Benzyl Bromide → Benzyl 6,6-dibromopenicillanate

Participants

Reaction Steps

To a solution of 54 g. (0.165 mole) of 6,6-dibromopenicillanic acid in 350 ml. of N,N-dimethylacetamide was added 22.9 ml. (0.165 mole) of triethylamine and the solution was stirred for 40 minutes. Benzyl bromide (19.6 ml., 0.165 mole) was added and the resulting mixture was stirred at room temperature for 48 hours. The precipitated triethylamine hydrobromide was filtered off, and the filtrate was added to 1,500 ml. of ice-water, adjusted to pH 2. The mixture was extracted with ether, and the extracts were washed successively with saturated sodium bicarbonate, water and brine. The dried (MgSO4) ether solution was evaporated in vacuo to give an off-white solid, which was recrystallized from isopropanol. This afforded 70.0 g. (95% yield) of the title compound m.p. 75°-76° C. The IR spectrum (KBr disc) showed absorptions at 1795 and 1740 cm-1. The NMR spectrum (CDC13) showed absorptions at 1.53 (s,3H), 1.58 (s,3H), 4.50 (s,1H), 5.13 (s,2H), 5.72 (s,1H) and 7.37 (s,5H)ppm.

Provenance & Evidence