4-Methylmorpholine → (S)-3-Methyl-2-[[methyl-(2-pyridinylmethyl)amino]carbonyl]aminobutyric acid methyl ester

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Reaction Steps

A mixture of 1.61 g (7.2 mmol) of 2-(N-methylamino)methyl)pyridine dihydrochloride and 1.14 g (7.2 mmol) of α-isocyanato-valine methyl ester in 40 ml of dichloromethane was treated with 2 ml (18 mmol) of 4-methylmorpholine. After being stirred for 2 h, the solution was partitioned between dichloromethane and water, dried over Na2SO4, and concentrated. Chromatography on silica gel using 2% methanol in chloroform provided 1.94 g (96%) of the desired compound (Rf 0.32, 5% methanol in chloroform) as a colorless oil. 1H NMR (CDCl3) δ 0.93 (d, J=7 Hz, 3 H), 0.97 (d, J=7 Hz, 3 H), 2.16 (m, 1 H), 3.03 (s, 3 H), 3.72 (s, 3 H), 4.43 (dd, J=8, 5 Hz, 1 H), 4.55 (s, 2 H), 6.15 (br, 1 H), 7.22 (dd, J=8, 6 Hz, 1 H), 7.28 (d, J=6 Hz, 1 H), 7.69 (br t, 1 H), 8.55 (d, J=5 Hz, 1 H).

Provenance & Evidence