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 ethyl 2-amidinoacetate [for preparation see: Liebigs Ann. Chem., 1561 (1981)] are initially introduced into 172 ml of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone. 56.0 ml (0.45 mol) of ethyl bromopyruvate are added dropwise in the course of 30 min and the mixture is then warmed to 60° C. for 3 h. The dark-brown reaction solution is poured onto 1 liter of ice water and extracted with 1 liter of ethyl acetate and twice with 0.5 liter of ethyl acetate each time. The organic phases are washed 3 times with 0.5 liter of water and 0.5 liter of brine, dried (Na2SO4) and evaporated. Column chromatography (SiO2, hexane/ethyl acetate [1:1]) and crystallization from diethyl ether-hexane yields 2-amino-3,5-bis(ethoxycarbonyl)-1H-pyrrole; m.p. 147-149° C.; MS: (M)+=226.

Provenance & Evidence