yl-2-(3-chloro-4-methanesulfonyl-phenyl)-2-isobutoxyimino-acetamide (86 mg, 60%) as a white solid after lyophilization from aqueous acetonitrile: LC-MS (ESI) m/e calcd for C20H20ClN3O4S2 [M+] 465.06, found 466 [M+H+]; H1-NMR (400 MHz, CDCl3) δ ppm 0.97 (d, J=6.6 Hz, 6 H, 2×CH3), 2.09 (m, 1 H, CH), 3.32 (s, 3 H, SO2CH3), 4.12 (d, J=6.8 Hz, 2 H, OCH2), 7.35 (brt, J=7.8 Hz, 1H, Ar), 7.48 (brt, J=7.8 Hz, 1H, Ar), 7.63 (dd, Jo=8.2, Jm=1.6 Hz, 1 H, Ar), 7.74 (d, Jm=1.6 Hz, 1 H, Ar), 7.83 (m, 2H, Ar), 8.24 (d, Jo=8.2 Hz, 1 H, Ar), 10.25 (brs, 1 H, NH).

Provenance & Evidence