Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• presented in Scheme 5. As can be seen, the yields of the target compounds 4 vary from good to moderate per two steps of synthesis. The introduction of acceptor substituents in both the aniline and arylidene moieties of the DAS molecule leads to a decrease in the yield of the final spirocycle. The structure

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• outlined in Scheme 3. To our delight, various amines (2p–r), including aniline, N-methylaniline, and naphthylmethylamine are also compatible under the optimal conditions to give the corresponding amination products (3ap–ar) in moderate to high yields. For this amination method, it was necessary to

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• ]. After the determination of the molecular structure of indigo in 1883, various precursors such as isatin (1), cinnamic acid (2), 2-nitrobenzaldehyde (3), aniline (4), 2-aminobenzoic acid (5), phenylglycine (6), 1-(1H-indol-1-yl)ethan-1-one (7) and indole (8) have been used in the synthesis (Figure 1) [4

• significant difference in the values of β-angles, which results in some differences in the densities [10]. The solubility of crystalline indigo is poor even in polar solvents such as aniline, nitrobenzene, phenol, phthalic anhydride, DMSO, and DMF upon heating. The reason for the low solubility and high

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• careful review of the product structure it was revealed that the purported dibenzodiazepine products were, in fact, diarylimines, which resulted from a nucleophilic addition of the aniline reagents to the aldimine substrates, followed by elimination of an tosylamine product. This was one of the principle

• reactions described in Table 1, involving Mo(CO)6 were 20 °C higher than the reactions described in Table 2 and/or (b) Mo(CO)6 acts as a co-catalyst. An investigative study was thus undertaken to elucidate the effect of the molybdenum reagent on the reaction using a simple model system consisting of aniline

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• when the TCBD moiety was incorporated at the axial position of the subphthalocyanine (SubPc) core (Figure 3) [131]. Axially chiral SubPc–TCBD–aniline conjugates 59 and 60 were characterized via optical-resolution analysis through chiral HPLC using a Chiralpak IC column. The researchers unequivocally

• perpendicular to that of the aniline moiety. The calculations indicated the presence of accessible S1/S0 CIs. In the lowest-energy S1/S0 CI geometry, the aniline moiety exhibited a pronounced quinoidal character and the carbon atom directly linked to the butadiene moiety exhibited a conspicuous radical nature

• wavelength corresponding to the low-energy CT absorption), the direct formation of a CS state, characterized as ZnPc•+–TCBD•−, can be observed. SubPc–TCBD–aniline conjugates 59 and 60 exhibited distinct physicochemical properties, depending on whether the peripheral substituents introduced into the SubPcs

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• -difluoroalkenes and the co-elution of the aniline byproducts during column chromatography with the desired products affected the overall yield of the reaction. For a complete optimization list with all conditions that were screened, see Supporting Information File 1. With the optimized conditions in hand, we

• chemistry applications. In the reaction with piperidine, we observed unreacted organic azide 2b by TLC and 1H NMR analyses. Based on the 1H NMR analysis, 0.4 equiv of 2b had reacted to form the product, 0.9 equiv of 2b had decomposed to form aniline, and the remaining 0.2 equiv of 2b was unreacted

• . Additionally, 30% of the aniline byproduct was also isolated, which explains the modest yields of this reaction and the sluggish nature. To investigate the mechanism of the current transformation, we conducted a series of experiments including a time course of the reaction using 19F NMR spectroscopy (Figure 3

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• the para-position to the amino group, and when the para-position of aniline was occupied by another group, ortho-substituted products were identified. Fu′s research group established an isothiocyanatoalkylthiation of styrenes 9 in the presence of isothiocyanate 154 and N-(organothio)succinimides 1

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• allylation of lithium (trimethylsilyl)amides prepared in situ from the parent amines by a lithiation/silylation/lithiation sequence (Table 1). Using this protocol, α-(aminomethyl)acrylates 5 and 6 derived from benzhydrylamine and aniline were prepared in high yields (Table 1, entries 1 and 2). The procedure

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• effective. This method afforded the products with high selectivity and it could be extended to a variety of substrates, such as benzoxazole, benzothiazole, oxazole, and even acidic hydrocarbons and aniline. Fukuzama and co-workers [91] accomplished the C–H carboxylation of benzoxazole and benzothiazole

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• in this three-component reaction. For investigating the scope of this reaction, aniline was also used in the reaction, but in this case no expected dispirooxindoles could be obtained. In order to investigate the scope of this reaction, similar dimedone adducts of 3-phenacylideneoxindoles were used in

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

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• straightforward and efficient method for the N-arylation of primary arylamines and secondary amines with 1,3-cyclohexanedione-derived aryliodonium ylides in the presence of copper catalysts in water as a solvent. Results and Discussion To test our hypothesis, we commenced our studies by treatment of aniline (1a

• ) with iodonium ylide 2-(phenyl-λ3-iodaneylidene)cyclohexane-1,3-dione (2a) obtained from 1,3-cyclohexanedione in the presence of copper salts as catalysts. The detailed optimization studies are described in Table 1. Initially, we treated aniline (1a, 0.2 mmol) with iodonium ylide 2a (0.24 mmol) in the

• , CuCl2, CuBr2, and CuSO4·5H2O (Table 1, entries 4–7) with maintaining the same reaction conditions. Among these salts, CuSO4·5H2O afforded a relatively higher yield of the product diphenylamine (3a, Table 1, entry 4). Inspired by this observation, we carried out the N-arylation of aniline (1a) with

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• , without isolation of the intermediate 3-(2-oxopropyl)piperidin-4-one 5a, the reaction mixture after acid hydrolysis was treated with aniline and the desired tetrahydro-1H-pyrrolo[3,2-с]pyridine 6а was isolated in 19% yield only (Scheme 4). Finally, we studied some reactions of the obtained tetrahydrofuro

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• -pyrrolyl, trifluoromethyl and alkynyl as other three substituents (Scheme 15c) [42]. In 2020, a completely para-selective aza-Friedel–Crafts protocol with N-monosubstituted aniline derivatives 59 catalyzed by the chiral phosphoric acid P19 was disclosed by Zhu, Zhang and co-workers [43]. The electrophilic

• with π–π interactions between the catalyst’s aryl group and the aryl substituent at the nitrogen in the aniline 59 (Scheme 16a) [43]. Recently, Fan and co-workers reported a chiral phosphoric acid P20-assisted enantioselective aza-Friedel–Crafts reaction between α-naphthols 17 and isatin-derived

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

• with electron‐donating groups (i.e., OMe, Me) reacted much faster than aniline and furnished the pyrroles in excellent yields. In addition, the reaction of more sterically hindered aniline with 2,5-dimethoxytetrahydrofuran gave moderate yields and less sterically hindered aniline gave good yields. This

• ). The function of squaric acid as a catalyst was not clear, but the authors suggested that the Brønsted acidity of squaric acid affects the reactivity and selectivity of this process. The tentative mechanism of this protocol was proposed (Scheme 13b), in which a reversible acid–base reaction of aniline

• 28 with squaric acid afforded anilinium squarate salt A. Further, a catalytic amount of squaric acid hydrolyzes 2,5-dimethoxytetrahydrofuran (2) to give a 1,4-dicarbonyl compound B in water. Finally, N-phenylpyrrole 29 was obtained by condensation of activated 1,4-dicarbonyl compound with aniline. In

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• (Scheme 6). This means that the cleavage of the amide group that evolves aniline (pKa = 4.6) occurred smoothly after the initial thiazole ring closure (through 12a’ in Scheme 6). The addition of a thiophile (trimethyl phosphite) does not turn the reaction toward ECR and only decreases the yield of 13

• group. The leaving abilities of "aniline" nitrogen (anilinium has a pKa = 4.60 in water) [22] in intermediate 16 (Scheme 7) and "phenethylamine" nitrogen (2-phenyl-2-propylammonium has a pKa = 10.38 in water) [34] in 7a (Scheme 3) must differ by several orders of magnitude, which makes the irreversible

• leaving aniline moiety, prefers cyclization to give 13 (Scheme 6). Another key factor for successful ECR concerns the acidity of C–H in particular α-thioiminium salts 6a,b, 10a,b, 12a, 15 (pKaC) or the ease of proton transfer between the carbon and nitrogen in imidothioate followed by formation of the

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• deliver N-arylsulfonylimines under mild reaction conditions is highly desirable. Previously, we reported a tandem oxidative intramolecular cyclization of N-aryl(benzyl)amines, having an internal nucleophile substituted at the ortho-position in the aniline ring, to nitrogen heterocycles using potassium

• persulfate (K2S2O8) as the exclusive reagent [14]. The mechanistic study revealed that an initial oxidation to an iminium ion could be the key intermediate in the intramolecular cyclization step. In sharp contrast, when N-aryl(benzyl)amines that do not have an ortho-substituted nucleophile in aniline ring

• of the intermediate product 2c and 2-aminobenzamide gave 2-(p-tolyl)quinazolin-4(3H)-one (4b) in 85% yield. Furthermore, when various other ortho-substituted aniline derivatives such as 2-aminobenzylamine, 2-aminothiophenol, and o-phenylenediamine are reacted with imine 2a in a similar manner, the

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• '-dibromostilbenes 61 by means of a double Buchwald–Hartwig amination gave yields between 62% and 96% using aniline as the amine reactant (Scheme 13). The reaction proved to be compatible with both aromatic and aliphatic amines and the reaction time varied between 11 and 24 hours. Fluoro, chloro, nitrile, alkyl, and

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• )benzonitrile and N,N-dimethyl-4-((4-nitrophenyl)ethynyl)aniline in chloroform solution are 373 and 416 nm, respectively [35]. In the same time, λmax for 2-((4-nitrophenyl)ethynyl)-1,8-bis(dimethylamino)naphthalene is 474 nm [36]. The red shift observed in the spectrum of this compound as well as in the spectra

• solution (chloroform and acetonitrile were tested). For comparison, N,N-dimethyl-4-((4-nitrophenyl)ethynyl)aniline demonstrates a weak fluorescence with an emission maximum at 550 nm (EtOH) [37]. The optical band gaps (Egopt), estimated from the onset point of the absorption spectra, ranged within 2.39 eV

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

• . Such a change in the reaction selectivity could be explained by the influence of a higher nucleophilicity of the examined alkylamines in comparison with benzylamine. Then, we tried to involve less nucleophilic amines to the proposed approach. For these, we examined a reaction of APBTT 1a with aniline

• the model reaction of APBTT 1a and aniline (11a) were optimized. The best yield of PBTA 12aa was observed when butyl acetate was used as the solvent and heated at 130 °C for 3 h (entry 3, Table 3). Heating the reaction mixture in toluene (entry 7, Table 3) showed a good yield too. Since the product

• closed microreaction V-vial. Reaction of APBTT 1a with an excess of benzylamine. Reaction of APBTT 1a with morpholine. Reaction of APBTT 1a with aniline (11a). Derivatization of PBTA 12aa. Reaction of APBTTs 1a–h and arylamines 11a–d. Isolated yields are given; reaction scale: a mixture of 1 (0.45 mmol

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• 20% yield. Although yields were slightly diminished, unsymmetrical bridgehead-monosubstituted oxabenzonorbornadiene led solely to the 1,2,4-trisubstituted regioisomer (Scheme 7), similar to that observed by Gutierrez and Molander [39]. Selected substituents on the aniline motif were found to hamper

• photoexcitation of the photosensitizer 43 to form 44 which can oxidize aniline 36a to give radical cation 46 (Scheme 7). Deprotonation by DBU produces the radical 40. The radical anion photosensitizer 45 can reduce Ni(I) to Ni(0), closing the first catalytic cycle. The Ni(0) complex can undergo oxidative addition

• those with hydrocarbon, ether, acetal, and ester functionalities; although, aniline nucleophiles only resulted in the one step asymmetric ring-opening (ARO) product under the standard reaction conditions. Fortunately, the authors noted the addition of triethylamine allowed for aniline nucleophiles to

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• proved to be a potent reaction medium in catalytic hydrosilylation [53], hydroamination and hydroarylation [54], as well as for the synthesis of nanoparticles [55][56]. Results and Discussion Ionic liquids 1–6 were synthesized via a three-step procedure starting from commercially available aniline

• derivatives (see Scheme 1). First, the arylimidazole is obtained through a ring closing reaction using an aniline derivative, glyoxal, formaldehyde and ammonium chloride. The following alkylation with hexyl bromide yields the bromido ionic liquid. TAAILs 1–6 are then formed by an anion exchange reaction using

A novel bis-triazole scaffold accessed via two tandem [3 + 2] cycloaddition events including an uncatalyzed, room temperature azide–alkyne click reaction

• Ksenia Malkova,
• Andrey Bubyrev,
• Vasilisa Krivovicheva,
• Dmitry Dar’in,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1636–1641, doi:10.3762/bjoc.18.175

• ] which underwent aromatization with the loss of sulfur dioxide and N-Boc-aniline. The multicomponent character and the fairly large scope of this reaction allows to place pairwise reactive groups in the aldehyde and the amine components, which would set a scene for further elaboration of the product’s

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• two options for the generation of 4-ethoxy-2,3,6-triaminopyridine (9). One possibility comprised the deprotection of the dicarbamate 5 with potassium hydroxide giving the diamine 6, followed by azo coupling with the diazonium salt obtained from aniline and sodium nitrite to give azo compound 7