Ethyl bromopyruvate → diethyl 5-amino-1H-pyrrole-2,4-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

At 0-5° C., 56.0 g (0.43 mol) of 2-amidino-acetic acid ethyl ester [for preparation see: Liebigs Ann. Chem., 1561 (1981)] are introduced into 172 ml of DMPU. 56.0 ml (0.45 mol) of bromopyruvic acid ethyl ester are added dropwise thereto within the course of 30 min and the reaction mixture is then heated at 60° C. for 3 hours. The dark-brown reaction solution is poured into 1 liter of ice-water and extracted with 1 liter of ethyl acetate and twice with a 0.5 liter of ethyl acetate each time. The organic phases are washed three times with a 0.5 liter of water and a 0.5 liter of brine, dried (Na2SO4) and concentrated by evaporation. Column chromatography (SiO2, hexane/ethyl acetate [1:1]) and crystallization from diethyl ether/hexane yield the title compound; m.p. 147-149° C.; MS: (M)+ =226.

Provenance & Evidence