5-Benzyloxycarbonylamino-2-(4-methyl-imidazol-1-yl)fluorobenzene (54 g, 0.166 M) was dissolved in a mixture of dry tetrahydrofuran (600 ml) and 1,3-dimethyl-2,4,5,6-tetrahydro-2(1H)-pyrimidinone (100 ml) under nitrogen, cooled to −70°, and treated with a solution of n-butyllithium (1.6 M in isohexane, 114 ml), over 30 minutes. After stirring for 30 minutes at −70°, a solution of (R)-glycidylbutyrate (26.35 g, 0.183 M) in dry tetrahydrofuran (50 ml) was added over 15 minutes. Stirring was continued for 16 hours allowing the temperature to rise to ambient. The mixturc was treated with aqueous sodium bicarbonate (5%, 500 ml) and EtOAc (800 ml), and undissolved solid was removed and washed well with diethyl ether to give title product (16.3 g). The aqueous layer was further extracted with EtOAc (2×750 ml), the combined extracts dried (magnesium sulfate) and evaporated, and the residue triturated with diethyl ether. The resulting solid was recrystallisd from ethanol to give more product (10.9 g). MS (ESP): 292 (MH+) for C14H14FN3O3.
