Synthesis
Methyl 3-hydroxy-2-naphthoate is obtained by reacting 3-hydroxy-2-naphthoic acid with methanol in sulphuric acid.
3-hydroxy-2-naphthoic acid (1.00 g, 5.31 mmol) was dissolved in methanol (20 ml)
and concentrated sulphuric acid (1 ml) and left to reflux overnight with stirring.
The reaction mixture was washed with brine (2×10 ml) and extracted with ethyl
acetate (3 × 10 ml) upon cooling. The organic extracts were collected, dried with
magnesium sulphate and concentrated in vacuo to give the title compound as a
yellow powder (976 mg, 91%): mp: 81℃(Lit.: 75 – 76℃);
vmax/cm-1 3178 br.
m (O-H), 2952 w (aro. C-H), 1515 m (aro. C=C); δH (300 MHz; CDCl3) 10.47 (1H,
s, OH), 8.47 (1H, s, C(1)H), 7.79 (1H, d, J 8.3, C(5)H or C(8)H), 7.68 (1H, d, J 8.3,
C(5)H or C(8)H), 7.50 (1H, td, J 7.5, 1.1, C(6)H or C(7)H), 7.36-7.29 (2H, m,
C(4)H and C(6)H or C(7)H), 4.02 (3H, s, OCH3); δC (75 MHz; CDCl3) 170.3 (Ar-
C), 156.3 (Ar-C), 137.9 (Ar-C), 132.5 (Ar-CH), 129.2 (Ar-CH), 129.1 (Ar-CH),
127.1 (Ar-C), 126.3 (Ar-CH), 124.0 (Ar-CH), 114.2 (Ar-C), 111.7 (Ar-CH), 52.6
(OCH3); m/z (-ES) 201 (100%, [M-H]-), 202 (14%, [M]-).
