O-(propan-2-yl)hydroxylamine hydrochloride → methyl (2E)-2-(3-chloro-4-methylsulfonylphenyl)-2-propan-2-yloxyiminoacetate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

(3-Chloro-4-methanesulfonyl-phenyl)-oxo-acetic acid methyl ester (prepared as in Example 1, 1.30 g, 4.70 mmol) was stirred in methanol (9.5 mL) and warmed in a 70° C. oil bath. O-Isopropyl-hydroxylamine hydrochloride (786 mg, 7.04 mmol) was added. After 7 h, the reaction mixture was allowed to cool and concentrated in vacuo. The residue was dissolved in ethyl acetate (100 mL) and washed with 0.2 M aqueous potassium bisulfate solution (50 mL), 50% aqueous sodium bicarbonate solution (50 mL) and brine (50 mL). The organic phase was dried over magnesium sulfate and concentrated in vacuo. Purification by flash column chromatography (Merck silica gel 60, 40-63 μm; 20% ethyl acetate/hexanes to 33% ethyl acetate/hexanes) afforded (E)-(3-chloro-4-methanesulfonyl-phenyl)-isopropoxyimino-acetic acid methyl ester as a faintly yellow oil contaminated with an unknown impurity (645 mg, <41%): LC-MS (ESI) m/e calcd for C13H16ClNO5S [M+] 333.04, found 334 [M+H+].

Herkunft & Nachweise