Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• (sp2)–H radical sulfenylation of enaminones or chromones has emerged as a popular strategy using various sulfenyl precursors such as thiophenols [38][39][40], sulfonyl hydrazides [41][42], disulfides [43], KSCN [44], S8 [45], methylsulfinyl derivatives [46], sodium sulfinates [47], and thiosulfonates

• this study, we report the synthesis of corresponding disulfides under the catalysis of TBAI (tetrabutylammonium iodide) using sodium alkyl or aromatic sulfinates as sulfur sources. Sodium sulfinates are more stable than sulfonyl hydrazides, sulfonyl chlorides, and thiols, and there is no need to add

Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• a central theme of the work carried out by our research group in recent years, focusing on the formation of the S–N bond by applying the umpolung reactivity of HIRs, in particular in the preparation of sulfonamides and sulfonyl hydrazides [22][23]. In both approaches, a sulfonyl-containing

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• the ester function, as previously reported [32][33][34][35]. The corresponding adducts 5a–f were isolated with good yields from 66 to 88%. In the case of hydrazides 5e and 5f, the mixture of diastereomers (1:1 ratio) could not be separated at this stage. Although no stereoselectivity is observed, it

• can be noticed that the presence of an amino acid is compatible with the conditions of the reaction and did not interfere or significantly decrease the yield of the reaction (Scheme 3). Then, the N-carboxylate hydrazides 5a–d were firstly oxidized with iodine in the presence of potassium carbonate to

• hydrazine [36], allowed the expected compounds 6e and 6f to be obtained in good yields. This methodology was applied to the previous hydrazides 5a–d giving the corresponding compounds 6a–d in similar yields. As expected, no isomerization occurred during the oxidation, leading exclusively to the imine and

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

• Andrey N. Komogortsev,
• Constantine V. Milyutin and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

• was isolated in unchanged form. It should be mentioned that the key step of the studied recyclization is an intramolecular nucleophilic addition of a nitrogen atom at the double bond of the pyranone ring. Comparing the chemical properties of the considered amides and hydrazides it can be assumed that

• bases under conditions described earlier for corresponding hydrazides. So, among the employed basic agents (Et3N, DABCO, DBU, DMAP, K2CO3, AcONa) only in the case of DBU the expected recyclization was observed and the target product 4a was obtained in 15% yield. In order to enhance the yield of compound

• synthesized products is different from previously described 3-acetyltetronic acids 2 obtained from the corresponding hydrazides 1. As well as in the case of compounds 2 for the amide derivatives 4 the double bond between pyrrolidinone and furanone parts has E-configuration. Only for sterically hindered

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• substrates according to this method. However, attempts to carry out the reaction sequence with unprotected hydrazine were unsuccessful. Alternatively, Mitsunobu reagent 23 can be reacted with in situ generated benzyne (from o-(trimethylsilyl)phenyl triflate) to provide the hydrazides for the concomitant

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• triple alkylation of ammonia with α-halohydrazones 9a–e following a protocol previously developed by us [35] (Scheme 2a). Halohydrazones 9a–e were prepared by condensation of readily available chloroacetone or bromoacetaldehyde (generated from the corresponding diethyl acetal) with hydrazides or

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

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• ]. Examining a broad range of hydrazides in the condensation reaction with menadione, Bouhadir and co-workers reported the synthesis of various menadione acylhydrazone derivatives [126]. In this work, various acylhydrazides prepared by reaction of hydrazine hydrate with different esters were reacted with

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

• Alla I. Vaskevych,
• Nataliia O. Savinchuk,
• Ruslan I. Vaskevych,
• Eduard B. Rusanov,
• Oleksandr O. Grygorenko and
• Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

• includes the reaction of readily available anthranilic amides or hydrazides with pent-4-yn-1-ols or -carboxylic acids promoted by PdCl4 [15], Au(І) [16][17][18] or Cu(ІІ) [19] salts. In another version, the target compounds were obtained by iodine-catalyzed reaction of the aforementioned anthranilic acid

• halogenoketones or ketocarboxylic acids upon action of SnCl2·H2O, TiCl4/Zn, or Fe/CH3COOH can be mentioned [28][29][30]. 1-Aryl-substituted tetrahydropyrrolo[1,2-a]quinazolin-5-ones can be also obtained by a Brønsted acid-catalyzed annulation of arylcyclopropane aldehydes and N′-anthranilic hydrazides [31], as

Copper-mediated oxidative C−H/N−H activations with alkynes by removable hydrazides

• Feng Xiong,
• Bo Li,
• Chenrui Yang,
• Liang Zou,
• Wenbo Ma,
• Linghui Gu,
• Ruhuai Mei and
• Lutz Ackermann

Beilstein J. Org. Chem. 2021, 17, 1591–1599, doi:10.3762/bjoc.17.113

• , hydrazides 1 with electron-donating or electron-withdrawing substituents were efficiently converted in the C–H/N–H activation annulation process. Notably, a wide range of valuable electrophilic functional groups, such as halogen, methylthio, cyano, amino, and ester groups, were well compatible, which should

• C−H/N−H activation. Copper-mediated oxidative C−H/N−H functionalization of hydrazides 1 with ethynylbenzene (2a). Copper-mediated oxidative C−H/N−H functionalization of 1 with alkynes 2. Decaboxylative C−H/N−H activation and cleavage of the directing group. Summary of key mechanistic findings

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• isotopically-labeled hydrazides could also be employed. Notably, this methodology considerably shortened the existing synthetic routes for adding a methyl group to olefins. More recently, the Bradshaw group has been exploring the potential use of tosyl hydrazones in reductive couplings with olefins initiated

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• -amidinopyrazole under the same reaction conditions. Edmont et al. extended this method using hydrazides as nucleophiles to produce potential hypoglycemic quinoline carboxyguanidine derivatives (Scheme 33) [70]. In this case, the “biguanidylation” reagent could convert the hydrazide into the desired compound

Hydrazides in the reaction with hydroxypyrrolines: less nucleophilicity – more diversity

• Dmitrii A. Shabalin,
• Evgeniya E. Ivanova,
• Igor A. Ushakov,
• Elena Yu. Schmidt and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2021, 17, 319–324, doi:10.3762/bjoc.17.29

• synthesis of three types of highly functionalized azaheterocyclic scaffolds (dihydropyridazines, tetrahydropyridazines, and partially saturated tricyclic systems) from readily available hydroxypyrrolines and hydrazides are described. The directions of the transformation of a common initial intermediate

• , namely a Brønsted acid-activated hydroxypyrroline, depend on the reaction conditions and the structure of the hydrazides. Keywords: hydrazides; pyridazines; pyrrolines; recyclization; ring expansion; Introduction Di- and tetrahydropyridazines are valuable heterocyclic motifs which are utilized as key

• emphasis on the nature of hydrazine derivatives still remains obscure. Meeting this challenge becomes particularly important in view of the significance of the less nucleophilic hydrazides as N–N-bond containing starting materials in drug discovery [13][14][15][16]. Herein, we report how a lower

Efficient [(NHC)Au(NTf₂)]-catalyzed hydrohydrazidation of terminal and internal alkynes

• Maximillian Heidrich and
• Herbert Plenio

Beilstein J. Org. Chem. 2020, 16, 2080–2086, doi:10.3762/bjoc.16.175

• effect was weaker, but nonetheless the conversion of the electron-deficient hydrazides (R = NO2) was slightly more efficient than with the electron-rich hydrazides (R = NMe2). Conclusion In conclusion, we have demonstrated the efficient hydrohydrazidation of various terminal and internal alkynes

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• 154a), and the presence of an electron-donating group increases the yield of isoxazoline (product 154g compared to product 154a). Another approach to the synthesis of isoxazolines with a sulfonyl moiety is the reaction of unsaturated oximes 155 with sulfonyl hydrazides 156 under the action of TBHP and

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion

• Christina Görgen,
• Katharina Boden,
• Guido J. Reiss,
• Walter Frank and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1360–1370, doi:10.3762/bjoc.15.136

• Chemie und Makromolekulare Chemie, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.15.136 Abstract A consecutive three-component activation–alkynylation–cyclization reaction of (hetero)aryl glyoxylic acids, oxalyl chloride, arylacetylenes, and hydrazides efficiently forms 1,5-diacyl-5

• acids 1, oxalyl chloride, arylacetylenes 2, and hydrazides 4 were reacted in 1,4-dioxane and in the presence of catalytic amounts of copper(I) iodide in a one-pot activation–alkynylation–cyclization sequence to give 1,5-diacyl-5-hydroxypyrazoline 5 after flash chromatography on silica gel in moderate to

• –cyclization sequence of (hetero)arylglyoxylic acids, oxalyl chloride, arylacetylenes, and hydrazides does not form aromatic pyrazoles, but rather 1,5-diacyl-5-hydroxypyrazolines, i.e., the aromatizing elimination of water does not occur under these neutral conditions. This novel one-pot synthesis of 1,5

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• bis(1,5-disubstituted tetrazoles). Methyl isocyanoacetate 13a was used as an essential component in the first hydrazino-Ugi-azide reaction allowing consecutive Ugi reactions to take place. In the first step, 13a, hydrazides, aldehyde or ketone, trimethylsilyl azide (TMSN3) and ZnCl2 (10 mol %) in

• corresponding hydrazides 15, which were used in a second hydrazine-Ugi-azide reaction with various ketones, to obtain the acylhydrazino bis(1,5-disubstituted tetrazoles) 16 in yields ranging from 45–70%. Consecutive Ugi reactions for the synthesis of substituted α-aminomethyl tetrazoles have also been described

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium

• Nadia Bouzayani,
• Jamil Kraїem,
• Sylvain Marque,
• Yakdhane Kacem,
• Abel Carlin-Sinclair,
• Jérôme Marrot and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2018, 14, 2923–2930, doi:10.3762/bjoc.14.271

• (Scheme 2, Table 1) in a sealed tube in the presence of Et3N and under solvent-free conditions. From green chemistry point of view, this enhanced procedure appears to be a good alternative of the precedents for the synthesis of hydrazides 3a–m [26][27][28][29]. Moreover, the phenylglycine phenylhydrazide

• the main difference with the known reaction [51] between the hydrazides 3 and the phthalaldehydes in which two diasteroisomers have been observed. If the amino acid residue (R on the Scheme 5) enough implicates steric hindrance with the carboxyaromatic part of B, the pathway with disfavored transition

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

• 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

Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

• Amrita Das,
• Mitasree Maity,
• Simon Malcherek,
• Burkhard König and
• Julia Rehbein

Beilstein J. Org. Chem. 2018, 14, 2520–2528, doi:10.3762/bjoc.14.228

• reports on direct C–H functionalization using transition metals or metal free [37][38][39] conditions and different sources of sulfur, for example arylsulfonyl chlorides, sodium arylsulfinates, sulfinic acids and arylsulfonyl hydrazides have been reported (Scheme 1). However, the protocols require

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• acids – potent xanthine oxidoreductase inhibitors [40] or even 3,4-unsubstituted pyrazoles [16]. Both pyrazole carboxylic groups can be also modified to hydrazides and oxazole rings [26] or a new condensed pyridazine ring [27]. Less reactive dipolarophiles such as dibenzoylacetylenes (1,4-diphenylbut-2

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• synthesis of many naturally occurring compounds which exhibit biological and pharmaceutical activity [61]. A typical example of the generation of resonance-stabilized phosphorus ylides 65 comprises triphenylphosphine, dialkyl acetylenedicarboxylate, and arylsulfonic hydrazides providing the corresponding

• phosphorus ylides via the reaction of triphenylphosphine with dialkyl acetylenedicarboxylates and arylsulfonic hydrazides. Synthesis of resonance-stabilized phosphorus ylides in the reaction of triphenylphosphine, dialkyl acetylenedicarboxylates, and aryl hydrazines. Synthesis of resonance-stabilized

Consecutive hydrazino-Ugi-azide reactions: synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles

• Angélica de Fátima S. Barreto,
• Veronica Alves dos Santos and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2017, 13, 2596–2602, doi:10.3762/bjoc.13.256

• , followed by a hydrazinolysis step and a second hydrazine-Ugi-azide reaction to provide the desired acylhydrazino bis(1,5-disubstituted tetrazoles). Recently we have reported the synthesis of acylhydrazino-peptomers by a similar strategy [31]. The hydrazides 2a–c were prepared by the reaction of esters 1, 4

• and 6 with hydrazine monohydrate, following a known procedure (Scheme 2) [31]. To access the acylhydrazino-tetrazoles, the hydrazides 2a–c were subjected to a multicomponent reaction comprising an aldehyde or ketone 7a–h, trimethylsilyl azide (TMSN3, 8), methyl isocyanoacetate (9) and ZnCl2 (10 mol

• modification reactions. Tetrazole-containing drugs. Synthesis of acylhydrazino bis(1,5-disubstituted tetrazoles) through two hydrazino-Ugi-azide reactions and a hydrazinolysis step. Synthesis of hydrazides 2a–c. Reagents and conditions: (i) N2H4·H2O, EtOH, reflux, 2–3 h; (ii) CH3I, NaHCO3, DMF, rt, 46 h; (iii