Potassium Carbonate → 3-(2,1,3-Benzothiadiazol-5-yl)-4-(4-cyclopentyloxy-3,5-dimethoxy-benzyl)-5-hydroxy-5-(4-methoxyphenyl)-5H-furan-2-one

Participants

Reaction Steps

0.368 g of 4-cyclopentyloxy-3,5-dimethoxybenzaldehyde (“A”) and 0.52 g of ethyl 2-(2,1,3-benzothiadiazol-5-yl)-4-(4-methoxyphenyl)-4-oxobutanoate, m.p. 89° (obtainable by reaction of 5.5 g of ethyl 2-(2,1,3-benzothiadiazol-5-yl)acetate with 5.5 g of 2′-bromo-4-methoxyacetophenone and 4 g of potassium carbonate in 200 ml of acetone, 18 hours under reflux; ethyl 2-(2,1,3-benzothiadiazol-5-yl)acetate, m.p. 40-41° is obtained by reaction of 24.3 g of ethyl 3,4-diaminophenylacetate and 26.9 ml of thionylaniline in 80 ml of toluene, 4 hours under reflux) are added to a solution of 34 mg of sodium in 10 ml of ethanol and the mixture is heated under reflux for one hour. After addition of 1.4 ml of acetic acid, it is heated for a further 16 hours. The solvent is removed and the residue is worked up in the customary manner. 3-(2,1,3-Benzothiadiazol-5-yl)-4-(4-cyclopentyloxy-3,5-dimethoxy-benzyl)-5-hydroxy-5-(4-methoxyphenyl)-5H-furan-2-one is obtained, FAB 575.

Provenance & Evidence