141981-59-1

Basic information

• Product Name: 4-(4-methoxybenzyl)-5-methyl-4H-pyrazole-3,4-dicarboxylic acid dimethyl ester
• Synonyms: 4-(4-methoxybenzyl)-5-methyl-4H-pyrazole-3,4-dicarboxylic acid dimethyl ester
• CAS NO: 141981-59-1
• Molecular Weight: 318.329
• Mol File: 141981-59-1.mol
• Article Data: 1

Chemical Properties

• CAS DataBase Reference: 4-(4-methoxybenzyl)-5-methyl-4H-pyrazole-3,4-dicarboxylic acid dimethyl ester(CAS DataBase Reference)
• NIST Chemistry Reference: 4-(4-methoxybenzyl)-5-methyl-4H-pyrazole-3,4-dicarboxylic acid dimethyl ester(141981-59-1)
• EPA Substance Registry System: 4-(4-methoxybenzyl)-5-methyl-4H-pyrazole-3,4-dicarboxylic acid dimethyl ester(141981-59-1)

Safety Data

• Hazardous Substances Data: 141981-59-1(Hazardous Substances Data)

Upstream product

• 154196-69-7 2-methoxy-5-(4-methoxybenzyl)-2,5-dimethyl-Δ³-1,3,4-oxadiazoline 
• 762-42-5 dimethyl acetylenedicarboxylate 
• 141981-51-3 3-(4-methoxybenzyl)-3-methyl-3H-pyrazole-4,5-dicarboxylic acid dimethyl ester 

Downstream Products

• 141981-53-5 1-(4-methoxybenzyl)-5-methyl-1H-pyrazole-3,4-dicarboxylic acid dimethyl ester 
• 141981-57-9 1-(4-methoxybenzyl)-3-methyl-1H-pyrazole-4,5-dicarboxylic acid dimethyl ester 
• 1515-81-7 1-methoxy-4-(methoxymethyl)benzene 
• 37387-73-8 5-methyl-1H-pyrazole-3,4-dicarboxylic acid dimethyl ester 

Relevant articles and documents

Studies of "formal" [1,5]-sigmatropic thermal rearrangements of dimethyl 3-alkyl-3-methyl-3H-pyrazole-4,5-dicarboxylates and dimethyl 4-alkyl-5-methyl-4H-pyrazole-3,4-dicarboxylates

Studies of the thermal rearrangements of 3H-pyrazoles, 10a - e, in benzene/toluene, chloroform, and methanol solvents are described. The mechanism for rearrangement appears to be two-step, involving discrete ion-pair intermediates. Large rate enhancements for these rearrangements in methanol and cation trapping by methanol are consistent with the proposed mechanism. Observed rate constants for the rearrangements of 3H-pyrazoles 10c, 10d, and 10e in benzene-d6 were determined. Insight into the sense of rearrangement by an ion-pair mechanism is also provided by analysis of the 1H NMR spectra of the product mixtures. 3H-Pyrazoles 10b and 10e rearrange to afford 4H-pyrazoles 13b and 13e, respectively, and the thermal rearrangements of these pyrazoles in benzene-d6 and methanol are described. Rate constants for the rearrangements of these more stable pyrazole isomers in benzene-d6 were also determined. Cation-trapping experiments with methanol suggest that the 4H-pyrazoles also rearrange by a two-step mechanism, involving discrete ion-pair intermediates. Furthermore, it appears that different ion-pair intermediates are formed from the 3H-pyrazoles 10b and 10e, compared to the 4H-pyrazoles 13b and 13c, on the basis of cation-trapping experiments.