Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• -[1,1'-biphenyl]-2-amines 3 with sodium nitrite and an acid under aqueous conditions. Recently, Wencel-Delord and co-workers disclosed an improved protocol toward diazonium intermediates 2 under non-aqueous conditions (t-BuONO and MsOH in acetonitrile) [4]. Nevertheless, the improved method still

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

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• to proceed using this route. In this study, we explored three distinct approaches commonly employed for the introduction of the oximino group into a molecule. The first approach is based on the generation of the nitrosonium ion from sodium nitrite under acidic conditions (Scheme 5, top) [58][59

• results, thiazole 2b, benzothiazole 2i and benzimidazole 2t react very well with sodium nitrite in an acidic environment (Scheme 6, red section). Among the various subclasses of compounds, pyrazole 2l exhibited a high reactivity using t-BuONO and EtONa in ethanol (Scheme 6, red section). On the other hand

Tetrabutylammonium iodide-catalyzed oxidative α-azidation of β-ketocarbonyl compounds using sodium azide

• Christopher Mairhofer,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1510–1517, doi:10.3762/bjoc.20.135

• : 65.0–67.5 °C. General α-nitration procedure Sodium nitrite (15.2 mg, 220 µmol, 2.2 equiv) and TBAI (7.4 mg, 20 µmol, 20 mol %) were suspended in a stirred solution of the respective starting material (100 µmol, 1.00 equiv) in 1.0 mL of DCE at rt. Then, a solution of anhydrous dibenzoyl peroxide (29.1

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• , Supporting Information File 1). Next, we analyzed the function of CmaA6, which was predicted to catalyze the diazotization of 3-aminocoumaric acid (3-ACA, 3) in p-coumaric acid biosynthesis. As expected, 3-diazocoumaric acid (3-DCA, 4) was synthesized by CmaA6 in the presence of ATP and sodium nitrite

• in the Cma system using in vitro enzyme assays. (i) CmaA1 loads 3,4-AHBA (1) onto holo-CmaA3 using ATP. (ii) CmaA6 catalyzes the diazotization of 3-ACA (3) to produce 3-DCA (4) in the presence of ATP and sodium nitrite. By analogy with the Ava system, we concluded that the Cma system biosynthesizes p

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• mesitylamine with sodium nitrite and acetic acid followed by a substitution of the intermediate diazonium salt with sodium azide [68]. All our attempts to prepare 2-azido-1,3-diisopropylbenzene along the same lines failed. Nevertheless, its in situ formation in the presence of phenylacetylene led to the

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• derivatives; sodium nitrite; transition metals; Introduction The isoxazole derivatives not only exist in many natural products [1][2][3] and pharmaceutical intermediates [4][5][6][7], but also have great application values in organic synthesis [8][9] (Figure 1). In the past decades, many methods have been

• holds significant potential due to their cost-effectiveness as compared to heavy metals. This renders them highly valuable for various applications in the field. Herein, we successfully developed a method that uses sodium nitrite as the source of nitrile oxide, and only applies aluminium trichloride as

• the Lewis acid to realize the sp3 C–H-bond activation of nitrogen heterocycles to synthesize isoxazole derivatives. Results and Discussion At the outset of this study, we chose the reaction of 2-methylquinoline (2a) with phenylacetylene (1a) in the presence of AlCl3 (3 equiv) and sodium nitrite (10

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

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• hydrazine and sodium nitrite. Further derivation of 11f led to compounds 11g–l which include different substitution patterns for R2. The tetrazolo[1,5-a]quinoxaline products 11a–l were obtained in yields of 36% to 81% for all steps (see Supporting Information File 1 for the entire scheme). Starting from 11a

New synthesis of a late-stage tetracyclic key intermediate of lumateperone

• Mátyás Milen,
• Bálint Nyulasi,
• Tamás Nagy,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2022, 18, 653–659, doi:10.3762/bjoc.18.66

• the basic patent and also discussed in a later scientific publication [7][8] (Scheme 1). According to this procedure, treatment of the commercially available, but quite expensive 3,4-dihydroquinoxalin-2(1H)-one (2) with sodium nitrite gave the N-nitroso derivative 3. Reduction of the latter with zinc

• transformed into N-nitroso derivative 32 by treatment with sodium nitrite in aqueous acetic acid. The next two steps, reduction of the nitroso group to hydrazine derivative 33 and its coupling with piperidinone 5 in a Fischer indole synthesis, were telescoped to form tetracyclic product 34. The latter was

Synthesis of new pyrazolo[1,2,3]triazines by cyclative cleavage of pyrazolyltriazenes

• Nicolai Wippert,
• Martin Nieger,
• Claudine Herlan,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2021, 17, 2773–2780, doi:10.3762/bjoc.17.187

• the designed synthetic route, 3-(3,3-diisopropyltriaz-1-en-1-yl)-1H-pyrazole-4-carbonitrile (15) was synthesized in a first step using the commercially available 3-amino-1H-pyrazole-4-carbonitrile (16). Thus, the aminopyrazole was diazotized in aqueous media using hydrochloric acid and sodium nitrite

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• was harvested and mixed with an equal volume of Griess reagent. After 10 min, the absorbance was measured at 570 nm with a microplate reader (Emax, Molecular Devices, Sunnyvale, CA, USA). Graded sodium nitrite solution was used as a standard to gauge NO2 concentration. Cell viability was assessed by

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• synthase (NOS) inhibitor ʟ-NMMA was employed. Graded sodium nitrite solutions were utilized to determine the nitrite concentrations. An MTT assay was used for the cell viability assay. Nerve growth factor and cell viability assays. Analogous as described in [13]. The C6 glioma cells (Korean Cell Line Bank

Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study

• Csilla Hargitai,
• Györgyi Koványi-Lax,
• Tamás Nagy,
• Péter Ábrányi-Balogh,
• András Dancsó,
• Gábor Tóth,
• Judit Halász,
• Angéla Pandur,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2020, 16, 1636–1648, doi:10.3762/bjoc.16.136

• nitrosation (with sodium nitrite in acetic acid), and in Mannich reactions [12]. For the formation of dimers 5, various mechanisms were envisaged. Nevertheless, the formation of any dimer-like product structurally similar to 3a has not been observed so far. In this report we describe our efforts to extend the

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

• synthesis of protected anilines by employing organic photoredox catalyst 4 with sodium nitrite as a cost-efficient source of NO2 at room temperature (Scheme 16) [145]. They also tried to perform the same reaction in the absence of light and photocatalyst, but no reaction progress was observed. As reported

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

• -phenylthiophene-2-carboxylate (1a) with sodium nitrite in aqueous HCl or HBr solution failed due to the poor solubility of its hydrohalide salts, while when 3-amino ester 1a was treated with tert-butyl nitrite and CuBr2 in acetonitrile solution, we observed only significant decomposition of starting compound. In

• this respect, we elaborated our own procedure for the preparation of aryl-substituted methyl 3-chlorothiophene-2-carboxylates 2, which consists of diazotization of the corresponding 3-aminothiophene-2-carboxylates 1 in acetonitrile solution with an aqueous sodium nitrite (1.1 equiv) solution in the

Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• conditions (catalytic palladium on carbon and hydrazine hydrate) was found to be the most efficient method for obtaining monoaminocalix[4]arene 10 in essentially quantitative yields (Scheme 3). The azide-Sandmeyer reaction on monoaminocalix[4]arene 10 was then attempted using sodium nitrite and p

• generated separately, using sulfuric acid and sodium nitrite, prior to being added to the monoaminocalix[4]arene 10 at 0 °C. After diazotization (15 min), an aqueous solution of sodium azide was added dropwise. After two hours at 0 °C the reaction was extracted with ethyl acetate, and the monoazidocalix[4

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• solution: Aniline (0.90 mL, 10.00 mmol) was dissolved in a mixture of concentrated hydrochloric acid (5 mL) and distilled water (20 mL). A solution of sodium nitrite (0.83 g, 12.00 mmol) in distilled water (5 mL) was prepared in a test tube. The sodium nitrite solution was added dropwise to the acidic

Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate

• Andrew T. King,
• Hugh G. Hiscocks,
• Lidia Matesic,
• Mohan Bhadbhade,
• Roger Bishop and
• Alison T. Ung

Beilstein J. Org. Chem. 2019, 15, 1347–1354, doi:10.3762/bjoc.15.134

• - method b Compound 5 (0.23 g, 0.505 mmol, 1 equiv) was dissolved in acetonitrile (10 mL) at room temperature before acetic acid (0.96 mL, 14.76 mmol, 29 equiv) and concentrated hydrochloric acid (0.98 mL, 27 mmol, 54 equiv) was added dropwise to the solution over 2 min at −10 °C. Sodium nitrite (0.123 g

Azologization of serotonin 5-HT₃ receptor antagonists

• Karin Rustler,
• Galyna Maleeva,
• Piotr Bregestovski and
• Burkhard König

Beilstein J. Org. Chem. 2019, 15, 780–788, doi:10.3762/bjoc.15.74

• acetic acid [65] provided both quinoxaline azobenzene derivatives in good yields. The methoxy-substituted quinoxaline azobenzene derivative 12a was synthesized via a different synthetic route depicted in Scheme 3. In a first step, p-toluidine (4a) was diazotized using sodium nitrite and subsequently

• photochromic derivatives with varying electronic and thus photochromic properties. The respective arylamines 13a–c were converted into their corresponding hydrazines 14a–c via diazonium-salt formation using sodium nitrite and subsequent reduction using tin(II) chloride [70]. The following nucleophilic

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• organic layer was washed with brine and dried over magnesium sulfate. The solvents were evaporated and the remaining solid was dissolved in 4.4 mL acetic acid at 0 °C. The mixture was stirred while a solution of sodium nitrite (839 mg, 12.17 mmol, 7.4 equiv) in 1 mL of deionized water was added dropwise

• . The mixture was stirred for another 3 h, after the solution of sodium nitrite had been added. 55 mL dichloromethane were added and the organic layer was washed twice with saturated sodium hydrogen carbonate solution and dried over magnesium sulfate. The solvents were evaporated and 340 mg of a pink

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• heated to reflux for 24 h. After cooling down to room temperature, the solution was filtered, washed with 1 N HCl and acetone, and then dried. The resulted material was named as graphene (GR, 143). In order to sulfonate the GR (143), sodium nitrite and sulfanilic acid (144) were added to a sonicated

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• ][52]. There are also examples of a radical treatment of a graphene-family material in an aqueous environment with water-soluble sodium nitrite as the additive [53][54][55][56][57]. It is well-known that, in an aqueous environment, a diazonium salt undergoes a side reaction that results in the

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• compound 267. Nitro compound 267 was also hydrogenated to produce 7-amino derivative 264. Diazoketone 265 was prepared from 264 with sodium nitrite in fluoroboric acid (HBF4) and its Wolff rearrangement under reflux conditions in water gave 1-hydroxy-2-naphthoic acid (266). Acetylation of 264 with sodium