Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• influenced by the electronic effects induced by the substituents of the aniline unit (Table 1). Detailed information about characterization data for compounds 2a–l is given in Supporting Information File 1. X-ray crystallographic data In order to bring evidence of the geometry and arrangement of 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

• straightforward approach for accessing various N-(hetero)aryl-4,5-unsubstituted pyrroles, and some of the pyrrole products are not accessible with the methods reported hitherto. Results and Discussion Initially, a mixture of aniline (1a), α-bromoacetaldehyde acetal (2a), and ethyl acetoacetate (3a) was treated

• obtained for 4o and 4p were slightly inferior. Gratifyingly, a 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)aniline also participated smoothly in this reaction, and the expected product 4q can be obtained in 75% yield. This fluorinated substituent on the aniline ring has been identified as the key precursor

• with aniline (1a) or amantadine in the presence of HATU or EDCI to form the multisubstituted pyrrole-3-carboxamide derivatives 4x and 4y (Scheme 4). These skeletons have been proven to be promising inhibitors for the production of cytokines [47]. A plausible mechanism for the model reaction was

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• investigation, the LS-FAS-Cu was also found to be an efficient catalyst for the synthesis of aminonaphthalene derivatives (Table 5). The substituent effect of aniline was examined systematically, and the results showed that anilines bearing electron-donating groups such as Me, OMe and t-Bu at the para-position

• )acetophenone could react smoothly, generating the target products 10k–o in excellent yields. Unfortunately, aniline substituted with a strong electron-withdrawing group at the para-position and 2-(phenylethynyl)acetophenone substituted with an electron-donating group were reluctant to react under this

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

• Matthias Hardy,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

• employed the linear platinum(II)-bis(acetylide) metalloligand 3 that bears two 4-aniline moieties (Scheme 1). In order to synthesize this key compound, we followed known procedures to first isolate 4-ethynylaniline (1) [52] that was subsequently transformed into metalloligand 3 [53] upon treatment with

• trans-[Pt(PBu3)2Cl2] (2). The aniline moieties in 3 were further transformed into chelating pyridylimine binding sites in the following subcomponent self-assembly process when six equivalents of metalloligand 3 were reacted with twelve equivalents of pyridine-2-carbaldehyde and four equivalents of iron

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• Oxone™ (Wegner et al. [19][20][21], Scheme 1). Isolation of 3 was achieved, however, a one pot approach including a subsequent Baeyer–Mills reaction to yield 10 is preferred. 1-Iodo-3-nitrosobenzene (6) cannot be prepared by oxidation of the corresponding aniline because hypervalent iodine is formed [22

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• then reduce 3-nitrobenzoic acid to the corresponding aniline 25 to turn over the cobalt cycle. Simultaneously, 23 condenses with the chiral primary amine catalyst 26 to give enamine intermediate 27, which can be intercepted by 24 to generate imine intermediate 28, which is finally hydrolysed to turn

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• descending order of impact according to OSI values given in Table 1: benzene (12.000), aniline (10.350), toluene (10.150), nitrobenzene (10.130), cyclohexane (8.777), diethyl ether (8.421), acetic anhydride (8.309), petroleum ether (7.734), ethyl acetate (7.597), N,N-dimethyltoluidine (7.592), methyl tert

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• = 2.0 Hz, 1H) ppm, respectively. Crucially, it is apparent that using the photoredox conditions described in Scheme 3, the aniline nucleophile adds primarily at the α-position of the allenamide 15; this is in contrast to the archetypal electrophilic activation modes where comparable nucleophiles add to

• (32 to 35) in moderate to good isolated yields. 4-Bromo-2-fluoroaniline was also examined as a nucleophile, as we had previously shown this to be an effective aniline platform for developing linezolid analogues, and this delivered two N,N’-allylaminals 36 and 37, respectively. Masson had previously

• the conjugated N-acyliminium intermediate 14. Photoredox Ir-catalyzed intermolecular addition of bromide 18 and aniline 16 to allenamide 15. Reaction scope (a) allenamide; (b) arylamine nucleophile; (c) alcohol nucleophile. (a) Tentative mechanism for the photoredox-catalyzed formation of the

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

• used for the photocatalytic generation of H2O2, the degradation of methylene blue dye, and the reduction of nitrobenzene to aniline. Although it was an interesting and novel approach to efficiently irradiating HPCats, the report did not address the potential concerns with the heat dissipation from the

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• ) [19], N-methyl-2-pyridone 7 (δ 139.5) [20], 2,4-dimethoxy-3-methylquinoline (8, δ 147.0) [21], and 2-methoxypyridine 9 (δ 147.2) [22] supported a 2-quinolone form 1 but not 2-quinolinol 2 (Figure 2, Table 1). The same structure was synthesized from diethyl malonate and aniline (see Supporting

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• approach was based on the one-electron reduction of diazonium salts (see the case of 13.3+ in Scheme 13), formed in situ by the reaction of the chosen 2-heteroaryl aniline (e.g., 13.1) with tert-butyl nitrite (1.5 equiv). Formation of the aryl radical 13.4· and following addition onto an alkyne moiety (e.g

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• ⋅LiCl solution, in the collection flask, away from a heat source. System scope: Bis(trimethylsilyl)amine (HMDS), diphenylamine (Ph2NH), aniline (PhNH2), and 2,2,6,6-tetramethylpiperidine (TMPH) were selected as substrates. Ph2NH, HMDS, and PhNH2 due to their lower pKa (25, 30, and 31, respectively, in

Distinctive reactivity of N-benzylidene-[1,1'-biphenyl]-2-amines under photoredox conditions

• Shrikant D. Tambe,
• Kwan Hong Min,
• Naeem Iqbal and
• Eun Jin Cho

Beilstein J. Org. Chem. 2020, 16, 1335–1342, doi:10.3762/bjoc.16.114

• unprecedented reductive coupling of N-benzylidene-[1,1'-biphenyl]-2-amines with an aliphatic amine. The presence of a phenyl substituent in the aniline moiety of the substrate was critical for the reactivity. The reaction proceeded via radical–radical cross-coupling of α-amino radicals generated by proton

• photocatalytic synthetic methods are mainly limited to aniline-based substrates and do not encompass aliphatic amines. We planned the synthesis of 1,2-diamine compounds having an aliphatic amine moiety by the intermolecular coupling of N-benzylidines with aliphatic amines that not only act as coupling partner

• 2p), did not have any significant impact on the reaction outcome. The heteroaryl ring-bearing substrates (2n and 2o) also underwent the transformation, and furnished the valuable vicinal diamine products. The modifications on the aniline moiety were also suitable, and substrates with both electron

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• crystals (Figure 5) reached a plateau at 160 °C after 5.9% of the mass was removed as water. The plateau was maintained until 340 °C, when the sample underwent an endothermic decomposition. The decomposition produced sulfur dioxide, naphthalene, and aniline, according to the infrared spectra of the

• Brønsted acid catalyst) cation exchange resin IR-120, which contains sulfonic acid functionalities, was mixed in its hydrogen form with aniline to give a model of F-1. An attempted use of the resulting compound with the same amount of ammonium groups as in F-1 for the conversion of the epoxide 2 into the

Accelerating fragment-based library generation by coupling high-performance photoreactors with benchtop analysis

• Quentin Lefebvre,
• Christophe Salomé and
• Thomas C. Fessard

Beilstein J. Org. Chem. 2020, 16, 982–988, doi:10.3762/bjoc.16.87

• electrochemically-mediated nickel-catalyzed cross-couplings. Electron-deficient aniline products are less prone to oxidative decomposition. BCP-amines were viable coupling partners but gave the corresponding products 1a–e in poor purities. Simple azetidines partook the reaction to give 2a–c while azaspiro[3,3

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• significantly. However, with the aniline derivative 69 (R = Ph on nitrogen), the ee dropped precipitously (Scheme 15). Chen et al. used a paracyclophane-based NHC ligand, along with Cu2O, to perform similar asymmetric 1,2-silyl additions onto activated imines. For several substrates (47) studied, the chemical

Microwave-assisted efficient and facile synthesis of tetramic acid derivatives via a one-pot post-Ugi cascade reaction

• Yong Li,
• Zheng Huang,
• Jia Xu,
• Yong Ding,
• Dian-Yong Tang,
• Jie Lei,
• Hong-yu Li,
• Zhong-Zhu Chen and
• Zhi-Gang Xu

Beilstein J. Org. Chem. 2020, 16, 663–669, doi:10.3762/bjoc.16.63

• tetramic acid derivatives with potential interesting biological activities via an Ugi/Dieckmann cyclization strategy. Results and Discussion We initially stirred a mixture of ethyl glyoxylate (1a), aniline (2a), 2-(4-chlorophenyl)acetic acid (3a), and benzylisonitrile (4a) in methanol at room temperature

Preparation and in situ use of unstable N-alkyl α-diazo-γ-butyrolactams in Rh^II-catalyzed X–H insertion reactions

• Maria Eremeyeva,
• Daniil Zhukovsky,
• Dmitry Dar’in and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2020, 16, 607–610, doi:10.3762/bjoc.16.55

• , that we observed with 2,6-dimethylaniline. With this unreactive, sterically hindered aromatic amine, 6c is likely to undergo either the unwanted N2→O oxidation or dimerize to bishydrazone 5, whereupon the resulting intermediate would be eventually trapped by the aniline to give 8b (Scheme 2). The

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• under air, N,N-dialkylated aniline derivatives were reacted with various N-substituted maleimides and benzylidenemalonitrile to provide polysubstituted tetrahydroquinolines in moderate to good yields. When N-aryltetrahydroisoquinoline was used instead of N,N-dialkylated anilines, octahydroisoquinolo[2,1

• -a]pyrrolo[3,4-c]quinoline derivatives were obtained for the first time. This transformation starts with the oxidation of the excited photocatalyst with O2. The aniline is then oxidized into an N-centered radical cation, which further gives the α-amino radical. The latter reacts with the maleimide to

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• patterns. Moreover, synthesis of pentamethine cyanines II follows a route requesting cb (Scheme 4) as precursor. There serve some aldehydes as source to synthesize this precursor by reaction with aniline. Similar reaction philosophy also follows synthesis of cb-0 (Scheme 4) to synthesize open heptamethines

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• phosphorus can be adjusted by changing the bulkiness of substituents around both, the N and P centers [99]. When reacting anilines and chlorophosphines under basic conditions they undergo P–N bond formation affording conventional aminophosphines [100][101]. A facile alternative method replaces the aniline

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• , the reaction is initiate with the excitation of the photocatalyst, which further oxidizes the aniline derivative 106 to generate the arene radical cation 108. Then, the intermediate 109 is formed by deprotonation, which, upon reaction with a nitrate radical, gives the desired product 107. Aryl C–H

• catalyst. Proposed mechanism for the trifluoromethylation of 88. Plausible mechanism for the synthesis of substituted coumarins. Mechanism proposed for the phosphonylation reaction of 100. Plausible mechanism for the nitration of aniline derivatives via photoredox catalysis. Proposed mechanism for the

Combination of multicomponent KA² and Pauson–Khand reactions: short synthesis of spirocyclic pyrrolocyclopentenones

• Riccardo Innocenti,
• Elena Lenci,
• Gloria Menchi and
• Andrea Trabocchi

Beilstein J. Org. Chem. 2020, 16, 200–211, doi:10.3762/bjoc.16.23

• the equatorial alcohol, although in lower yield. The use of CeCl3 together with EtMgBr was found particularly effective to suppress conjugate additions, with similar yield as reported for analogous substrates [56]. Subsequent acid-catalyzed displacement of the hydroxy moiety with aniline in the

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• using an aqueous ammonium sulfide solution to furnish aniline 6 in 65% yield [20]. After oxidation of 6 to its nitroso analogue 7 [21], a Baeyer–Mills reaction with aniline yielded the targeted azobenzene building block 8 in 87% yield (i.e., 53% yield over four steps). After the successful synthesis of

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• over Mg2+ ions, and relative insensitivity to pH in biological media due to the relatively low pKa of the electron-poor aniline nitrogens [1]. BAPTA-type molecules complex Ca2+ in an octacoordinated fashion, involving the two aniline functions, the two central ether oxygens and the four carboxylates

• then underwent a regioselective monodeprotection to generate a lone phenol group. The phenolate was reacted with 1,2-dibromoethane and the nitrobenzene groups were reduced to the corresponding anilines giving 1a. The double aniline 1a was alkylated using ethyl bromoacetate under basic conditions in

• noted: N–Ca2+: 2.35 and 2.49 Å cf. 3.24 and 3.03 Å. Smaller differences were noted considering the COO−–Ca2+: 2.20, 2.19, 2.29 and 2.70 Å cf. 2.21, 2.21, 2.23 and 2.23 Å or the ether linkage O–Ca2+: 2.44 and 2.49 Å cf. 2.46 and 2.51 Å. Most significantly, the aniline N–N distance is stretched from 4.71