N-(tert-butoxycarbonyl)glycine → methyl N-(tert-butoxycarbonyl)glycylglycinate

Participants

Reaction Steps

N-tert-butoxycarbonyl glycine (10.57 g, 60.33 mmol) and glycine methyl ester hydrochloride (7.58 g, 60.4 mmol) were dissolved in DMF (60 mL). N,N-diisopropylethyl amine (7.80 g, 60.4 mmol) and HOBt hydrate (9.24 g, 60.3 mmol) dissolved in DMF (40 mL) were added. The solution was cooled to 0° C. (icebath) and EDC hydrochloride (12.72 g, 66.35 mmol) added in small portions. The reaction mixture was stirred for 15 hours before the solvent was evaporated. The residue was taken up in EtOAc (300 mL) and washed with 2 M aqueous H2SO4 (3×50 mL), 7.5% (w/w) aqueous K2CO3 (3×50 mL) and saturated brine (50 mL). The solution was dried with anhydrous MgSO4 and the solvent evaporated affording the title compound as a clear liquid (10.34 g, 70%) with spectral characteristics in accordance with literature data8; δH (300 MHz; d6-DMSO) 8.17 (1H, t, J 6, NH(Gly2)), 6.97 (1H, t, J 6, NH(Gly1)), 3.85 (2H, d, J 6, CαH2(Gly2)), 3.62 (3H, s, OCH3), 3.57 (2H, d, J 6, CαH2(Gly1)), 1.38 (9H, s, (CH3)3); δC (75 MHz; d6-DMSO) 170.2, 169.9, 155.7, 78.0, 51.6, 42.9, 40.4, 28.1; m/z (ESI) 269.1110 ([M+Na]+; C10H18N2O5 requires 269.1113)

Provenance & Evidence