2-Cyano-6-methoxy benzothiazole → 2-Cyano-6-hydroxybenzothiazole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Dry pyridinium hydrochloride (34.0 g, 0.294 mol) and 2-cyano-6-methoxy-benzothiazole (Aldrich Chemical Co., 3.0 g, 0.016 mol) were added into a 500 mL round bottom flask which was preheated in an oil bath at 100° C. The bath temperature was increased to 190° C. and the reaction mixture was refluxed at this temperature for 2 h. After the completion of reaction, it was cooled to room temperature to obtain a yellow solid which was dissolved in methanol. Silica was added to this solution and evaporated to dryness. This material was then chromatographed using 30% ethyl acetate/hexane to obtain 2.7 g of the product as a white solid (95%): mp 120° C.; 1H NMR (CD3OD) δ 5.68 (bs, 1H), 8.02-8.82 (m, 3H); --C NMR (CD3OD) δ 106.96, 114.26, 119.59, 126.53, 133.83, 138.93, 147.25, 160.23; MS m/e (rel intensity) 176 (100), 151 (3), 124 (5), 96 (15), 85 (4), 69 (7), 57 (5); Exact mass: calcd 176.0044, found 176.0047. ##STR25##

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