Pentamethylbenzene → 2H-1-Benzopyran-7-ol, 3-(2-hydroxy-4-methoxyphenyl)-

Participants

Reaction Conditions

Reaction Steps

To a solution of B4 (0.45 g, 0.1 mmol) and pentamethylbenzene (0.158 g, 1 mmol) in anhyd CH2Cl2 (30 mL) at −78° C., BCl3 (0.2 mmol) was dropwise added under N2. The reaction mixture was stirred at −78° C. and after 15-20 min the reaction was quenched with 20 mL of CHCl3/MeOH (10:1) mixture. The resulting mixture was warmed to rt. The organic solvents were evaporated under vacuum. The residues were purified by column chromatography [Silica gel 35 mm dia, 8 inch thick, EtOAc/hexanes (1:2)] to obtain B6 (0.17 g, 0.61 mmol, 61%) as brownish solid: mp 150-154° C.; TLC Rf=0.48 [EtOAc/hexanes (1:2)]; 1H NMR (CD3OD, 600 MHz) δ 7.14 (1H, d, J=8.4 Hz), 6.88 (1H, d, J=8.4 Hz), 6.53 (1H, s), 6.42 (1H, dd, J=2.4, 8.4 Hz), 6.37 (1H, d, J=2.4 Hz), 6.33 (1H, dd, J=2.4, 8.4 Hz), 6.24 (1H, d, J=1.8 Hz), 4.95 (2H, s), 3.75 (3H, s); 13C NMR (CD3OD, 150 MHz) δ 161.8, 159.1, 157.3, 155.9, 130.1, 130.0, 128.4, 121.4, 119.9, 117.6, 109.4, 106.1, 103.4, 102.4, 69.2, 55.6; Anal. (%) calcd for C16H14O4.0.1 H2O, C 70.63, H 5.26, found C 70.42, H 5.20.

Provenance & Evidence