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

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Reaction Steps

A solution of 2.68 g (22.0 mmol) of 2-(methylaminomethyl)-pyridine, from step 3a above, and 5.02g (20.0 mmol) of phenoxycarbonyl-L-valine methyl ester, from step 3b above, in 20 mL of 1,4-dioxane was purged with N2. The solution was then heated at reflux for four hours under a N2 atmosphere, then the solution was concentrated in vacuo. The resulting residue was dissolved in ethyl ether and extracted into 1N HCl. The aqueous layer was adjusted to about pH 9 with solid sodium carbonate and extracted twice with methylene chloride. The organic layers were combined and washed with 0.2M phosphate buffer at pH 7.0. The organic layer was dried over sodium sulfate, filtered and concentrated in vacuo, affording 5.17 g of the title product as a light yellow oil. NMR (CDCl3)δ0.95 (dd,3H), 2.19 (m, 1H), 3.03 (s,3H), 3.72 (s,3H), 4.42 (dd, 1H), 4.54 (s,2 H), 6.14 (bs,1H), 7.26 (m,2H), 7.70 (dt,1H), 8.56 (m, 1H) .

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