Trifluoroacetic acid → N-(4-fluoro-2-methylsulfanyl-benzyl)-O-methyl-hydroxylamine hydrochloride

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Reaction Steps

To a stirred solution of 4-fluoro-2-methylsulfanyl-benzaldehyde-O-methyl-oxime (5.982 g, 29.58 mmol) in CH2Cl2 (30 mL) was added trifluoroacetic acid (30 mL) followed by triethylsilane (14 mL, 90 mmol). After stirring for 6 h, the reaction mixture was concentrated and the resulting residue was taken up in saturated aqueous NaHCO3 (100 mL) and extracted with ethyl acetate (3×75 mL). The combined organic extracts were dried over anhydrous Na2SO4, filtered, and concentrated to give a viscous oil. The crude product was re-dissolved in anhydrous ether and 2M HCl/ether w (18 mL) was added. The resulting white solid was filtered and dried to yield the desired product as the HCl salt (6.666 g, 93% yield). 1HNMR (500 MHz, DMSO-d6) δ: 11.44 (1H, br s), 7.66–7.59 (1H, m), 7.24 (1H, dd, J=10.1, 2.1 Hz), 7.08 (1H, td, J=8.6, 2.4 Hz), 4.85 (2H, s), 3.82 (3H, s), 2.53 (3H, s). MS calcd for C9H13FNOS (M+H): 202.07. found: 202.07.

Provenance & Evidence