Methyl chloroformate → [2-[[2,6-bis(1-Methylethyl)phenyl]amino]-2-oxoethyl](diphenylmethyl)carbamic acid methyl ester

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Reaction Steps

Several milliliters of methylchloroformate was added to the product from Example 4 (0.60 g) in a mixture of excess NEt3 and EtOAc at room temperature. Vigorous outgassing occurred with the formation of a precipitate. The solution was stripped to dryness and the residue taken up in a mixture of 50 mL THF and 50 mL saturated NaHCO3 solution. Excess methyl chloroformate was added at room temperature. This solution was allowed to sit 5 days at room temperature. The reaction mixture was diluted with EtOAc and washed with aqueous K2CO3 solution and aqueous NaCl solution. The organic layer was dried over MgSO4, filtered, and concentrated to a white solid. The solid was slurried in hexane/EtOAc 9/1 and collected by filtration. 0.55 g (80%). NMR (CDCl3) δ 1.06 (12H, d), δ 2.56 (2H, m), δ 3.84 (3H, s), δ 4.20 (2H, s), δ 6.80 (1H, bs), δ 7.0-7.5 (13H, m). IR (KBr) 3443, 2963, 1705, 1685, 699 cm-1.

Provenance & Evidence