[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][CH2:3][CH:2]1[C:11]([OH:13])=[O:12].[CH2:14](O)[CH3:15].OS(O)(=O)=O>C(Cl)Cl.O>[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][CH2:3][CH:2]1[C:11]([O:13][CH2:14][CH3:15])=[O:12]Chroman-2-carboxylic acid (35.6 g, 0.2 mol) prepared according to the method of Augstein et al., J. Med. Chem., v. 11, pp. 844-848, 1968) and absolute ethanol (24.3 g, 0.6 mol) were combined in 300 ml of CH2Cl2. H2SO4 (0.6 ml, 96%) was added and the mixture gently refluxed for 21 hours, then cooled and diluted with 500 ml H2O. The organic layer was separated, washed with saturated NaHCO3 and then H2O, dried (MgSO4) and stripped to yield present title product as an oil; 38.6 g (93%); 1H-NMR (CDCl3), 300 MHz) delta 7.12 (t, 1H), 7.02 (d, 1H), 6.92 (d, 1H), 6.85 (t, 1H), 4.71 (q, 1H), 4.25 (q. 2H), 2.80 (m, 2H), 2.22 (m, 2H), 1.29 (t, 3H).
Loading…
