104891-45-4

Basic information

• Product Name: 1H-Pyrrole, 2,5-bis(4-methoxyphenyl)-1-methyl-
• CAS NO: 104891-45-4
• Molecular Formula: C19H19NO2
• Molecular Weight: 293.365
• Mol File: 104891-45-4.mol
• Article Data: 4

Chemical Properties

• CAS DataBase Reference: 1H-Pyrrole, 2,5-bis(4-methoxyphenyl)-1-methyl-(CAS DataBase Reference)
• NIST Chemistry Reference: 1H-Pyrrole, 2,5-bis(4-methoxyphenyl)-1-methyl-(104891-45-4)
• EPA Substance Registry System: 1H-Pyrrole, 2,5-bis(4-methoxyphenyl)-1-methyl-(104891-45-4)

Safety Data

• Hazardous Substances Data: 104891-45-4(Hazardous Substances Data)

Upstream product

• 15982-64-6 1,4-bis(4-methoxyphenyl)butane-1,4-dione 
• 74-89-5 methylamine 
• 96-54-8 N-Methylpyrrole 
• 98-68-0 4-methoxy-phenyl-sulphonyl chloride 
• 623-12-1 4-chloromethoxybenzene 
• 104-92-7 1-bromo-4-methoxy-benzene 
• 21399-34-8 1,2-bis(1-(4-methoxyphenyl)ethylidene)hydrazine 

Relevant articles and documents

Eco-friendly solvents for palladium-catalyzed desulfitative C-H bond arylation of heteroarenes

Herein, we report the Pd-catalyzed regioselective direct arylation of heteroarenes in which benzenesulfonyl chlorides are used as coupling partners through a desulfitative cross-coupling that can be performed in diethyl carbonate (DEC) or cyclopentyl methyl ether (CPME) as green and renewable solvents or even in neat conditions instead of dioxane or dimethylacetamide (DMA). Under these solvent conditions, the reaction proceeds with a wide range of heteroarenes. C2- or C5-arylated products were obtained with furan and pyrrole derivatives. Benzofuran was also arylated regioselectively at the C2-position, whereas the reaction proceeds selectively at the C3- or C4-positions if thiophenes and benzothiophenes are used. Moreover, in some cases, especially with 1-methylindole, solvent-free conditions afforded better regioselectivities and/or yields than the reaction performed in the presence of solvents.

Intermediates in the Paal-Knorr Synthesis of Pyrroles

The mechanism of Paal-Knorr reaction between a 1,4-dicarbonyl compound and ammonia or a primary amine to form a pyrrole is explored.In aprotic solvents and in aqueous solutions near neutrality, d,l diastereomers of 3,4-dimethyl- and 3,4-diethyl-2,5-hexanediones (1r and 2r) formed pyrroles 1.3-57.0 times faster than the corresponding meso diastereomers (1m and 2m).This contradicts any intermediate, such as the enamine 15, which does not remain saturated at both the 3- and 4-positions through the rate-determining step.The demonstrated stereoisomeric difference in reactivity coupled with the following results support the hemiaminal (9) as the intermediate undergoing cyclization in the rate-limiting step of the Paal-Knorr reaction: (1) The reaction rate was adversely affected by increase in the size of the alkyl substituents on the dione. (2) Racemic 2,3-dimethyl-1,4-diphenyl-1,4-butanedione (3r) was more reactive toward ammonium acetate (2.2:1) and 2-aminoethanol (11.2:1) than the meso isomer (3m), ruling out the involvement of the less substituted enamine 14. (3) The relative rate of pyrrole formation of 1,4-diphenyl-1,4-butanedione (5) and its dimethoxy (6) and dinitro (7) derivatives (1:0.3:6) does not support cyclization of the imine (11) to the pyrrolinium ion (12). (4) The rates of reaction of 2,2,3,3-tetradeuterio-1,4-diphenyl-1,4-butanedione (5D) and perdeuterio-2,5-hexanedione (4D) were very close to those of unlabeled diketones, indicating the absence of a primary isotope effect in the reaction. (5) Neither the isomerization of the unreacted diastereomers of 1, 2, and 3 nor hydrogen exchange of 4D and 5D was detected during the reaction.