Niclosamide → HCID 68760257, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A suspension of (R)-(−)-2,2-Dimethyl-5-oxo-1,3-dioxolane-4-acetic acid (Sigma-Aldrich, St. Louis, Mo.) (2.17 g, 12.46 mmol) in chloroform (24 mL) was treated with oxalyl chloride (2.11 mL, 25 mmol) and a drop of N,N-dimethylformamide was added. The progression of reaction was monitored by the observation of gas evolution by means of a bubbler. After 2 hours at room temperature, the reaction mixture was warmed to 50° C. for 2 hours, cooled to room temperature, and concentrated to remove volatiles. This residue was diluted with chloroform (10 mL) and added to a suspension of 5-Chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide (2.04 g, 6.23 mmol) in pyridine (30 mL) in which 4-dimethylaminopyride (20 mg) had been previously dissolved. The reaction mixture was stirred at room temperature for 16 h and then was partitioned between 1N aqueous HCl and ethyl acetate. The ethyl acetate solution was dried over magnesium sulfate and concentrated to a dark oil. The residue was dissolved in chloroform and placed upon a short column of silica gel (60 mm i.d.×15 mm). The product was eluted with chloroform and concentrated to an oil. The product was crystallized with a mixture of hexanes and ethyl acetate. 1HNMR (300 MHz, DMSO-d6): δ1.456 (s, 3H), 1.495 (s, 3H), 4.939 (m, 1H), 7.352 (d, J=9 Hz, 1H, H3), 7.730 (dd, J=3.9 Hz, 1H, H4), 7.851 (d, J=3 Hz, 1H, H6), 8.110 (d, J=9 Hz, 1H, H6′), 8.255 (dd, J=3, 9 Hz, 1H, H5′), 8.411 (d, J=3 Hz, 1H, H3′), 10.481 (s, 1H, NH).

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