A two-step synthesis of tetrasubstituted pyrroles from esters of a-amino acids has been applied as a simple undergraduate laboratory experiment, which illustrates the utility of amino acids in heterocyclic synthesis. The enamine, prepared by an addition of L-phenylalanine ethyl ester to dimethyl acetylenedicarboxylate was cyclized in presence of sodium methoxide in methanol giving 5-benzyl-4-hydroxy-2,3-di(methoxycarbonyl)pyrrole in 63-72 % yield. The procedure represents an alternative to classical pyrrole syntheses which are usually included in practical undergraduate organic chemistry.
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