Synthesis Of Pyrrole Derivatives Research Articles

Iron‐Catalyzed Synthesis of Pyrrole Derivatives and Related Five‐Membered Azacycles

AbstractPyrrole derivatives and their related five‐membered azacycles are a class of important five‐membered aromatic nitrogen heterocyclic compounds, and their synthesis attracted much the attention of organic chemists. Iron catalysis has been widely used in various organic transformations owing to their excellent catalytic activity, environmentally benign character, easy accessibility and low price. Over the past decades, a variety of facile and effective syntheses of pyrrole derivatives and related five‐membered azacycles based on iron catalysis has been reported. In this Minireview, the development of the iron‐catalyzed synthesis of pyrrole derivatives and their related five membered azacycles is reported in a comprehensive way, covering the literature up to March 2021.

Synthesis of Pyrrole Derivatives via Cycloaddition Reaction of Reissert Hydrofluoroborate Salts with α-Bromoacrylamides

An investigation of α-bromoacrylamide as a dienophile for the cycloaddition reaction of Reissert hydrofluoroborate salt of quinoline/phenanthridine has been carried out. The optimized condition has been developed for the [4+2] cycloaddition reaction of Reissert hydrofluroborate salt and α-bromoacrylamide by using K2CO3 in DMF under moderate temperature to afford highly functionalized pyrrole derivatives (6a-f and 7a-f) in very good to excellent yield. The structures of newly synthesized compounds were established based on FT-IR, Mass, 1H and 13C NMR spectral techniques. Besides, the structure of compound 7a has been confirmed by 2D NMR experiments (COSY and HSQC).

Application of β‐Nitrostyrene in Multicomponent Reactions for the Synthesis of Pyrrole Derivatives

Abstractβ‐nitrostyrene is an important and effective starting material for the synthesis of heterocycle compounds such as pyrrole derivatives via multicomponent reactions. β‐nitrostyrene in its reactions undergoes Michael addition. Pyrroles derivatives are an important group of heterocycle compounds that have many biological and pharmacological activities and are exist in the structure many of natural products. Usually, synthesis of pyrrole derivatives by β‐nitrostyrene performed through multicomponent reactions. In this review, synthesis of pyrroles derivatives by β‐nitrostyrene through multicomponent reactions is discussed.

Transition Metal‐Catalyzed and Metal‐Free Cyclization Reactions of Alkynes with Nitrogen‐Containing Substrates: Synthesis of Pyrrole Derivatives

AbstractThis review describes the efforts in the synthesis of pyrrole derivatives using the reaction of alkynes with nitrogen‐compounds under transition metal‐catalyzed and metal‐free conditions, in the past decade. We initially focused on the methods of preparation of pyrrole derivatives using reactions catalyzed by transition metal. In this part, we described the syntheses of 1‐pyrrolines, 2‐pyrrolines, 3‐pyrrolines, pyrroles, and pyrrolidines following an alphabetical order of the transition metal used for the synthesis. Subsequently, we presented the synthesis of these pyrrole derivatives under metal‐free conditions.

Silica tungstic acid and sulphated silica tungstic acid as highly efficient solid acid catalysts for the synthesis of pyrrole derivatives

In the present study silica supported tungstic acid (STA) and sulphated silica tungstic acid (SSTA) were applied as efficient and cost-effective solid acid catalysts in the synthesis of N-substituted pyrrole derivatives via the Paal–Knorr reaction of 2,5-hexadione with aromatic and aliphatic amines at room temperature. The reaction completed in short time under mild conditions with high yield. The catalysts could be easily recovered upon reaction completion. Structures of all products were confirmed by elemental analysis, FT-IR, 1H and 13C NMR spectra.

Microwave‐activated Synthesis of Pyrroles: A Short Review

In the current scenario for continuous requirement of better drugs, medicinal chemists must visage the challenging task of preparing novel patentable compounds, combining high activity and selectivity, good drug‐likeness, and pharmacokinetic properties. There is an acute need of new molecules in both lead identification and lead optimization. Chemists thoroughly scrutinize ways to simplify synthetic protocols using green chemistry approaches, for example, microwaves. Reduction in the reaction time by the use of microwaves has emerged as a promising method for bringing out new leads in organic synthesis. Among the azaheterocyclic systems, synthesis of pyrrole moiety has been a highly attractive and an inspiring proposition. It has been found to be an inbuilt pharmacophore of various momentous pharmacologically active compounds in medicinal chemistry. This article outlines the basic principles of microwave technology and its use in the synthesis of pyrrole derivatives wherein this technology has made a tremendous impact.

Efficient, Three-Component Synthesis of Pyrrole Derivatives Catalyzed by Iodobenzene and Oxone

A simple and highly efficient three-component method using easily available amines, nitrostyrene, and diketones in one pot has been developed for synthesis of pyrroles in the presence of catalytic amounts of iodobenzene and Oxone as oxidant. The protocol has been used to afford wide range of pyrroles in moderate to good yields.

Microwave-assisted facile synthesis of trisubstituted pyrrole derivatives

We report efficient synthesis of pyrrole derivatives by use of microwave irradiation. Quantitative yields were obtained in short reaction times. Low yields of product were obtained from alicyclic amino unsaturated ketone derivatives; higher yields were obtained from aliphatic amino unsaturated ketone derivatives.

The acidic ionic liquid [BSO3HMIm]HSO4: a novel and efficient catalyst for one-pot, three-component syntheses of substituted pyrroles

Abstract An acidic ionic liquid 3-methyl-2-(1-sulfobutyl)-1H-imidazolium hydrogensulfate, [BSO3HMIm]HSO4, was used as an efficient catalyst for the synthesis of a variety of pyrrole derivatives via a one-pot, three-component condensation of amines, nitroolefins, and 1,3-dicarbonyl compounds. Good to excellent yields of 72–96% were obtained under reflux in ethanol. The catalyst could easily be recovered and recycled up to six times, resulting in good yields without prolonging the reaction time. This method was also efficient in large-scale preparation. The procedure could be easily expanded to a one-pot, four-component reaction. This ionic liquid-catalyzed reaction provided an environmentally friendly alternative to the synthesis of pyrrole derivatives.

Synthesis of Pyrrole Derivatives from Diallylamines by One-Pot Tandem Ring-Closing Metathesis and Metal-Catalyzed Oxidative Dehydrogenation

A series of aryl-substituted pyrrole derivatives was synthesized from diallylamines through a ruthenium carbene catalyzed ring-closing metathesis reaction and in situ oxidative dehydrogenation reaction catalyzed by FeCl3·6H2O or CuCl2·2H2O in the presence of O2. The reaction was mild, simple, and convenient. An oxygen atmosphere played a critical role in obtaining high conversion of substituted pyrroles in the proposed catalytic system.

One-pot tandem reactions for direct conversion of thiols and disulfides to sulfonic esters, and Paal–Knorr synthesis of pyrrole derivatives catalyzed by TCCA

A convenient synthesis of sulfonic esters from thiols and disulfides is described. In situ preparation of sulfonyl chlorides from thiols is accomplished by oxidation with trichloroisocyanuric acid (TCCA), tetra-butylammonium chloride (t-Bu4NCl), and water. The sulfonyl chlorides are then further allowed to react with phenol derivatives in the same reaction vessel. Also, a facile synthesis of N-substituted pyrroles by the reaction of hexane-2,5-dione with primary amines has been accomplished using TCCA as a catalyst under mild condition with excellent yields.

ChemInform Abstract: Solvent‐Free Synthesis of Pyrrole Derivatives.

AbstractA one‐pot synthesis of pyrrole derivatives via the reaction between activated carbonyl compounds, primary amines and 1,3‐dicarbonyl compounds under solvent‐free conditions is described.

Solvent‐free synthesis of pyrrole derivatives

AbstractA one‐pot synthesis of pyrrole derivatives via reaction between activated carbonyl compounds, primary amines, and 1,3‐dicarbonyls under solvent‐free conditions is described. J. Heterocyclic Chem., (2012).

ChemInform Abstract: Synthesis of Pyrrole Derivatives from 5,6-Dihydro-4H-1,2-oxazines via Reductive Deoxygenation by Use of Fe3(CO)12.

α-Bromooximes such as α-bromoacetophenone oxime and ethyl 3-bromo-2-(hydroxyimino)propanoate react with enamines to give 5,6-dihydro-4H-1,2-oxazines in good yields. Dihydro-1,2-oxazine derivatives are also obtained by the reaction of α-bromooximes with vinyl ethers and silyl enol ethers in the presence of Na2CO3. Dihydro-1,2-oxazines can be converted into pyrrole derivatives via reductive deoxygenation by treating with Fe3(CO)12 in moderate to excellent yields. Iron carbonyl complexes other than Fe3(CO)12 are also effective for the pyrrole-forming reaction. The efficiency of the complexes for this reaction decreases in the order: Fe3(CO)12>>Et3NH[HFe3(CO)11]>Fe2(CO)9>>Fe(CO)5. Both of the dihydro-1,2-oxazine- and pyrrole-forming reactions can be carried out in a single flask, giving pyrrole derivatives in good yields.

Structure-based design and synthesis of pyrrole derivatives as MEK inhibitors

A novel series of pyrrole inhibitors of MEK kinase has been developed using structure-based drug design. Optimization of the series led to the identification of potent inhibitors with good pharmaceutical properties.

Facile Synthesis of 1,2,3,4-Tetrasubstituted Pyrroles from Baylis-Hillman Adducts

Suitably functionalized pyrroles are the basic skeleton of many biologically important substances and numerous synthetic methods of pyrroles have been investigated extensively. However, the synthesis of pyrrole derivatives from Baylis-Hillman adducts was not developed much. Recently, we reported the synthesis of 2,3,4-trisubstituted pyrroles starting from the rearranged aza-Baylis-Hillman adducts (Scheme 1). Meantime we presumed that we could synthesize 1,2,3,4tetrasubstituted pyrrole derivatives by using the synthetic approach in Scheme 2. As shown in Scheme 2, we imagined that the reaction of Baylis-Hillman acetate 1, as the representative example, and secondary amine derivatives 2a-d could give the corresponding SN2' product 3a-d, which could be cyclized to 4a-d under basic conditions. The following acid-catalyzed dehydration and concomitant double bond isomerization of 4a-d would provide desired pyrroles 5a-d. Among the examined conditions the use of K2CO3 in CH3CN gave the best results for the preparation of 4a-d. As expected we could not observe the formation of 3 (except for 3c, entry 3 in Table 1), instead we obtained 4a-d directly in 50-74% yields as inseparable syn/anti mixtures in a one-pot reaction. Based on the H NMR spectra of 4a-d the ratio of syn/anti was 4:1 to 2:1 (footnotes b-d in Table 1), however, we did not confirm which isomer is the major one. For the reaction of 1 and 2c we isolated 3c in 34% yield (entry 3 in Table 1) together with 4c in 50% yield. For the synthesis of compound 4d (entry 4) we used 2d in slightly excess amount (footnote e in Table 1). The following dehydration step of 4a-d was carried out under the influence of p-TsOH (20-40 mol%) in benzene and we obtained the desired compounds 5a-d in 41-64% yields. Isomerization of double bond occurred during the dehydration stage simultaneously to afford pyrroles directly. The results are summarized in Table 1. However, the reaction of 1 and 2e showed somewhat different reactivity as compared with those of 2a-d (Scheme 3). When we carried out the reaction of 1 and 2e in CH3CN at room temperature the reaction did not show the formation of any new compounds in appreciable amounts presumably due to the limited solubility of 2e in CH3CN. Thus we elevated the temperature to refluxing, however, rearranged acetate was the major product in this case. After many trials we could obtain 3e in 74% yield in aqueous CH3CN at room temperature. In aqueous CH3CN the compound 2e was dissolved completely and the rearrangement of acetate group of 1 to the primary position was minimized at room temperature. With this compound 3e in our hand we prepared 4e under the same conditions of Table 1 (CH3CN,

Remarkable Solvent Effect in Barton—Zard Pyrrole Synthesis: Application in an Efficient One‐Step Synthesis of Pyrrole Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthesis of Pyrrole Derivatives Through Functionalization of 3,4‐Bis(lithiomethyl)dihydropyrroles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Pyrrole Derivatives through Functionalization of 3,4‐Bis(lithiomethyl)dihydropyrroles

AbstractBis(2‐lithioallyl)amines 2, substituted at the double bonds, undergo intramolecular carbolithiation of a lithiated double bond in different solvents to afford dilithiated dihydropyrroles 3. Treatment of these dianions with electrophiles allows the preparation of functionalized pyrrole derivatives 5 and 6. Interestingly, treatment of these dianions with carboxylic esters selectively affords either keto or hydroxy compounds (9 or 10), depending on the conditions. Several experiments have been carried out in order to clarify the mechanism of this selective transformation. Finally, dilithiated dihydropyrrole 3a could be transformed in a three‐step procedure into the corresponding 3,4‐bis(bromomethyl) derivative 31, which can easily be converted into bicyclic pyrrole compounds 32−33 by treatment with different nucleophiles. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthesis of Pyrrole Derivatives by Palladium‐Catalyzed Cyclization of γ,δ‐Unsaturated Ketone O‐Pentafluorobenzoyloximes.

AbstractFor Abstract see ChemInform Abstract in Full Text.