130460-33-2

Upstream product

• 70-11-1 α-bromoacetophenone 
• 130459-95-9 2-Methyl-3-oxo-2-(2-oxo-2-phenyl-ethyl)-succinic acid diethyl ester 
• 759-65-9 diethyl oxalpropionate 
• 130460-24-1 2-Hydroxy-3-methyl-5-phenyl-3,4-dihydro-2H-pyrrole-2,3-dicarboxylic acid diethyl ester 

Downstream Products

• 130460-56-9 3-Methyl-5-phenyl-pyrrole-1,2-dicarboxylic acid diethyl ester 
• 130460-50-3 3-Methyl-5-phenyl-1H-pyrrole-2,4-dicarboxylic acid diethyl ester 

Relevant academic research and scientific papers

THE SYNTHESIS AND CHEMISTRY OF AZOLENINES. PART 18. PREPARATION OF 3-ETHOXYCARBONYL-3H-PYRROLES VIA THE PAAL-KNORR REACTION, AND SIGMATROPIC REARRANGEMENTS INVOLVING COMPETITIVE ESTER MIGRATIONS TO C-2, C-4 AND N.

3H-Pyrrole-3-carboxylic esters (4) have been prepared, in some cases together with isomers (5) and (6) having exocyclic double bonds, by cyclization of suitably substituted 2-ethoxycarbonyl-1,4-diketones (1) with liquid ammonia, followed by dehydration of the isolable 2-hydroxy-3,4-dihydro-2H-pyrrole intermediates (2) and (3) with aluminia in boiling solvents.Prolonged heating in toluene or p-xylene converts the 3H-pyrroles (4) quantitatively into isomeric 4-esters (11) and N-esters (13) of 1H-pyrroles via competitive sigmatropic rearrangements.Isolable intermediate 2H-pyrrole-2-carboxylic esters (12) are converted similarly into the same products, under the same conditions.Detection of 3H-pyrroles (4) as intermediates in the latter reaction demonstrates for the first time the reversibility of the thermal 2H-pyrrole to 3H-pyrrole interconversion.