Triethylamine → tert-butyl(2S,3S)-3-methyl-2-{3-[(6-methyl-2-pyridinyl)methyl]-2-oxo-1-imidazolidinyl}pentanoate

Participants

Reaction Conditions

Reaction Steps

A solution containing the product from Example 3G (6.18 g, 26.9 mmol) in dichloromethane (160 mL) was treated with 6-methyl-2-pyridinecarboxaldehyde (3.25 g, 26.8 mmol) and magnesium sulfate (16.3 g, 135.4 mmol) g), stirred at 25° C. for 18 hours, filtered and concentrated. A solution of the residue in methanol (160 mL) was treated with sodium borohydride (1.2 g, 31.7 mmol), stirred at 25° C. for 1 hour, quenched with water, stirred for 15 minutes, and followed by evaporation of the solvent. The concentrate was partitioned between ethyl acetate and saturated NaHCO3, and the organic phase was washed with brine and dried over MgSO4, filtered and concentrated. A solution of the residue (9.1 g, 26.8 mmol) in 1,2-dichloroethane (550 mL) was treated with N,N-disuccinimidyl carbonate (8.24 g, 32.2 mmol) and triethylamine (3.7 mL, 26.5 mmol), stirred at 25° C. for 68 hours, partitioned with 10% Na2CO3, and the organic phase was washed with additional 10% Na2CO3 solution and brine, dried over MgSO4, filtered and concentrated. The residue was chromatographed on silica gel eluting with 0-100% ethyl acetate/dichloroform to give the title compound (6.15 g, 63% yield).

Provenance & Evidence