Toluene → {4-[4-(2-Benzyloxycarbonylaminoethoxy)phenyl]butyl}carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

[4-(4-Hydroxyphenyl)butyl]carbamic acid tert-butyl ester (38 g, 0.143 mole), cesium carbonate (84 g, 0.257 mole), and (2-bromoethyl)carbamic acid benzyl ester 14 (59 g, 0.23 mole) were combined in DMF (200 ml). The mixture was mechanically stirred under nitrogen at 63° C. for 5.5 h, and allowed to stand at room temperature overnight. An additional amount of (2-bromoethyl)carbamic acid benzyl ester 14 (5 g, 0.019 mole) and cesium carbonate (7.1 g, 0.21 mole) were added, and the reaction was further stirred at 65° C. for 1 h. Toluene was then added, and the stirring mixture was allowed to cool to room temperature. The mixture was suction filtered through a medium sintered glass buchner funnel and washed with toluene. The solvents were removed under vacuum at 75° C. The remaining oil was washed with hexanes (2×400 mL), then dissolved in ether (500 ml) and washed with a mixture of water and brine (10:1, 4×100 mL). The remaining solution was suction filtered through a 30 g pad of silica gel and the solvent evaporated. The residue was washed with hexanes (3×400 ml), and then placed under vacuum for 2 h to afford 61.8 g of the product 15 which was used without further purification. 1H NMR (300 MHz, CDCl3) δ 1.45 (s, 9H), 1.54 (m, 4H), 2.56 (t, 2H), 3.20 (m, 2H), 3.50 (m, 2H), 3.98 (t, 2H), 4.75 (br s, 1H), 5.00 (br s, 1H), 5.09 (s, 2H), 6.80 (d, 2H), 7.06 (d, 2H), 7.34 (m, 5H).

Provenance & Evidence