Diisopropylamine → 3-Amino-3-[4-benzyloxy-7-(4-chloro-phenylsulfanyl)-3-methoxybicyclo[4.2.0]octa-1,3,5-trien-7-yl]-acrylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of ethylmagnesium bromide (3.26 mL of a 3M solution in diethyl ether, 9.8 mmol) in anhydrous tetrahydrofuran (10 mL) at 0° C. under nitrogen is added diisopropylamine (2.75 mL, 19.6 mmol). The mixture is stirred at 0° C. for 1 hour. t-Butyl acetate (0.5 mL, 3.6 mmol) and a solution of 1.0 g (2.45 mmol) of 4-benzyloxy-7-(4-chloro-phenylsulfanyl)-3-methoxybicyclo[4.2.0]octa-1,3,5-triene-7-carbonitrile in anhydrous tetrahydrofuran (10 mL) are added successively, and the resulting mixture is stirred for an additional hour. The reaction is quenched with aqueous ammonium chloride and the product mixture is extracted with ethyl acetate. The ethyl acetate extract is washed with brine, dried over anhydrous sodium sulfate and passed through a plug of silica to give 3-amino-3-[4-benzyloxy-7-(4-chloro-phenylsulfanyl)-3-methoxybicyclo[4.2.0]octa-1,3,5-trien-7-yl]-acrylic acid tert-butyl ester as a clear oil, that solidified upon standing, mp 112-115° C.

Provenance & Evidence