Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

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

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

• ][9]. Wherein, the wide variety of easily available starting butenolides and amines allows one to create a huge array of practically useful products. At the same time, the application of hydrazine derivatives expands the range of formed heterocycles. So, along with the aforementioned N-substituted

• process with hydrazine derivatives is known in the literature. Therefore, the study of recyclizations of heterocyclic systems containing the 3-acylfuran-2(5H)-one core under action of various hydrazines is of a great interest. Ongoing our research in the field of allomaltol chemistry in the present

• amines and 2H-furo[3,2-b]pyran-2-ones 1 without electron-donating units at the aryl fragment (Scheme 3). Further, we investigated the interaction of furanones 1 with various hydrazine derivatives 6. For this purpose, we tested the model reaction of furanone 1a with phenylhydrazine 6a under various

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• reacts with hydrazine hydrate and is heated to reflux, forming a pyrazolinone 2. This product is then chlorinated at the α-carbon, introducing a leaving group, to yield 3. The parent pyrazolinone 3 is subsequently treated with a base (either K2CO3 or N,N-diisopropylethylamine) to form the bimane 4. For

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• . Levulinoyl protection: Levulinic acid (Lev, 27) as protecting group which can be cleaved using hydrazine hydrate in AcOH, also yields highly selective 1,2-trans glycosides [95][96] and was implemented as a substitute for acetyl or benzoyl protection [97][98]. van Boom et al. also showed the use of a masked

• ] or hydrazine dithiocarbonate [116][117]. Owing to its versatile selectivity, it has been widely used in oligosaccharide synthesis [118][119][120][121][122] to implement the neighbouring group participation protocol, thereby producing 1,2-trans glycosides in high yield and selectivity without

Synthesis, characterization, antimicrobial, cytotoxic and carbonic anhydrase inhibition activities of multifunctional pyrazolo-1,2-benzothiazine acetamides

• Ayesha Saeed,
• Shahana Ehsan,
• Muhammad Zia-ur-Rehman,
• Erin M. Marshall,
• Sandra Loesgen,
• Abdus Saleem,
• Simone Giovannuzzi and
• Claudiu T. Supuran

Beilstein J. Org. Chem. 2025, 21, 348–357, doi:10.3762/bjoc.21.25

• the derivative of 1,2-benzothiazine-3-carboxylate 4. Compound 4 was reacted with an excess of hydrazine monohydrate to introduce the pyrazole moiety into the benzothiazine scaffold. Subsequently, pyrazolobenzothiazine 5 was elaborated with alkylating agents 6a–h to give N-alkylated (monoalkylated

• of pyrazolo-1,2-benzothiazine derivative 5 A solution of compound 4 (269 mg, 1 mmol) in ethanol (10 mL) was refluxed with excess of hydrazine monohydrate for 24 hours. After the completion of reaction, unreacted hydrazine was removed under vacuum. Cold acidified water was poured into the residue

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

• prevented their widespread use on a large scale. Recently, research efforts have focused on exploring alternative reagents that offer the advantages of being odorless and more stable than thiols. These alternatives include sulfonyl chloride [26], sulfonyl hydrazine [27], carbon disulfide [28], and sodium

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• begins with a nucleophilic attack of hydrazine on the aldehyde, activated by the copper salt, to give the corresponding hydrazone XXVIII. Subsequently, the formation of a Mannich-type intermediate XXIX was hypothesized by interaction between the hydrazone and the alkene mediated by Cu(OTf)2 coordination

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• enantioselectivities (87–99% ee) [49]. Furthermore, to demonstrate the synthetic potential of the methodology, further transformations were carried out. Firstly, the N-alkylation of 78e with ethyl bromoacetate led to the synthesis of tetrasubstituted hydrazine 79 in an excellent yield. This derivative has a newly

• formed N–N axis conducting to the origin of diastereoselectivity in the reaction. The treatment of 79 with base afforded the pyrrolinone 80 in 82% yield. On the other hand, the deprotection of derivative 78f led to the hydrazine 81 in an excellent yield. All the derivatizations occurred with the

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

• 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

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• trichloroacetimidate 10e by reaction with hydrazine and subsequent treatment with trichloroacetonitrile. The same synthesis was carried out also with the β-configured analogue of 10a. However, employment of the α-anomer 10a proved to be advantageous in terms of yield. The reaction of 1d with 10e afforded indigo-N

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

• -hydroxypyran-4-ones with hydrazine are known [30][31]. At the same time all considered recyclizations proceed under action of additional components and the intramolecular variant of this reaction is not described in the literature. It can be supposed that in the case of a substrate containing an allomaltol

• fragments and hydrogen bonds leads to the alteration in chemical behavior. Based on the aforementioned stability of tetronic acids 4 toward action of MeOH we supposed that various derivatives at the hydroxyethylidene group can be synthesized. For example, interaction of compound 4a with hydrazine in

• . Experimental procedure for the synthesis of compound 7 The mixture of tetronic acid 4a (0.37 g, 1 mmol) and hydrazine hydrate (0.1 g, 2 mmol) in EtOH (5 mL) was refluxed for 2 h. The resulting precipitate was filtered off and washed with EtOH (3 × 5 mL). (3E,5E)-3-(1-Hydrazinylethylidene)-5-(3-oxo-2-phenethyl

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• )hydrazine ((Me3Si)2N–N(SiMe3)2, 10) undergoes ultraviolet light-induced homolysis of the N–N single bond of 10 to form bis(trimethylsilyl)aminyl radical ((Me3Si)2N•, 11). The aminyl radical 11 adds to tert-butyl isocyanide to form the corresponding imidoyl radical 2 (R = t-Bu, E = (Me3Si)2N), as confirmed

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

• is that the reaction with methylhydrazine leads to two different regioisomers. Shen et al. used a concept developed by them for the C-acylation of β-ketoesters for the one-pot synthesis of pyrazoles. SmCl3-catalyzed acylation of these yields the 1,3-diketones 4, and after cyclization with hydrazine

• acetylacetonate 20. Extension of the sequence by cyclization with hydrazine leads to the pyrazole products 21 (Scheme 5) [53]. The method works best with acetylacetonates, since deprotonation of other diketones with NaOEt leads to deactivation of the isothiocyanates. A limitation of the method is the formation of

• pyrazole synthesis is the synthetic accessibility of hydrazines. To circumvent this limitation, arylboronic acids can be coupled with Boc-protected diimide 23 under copper catalysis to form the hydrazine precursor in situ. Subsequent removal of the Boc groups and cyclocondensation with 1,3-dicarbonyl

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• ; Introduction Hydrazones represent an important class of organic compounds. They can be readily prepared through the condensation of hydrazine derivatives with aldehydes or ketones. They have found widespread applications in materials sciences and supramolecular chemistry [1][2][3][4][5]. Importantly, they are

• substrate (1-(diphenylmethylene)-2-(4-nitrophenyl)hydrazine), which displayed three oxidation peaks (0.9, 1.7 and 2.2 V vs Ag+/Ag in HFIP ). The authors assumed that the two first peaks would correspond to the oxidation of 8 to 10 and 11 to 12 and that the oxidation of 10 would be responsible for the final

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• the electrophile [16][17][18]. In addition, C–C double bonds of the norcorrole skeleton outside the π-delocalization pathway exhibit a reactivity similar to an alkene to afford hydrogenated norcorroles by hydrogenation [19] or reduction with hydrazine [20] and [3 + 2]-cycloadducts with 1,3-dipoles [21

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• from 17α-hydroxyandrost-4-en-3-one (150) in a two-step sequence [64]. An initial condensation between 4-aminoantipyrine and the carbonyl group of 150 led to the imine 151. Then, treatment of the latter with hydrazine provoked an addition to the imine carbon, followed by a dehydrative cyclization. To

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• -cyclohexenones with nucleophilic nitrogen sources like ammonia, amines and hydrazine [14]. The reactions were regarded as via simple nucleophilic addition along with Pd-catalyzed dehydrogenative aromatization in these elegant works (Scheme 1, (1)). The Semmler–Wolff reaction is often implemented in the synthesis

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

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

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• elaborated. The suggested approach can be applied to various aromatic and heterocyclic hydrazines. At the same time for unsubstituted hydrazine the Boulton–Katritzky recyclization is not implemented. In this case the opening of the pyranone ring was observed leading to pyrazolylisoxazole derivatives. Both

• terarylenes containing an allomaltol fragment were developed in our group [21][22][23][24][25][26]. Ongoing the research in this area, herein, we studied the reaction of aroyl containing substituted pyrano[2,3-d]isoxazolones 1 with various hydrazine hydrochlorides 2. It was shown that formed hydrazones 3

• order to test the Boulton–Katritzky reaction for unsubstituted hydrazones we investigated the condensation of ketone 1d with hydrazine. The process was carried out with 3-fold excess of hydrazine hydrate in EtOH at reflux for 4 h. Unexpectedly, in this case instead of desired hydrazone 3n we have

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• hydride. In 2018, the Milstein group demonstrated a partial hydrogen-borrowing reaction with a manganese-pincer complex by coupling alcohols and hydrazine to form N-substituted hydrazones. Benzylic and aliphatic alcohols were studied with hydrazine using Mn(t-Bu-PNN)(CO)2Br (Mn5, 3 mol %) and a catalytic

• condenses with hydrazine followed by reduction and condensation with another aldehyde to afford the N-substituted hydrazones (Scheme 8). Balaraman and co-workers established a phosphine-free manganese catalyst generated in situ from a manganese precursor and a ligand for the N-alkylation of anilines with

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• secured due to the favorable hydrogen bonding (O–H∙∙∙N) between the oxime units; this idea is supported by 1H NMR spectroscopy which shows the presence of two distinct hydroxyl proton signals. The reduction of 7d in the presence of Pd/C and hydrazine monohydrate afforded 1,10-phenanthroline-5,6-diamine

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• ). Correspondingly, [1,3]thiazolo[4,5-b]pyridine 5 remained unchanged upon application of methods that had been successfully utilized in the hydrogenation of 1,3-benzothiazoles, involving diboronic acid or hydrazine hydrate as key reagents [21] in protic solvents at an elevated temperature (Table 1, entries 3 and 4

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• the two metallic centers in the tweezers cavity in a bridging mode. For the heterometallic Zn/Au system, luminescence quenching was observed in the closed state. The pyridine-hydrazine-pyridine unit has been extensively studied by Lehn and co-workers in coordination-responsive supramolecular polymers

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• of 3,4-dimethoxybenzaldehyde with 5-substituted 2-picoline derivatives in low to moderate yields ranging from 13% (2f) to 65% (2a) (Scheme 2). The amino-substituted derivative 2b was synthesized by reduction of the nitrostyrylpyridine 2a with Pd/C and hydrazine in 83% yield. Subsequent acylation of

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• -membered macrocycle, 2,10-dimethyl-2,8,10,16-tetrahydrodipyrazolo[3,4-e:3',4'-l][1,2,4,8,9,11]hexaazacyclotetradecine-4,12-diamine, by the reaction with excess hydrazine under various conditions was studied in detail. The reaction proceeded through the initial formation of 4-imino-2-methyl-2,4-dihydro-5H

• -2-methyl-2,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5-amine described by Baraldi et al. [41] using the reaction of 3-[(ethoxymethylene)amino]-1-methyl-1H-pyrazole-4-carbonitrile with excess hydrazine hydrate in EtOH under reflux. However, a pyrazole-fused 1,2,4,8,9,11-hexaazamacrocycle was unexpectedly

• the detailed studies of the hydrazine-promoted transformation of 3-[(ethoxymethylene)amino]-1-methyl-1H-pyrazole-4-carbonitrile (4) or 4-imino-2-methyl-2,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5-amine (8) into 2,10-dimethyl-2,8,10,16-tetrahydrodipyrazolo[3,4-e:3',4'-l][1,2,4,8,9,11

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96