Imidazole → Methyl 6-tert-butyldimethylsilyloxy-2-naphthoate

Participants

Reaction Steps

A 10 mL round bottom flask fitted with magnetic stirrer and pressure-equalizing dropping funnel was charged with 3 mL of DMF which had been dried by vacuum distillation from CaH2. Methyl 6-hydroxy-2-naphthoate (1.01 g, 5 mmol) and t-butyldimethyl silyl chloride (0.83 g, 5.5 mmol) were added and the atmosphere replaced with nitrogen. A solution of imidazole (0.75 g, 11 mmol) in 3 mL of dry DMF was added via the dropping funnel over 15 minutes, and stirring continued for 4 hours. TLC analysis (SiO2, 5% ethyl acetate/hexane) showed clean conversion to a new material. The solution was poured into 50 mL of 1% aq. Na2CO3 solution and extracted with 3-35 mL portions of pentane. The combined pentane solutions were washed with 25 mL of water, 25 mL of brine and dried over MgSO4. Evaporation of the pentane yielded 1.45 g of slightly yellow solid. Purification by column chromatography on silica using 5% (V/V) ethyl acetate/hexane as eluent afforded 1.4 g (88%) of white solid after recrystallization from pentane: mp 72°-72.5° C.; 1H NMR delta 0.266 (s, 6H), 1.022 (s, 9H), 3.958 (s, 3H), 7.19-8.53 (m, 6H); 13C NMR delta -4.35, 18.23, 25.64, 52,03, 114.74, 122.87, 125.38, 125.62, 126.75, 128.16, 130.87, 130.95, 137.10, 155.69, 167.36; IR (KBr) 2950, 2860, 1715, 1635, 1605, 1480, 1290, 1210 cm1 ; MS m/e (rel. intensity) 316 (33, 285(7), 260 (33), 259 (100), 200 (11), 185 (13), 141 (8). ##STR28##

Provenance & Evidence