Hydrochloric Acid → HCID 54347405, compound

Participants

Reaction Conditions

Reaction Steps

1,2,3,9-tetrahydro-9-oxo-cyclopenta[b][1]benzopyran-7-carboxylic acid, m.p. 273°-275° C. (1.6 g) was reacted with 2-methoxy-benzaldehyde (1 g) in methanol (60 ml) in the presence of sodium methylate (1.3 g) under stirring at 45° C. for 7 hours. After cooling, the reaction mixture was acidified with 37% HCl and the precipitate was filtered and washed with methanol and then with water until neutral. Crystallization from chloroform-ethanol gave 1.2 g of 3-(2-methoxy-benzylidene)-1,2,3,9-tetrahydro-9-oxo-cyclopenta[b][1]benzopyran-7-carboxylic acid, m.p. 291°-295° C., NMR (CH3COOD) δ ppm: 3.36 (bs) (4H, C-1 and C-2 protons), 4.09 (s) (3H, --OCH3), 7.09-7.87 (m), (4H, phenyl protons), 8.07 (d) (1H, C-5 proton), 8.41 (bs) (1H, =CH--), 8.76 (dd) (1H, C- 6 proton), 9.28 (d) (1H, C-8 proton).

Provenance & Evidence