Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• group during the reaction. The structures of compounds 5a–e were confirmed by 1H and 13C NMR spectroscopy and HRMS, as well as X-ray diffraction analysis of a single crystal of compound 5b. The involvement of arylhydrazines 3b,c in the reaction with enamines 2a–d similarly leads to the formation of 1

• -aryl-5-amino-4-thiocarbamoyl pyrazoles 6a–f with yields of 63–86% (Scheme 3). However, we have found that when replacing hydrazine hydrate with arylhydrazines and arylsulfonylhydrazines, the reaction in ethanol was not detected, neither at room temperature nor at reflux. The progress was achieved only

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• . Again, in 2018, Yang et al. [26] synthesized functionalized dispiro[indoline-3,1-cyclopentane-3,3-indolines] via cyclodimerization of 3-phenacylideneoxindolines with benzoyl hydrazides and arylhydrazines. Encouraged by these synthetic methodologies and in continuation to our efforts towards the

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• reacted with different amines 42a–c in the presence of an ethanol–water mixture under ultrasonication, followed by reaction with arylhydrazines, which led to hydrazones 44a–l according to the classical procedure that employs methanol at room temperature. All compounds were evaluated against different

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

• Ryan M. Alam and
• John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

• , indazole ring-closure [10][11]. For example, several reports have highlighted the use of N-alkyl or N-arylhydrazines in the regioselective synthesis of 1H-indazoles, from the corresponding ortho-haloaryl carbonyl or nitrile, in good to excellent yield (Scheme 1) [12][13][14]. Alternative strategies to

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• ][45][46][47]. Moreover, arylhydrazones and arylhydrazines/hydrazines can be used as well, respectively, as partners in [4 + 2] cyclization reactions [48][49][50][51] or by reacting mostly with carbonyl derivatives [52][53][54][55]. From the state-of-the-art, a strategy that promotes the synthesis of

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

• obtained under photoredox-catalyzed conditions by using diaryldiodonium salts [57], arylsulfonyl chlorides [63], or aryl bromides [64] as the source of aryl radicals. A peculiar case is described in Scheme 7, path b, where arylhydrazines functioned as arylating agents to afford derivatives 7.4a–d by having

• recourse to the photoorganocatalyst eosin B dye [65]. The generation of phenyl radicals from arylhydrazines was assured even when using the covalent organic framework 2D-COF-1 in place of eosin B [66]. Notably, the use of 2D-COF-1 allowed to extend the protocol to the synthesis of 6-alkylphenanthridines

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

• Nadezhda S. Demina,
• Nikita A. Kazin,
• Nikolay A. Rasputin,
• Roman A. Irgashev and
• Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

• ketones were used to synthesize new N,S-heterotetracenes, namely 9H-thieno[2',3':4,5]thieno[3,2-b]indoles by their treatment with arylhydrazines in accordance with the Fischer indolization reaction. Keywords: Fiesselmann thiophene synthesis; Fischer indole synthesis; N,S-heteroacene; thieno[3,2-b

• arylhydrazines 5b–d containing electron–acceptor substituents or electron–donor ones. There was no obvious change in the yields of compounds 6l–o (78–84%, Scheme 3), which may indicate that the starting ketones had a rather high reactivity. To confirm the structure of TTI derivatives 6, we attempted to grow

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

• Aleksandr S. Krylov,
• Artem A. Petrosian,
• Julia L. Piterskaya,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

• amidines and amides was observed [4]. Moreover, the formazan-type products, the formation of which was observed in reactions of chloroethynylphosphonates with arylhydrazines, were not detected [16]. The structures of [1,2,4]triazolo[4,3-a]pyridines 3–8 were confirmed by IR, 1Н, 13C and 31P NMR spectroscopy

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• de Santa Maria – UFSM, 97105-900, Santa Maria, RS, Brazil 10.3762/bjoc.14.256 Abstract A one-pot iodine-catalyzed multicomponent reaction has been developed for the selective preparation of 5-amino-4-(arylselanyl)-1H-pyrazoles from a diverse array of benzoylacetonitriles, arylhydrazines and diaryl

• β-ketonitriles, arylhydrazines and aryl sulfonyl hydrazides as sulfur source [21]. The chemistry of iodine-catalyzed transformations has emerged as a greener, efficient and economical alternative to transition metals in organic synthesis [22][23][24]. However, the synthesis of selenium-containing 5

• -aminopyrazoles under iodine-catalyzed three-component reaction was not described so far. In view of this, we present a direct and selective multicomponent strategy to synthesize 5-amino-4-(arylselanyl)-1H-pyrazoles 4 by reacting benzoylacetonitrile derivatives 1, arylhydrazines 2 and diorganyl diselenides 3

Microwave-assisted synthesis of biologically relevant steroidal 17-exo-pyrazol-5'-ones from a norpregnene precursor by a side-chain elongation/heterocyclization sequence

• Gergő Mótyán,
• László Mérai,
• Márton Attila Kiss,
• Zsuzsanna Schelz,
• Izabella Sinka,
• István Zupkó and
• Éva Frank

Beilstein J. Org. Chem. 2018, 14, 2589–2596, doi:10.3762/bjoc.14.236

• liberation of the arylhydrazines from their hydrochloride salts in EtOH in the presence of NaOAc. The reaction rates were found to depend on the electronic character of the substituent present in the phenylhydrazine applied. The antiproliferative activities of the structurally related steroidal pyrazol-5

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• -oriented ester group. The only products obtained are 1,2-dihydropyrazole-3-carboxylates 62 in good yield. Interestingly, reactions with arylhydrazines afforded, in the presence of ammonium or sodium acetate, 5-aminopyrazole-3,4-dicarboxylates 63 [64] (Scheme 20). Apparently, in these cases, the

Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents

• Josef Jansa,
• Ramona Schmidt,
• Ashenafi Damtew Mamuye,
• Laura Castoldi,
• Alexander Roller,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2017, 13, 895–902, doi:10.3762/bjoc.13.90

• -diketones with arylhydrazines, halogenation of the resulting 1,3,5-triarylpyrazoles in the 4-position and further functionalization via Negishi cross-coupling [23][24] or halogen–lithium exchange reaction (Scheme 1). The resulting compounds amongst others seem to be interesting as potential complexing

Synthesis of constrained analogues of tryptophan

• Elisabetta Rossi,
• Valentina Pirovano,
• Marco Negrato,
• Giorgio Abbiati and
• Monica Dell’Acqua

Beilstein J. Org. Chem. 2015, 11, 1997–2006, doi:10.3762/bjoc.11.216

• the substitution pattern of starting materials (substituted arylhydrazines and cyclohexanones) and is therefore useful mainly for the synthesis of symmetrically or unsubstituted derivatives [16][17]. Recently, our research group described the synthesis of tetrahydrocarbazole derivatives by Diels–Alder

One-pot four-component reaction for convenient synthesis of functionalized 1-benzamidospiro[indoline-3,4'-pyridines]

• Chao Wang,
• Yan-Hong Jiang and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2014, 10, 2671–2676, doi:10.3762/bjoc.10.281

• generation of Huisgen’s 1,4-dipoles are aromatic heterocycles such as N-alkylimidazole, pyridine, quinoline, isoquinoline and primary aromatic amines. In recent years, other nitrogen-containing nucleophiles such as hydrazine and arylhydrazines are also used to generate Huisgen’s 1,4-dipoles in domino

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• also been tested (acrylates, maleic anhydride) giving no products or unsatisfactory results. A large range of aldehydes, as aliphatic, electron-rich or electron-poor benzaldehyde, could be used. Only very hindered aldehydes did not afford any product and both mono- and disubstituted arylhydrazines have

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• arylhydrazines 18 [134]. In both cases, the sulfoxide group preferentially adopts a rigid S-cis conformation [135], situating the sulfinylic oxygen in 1,3-parallel arrangement with the neighbouring hydrogen (blue arrow, Scheme 1). This arrangement is essential to force a specific final conformation of the

Chemistry of polyhalogenated nitrobutadienes, 10: Synthesis of highly functionalized heterocycles with a rigid 6-amino-3-azabicyclo[3.1.0]hexane moiety

• Viktor A. Zapol’skii,
• Jan C. Namyslo,
• Armin de Meijere and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2012, 8, 621–628, doi:10.3762/bjoc.8.69

• by transamination and subsequent intramolecular SNVin reaction. The structure of an analogous derivative of this heterocycle was previously confirmed by X-ray crystallography [5]. On the other hand, nitrodiene 25 was treated with arylhydrazines to give the persubstituted aminonitropyrazoles 27–28 in

Synthesis of oleophilic electron-rich phenylhydrazines

• Aleksandra Jankowiak and
• Piotr Kaszyński

Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29

• : arylhydrazines; methodology; synthesis; Introduction Mono-arylhydrazines I are important intermediates in the synthesis of a number of heterocycles, including indoles [1] and some azoles (for example [2][3]), many of which exhibit biological activity and are used in drug development [4][5][6]. Arylhydrazines

• obtained by using classical methods, such as the reduction of diazonium salts [13][14][15]. In contrast, electron-rich arylhydrazines are far less numerous and their preparation is complicated by oxidative instability. To access functionalized and sensitive arylhydrazines several methods involving the

• arylboronic acid V to AD [18][19][20]. The latter method is especially suited for arylhydrazides substituted with sensitive functional groups. Protected electron-rich arylhydrazines, hydrazides II, containing the 2,2,2-trichloroethyl group (R = CH2CCl3) are conveniently prepared by direct electrophilic

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• the two possible regioisomers was obtained preferentially depending on the hydrazine derivatives used, N-alkyl- and N-arylhydrazines giving opposite regioselectivities [15]. The carbonylative coupling of terminal alkynes with aryl (and heteroaryl) halides was proposed by Mori and coworkers as a

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

• formed through a AuPPh3Cl catalyzed cyclization reaction [139]. Using gold complex [XPhosAu(NCCH3)SbF6] as the catalyst, Jurberg and Gagosz prepared the cinnoline derivatives 261 by the hydroarylation of N-propargyl-N-arylhydrazines 260 [140]. With the gold complex [Mes3PAu]NTf2, an alkynyl ether moiety

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• reaction of 2-chloro-2-chlorodifluoro/trifluoromethyl-1-cyano-1-diethoxy phosphorylethylene 108 with arylhydrazines in refluxing carbon tetrachloride results in the rapid replacement of the chlorine atom with the terminal NH2 group of arylhydrazines to give intermediates 109, which is slowly transformed

• phosphonates (TFMCPs) 111 with arylhydrazines have been studied: TFMCPs 111 can be used as precursors of 2,3-dihydro-1H-pyrazoles 114 modified by both trifluoromethyl and diethoxyphosphoryl groups. Arylhydrazines add rapidly to the alkene double bond of 111 (X = CF3) at room temperature to produce an adduct