2,3-dihydro-7-hydroxy-8-propyl-4H-1-benzopyran-4-one → HCID 54353647, compound

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Reaction Steps

Using the procedure of example 11 and starting with 0.28 g (1.4 mmol) of 2,3-dihydro-7-hydroxy-8-propyl-4H-1-benzopyran-4-one and 0.65 g (1.41 mmol) of 2-[[5 -[(methylsulfonyl)oxy]pentyl]oxy]-4-(4-methoxy-4-oxobutoxy)benzenepropanoic acid methyl ester (from example 137), 4-(4-methoxy-4-oxobutoxy)-2-[5-[(3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl)oxy]pentyloxy]benzenepropanoic acid methyl ester was obtained in 75% yield (0.6 g) as a solid, mp 58°-59° C. This diester (1.05 mmol) was saponified with 3 mL of 3N aqueous lithium hydroxide in 30 mL of tetrahydrofuran, at room temperature, for 16 hr. Work-up as in example 4 but using dichloromethane rather than ether gave a solid acid which was flash-chromatographed on silica gel, eluting with 95:5:1 chloroform-methanol-acetic acid. Recrystallization from ethyl acetate gave 0.44 g (78%) of pure 4-(3-carboxypropoxy)-2-[5-[(3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl)oxy]pentyloxy]benzenepropanoic acid as a colorless solid, mp 163°-164° C.

Provenance & Evidence