Ugi bisamides based on pyrrolyl-β-chlorovinylaldehyde and their unusual transformations

• Alexander V. Tsygankov,
• Vladyslav O. Vereshchak,
• Tetiana O. Savluk,
• Serhiy M. Desenko,
• Valeriia V. Ananieva,
• Oleksandr V. Buravov,
• Yana I. Sakhno,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2024, 20, 1773–1784, doi:10.3762/bjoc.20.156

• ; post-Ugi transformation; pyrrole derivative; Ugi reaction; Introduction One of the keys to the development of mankind is the constant search for new substances and advanced materials. Today, we have powerful tools at our disposal that allow us to create entire libraries of structurally complex organic

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• order to optimize the reaction conditions. Among these, 10 mol % Mn(NO3)2∙4H2O was selected as the best catalyst for the synthesis of the pyrrole derivative 67, with yields of 19–89% under MW in solvent-free conditions at 120 °C for 20 min. According to the results of this study, it was discovered that

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• to the plausible pathway shown in Scheme 6. As we expected, the nucleophile 2a attacked on the position C4 of the substrate 1a, which resulted in the cleavage of the S5–C4 bond and the formation of a thiol intermediate A (1-(2-thiophenyl)pyrrole derivative generated in situ as a precursor analog for

• the cleavage of the S–C bond of the 1,4-benzothiazine moiety under the action of the nucleophile to form in situ a 1-(2-thiophenyl)pyrrole derivative that undergoes an intramolecular cyclization to give the target pyrrolobenzothiazoles 3, 7, and 12. The developed approach works well with alkanols 2

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

• Ramazan Koçak and
• Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

• corresponding ketone 10bc. Eventually, pyrrole derivative 10bc, having a carbonyl group, was obtained by these reactions (Scheme 7). In order to increase the conjugation of dibenzosuberenone 1 for the photophysical aspect, the p-quinone methide derivative of dibenzosuberenone 11 was synthesized according to the

Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles

• Wenbo Huang,
• Kaimei Wang,
• Ping Liu,
• Minghao Li,
• Shaoyong Ke and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2920–2928, doi:10.3762/bjoc.16.241

• h of reaction (Table 1, entry 2). To our surprise, the N-aryl-4,5-unsubstituted pyrrole derivative 4a was isolated in 80% yield when 10 mol % of AlCl3 was used as the catalyst (Table 1, entry 3). FeCl3 and NiCl2 were also proven to catalyze this reaction, but the yield of 4a was inferior to those

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• (Scheme 4). In this case, copper catalyst and alkynes are also used but, unlike the above method, alkynes 18 are monosubstituted. The third component is an indole or pyrrole derivative 19 and the result of the reaction is a 3,3-disubstituted isoindolinone derivative 20, which contains a newly formed

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• , who treated pivalonitrile (1) with lithiated methoxyallene 2 and isolated the expected primary addition product 3 [21]. This intermediate was subjected to different cyclization conditions (Scheme 1) and the desired pyrrole derivative 4 was produced under specific conditions employing silver nitrate as

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• ), pyrrole derivative 7 was obtained as a colorless solid (162 mg, 0.53 mmol, 71%). 4-Methyl-2-(3-methylbut-3-en-1-yl)-1-tosyl-2,5-dihydro-1H-pyrrole (7) 1H NMR (400 MHz, CDCl3) δ 7.69 (d, J = 8.3 Hz, 2H, H-13), 7.28 (d, J = 8.3 Hz, 2H, H-14), 5.19 (dt, J = 3.3, 1.6 Hz, 1H, H-3), 4.72–4.65 (m, 2H, H-10

Hydroquinone–pyrrole dyads with varied linkers

• Hao Huang,
• Christoffer Karlsson,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 89–96, doi:10.3762/bjoc.12.10

• microwave heating [22], allowing the reaction to be completed in half an hour with 95% yield. A second Sonogashira reaction of 10 with 3-iodo-1-(triisopropylsilyl)-1H-pyrrole afforded the protected pyrrole derivative 4d. For this second Sonogashira reaction, these conditions, when attempting to couple 10 to

The marine sponge Agelas citrina as a source of the new pyrrole–imidazole alkaloids citrinamines A–D and N-methylagelongine

• Christine Cychon,
• Ellen Lichte and
• Matthias Köck

Beilstein J. Org. Chem. 2015, 11, 2029–2037, doi:10.3762/bjoc.11.220

• pyrrole–pyridinium alkaloid N-methylagelongine (5) was also isolated from Agelas citrina. Compound 5 is the N-methylated pyrrole derivative of agelongine (12). The debromo compound is known as daminin (21). The citrinamines A–D (1–4) were tested against several pathogenic bacteria, fungi, and cultures of

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• is the pyrrole derivative 22, in the air its light colour deepens quickly to brown. The electrolyses proceed uniformly. The current reaches after a short induction period (1–3 min) depending on the substrate a maximal current of 250–450 mA, which then decreases exponentially to zero. The dichloro

Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

• Fatma Belkessam,
• Aidene Mohand,
• Jean-François Soulé,
• Abdelhamid Elias and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 2912–2919, doi:10.3762/bjoc.10.309

• et al. [38]. A fluorescent π-conjugate thiophene derivative bearing spiro[fluorene-9,4’-[4H]indeno[1,2-b]furan] substituents at C2 and C5 has been prepared in 46% yield by this reaction using Pd(OAc)2 (5 mol %) associated to PPh3 (10 mol %) as catalytic system [39]. A pyrrole derivative was coupled

N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides

• Ismail Özdemir,
• Nevin Gürbüz,
• Nazan Kaloğlu,
• Öznur Doğan,
• Murat Kaloğlu,
• Christian Bruneau and
• Henri Doucet

Beilstein J. Org. Chem. 2013, 9, 303–312, doi:10.3762/bjoc.9.35

• suitable for X-ray analysis could be obtained. Arylation with Pd–NHC complexes We initially examined the direct 5-arylation of 1-methylpyrrole-2-carboxaldehyde (10) with 4-chlorobenzonitrile (11) using these nine Pd–NHC complexes. We had previously observed that with this pyrrole derivative a high yield of

• -methylpyrrole-2-carboxylate (25) also reacts with 4-chlorobenzonitrile (11) to give 26 in good yields with catalysts 2, 8 and 9 (Table 3). No significant decarboxylation of the pyrrole derivative was observed in the course of this reaction. Three aryl chlorides have also been coupled with 1-methylpyrrole (27

• observed during the coupling of 4-(trifluoromethyl)chlorobenzene (13) with this pyrrole derivative, and 30 was obtained in low yields (Table 4, entries 11–15). Finally, the reactivity of 1-phenylpyrrole (31) with two aryl chlorides was examined (Table 5). Again, good yields in 32 were obtained with

Carbohydrate-auxiliary assisted preparation of enantiopure 1,2-oxazine derivatives and aminopolyols

• Marcin Jasiński,
• Dieter Lentz and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2012, 8, 662–674, doi:10.3762/bjoc.8.74

• (Figure 1) by retro-nitroso-ene reaction was discussed in earlier work [13], but the formation of pyrrole derivative 5 is unprecedented for the reactions of nitrones and lithiated alkoxyallenes. The 1H NMR spectrum of 5 shows four singlets (3H each) assigned to three methyl groups and one methoxy

• quaternary carbon atoms in the 13C NMR spectrum evidenced the presence of the pyrrole structure. Finally, the HMBC experiment proved the proposed substitution pattern at the pyrrole ring. HRMS and elemental analysis allowed identification of 5 as a 2,3,4,5-tetrasubstituted pyrrole derivative. As shown in

• the tetrasubstituted pyrrole 5. The structure of the intermediate double-addition product H suggests that other by-products may be formed, e.g., two different N-allenylmethyl-substituted 3,6-dihydro-2H-1,2-oxazines or an isomeric pyrrole derivative. The numerous sets of signals in the 1H NMR spectrum

Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

• Elena Borsini,
• Gianluigi Broggini,
• Andrea Fasana,
• Chiara Baldassarri,
• Angelo M. Manzo and
• Alcide D. Perboni

Beilstein J. Org. Chem. 2011, 7, 1468–1474, doi:10.3762/bjoc.7.170

• should be noted that the 1-unsubstituted pyrrole derivative 1a did not undergo cyclization, under various conditions, based on both Au(III) and Au(I) catalysts (Table 1, entries 1–5). Otherwise, AuCl3 was able to promote the intramolecular reaction of the methyl-substituted substrate 1b giving two

An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives

• Rajeshwar Reddy Sagyam,
• Ravinder Buchikonda,
• Jaya Prakash Pitta,
• Himabindu Vurimidi,
• Pratap Reddy Padi and
• Mahesh Reddy Ghanta

Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66

• and subsequent decarboxylation was carried out on pyrrole derivative 15 to afford the 2,3-diaryl pyrrole derivative 16 (Scheme 3). With a view to extending this protocol to aliphatic systems such as α,β-unsaturated ketones, carbamate 3 was treated with crotonaldehyde under similar conditions. However

Knorr- Rabe partial reduction of pyrroles: Application to the synthesis of indolizidine alkaloids

• Brendon S. Gourlay,
• John H. Ryan and
• Jason A. Smith

Beilstein J. Org. Chem. 2008, 4, No. 3, doi:10.1186/1860-5397-4-3

• reaction of 2,5-dialkylpyrroles gives predominantly the trans 3-pyrroline isomer (Scheme 2) [7][8][9]. Results and Discussion The synthetic plan that we adopted was to construct a bicyclic pyrrole derivative by exploiting the natural reactivity of pyrrole and then to partially reduce the heterocyclic core