Practical synthesis of indoles and benzofurans in water using a heterogeneous bimetallic catalyst

• Cybille Rossy,
• Eric Fouquet and
• François-Xavier Felpin

Beilstein J. Org. Chem. 2013, 9, 1426–1431, doi:10.3762/bjoc.9.160

• with aryl acetylenes suggesting a strong halide effect and a sensitivity of the Pd–X bond under our reaction conditions. Indeed, the coupling of aryl acetylenes with bromo-anilines and bromo-phenols showed lower conversion compared to the iodo-congeners. We further evaluated the potential of our Pd–Cu

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• system was also applied to the oxygenation of 1,3,5-triisopropylbenzene [17]. However, in this case the conversion of all isopropyl groups was far from being reached, with mono- and di-phenols being the major products, while the yield in benzene-1,3,5-triol was close to 1%. Sheldon and co-workers tested

Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

• Josué M. Silla,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2013, 9, 1127–1134, doi:10.3762/bjoc.9.125

• for 2-monohalogen substituted phenols [12]. In fact, organic fluorine has been found to hardly ever participate in hydrogen bonding [13], despite the appearance of this interaction in 8-fluoro-4-methyl-1-naphthol [14], 2'-fluoroflavonols [15], 2-fluorobicyclo[2.2.1]heptan-7-ols [16] and 2

A chemist and biologist talk to each other about caged neurotransmitters

• Graham C.R. Ellis-Davies

Beilstein J. Org. Chem. 2013, 9, 64–73, doi:10.3762/bjoc.9.8

• are water stable [56]. When phenols (e.g., serotonin or capsaicin) are caged via the carbonate, they are effectively stable and released quickly [61][62]. It is also important to note that the stability of all these “acid-like” caged compounds depends on the pH of the aqueous solution. All are more

Iron-containing mesoporous aluminosilicate catalyzed direct alkenylation of phenols: Facile synthesis of 1,1-diarylalkenes

• Satyajit Haldar and
• Subratanath Koner

Beilstein J. Org. Chem. 2013, 9, 49–55, doi:10.3762/bjoc.9.6

• Satyajit Haldar Subratanath Koner Department of Chemistry, Jadavpur University, Kolkata 700032, India 10.3762/bjoc.9.6 Abstract The addition of phenols to aryl-substituted alkynes to form 1,1-diarylalkenes was carried out by using the Fe-Al-MCM-41 catalyst. The catalyst showed remarkable

• improvement in time and yield in comparison to other solid catalysts. The heterogeneous catalyst can be reused at least three times without a significant loss in activity. Keywords: 1,1-diarylalkenes; heterogeneous catalysis; Fe-Al-MCM-41; Introduction The direct vinylation of phenols has received

• synthesis. Thus, the development of simple methods concerning such vinylation reactions of phenols always remains an important process. Mizoroki–Heck-type reaction could be considered as an efficient procedure for the synthesis of such vinylated phenols [18][19]. There are a number of reports available in

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

• Ishmael B. Masesane and
• Zelalem Yibralign Desta

Beilstein J. Org. Chem. 2012, 8, 2166–2175, doi:10.3762/bjoc.8.244

• [28], as catalytic reagents for silylation of alcohols, phenols, and thiols using hexamethyldisilazane [29], in conversion of urazoles to triazolinediones [30], and in oxidation of 1,3,5-trisubstituted pyrazolines [31]. Molecular sieves have been used as solid-phase catalysts in the preparation of 2

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• phenols in water/organic-solvent systems in the presence of hydrogen peroxide. In recent studies it was demonstrated that several para-substituted phenols, i.e., 4-tert-butylphenol, can be polymerized with HRP in high yield and relatively high molecular weights [13]. Also several polyphenols with further

• functional groups, such as nitrones, double bonds and imides, have been synthetized and investigated in our group [14][15][16][17][18]. There are also several natural phenols such as flavonoides, or isoflavonoides, which were also polymerized successfully [19]. 4-Ferrocenylphenol (2) has been the subject of

• , the enzyme-catalytic polymerization of phenols in general with HRP as catalyst leads to the formation of a copolymer containing phenylene and oxyphenylene moieties [32][33]. Accordingly, in the range of 1024–1174 cm−1 IR signals of the C–O stretching vibration of ether functionalities can be observed

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• .8.227 Abstract Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through C–N and C–O bond formation have been developed. The C–N cross-coupling reaction of

• report on coupling of amides, amino acid esters and phenols with N-protected 4-bromo-7-azaindole derivatives. Keywords: 7-azaindole; C–N bond; C–O bond; ligand; palladium catalyst; Introduction Palladium-catalyzed C–N and C–O bond-forming reactions between 4-substituted 7-azaindoles and amides, amines

• , amino acid esters or phenols have recently gained popularity among the scientific community for different drug-discovery and -development programs. Particularly, several 7-azaindoles (1H-pyrrole[2,3-b]pyridine) [1][2][3][4], including 4-substituted compounds [5][6][7][8] have found applications in

An efficient access to the synthesis of novel 12-phenylbenzo[6,7]oxepino[3,4-b]quinolin-13(6H)-one derivatives

• Wentao Gao,
• Guihai Lin,
• Yang Li,
• Xiyue Tao,
• Rui Liu and
• Lianjie Sun

Beilstein J. Org. Chem. 2012, 8, 1849–1857, doi:10.3762/bjoc.8.213

• -aminobenzophenone (1) with 4-chloroethylacetoacetate by using CAN (cerium ammonium nitrate, 10 mol %) as catalyst at room temperature. The substrates 3a–l were prepared through one-pot reaction of ethyl 2-(chloromethyl)-4-phenylquinoline-3-carboxylate (2) and substituted phenols. Our developed strategy, involving a

• with a variety of phenols with varying substituents in the presence of K2CO3 as base in MeCN under reflux as shown in Scheme 2. In this reaction, we adopted MeCN as the solvent of choice simply because of its low boiling point, bringing much convenience to the workup procedure. Thus, upon the

Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines

• Chittaranjan Bhanja,
• Satyaban Jena,
• Sabita Nayak and
• Seetaram Mohapatra

Beilstein J. Org. Chem. 2012, 8, 1668–1694, doi:10.3762/bjoc.8.191

• –Michael–aldol reaction for the highly stereogenic synthesis of chromenes. Enantioselective cascade oxa-Michael–Michael reaction of alkynals with 2-(E)-(2-nitrovinyl)-phenols reported by Wang. Domino oxa-Michael–Michael–Michael–aldol reaction of 2-(2-nitrovinyl)-benzene-1,4-diol with α,β-unsaturated

Arylglycine-derivative synthesis via oxidative sp³ C–H functionalization of α-amino esters

• Zhanwei Xu,
• Xiaoqiang Yu,
• Xiujuan Feng and
• Ming Bao

Beilstein J. Org. Chem. 2012, 8, 1564–1568, doi:10.3762/bjoc.8.178

• phenols with α-amino esters proceeded smoothly in the presence of meta-chloroperoxybenzoic acid as an oxidant under ambient conditions, to produce arylglycine derivatives in satisfactory yields. Keywords: α-amino ester; arylglycine; C–H functionalization; oxidation; synthesis; Findings Arylglycine

• -(disubstituted amino)acetates with indoles to achieve indolylglycine derivatives (Scheme 2, reaction 1) [16]. In the course of our continuous research on the direct functionalization of sp3 C–H bonds, we found that this new strategy could also be applied to the coupling reaction of naphthols and phenols with

• copper catalyst could not improve the yield of 3a (Table 1, entries 3 and 4). The solvents were then screened (Table 1, entries 5–10). The best result was observed when CH2Cl2 was used as the solvent (79%, Table 1, entry 5). Therefore, the subsequent reactions of naphthols and phenols with ethyl 2

Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers

• Nicola Otto and
• Till Opatz

Beilstein J. Org. Chem. 2012, 8, 1105–1111, doi:10.3762/bjoc.8.122

• tetramethylmagnolamine [6], and the antifungal diamine piperazinomycin [7] (Figure 1). A straightforward method for the formation of diaryl ethers is the Cu-catalyzed coupling of aryl halides with phenols, first reported by Fritz Ullmann in 1903 [8][9]. However, the classical protocol suffers from considerable

• phenols developed by Buchwald [10][11] and Hartwig [12][13] in the 1990s. Nevertheless, the use of this expensive metal in combination with sensitive and costly phosphine ligands limits the use of palladium catalysis for industrial-scale applications and economic aspects have led to a renaissance of the

• decomposition of the ligands. Conclusion A collection of 56 multidentate ligands were screened in a model system for the Ullmann diaryl ether synthesis of electron-rich phenols and aryl bromides. Structurally diverse ligands showed a catalytic activity in the coupling, but none of the ligands showed a higher

Synthesis and anion recognition properties of shape-persistent binaphthyl-containing chiral macrocyclic amides

• Marco Caricato,
• Nerea Jordana Leza,
• Claudia Gargiulli,
• Giuseppe Gattuso,
• Daniele Dondi and
• Dario Pasini

Beilstein J. Org. Chem. 2012, 8, 967–976, doi:10.3762/bjoc.8.109

• (the naphthyl rings of the binaphthyl units and the aryl moieties of the spacing units); electronic communication between them is present (Figure 2). It is interesting to note how the spectra of macrocycle (R,R)-12, bearing methoxy protected phenols, showed the most bathochromically shifted shoulder

Liquid-crystalline heterodimesogens and ABA-heterotrimesogens comprising a bent 3,5-diphenyl-1,2,4-oxadiazole central unit

• Govindaswamy Shanker,
• Marko Prehm and
• Carsten Tschierske

Beilstein J. Org. Chem. 2012, 8, 472–485, doi:10.3762/bjoc.8.54

• ) [65], respectively. The syntheses of the acids 2 and 4, and the 1,2,4-oxadiazole substituted phenols 1 and 3 were reported previously in the cited references. The final compounds were purified by crystallization from ethyl acetate/ethanol mixtures. All compounds represent the first examples in their

Perhydroazulene-based liquid-crystalline materials with smectic phases

• Zakir Hussain,
• Henning Hopf and
• S. Holger Eichhorn

Beilstein J. Org. Chem. 2012, 8, 403–410, doi:10.3762/bjoc.8.44

• stereochemistry on the liquid-crystalline properties in the resulting esters. We selected two different phenols for this esterification step, one with a nonpolar end group, an alkyl chain, and the other with a polar end group, a cyano moiety. The newly synthesized derivatives 8a and 8b (Scheme 4) and 10a and 10b

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity

• Krzysztof M. Borys,
• Maciej D. Korzyński and
• Zbigniew Ochal

Beilstein J. Org. Chem. 2012, 8, 259–265, doi:10.3762/bjoc.8.27

• aliphatic amines (products 7c–7h), aromatic primary amines (products 7i–7k) and phenols (products 7l–7o), with all the resulting compounds being obtained in >85% yields (Table 1; see Supporting Information File 1 for further details on products 7a–7o). At this point, two groups of the designed target

Ion-exchange-resin-catalyzed adamantylation of phenol derivatives with adamantanols: Developing a clean process for synthesis of 2-(1-adamantyl)-4-bromophenol, a key intermediate of adapalene

• Nan Wang,
• Ronghua Wang,
• Xia Shi and
• Gang Zou

Beilstein J. Org. Chem. 2012, 8, 227–233, doi:10.3762/bjoc.8.23

• -adamantylphenol derivatives through adamantylation of substituted phenols with adamantanols catalyzed by commercially available and recyclable ion-exchange sulfonic acid resin in acetic acid. The sole byproduct of the adamantylation reaction, namely water, could be converted into the solvent acetic acid by

• report on cation-exchange-resin-catalyzed adamantylation of phenols with adamantanols, although alkylation with alcohols is greener than that with alkyl halides. Herein, we report a process catalyzed by a recyclable acidic resin for an efficient and clean adamantylation of phenol derivatives by using

• -methylphenol or 3-methyl-4-(1-adamantyl)phenol, were observed for m-cresol (1d). The reaction of phenols bearing an electron-withdrawing group, e.g., –CHO (1f), –COCH3 (1h), –CO2Et (1g) and –NO2 (1i), needed a longer time to afford the 2-adamantylation products in good yields (Table 2, entries 5–8). When 4

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• -position of the phenols, also known as the “upper rim” (Figure 2). For the purposes of this review the term “oxacalix[n]arene” will be used as a generalization for this class of compounds. Although some aspects of homooxacalixarene chemistry have been reviewed [4][6][7][8], notably by Shokova and Kovalev

• took a further 20 years for a reproducible synthesis to be published. In 1983, Gutsche reported that the thermally induced dehydration of 2,6-bis(hydroxymethyl)phenols in xylene under reflux gave rise to the formation of homooxacalixarenes, some of them in reasonable yields, as shown in Scheme 1 [14

• , therefore different para-substituents must be introduced through the starting phenol in order to obtain derivatives with different groups at the upper rim. A number of other para-substituted bis(hydroxymethyl)phenols were therefore also cyclized in the presence of methanesulfonic acid (MsOH) or para

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

• benzoic acids 2 and hydrogenolytic deprotection of the hydroxy group according to [47]. The final products OH 1a–c were obtained by esterification of the phenols 3 with 4-(4-dodecyloxy-2-hydroxybenzylideneamino)benzoic acid (4), which exhibits a liquid-crystalline phase itself (Cr 204 N 269 I) [42]. It

• phenols 7a,b. Subsequently, their esterification with 4-(4-n-dodecyloxy-3-substituted-benzoyloxy)benzoic acids 2 was the final step needed to afford the compounds OH 2b, 2e, 2g. The selection of route A or B was determined by the better purity of the final products, but short reaction paths for the

Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene

• Aurélien Hameau,
• Sabine Fuchs,
• Régis Laurent,
• Jean-Pierre Majoral and
• Anne-Marie Caminade

Beilstein J. Org. Chem. 2011, 7, 1577–1583, doi:10.3762/bjoc.7.186

• Functionalized phenols based on tyramine were synthesized in order to be selectively grafted on to hexachlorocyclotriphosphazene, affording a variety of functionalized dendrons of type AB5. The B functions comprised fluorescent groups (dansyl) or dyes (dabsyl), whereas the A function was provided by either an

• instance, for the coupling with another dendron, and the B functions are either the dyes or the fluorescent groups. Due to the known, relatively easy functionalization of N3P3Cl6 by phenols, and the stability of the resulting compounds, we chose functionalized phenols as the A and B functions

• . Functionalized phenols 2, 3 and 4 are synthesized from tyramine (1). The N-Boc protected tyramine 2 is synthesized by using Boc2O. Tyramine cannot be used directly to introduce the amine functionality, because both the phenol and the amine group of tyramine are able to react with N3P3Cl6, thus the NH2 group has

Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold(I) or gallium trichloride

• Sergio Pascual,
• Christophe Bour,
• Paula de Mendoza and
• Antonio M. Echavarren

Beilstein J. Org. Chem. 2011, 7, 1520–1525, doi:10.3762/bjoc.7.178

• form 6–8-membered rings [29][30][31]. A similar reaction can also be carried out with GaCl3 [32] and Pt(II) [33] as catalysts. In contrast, alkynyl furans react with gold to give phenols by using Au(III), Au(I) [1][2][34][35][36][37], or Pt(II) as the catalyst [38][39]. In our efforts towards the

Translation of microwave methodology to continuous flow for the efficient synthesis of diaryl ethers via a base-mediated S_NAr reaction

• Charlotte Wiles and
• Paul Watts

Beilstein J. Org. Chem. 2011, 7, 1360–1371, doi:10.3762/bjoc.7.160

• reaction of chloroarenes to a series of para-substituted phenols to afford a general and efficient route to the diaryl ether subunit. Results and Discussion With the optimised conditions from Marafie and Moseley’s [15] stopped-flow investigation taken as a starting point, the synthesis of diaryl ethers

• reaction for the synthesis of 2-chloro-1-(4-methoxyphenoxy)-4-nitrobenzene (7), the next step in the investigation was to evaluate the effect of the para-substituent on the phenolic derivative. To do this a series of commercially available phenols were evaluated; 4-nitrophenol (8), 4-cyanophenol (9), 4

• -bromophenol (10) and 4-fluorophenol (11). Again after a reaction time of 30 s and a reactor temperature of 195 °C, the reactivities of the four phenols were compared before each reaction was optimised for diaryl ether isolation. As expected, Figure 8 illustrates that those phenol derivatives bearing an

Synthesis of diverse dihydropyrimidine-related scaffolds by fluorous benzaldehyde-based Biginelli reaction and post-condensation modifications

• Bruno Piqani and
• Wei Zhang

Beilstein J. Org. Chem. 2011, 7, 1294–1298, doi:10.3762/bjoc.7.150

• by the reaction of phenols with perfluorooctanesulfonyl fluoride, by following the reported procedure [13]. Compounds 1 were used as a limiting agent to react with urea/thiourea 2 and acetylacetone 3 for the Biginelli reactions. The reactions were promoted by Yb(OTf)3 as a catalyst [14][15

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• attractive approach to the synthesis of functionalized ethers and ketones. In particular, the intramolecular addition of oxygen nucleophile to C–C multiple bonds has become a very effective tool in the synthesis of oxygen heterocycles from readily available starting materials [11]. 2.1 Alcohols, phenols and

• phenols (318–321) and unsymmetrical bi- and terphenyls (Scheme 54) [159]. The reaction is greatly affected by the electronic properties of dienyne acid. The regioselective 1,6-cyclization/decarboxylation sequence only takes place when a strong electron-donating group is not directly linked to the triple

High chemoselectivity in the phenol synthesis

• Matthias Rudolph,
• Melissa Q. McCreery,
• Wolfgang Frey and
• A. Stephen K. Hashmi

Beilstein J. Org. Chem. 2011, 7, 794–801, doi:10.3762/bjoc.7.90

• -catalyzed conversion of the pure isomers. From the NMR spectra taken during the conversion (Figure 4), it could be clearly seen that no epimerization of the propargylic position occurred. In addition to the selective transformation to the phenols 37a and 37b as the main reaction products, partial removal of