1,4-Dibromobutane → 1,1-Dimethylethyl 4-{4-[(4-bromobutyl)oxy]butyl}benzoate

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Reaction Steps

To 1,1-dimethylethyl 4-(4-hydroxybutyl)benzoate (0.85 g, 3.4 mmol, e.g. which can be as prepared in Intermediate 23) was added 1,4-dibromobutane (1.22 ml, 10.2 mmol, 3 equivalents, commercially available e.g. from Aldrich), tetra-n-butylammonium bisulphate (0.034 g, 0.1 mmol, 0.03 equivalents) and aqueous sodium hydroxide solution (50% w/v NaOH, 5 ml). The resultant biphasic mixture was stirred at room temperature over the weekend (this can be e.g. about 64 hours), diluted with water (20 ml) and extracted with diethyl ether (50 ml). The organic extract washed with water (20 ml), dried (Na2SO4) and evaporated to dryness. The residue was purified by passing through a 50 g silica SPE cartridge eluting with cyclohexane (100 ml), 9:1 cyclochexane:ethyl acetate (100 ml), 4:1 cyclohexane:ethyl acetate (200 ml) and 1:1 cyclohexane:ethyl acetate (100 ml). The 4:1 cyclohexane:ethyl acetate fraction containing the product was evaporated to give the title compound (1.05 g). LCMS showed TRET=4.14 min with: MH+=385 (trace), and [MH]++18 adduct=402/404 (Bromine isotope pattern).

Provenance & Evidence