Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• conditions. The reactions proceed readily in refluxing acidified (pKa = 1–5) ethanol solutions of the amine hydrochlorides to give 2-monosubstituted derivatives of 3H-phenoxazin-3-ones in a moderate yield [10][17]. In the present work, we intended to explore the reaction of 3H-phenoxazin-3-ones with aromatic

• fluorescence quantum yield was determined relative to quinine bisulfate in 0.05 M H2SO4 as standard (ΦF = 0.52, excitation at 365 nm for 5a–c and 6a,b) [26] and cresyl violet perchlorate in ethanol (ΦF = 0.54, excitation at 510 nm for 10c) [27]. Mass spectrometric analysis was performed on a Bruker UHR-TOF

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• structure induced by the embedded heteropine ring. By way of example, the solubility of SeO-doped seco-HBC 29c is more than 100-fold higher than pristine HBC carrying four tert-butyl groups in both dichloromethane and ethanol. Ring contraction was next attempted on the series of heteropines synthesized

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• -phosphite intermediate was then oxidized with hydrogen peroxide to yield dibenzyl α-phosphate 6, achieving an overall yield of 89% for these two steps. Removal of the 2-(phenylsulfonyl)ethanol protecting group in compound 6 was successfully achieved through treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• voltage of 15 kV. To prepare the sample for SEM imaging, a few milligrams of the Pt-PCN material were dispersed in 1.0 mL of ethanol using sonication for 5 min. Subsequently, a thin film of the sample was obtained by drop-casting a few microliters of the suspended sample onto a conductive Cu foil

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• , amphiphiles PA-OCH3 and PA-OH were synthesized by reacting prePA under neat conditions with 1-(2-bromoethoxy)-2-(2-methoxyethoxy)ethane (67% yield over 2 steps after ion-exchange) and 2-[2-(2-chloroethoxy)ethoxy]ethanol (42% yield), respectively (Figure 2b). Imidazole-functionalized amphiphile PA-Im was

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• temperature. A similar yield of the target product 3a was obtained by the reaction in ethanol in the presence of NaOH at 0 °С (entry 11 in Table 1). The latter conditions can be an alternative for the synthesis of compounds 3. Synthesis of N-heteroaryl amidines 3 We hypothesized that both 3,3

• of the substituents in azides 2 was observed. We assume the higher yield of pyrimidine containing triazoles 3a–k by their lower solubility in 1,4-dioxane compared with the solubility of azole containing compounds 3l–s in both 1,4-dioxane and ethanol. With regard to the scope of diaminoacrylonitriles

• hydroxide, freshly prepared from sodium hydroxide (20 mg, 0.5 mmol) and ethanol (2 mL), and the resulting mixture was stirred at room temperature for 5–10 min. Then, the mixture was cooled to 0 °C, the corresponding azide 2 (0.5 mmol) was added and the resulting mixture were stirred for 30 min, after which

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• organic layer was dried over Na2SO4, filtered and the solvent was evaporated under reduced pressure. The crude product was purified by flash column chromatography eluting with a mixture of n-hexane/CH2Cl2 3:1 and then crystallized from ethanol to give the title compound DMB-TT-TPA (8) as a yellow powder

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• acid ester 9 was hydrolyzed under basic conditions in an ethanol/water mixture. After the reaction, the pH of the mixture was adjusted to 4 with hydrochloric acid, which resulted in the precipitation of the product 10 in excellent yield (95%). Next, carboxylic acid 10 was converted into the

• polar solvent, i.e., methanol, to its solution. The main requirement for the polar solvent is that it should not dissolve the catalyst while it should completely dissolve the product. Therefore, we investigated the solubility of the Michael adduct 14 in methanol, ethanol, propan-2-ol, Patosolv® (a

• mixture of 85% of ethanol and 15% of propan-2-ol), and acetonitrile. The highest solubility of 14 was found in acetonitrile (63 mg mL−1) and methanol (17 mg mL−1). In both of these solvents, a low solubility of the lipophilic catalyst 2 was measured (<0.5 mg mL−1). Based on these results, acetonitrile was

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• mmol, 0.226 g) and 2-hydroxy-3-methylbenzaldehyde (MBA, 1.0 mmol, 0.136 g), for hdz-CH3, or 2-hydroxy-3-nitrobenzaldehyde (NBA, 1.0 mmol, 0.167 g), for hdz-NO2, in 20 mL ethanol (Scheme 2). One drop of concentrated HCl was added to the mixture as a catalyst. After stirring at 50 °C for 4 h, the mixture

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• demonstrated interesting, reversible, solvent-directed macrocycle-to-macrocycle interconversions. The transformations between the [1 + 1] 36 and [2 + 2] 37 macrocycles were governed by the solvent. The smaller monomeric 36 was obtained as the major product in chloroform, methanol, and ethanol. The conversion

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• (cavity) and the other directional due to hydrogen bonds (hydroxy groups), leads to the formation of these complexes. Results and Discussion The addition of two equivalents of sec-amines to an ethanol solution of R[4]A results in the formation of a crystalline precipitate with limited solubility in non

• dipropylamine and diisopropylamine, complexes with a stoichiometry of 1:2 are formed (i.e., 1 molecule of R[4]A binding to 2 molecules of dipropylamine or diisopropylamine). Regardless of the quantity of amine added to the solution of R[4]A in ethanol (4 equiv, 2 equiv, and 1 equiv, respectively), a 1:2

• substituents with R[4]A in ethanol were synthesized. The composition of the complexes was determined based on the integration of amine proton signals in the 1H NMR spectra. For small molecule sec-amines such as N,N-dimethylamine, N,N-diethylamine, and cyclic amines (pyrrolidine, piperidine, morpholine, N

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

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• acetaldehyde have been reported [20][21][22][23][24]. The safety and handling problems associated with acetaldehyde can be solved by synthetic equivalents that can be generated in situ through different paths. Some examples are represented by vinyl acetate [25], silyl vinyl ethers [26], ethanol, pyruvic acid

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• -tetraarylporphyrins 1 were synthesized from the corresponding 2-nitro-meso-tetraarylporphyrins in two steps by following the literature procedure [42]. The first step involved an amination of copper(II) 2-nitro-meso-tetraarylporphyrins by using 4-amino-4H-1,2,4-triazole in the presence of NaOH in refluxing ethanol

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

• molecule cyano- and thioamide groups, as well as a fragment of enamine, each in principle being capable of interaction with hydrazine (3a) (Figure 2). First, we have studied the reaction of thioamides 1a–c with hydrazine (3a). It was found that the reaction proceeds smoothly in ethanol at 80 °C to form 3,5

• elimination of hydrogen sulfide (Scheme 2). Thus, we have shown that when 2-cyanothioacetamides 1a–c react with hydrazine hydrate (3a) in ethanol, both groups (thioamide and cyano) interact with hydrazine with the elimination of hydrogen sulfide and the formation of 3,5-diaminopyrazoles 4a–c (Scheme 2). It

• -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

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• resulted in a significant reduction in kinetics and selectivity (Table 1, entry 3). Other more green and biobased solvent alternatives, such as ethanol [36], can effectively replace the acetonitrile (for the complete scope of solvents, please consult Supporting Information File 1, Table S2), but reaction

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

• Xiu-Yu Chen,
• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• reaction was carried out in common solvents such as ethanol, methanol, dichloromethane, and chloroform at room temperature for two hours. The expected isoquinolino[1,2-f][1,6]naphthyridine derivative 4a was successfully obtained in 35%, 40% 70% and 65% yields, respectively (Table 1, entries 1–4). The

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• substrates, almost equal amounts of diastereomers were formed. Whereas 4b was isolated by recrystallization of the reaction mixture from ethanol, the other adducts 4c–g were easily isolated by column chromatography. For comparison with previously reported results, adduct 4b, derived from acetylacetone (3b

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

• 70–95%). The presence of a base and the type of solvent seems to be an important factor for the reaction course. In toluene, ionic liquid or in refluxing ethanol without a base [16][19][20] or in the presence of weakly basic pyridine [17][18][21] (pKa = 5.23 in water, 3.4 in DMSO, 3.3 in DMF, and

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• ppm are present. In addition to the aforementioned characterization methods, the crystal structure of 11g·0.5EtOH was determined by single-crystal X-ray diffraction analysis. Its asymmetric unit contains 12 crystallographically unique molecules of 11g (Z' = 12, Z = 24) and 6 independent ethanol

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke–Blackburn–Bienaymé and Ugi reactions

• Oleksandr V. Kolomiiets,
• Alexander V. Tsygankov,
• Maryna N. Kornet,
• Aleksander A. Brazhko,
• Vladimir I. Musatov and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2023, 19, 727–735, doi:10.3762/bjoc.19.53

• -chlorobenzaldehyde (5b), 4-methoxyaniline (6a) and tert-butyl isocyanide (3a). It should be especially noted that the solubility of compound 8a is very low (soluble in DMSO and N-methyl-2-pyrrolidone (NMP), slightly soluble in methanol, 1- and 2-propanol, acetone, DMF and insoluble in water, ethanol, acetonitrile

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

• recrystallization of the crude product from ethanol. Next, the oxidative dimerization of terminal alkynes 6a–e was carried out in an aerobic medium in the CuI/TMEDA/iPr2NH system at room temperature, which proved to be effective in the synthesis of butadiynes 1–4 [15] (Scheme 3). The desired diarylbutadiynes 5a–e

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• reaction with formation of ruthenium aggregates and mononuclear Ru(0) catalyst. A) Isolation test of a reaction intermediate; B) XPS and TEM (in ethanol) of the recovered solid phase: showing the presence of Ru aggregates. Ruthenium aggregate-catalyzed alkylation reaction. Scope of continuous flow furfural

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• proved to be important for the selectivity of the reaction, where significant cleavage of the benzyl group resulted when ethanol was the solvent of choice. Subsequent ester hydrolysis gave compound 112 (Scheme 22) [55]. In parallel, a Still–Gennari olefination using aldehyde 52 lead to the cis-alkene 113

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• flavonolignans as impurities) and were purchased from Sigma-Aldrich, St. Louis, MO, USA. Ethanol used for complex synthesis was of 96% concentration (v/v) and was purchased from ChimReactiv (Bucharest, Romania). The analysis of the FA profile of the hazelnut oil required the derivatization (transesterification

• to 1:1:1 or 3:1:1 were mixed in a preheated mortar at 60 °C. Then, 4 mL water and 1 mL ethanol for 1:1:1 complexes or 6 mL water and 1.5 mL ethanol for 3:1:1 complexes were added. The mixture was kneaded for at least 30 min, until a viscous paste is obtained. The mortar temperature decreases to the