Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• subject to photoirradiation with N-methylpyrrole, products corresponding to both β-dicarbonyl- (77, expected) and arene- (78, unexpected) functionalization were observed. When malonate-derived ylide 76a was reacted with N-methylpyrrole, it produced 77a in 61% yield. This presumably occurred via a reaction

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• ). Notably, the protocol was also applicable to 4-iodotoluene as a moderately deactivated aryl iodide and the C(sp2)–I bond cleavage occurred chemoselectively in the presence of a C(sp2)–Br bond. N-Methylpyrrole and various other substituted pyrroles could be applied as trapping agents for electron-poor aryl

• -Tribromopyrimidine (6a), whose core pyrimidine structure can be found in many biologically active compounds, could be sequentially substituted with 1,3,5-trimethoxybenzene and N-methylpyrrole to give 8a. The protocol also enabled the selective reductive dehalogenation at the benzylic position of 9a with green light

• the single electron reduction of aryl halides while simultaneously generating S4•−. Upon C(sp2)–X bond cleavage, an aryl radical is formed and trapped by a trapping reagent such as N-methylpyrrole, yielding the open-shell species 4•. Upon irradiation of S3•−, the excited species *[S3•−] oxidizes 4• to

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• and efficient organocatalyst. Recent promoted reactions by the resorcin[4]arene capsule include the intramolecular ether cyclization [34], the synthesis of bis(heteroaryl)methanes [35], the imine formation [36], the Michael addition reactions of N-methylpyrrole on methyl vinyl ketone [37], the

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

• Qiuxin Zhang,
• Weiyi Tan and
• Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

• 2f and 2g results in 10a and 10b. 9 and 10 would help test the effects of additional N-terminal modifications. To examine the necessity of enzymatic dephosphorylation, we replaced ᴅ-phosphotyrosine (py) in 2g, 2h, 6a–c by ᴅ-tyrosine to yield 11a, 11b, 12a–c, respectively. Attaching N-methylpyrrole on

• , we introduced the N-methylpyrrole (Py) units into the peptides obtained via solution-phase amide bond formation to produce 2a–h, 3a,b, 4a,b, 5a,b, 6a–c, 7, 8a,b, 11a,b, 12a–c, 13, 14, and 15a–c. We conjugated two Py units successively to the peptide ffpy and kept the Boc protecting group of the

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• significant influence, neither on yields nor on selectivities. Reactions under ball milling with N-methylpyrrole (NMP), iPr2EtN, DABCO, K3PO4·3H2O, N-methylmorpholine (NMM) (Table 3, entries 3–8) proceeded with yields of 53–82%. The highest value of diastereoselectivity was achieved only with triethylamine as

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• presence of a strong electron-donating substituent could compensate the extreme deactivating power of the CF3 group, favoring a further exploitation for synthetic purposes. In this context, Tidwell and Kwong-Chip compared the solvolysis of N-methylpyrrole 58 to 59 (Figure 9) [70]. A very similar rate was

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• -donating functional groups. Substrates containing pyridine, furan, and thiophene as heterocyclic fragments were also successfully converted into the corresponding alcohols 4. However, in the reaction of the enol ether derived from 2-acetyl-N-methylpyrrole, ketone 3p did not undergo reduction with sodium

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• demonstrated the safe use of gaseous CF3I as a reagent for the continuous flow PRC trifluoromethylation of 5-membered heterocycles, such as N-methylpyrrole (1, Scheme 1), with a high conversion and selectivity for the monofunctionalised product 2 [62]. The system achieved full conversion for a variety of

Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

• Sabrina Müller,
• Jannik Paulus,
• Jochen Mattay,
• Heiko Ihmels,
• Veronica I. Dodero and
• Norbert Sewald

Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

• promising strategy to obtain photoswitchable Im/Py hairpin polyamides capable of interacting with the dsDNA minor groove only in the Z-configuration. Keywords: azobenzene; DNA minor groove; N-methylimidazole; N-methylpyrrole; photoswitches; polyamide; Introduction The development of small chemical agents

• binders have been developed for all possible base pairings (AT, TA, GC, CG; 'pairing rules'). A GC pair is specifically being addressed in the minor groove by N-methylimidazole/N-methylpyrrole (Im/Py), while AT associates with the pair N-methylpyrrole/N-methylhydroxypyrrole (Py/Hp). The same applies to CG

• required because this allowed for an alignment between hydrogen-bonding groups in long polyamides and in the minor groove of DNA [41]. The Fmoc-protected heterocyclic amino acids 2 were obtained from N-methylpyrrole and N-methylimidazole, respectively (Scheme 2A). The N-terminal N-methylpyrrole and N

Mn-mediated sequential three-component domino Knoevenagel/cyclization/Michael addition/oxidative cyclization reaction towards annulated imidazo[1,2-a]pyridines

• Olga A. Storozhenko,
• Alexey A. Festa,
• Delphine R. Bella Ndoutoume,
• Alexander V. Aksenov,
• Alexey V. Varlamov and
• Leonid G. Voskressensky

Beilstein J. Org. Chem. 2018, 14, 3078–3087, doi:10.3762/bjoc.14.287

• nucleophiles was tested under selected conditions. Thus, employment of pyrrole as a nucleophile gave product 7a in 43% yield, and N-methylpyrrole facilitated desired compound 7b in 23% yield (Scheme 4). Isomeric 5-, 6- and 7-azaindoles were found to be appropriate nucleophiles too, producing the corresponding

Synergistic electrodeposition of bilayer films and analysis by Raman spectroscopy

• Saadeldin E. T. Elmasly,
• Luca Guerrini,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Neil J. Findlay,
• Karen Faulds and
• Peter J. Skabara

Beilstein J. Org. Chem. 2018, 14, 2186–2189, doi:10.3762/bjoc.14.191

• -workers demonstrated this technique through the manufacture of multilayer films [7][8], alternating PEDOT and poly(N-methylpyrrole) to develop symmetric supercapacitors [9]. However, in their work there was no attempt to de-dope the second layer, which is necessary for the electrochemical preparation of a

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• group of the guanine base [19]. 2.1. Polypyrroles and polyamides The first two MGBs discovered were distamycin A and netropsin (Figure 3). These naturally occurring molecules are characterized by repeating N-methylpyrrole units with one or more positively charged nitrogen atoms at the end. Their concave

• . Szerszenowicz et al. developed a new set of potential minor groove binders derived from netropsin and bis-netropsin analogs by replacing N-methylpyrrole rings with other heterocyclic rings and their antiproliferative activity was tested on MCF-7 breast cancer cells [60]. Suckling et al. recently designed and

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• polypurine site suitable for DNA triplex formation and overlaps with an A:T tract which is an ideal target for easily synthesized MGB containing only N-methylpyrrole moieties (Figure 4). For convenience of our work, a fluorescently labeled T4 hairpin covalent duplex containing the 29 base pair HIV polypurine

• -aminobutyric acid, Py – N-methylpyrrole carboxamide and Dp – N,N-dimethylaminopropylamine residues) was synthesized in the laboratory by solid-phase method [36][37] and used as a polyamide component. The first model is interesting for an anti-HIV strategy, but it is not suitable for visualization of dsDNA

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• -trifluorobenzenesulfonyl chloride to give the C5- and C2-arylated products 1 and 2 in 86% and 78% yields. Menthofuran, in which only the C2 position is available, also smoothly reacted with 2,3,4-trifluorobenzenesulfonyl chloride to give 3 in 84% yield. Using the same reaction conditions, N-methylpyrrole affords the 1

• -methyl-2-(2,3,4-trifluorophenyl)pyrrole (4) in 91% yield. It is important to note that 4 equiv of N-methylpyrrole were used in order to prevent the formation of the 2,5-diarylated pyrrole as a side product. Finally, both 2-pentylthiophene and benzothiophene were arylated in 76% and 82% yields

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• initio methods [50]. The pKa values for N-methylindole, N-methylpyrrole and N-(dimethylamino)pyrrole as CH acids in THF were experimentally determined by Fraser et al [51]. The latter are more related to our goals and were found to be in good agreement with those computed within the DFT framework

Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

• Tommaso Pecchioli,
• Manoj Kumar Muthyala,
• Rainer Haag and
• Mathias Christmann

Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83

• tested in the asymmetric Friedel–Crafts alkylation of N-methylpyrrole with α,β-unsaturated aldehydes. A variety of substituted enals was investigated to explore the activity of the catalytic system which was also compared with monovalent analogues. The catalyst 4b showed excellent turnover rates and no

• 4a–c was investigated in the Friedel–Crafts alkylation of N-methylpyrrole (11) with α,β-unsaturated aldehydes reported by MacMillan [53]. To make the results comparable, we normalized the loading of the multivalent catalysts 4a–c with respect to the number of single anchored imidazolidin-4-ones

• transformation, the most active catalyst 4b was selected for a screening of different enals in the alkylation reaction of N-methylpyrrole (11). A study on the substrate scope was further carried out under the established conditions (see Table 4, entry 4). A variety of substituted α,β-unsaturated aldehydes 14a–e

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• excess) were heated under air in the absence of a cosolvent (Table 8). Benzene, naphthalene and several disubstituted benzenes were successfully transformed with 39–99% NMR yields and 27–76% isolated yields (relative to the starting perfluoroalkyl iodide). N-Methylpyrrole was also perfluoroalkylated in

• high yield. The reaction proved very selective in several aspects, since 1,2- and 1,3-disubstituted benzenes were all preferentially functionalized at the 4-position; aryl C–H positions were perfluoroalkylated but not benzylic positions; and only the 2-position in N-methylpyrrole was functionalized. A

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

• contrast, in the case of 1-benzyl-2-methyl indolizine [81] both the pyrrole and the aromatic ring of the benzyl group undergo trifluoromethylsulfanylation. Only N-substitution occurs in the case of carbazole [80]. N-Methylpyrrole can be variously substituted depending on the conditions as illustrated in

• Scheme 16. Heating N-methylpyrrole in CHCl3/Py affords the 2-SCF3 derivative along with a small amount of 3-SCF3-N-methylpyrrole [83]. Attempted selective introduction of the second SCF3 group at −30 °C with C4F9SO3H to 2-trifluoromethylsulfanylpyrrole was unsuccessful and gave a mixture of 2,4- and 2,5

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• =OTf or BF4) were selected. Reactions with N-methylpyrrole and N,N-dimethylaniline gave similar results to those observed using Shreeve reagents. The authors demonstrated the possibility of trifluoromethylation of sulfur-containing compounds with a partial negative charge on the sulfur atom. Thus