Hydrochloric Acid → Methyl 8-oxo-5,6,7,8-tetrahydronaphthalene-2-carboxylate
Reaction equation
[C:1]1(=[O:14])[C:10]2[C:5](=[CH:6][CH:7]=[C:8]([C:11]([OH:13])=[O:12])[CH:9]=2)[CH2:4][CH2:3][CH2:2]1.[CH3:15]O.Cl>>[CH3:15][O:12][C:11]([C:8]1[CH:9]=[C:10]2[C:5]([CH2:4][CH2:3][CH2:2][C:1]2=[O:14])=[CH:6][CH:7]=1)=[O:13]Participants
4
Procedure
Part A--A mixture of 1-tetralon-7-carboxylic acid (7.0 g, 0.037 mol) in methanol (13.6 mL, 10.8 g, 0.30 mol) with a catalytic amount of hydrochloric acid (0.07 mL, 0.12 g, 0.0012 mol) was stirred at reflux over 5 hours. The cooled reaction mixture was poured into ice water and extracted with ethyl acetate. The combined organic layers were backwashed with water and brine, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The resulting solid was purified by flash chromatography using hexane:ethyl acetate::75:25. The resulting solid was triturated with hexane to give 1-tetralon-7-carboxylic acid methyl ester (3.61 g, 0.018 mol, 49%) as a yellow solid. mp=170°-172° C.; 1H NMR (CDCl3) d 8.7 (s, 1H), 8.15 (d, 1H, J=8.1 Hz), 7.35 (d, 1H, J=8.1 Hz), 3.95 (s, 3H), 3.05 (d, 2H, J=6.1 Hz), 2.7 (t, 2H, J=6.4 Hz), 2.15 (quintet, 2H, J=6.2 Hz).