(+/-)-3-(3-Cyclopentyloxy-4-methoxyphenyl)sulfanyl-7-phenylheptanoic acid → (+/-)-t-Butyl 3-(3-cyclopentyloxy-4-methoxyphenyl)sulfanyl-7-phenylheptanoate

Participants

Reaction Steps

A stirred solution of 3-cyclopentyloxy-4-methoxybenzenethiol (0.5 g, Reference Example 2) in anhydrous tetrahydrofuran (20 ml), at 0° C. and under nitrogen, was treated with a solution of n-butyllithium in hexane (0.03 ml, 2.5M). After stirring for 15 minutes the mixture was treated dropwise with a solution of t-butyl 7-phenyl-2-heptenoate (0.39 g, Reference Example 5) in tetrahydrofuran (5 ml) and then the mixture was allowed to warm to room temperature. After stirring at room temperature for 18 hours the reaction mixture was diluted with water (50 ml) and then extracted three times with ether (30 ml). The combined organic extracts were washed with brine (50 ml), then dried over magnesium sulphate and then evaporated. The residual pale yellow oil was subjected to flash chromatography on silica eluting with a mixture of petroleum ether and ethyl acetate (97:3, v/v) to give the title compound (0.5 g) as a colourless oil. NMR (CDCl3): δ1.44 (s,9H), 1.55 (m,8H), 1.95 (m,6H), 2.41 (m,2H), 2.60 (app t,2H), 3.25 (m,1H), 3.81 (s,3H) 4.74 (m,1H), 6.79 (d, 1H), 6.99 (dd,2H), 7.10-7.30 (m,5H). Mass spectrum (FAB): m/z 484 M+.

Provenance & Evidence