Chloroacetaldehyde → HCID 118511939, compound

Participants

Reaction Conditions

Reaction Steps

(R)-tert-Butyl 6-(benzyloxy)-4-((tert-butoxycarbonyl)amino)-3-oxohexanoate (724a, 6.60 g, 16.20 mmol) was treated with NH3 (2 M in MeOH, 81 mL, 162 mmol) and ammonium acetate (9.36 g, 121 mmol) at RT. The resulting mixture was stirred for at 50° C. for 30 min, then treated with chloroacetaldehyde (50 wt % in water, 10.42 mL, 81 mmol) and stirred at 50° C. for 2 h. The reaction mixture was stirred at RT overnight (16 h). The reaction mixture was concentrated to remove most of MeOH and partitioned between sat'd NaHCO3 (100 mL) and EtOAc (100 mL). The aqueous layer was extracted with EtOAc (2×50 mL), and the combined organic extracts were washed with water and brine, dried over anhydrous MgSO4, filtered, and concentrated under reduced pressure (rotary evaporator) to afford the crude product as a brown oil. The crude residue was purified on an ISCO Combiflash RF (160 g Thomson SingleStep column, using a gradient of 0-10% EtOAc in DCM) affording (R)-tert-butyl 2-(3-(benzyloxy)-1-((tert-butoxycarbonyl)amino)propyl)-1H-pyrrole-3-carboxylate (724b, 4.31 g, 10.01 mmol, 61.8% yield) as a light yellow viscous oil upon concentration of the product containing fractions. m/z (ESI, +ve) 453.2 (M+Na)+.

Provenance & Evidence