62128-44-3

Upstream product

• 96-54-8 N-Methylpyrrole 
• 4229-44-1 N-methylhydroxyamine hydrochloride 
• 122-01-0 4-chloro-benzoyl chloride 
• 762-42-5 dimethyl acetylenedicarboxylate 
• 58948-38-2 2-(4-Chlorophenyl)-1,3-benzoxathiolium tetrafluoroborate 
• 112816-91-8 3-[2-(4-Chloro-phenyl)-benzo[1,3]oxathiol-2-yl]-1-methyl-1H-pyrrole 
• 76024-67-4 2,4-bis(4-chlorobenzoyl)-1-methylpyrrole 
• 100-66-3 methoxybenzene 
• 97188-31-3 (1-benzenesulfonyl-1H-pyrrol-3-yl)-(4-chlorophenyl)methanone 
• 124-41-4 sodium methylate 
• 62128-32-9 (4-chlorophenyl)(1-methyl-1H-pyrrol-2-yl)methanone 

Relevant academic research and scientific papers

A mild and facile one-pot synthesis of N-methyl-3-acyl- pyrroles

N-Methyl-3-acylpyrroles were synthesized via a multicomponent reaction of dimethylacetylene dicarboxylate (DMAD), N-methylhydroxylamine and acylchlorides in the presence of KHCO3. For comparison both conventional and microwave protocols were examined in this procedure. The reaction is clean and gives the products in good to excellent yields under conventional heating conditions at 40 °C in anhydrous dichloromethane.

General Methods for Synthesizing 2,4-Diacylpyrroles and their Precursors Containing One or Two Masked Acyl Groups

A thorough study of the synthesis of 2,4-diacylpyrroles by direct acylation of pyrrole and 2- and 3-acylpyrroles is reported.Among these, Friedel-Crafts acylation of 3-acylpyrroles is the most general and advantageous method because it utilises easily accessible starting materials.In addition it is always regiospecific and readily provides 2,4-diacylpyrroles containing identical or different acyl groups in very high yields (81-100percent) under mild conditions, Alternative procedures concern the synthesis of precursors of 2,4-diacylpyrroles containing one or two acyl groups masked by a 1,3-benzodithiolyl or 1,3-benzoxathiolyl group and subsequent hydrolysis with HgO-35percent aq.HBF4-Me2SO.Overall yields are always good (52-60percent).Indirect acylation constitutes a secure complement to direct acylation when it is necessary to operate in the presence of protected acyl groups.

Acylation of Pyrrole and N-Methylpyrrole with 1,3-Benzoxathiolium Tetrafluroborates. A High-Yield Method for the Synthesis of Diacylpyrroles

2-Substituted 1,3-benzoxathiolium tetrafluoroborates (I) were used as masked acylating agents for pyrrole and N-methylpyrrole.The reactions on pyrrole (II) were regiospecific, and according to the molar ratio of the reagents (I:II = 1:3 or 2.5-3:1), 2-acylpyrroles were obtained in moderate to good yields (38-82percent) and 2,5-diacylpyrroles were obtained in excellent yields (in most cases, quantitative).The reactions on N-methylpyrrole (III) were not regioselective, and both α- and β-positions were attacked.So, depending on the molar ratio of the reagents (I:III = 1:3 or 2,5-3:1), 2- and 3-acyl-N-methylpyrroles (9-51percent and 27-68percent yields, respectively) and 2,4- and 2,5-diacyl-N-methylpyrroles (60-93percent and 17-40percent, respectively) were obtained.A very interesting feature of the new method is the possibility of introducing two identical or different acyl groups in the pyrrole ring under mild conditions. 1H and 13C NMR spectra of all the new compounds and IR spectra, recorded in the gas phase, of 2- and 3-acylpyrroles and of 2,4- and 2,5-diacylpyrroles are reported.

Acid-Mediated Rearrangement of Acylpyrroles

N-Alkyl-2-acylpyrroles are converted by strong anhydrous acid to 1-alkyl-3-acylpyrroles.An equilibrium mixture of 2- and 3-acylpyrrole is produced by treatment of a 2- or 3-acyl NH pyrrole with acid.Pyrrolecarboxaldehydes similarly afford isomeric mixtures.A cross-ring migration, 7->8, is observed when the adjacent position is blocked.The mechanism of acid-mediated rearrangement of acylpyrroles is discussed.

Preparation of β-acyl pyrroles

A process for rearranging α-acyl pyrroles to β-acyl pyrroles which comprises reacting the former with an excess of a strong, anhydrous, non-oxidizing acid, preferably with heating.