Pyrrole-2,4-dicarboxylates

The Dieckmann cyclization of aminomethylenemalonates (1308) in boiling ethanol for 45 min, by the action of alkoxide, gave pyrrole-2,4-dicar-boxylates (1309) in 24-86% yields (77HI821 78CPB2224). Pyrrole-2,4-dicarboxylate (1309, R = H,R = Et) was also prepared in 71% yield from 1308 (R = H, R1 = Et) by reaction with sodium hydride in boiling benzene for 4 hr (78CPB2224). The 1-phenyl derivative (1309, R = Ph, R1 = Et) was prepared in 52% yield in an exothermic reaction of 1308 (R = Ph,... 

The pyrrolylthioacetate (105) undergoes Dieckmann ring closure when treated with sodium hydride to give the thieno[2,3-6]pyrrole-2,4-dicarboxylate (106) (65JOC184). 

Extrapolations and improvements to this approach continue to enlarge its usefulness - a,P-unsaturated sulfones react with isocyano-acetates and isocyano-nitriles to give pyrroles. Potassium carbonate can be used as the base, vinyl arenes and hetarenes react at the side-chain double bond to give 3-aryl(hetaryl)-pyrroles, and acetylenic-esters produce pyrrole-2,4-dicarboxylates, methyl t-butyl ether as solvent to avoid peroxides. ... 

Pyrrole-2,4-dicarboxylates. In the presence of this base, aldehydes condense with alkyl isocyanoacetates to form alkyl pyrrole-2,4-dicarboxylates in 50-70% yield. 

Catalytic Synthesis of Dimethyl 3-Cyclopropyl-1 H-pyrrole-2,4-dicarboxylate... 

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