1-(2-isopropyloxazol-4-yl)-N-methylmethanamine → N-((N-Methyl-N-((2-isopropyl-4-oxazolyl)methyl)amino)carbonyl)-L-valine Methyl Ester

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Reaction Steps

A solution of N-(((4-nitrophenyl)oxy)carbonyl)-L-valine methyl ester (0.903 g, 0.00305 mol) in anhydrous DMF (6 mL) was added to a solution of 2-isopropyl-4-(((N-methyl)amino)methyl)oxazole (9, 0.470 g, 0.00305 mol) in anhydrous DMF (6 mL) under argon, and the yellow solution was stirred at room temperature for 30 min. Solvent was removed by rotary evaporation in vacuo and the resulting oil dried on high vacuum for 1 hr. The residue was applied to a 150 g SiO2 flash column and eluted with 20% EtOAc/CH2Cl2 and 3% MeOH/CH2Cl2. The material obtained after concentration of the product fractions was repurified on a 100 g SiO2 flash column with a gradient of MeOH/CH2Cl2 (1%, 2%, 3%) to obtain the desired compound as an oil (0.515 g, 0.00165 mol, 54 %): 1H NMR (CDCl3) δ0.97 (dd, J1 =9 Hz, J2 =6.9 Hz, 6H), 1.33 (d, J=6.9 Hz, 6H), 2.11-2.23 (m, 1H), 2.98 (s, 3H), 3.00-3.13 (m, 1H), 3.77 (s, 3H), 4.23-4.36 (m, 2H), 4.36-4.42 (m, 1H), 5.79-5.86 (br d, 1H), 7.46 (s, 1H). Mass spectrum: (M+H)+ =312.

Provenance & Evidence