Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides

• Petar Štrbac and
• Davor Margetić

Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75

• , a synthetic methodology for the preparation of 1–3 was developed by Warrener and co-workers by a Zn/Ag couple debromination [13][14][15]. However, this methodology has some disadvantages, such as tedious preparation of the catalyst, the use of dry solvent and expensive silver acetate as well as side

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• corresponding products 5m with 92% yield, respectively. In addition to this, aliphatic aldehydes (cyclohexanecarbaldehyde, butyraldehyde) were well tolerated under the standard reaction conditions to produce the product 5n and 5o with good yield. The substrate scope of this methodology was extended to chloro

• (5m). Conclusion In summary, we have successfully developed efficient methodologies for synthesizing 1,2-disubstituted benzimidazoles and quinazolin-4(3H)-one derivatives under mechanochemical (ball milling at 21 Hz) conditions in the presence of DDQ. The developed methodology can be considered as a

• green and eco-friendly methodology due to its solvent-free and metal-free nature. So, it can also be regarded as an alternative pathway to the traditional solution-based protocols. We anticipate that our developed strategy will have a substantial impact on the field of organic synthesis. Our work on

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• reactions pyruvate showed increased affinity towards the investigated enzymes. Given the metabolic importance of pyruvate [33][34][35], it may be of interest to test different pyruvate converting enzymes if this trend is confirmed. Experimental Methodology Genes and expression strains The gene of the

Synthesis of sulfur karrikin bioisosteres as potential neuroprotectives

• Martin Pošta,
• Václav Zima,
• Lenka Poštová Slavětínská,
• Marika Matoušová and
• Petr Beier

Beilstein J. Org. Chem. 2022, 18, 549–554, doi:10.3762/bjoc.18.57

• methodology for the preparation of analogues of karrikins with one sulfur atom in position C2 or position 6, or two sulfur atoms in both positions was improved; however, observed biological activities towards AChE were rather low. Structures of naturally occurring karrikins. Target compounds with highlighted

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

• proves that two equivalents of 3-phenacylideneoxindole are required for reductive cyclodimerization. Conclusion In conclusion, we have successfully developed a simple and efficient methodology towards the one-pot synthesis of dispirocyclopentanebisoxindole derivatives through base-catalyzed reductive

• methodology and structural diversifications of this moiety are underway in our laboratory. Experimental General method: All commercially available chemicals were purchased from Aldrich, USA or Spectrochem, India, and used without further purification. All solvents were used as received. The progress of 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

• dichromate as oxidizing agent in the presence of sulfuric acid, instead of acetic acid, to obtain compound 10 in 62% yield within a shorter reaction time (Table 1, entry 2) [48]. The methodology using sodium dichromate and sulfuric acid was adapted to the industrial scale production of vitamin K3 (10

• generated from the carboxylic acid through decarboxylation mediated by [Ag+]-peroxydisulfate, followed by their coupling with the quinone, providing the respective alkylated product. One of the first practical applications of this methodology to produce menadione (10) was described by Ashnagar and co

• published an alternative and sustainable methodology, using phenyliodine(III) bis(trifluoroacetate) (PIFA) as an oxidizing agent of the demethylation reaction [86]. The hypervalent iodine(III) proved to be a good oxidizing agent in the formation of 10 (92% yield) (Table 3, entry 2). According to the authors

Synthesis of 5-unsubstituted dihydropyrimidinone-4-carboxylates from deep eutectic mixtures

• Sangram Gore,
• Sundarababu Baskaran and
• Burkhard König

Beilstein J. Org. Chem. 2022, 18, 331–336, doi:10.3762/bjoc.18.37

• reaction to furnish the corresponding 5-unsubstituted dihydropyrimidinone-4-carboxylate derivative 8 in good yield (entry 1, Table 1). Encouraged by this observation, we tested the generality of this methodology by employing various electron-donating as well as electron-withdrawing groups on the aryl ring

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• the 1,4-position of 1. On the other hand, the double bond of 2 hardly interacted with the 9,10-position of 1, because of the steric effect induced by the cage host A. This methodology was also compatible with several other anthracene substrates with different substituents at the 9-position. But when

• mode, the molecular container selectively binds with and shields a certain part of the guest molecule and leaves the remaining part exposed to the reaction medium. This methodology was firstly applied to the site-selective reduction reaction mediated by a cyclodextrin host. In 1991, the Takahashi group

• cyclodextrin as the anchoring template. For example, cyclodextrin would fix the steroid substrate with a certain set of orientation, which exposes one certain C–H bond to the metalloporphyrin catalytic moiety and produces site-selective oxidized product. As shown in Figure 8, in this methodology, the steroid

Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• electronic nature. Environment-friendly reaction conditions, easily accessible substrates, and broad substrate scope highlight the practicality of this methodology. Results of the acid-catalyzed intramolecular hydroindolation of cis-β-(α′,α′-dimethyl)-4′-methindolylstyrenes 17 were reported by Stokes and co

• this methodology to related substrates with free indolyl NH as such reactions resulted into a complex mixture (not shown here), possibly due to the decomposition of the substrates. Nevertheless, the same regioselectivity was observed when the FC-acylation of N-protected 3-(4-indolyl)propanoic acids 28g

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• , Chinchilla et al. reviewed the Sonogashira reaction demonstrating its wide generality and applicability, and the protocol has become a booming methodology in synthetic organic chemistry [6]. Thereafter, the same authors again compiled the Sonogashira reaction covering literature up to 2011 attesting the

Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• determined the stereoselectivity of the reaction arises from the unattractive interactions imposed from the sterically hindered endo-face of the bicyclic alkene. The mechanistic insights gained from this combined experimental and theoretical study will facilitate further future methodology development in

New advances in asymmetric organocatalysis

• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 240–242, doi:10.3762/bjoc.18.28

• asymmetric organocatalytic methods to assemble biologically relevant compounds is highlighted by a review article devoted to the syntheses of coumarin derivatives [16]. Conjugated additions of stabilized nucleophiles are the cornerstone of organocatalytic methodology. Recent advances in this area are covered

• catalysis relies on the deprotonation of one of the substrates, but basic conditions may limit the applicability of this methodology. A unique base-free variant of chiral phase-transfer catalytic alkylation of 2-oxindoles was developed by Connon and co-workers [23]. Pentacarboxycyclopentadienes are a unique

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• following treatment of acid 5 with hydrazine hydrate, followed by hydrazone formation with the corresponding aldehyde. When subjected to the reaction conditions, oxadiazoles 2k and 2l were obtained in low yield over this multi-step sequence. While unsuitable for large scale reactions, this methodology may

Trichloroacetic acid fueled practical amine purifications

• Aleena Thomas,
• Baptiste Gasch,
• Enzo Olivieri and
• Adrien Quintard

Beilstein J. Org. Chem. 2022, 18, 225–231, doi:10.3762/bjoc.18.26

• operations and waste generation, this methodology should rapidly find applications in organic chemistry laboratories but also possibly on industrial scale. Experimental Typical experimental procedure with dicyclohexylamine 1: Dicyclohexylamine (37 mg, 0.21 mmol, 1 equiv) and 2-methoxynaphthalene (33 mg, 0.21

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

• Soumyadip Basu,
• Sauvik Chatterjee,
• Suman Ray,
• Suvendu Maity,
• Prasanta Ghosh,
• Asim Bhaumik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

• new C5–C6-unsubstituted 1,4-DHPs under ultrasonic irradiation. The important focus of the methodology was to develop an environmentally friendly protocol with a short reaction time and a simple reaction procedure. The other advantages of this protocol are a wide substrate scope, a very good product

• of green chemistry [21]. The application of ultrasound in “traditional” reactions results in a lower reaction time, higher conversion, and simpler methodology and is termed sonochemistry. Ultrasonication is a modern trend in synthetic chemistry that supports the objective of green chemistry, namely

• with this methodology, as shown in Figure 5. The synthesized products were characterized by 1H NMR, 13C NMR, HRMS, and melting point analysis. The structure of the compounds was also confirmed by single-crystal XRD analysis of 4a (CCDC1949329, Figure 6). Plausible mechanism A plausible reaction

Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

• Sandeep Kumar,
• Jyotirmoy Maity,
• Banty Kumar,
• Sumit Kumar and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

• eventually brought about the need for newly designed and improved anti-HIV drugs with respect to their improved pharmacological properties [20]. With an idea to keep the presence of azide functionality and to introduce structural rigidity, Marquez et al. [21] developed a methodology for the synthesis of

• . [23] synthesized the tricyclic azido-isonucleoside analogue 5 and Imanishi et al. [24] synthesized the azido-nucleoside 6 with a conformationally restricted sugar moiety. Recently, we have developed a greener and efficient chemoenzymatic synthetic methodology for the synthesis of conformationally

• starting from diacetone ᴅ-glucofuranose were found to be 33.9 and 35.1%, respectively. In our earlier research work, bridged homolyxofuranosylpyrimidines were synthesized following a chemoenzymatic methodology where biocatalyst Novozyme 435 was used for regioselective acetylation of the primary hydroxy

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

• , pharmaceutical, and biological sciences. A lot of the literature in this area is quite old. Perhaps there are also opportunities in this area to apply modern chemistry methodology, and also in the development of more sophisticated sensors and dyes. Naphthoquinones are commonly used in organic synthesis. Some

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• established a methodology for the oxidative cyanation of tertiary amines using a heterogeneous Ru/C catalyst [29]. Most of the reported works involve the use of toxic cyanating agents like NaCN or TMSCN. In this protocol, the authors have exploited the cost-effective, less toxic, and easily available ethyl

• oxygen (Scheme 9 and Scheme 10). Thus, the authors came to the conclusion that the higher yields of cyanation product obtained in the case of the hydrogen peroxide system was due to the highly reactive oxoruthenium species and low-valence ruthenium species. Sain et al. disclosed a new methodology towards

• I which after coordination and subsequent NCTS insertion is transformed to intermadiate II. β-Elimination finally delivers the required product (Scheme 14). Later, Deb and co-workers developed a methodology towards the synthesis of N-(2-cyanoaryl)-7-azaindoles using [RuCl2(p-cymene)]2/AgOTf/NaOAc as

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• stapling and the most prominent methodology was developed by the groups of Grubbs and Verdine using ring-closing metathesis (RCM) [4][5][6]. The optimised protocol for these so-called hydrocarbon-stapled peptides uses α-methyl-, α-alkenylglycines in a distance of i, i + 3/i + 4 for one helix turn or i, i

• . The conformational preferences of the stapled peptide P5 and of the linear peptides P6 and aAxWt were investigated via extensive accelerated molecular dynamics simulations (aMD) as implemented within the Amber18 program package [85]. The aMD methodology developed by McCammon and co-workers [86] has

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• . Lineu Prestes 1524, 05508-900 São Paulo-SP, Brazil 10.3762/bjoc.17.206 Abstract Microwave-mediated N-arylation of 4-chloroquinazolines in THF/H2O rapidly and efficiently afforded a library of novel 6-halo-2-phenyl-substituted 4-anilinoquinazolines. The methodology was compatible with numerous ortho

• , which furnished the desired verubulin analog in 87% yield (Scheme 2) [27]. Inspired by this preliminary result, we decided to investigate this methodology to synthesize other bioactive derivatives, such as 6-halo-2-phenyl-substituted 4-anilinoquinazolines – the presence of an aryl group at C2 and bromo

• -bromo-4-chloro-2-phenylquinazoline (8a), which provided the respective products 15e–g in yields ranging from 92 to 96% (Scheme 4). Finally, to illustrate the importance and scope of the methodology, we used the commercially available 4-chloroquinazoline (16) and 4-chloro-2-methylquinazoline (17), which

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• strategy for aldehyde C–H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• ], nickel [20][21][22][23], and iridium [24][25][26][27] have taken center stage when it comes to the development of synthetic methodology. Although these late TMs have contributed enormously to the various fields of organic, inorganic, and organometallic chemistry, growing concerns regarding their economic

• first Fe-catalyzed cross-coupling reaction between Grignard reagents and vinyl halides [37]. As of late, the development of Fe-catalyzed cross-coupling methodology and mechanistic rationales have burgeoned [38]. Today, the rate of growth within the field of iron catalysis is much greater than that

• of both electron-donating and withdrawing groups on all three components of the reaction affording products in good yield; however, the reaction produced geometric isomers, consistently favoring the E isomer. The authors applied their methodology towards an asymmetric variant using a chiral

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• Discussion Synthesis of L1-M, L2-M, and L3-M According to our experience, concerning the most bioactive structural arrangement, the ligands L1, L2, and L3 were selected for this study (Scheme 1). Using the known methodology developed by our group, the starting compounds endo-prolinates 1, generated by 1,3

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• -aminoquinolines and salicylaldehydes and an easy purification methodology with yields of up to 91%. Photophysical experiments with the derivatives exhibited common transitions in these heterocycle units and corroborated the aromatic structures and good fluorescence quantum yield values for all compounds

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• methodology based on the trans-stereoselective epoxidation reaction of 2,3-dihydroisoxazoles followed by the regioselective hydrolysis of the corresponding isoxazolidinyl epoxide [15][16]. Very recently, we have reported the synthesis of γ-(hydroxyamino)-α,β-diols by the addition of Grignard reagents to