Yield:10155-37-0 67%

Reaction Conditions:

with sulfuric acid for 5 h;Heating / reflux;

Steps:

B2

Method B2; 4-HYDROXY-7-METHOXYBENZO RGL COUMARIN; Sodium 3-hydroxy-7-methoxy-2-naphthoate (Fluka) (4.36 g; 20 mmole) was suspended in methanol (50 ml). Concentrated sulfuric acid (3 mL) was added thereto and the reaction mixture was kept heating under reflux for 5 hours and then it was cooled to room temperature. Ethyl acetate (100 mL) and a saturated sodium bicarbonate solution (100 mL) were added to the mixture. After stirring the layers were separated and the organic layer was washed once again with a saturated sodium bicarbonate solution (100 mL). After drying with sodium sulfate the solvent was evaporated under reduced pressure. In the flask a crystalline product (3.1 g, 67 %) remained, which, in accordance with the process described under method BL and by recrystallization from methanol, yielded 1.4 g (58 %) of light brown crystalline 4- hydroxy-7-methoxybenzo [g] coumarin. 1H-NMR (300 MHz, DMSO-D6) RPPM : 3.89 (s, 3H); 5.65 (s, 1H); 7.30 (dd, J = 2.5 Hz; J = 9.0 Hz, 1H); 7.54 (d, J = 2.4 Hz, 1H); 7. 81 (s, 1H) ; 7.91 (D, J = 9.0 Hz, 1H); 8.35 (s, 1H); 12.59 (bs, 1H) ; MS M/Z : ES- (acetonitrile: water); [M-H]-241. 1.

References:

WO2005/10006,2005,A1 Location in patent:Page/Page column 65