2,3-dihydro-7-hydroxy-8-(phenylmethyl)-4H-1-benzopyran-4-one → 2-[5-[(3,4-dihydro-4-oxo-8-(phenylmethyl)-2H-1-benzopyran-7-yl)oxy]pentyloxy]benzenepropanoic acid methyl ester

Participants

Reaction Steps

Using the procedure of example 11 and starting with 1.2 g (4.72 mmol) of 2,3-dihydro-7-hydroxy-8-(phenylmethyl)-4H-1-benzopyran-4-one (from example 70) and 1.64 g (4.76 mmol) of 2-[[5-[(methylsulfonyl)oxy]pentyl]oxy]benzenepropanoic acid methyl ester (from example 72), 2-[5-[(3,4-dihydro-4-oxo-8-(phenylmethyl)-2H-1 -benzopyran-7-yl)oxy]pentyloxy]benzenepropanoic acid methyl ester was obtained in 91.5% yield (2.17 g) as a yellow oil. This diester (4.32 mmol) was saponified with 6.5 mL of 3N aqueous lithium hydroxide in 21 mL of tetrahydrofuran, at room temperature, for 48 hr. Work-up as in example 4 gave 2-[5-[(3,4-dihydro-4-oxo-8-(phenylmethyl)-2H-1-benzopyran-7-yl)oxy]pentyloxy]benzenepropanoic acid as an oil. This material was flash chromatographed on silica gel eluting with ethyl acetate-hexane mixtures giving 1.0 g (47.6%) of pure acid as a solid. Recrystallization from ethyl acetate-ether gave a colorless solid, mp 117°-118° C.

Provenance & Evidence