Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• commonly utilized as key intermediates for the synthesis of boron-containing peptidomimetics, which have been demonstrated to be efficient covalent ligands and valuable protease inhibitors endowed with various biological activities [5][6]. Going on with our interest in the synthesis of 3,3-disubstituted

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• natural substrate for sialidases and its chemical modification has been a useful approach to generate potent and selective inhibitors. Aiming at advancing the discovery of selective Trypanosoma cruzi trans-sialidase (TcTS) inhibitors, we have synthesised a small series of anomeric 1,2,3-triazole-linked

• differentiate both enzymes. Moreover, such selectivity might be reasoned based on a possible steric hindrance caused by a bulky hydrophobic loop that sits over the TcTS active site and may prevent the hydrophobic inhibitors from binding. The present study is a step forward in exploiting subtle structural

• the development of potent and selective inhibitors can serve as the basis for new therapeutics [3]. Despite the low primary sequence similarity among human, viral and non-viral sialidases (bacterial and protozoa), they all share a similar catalytic domain with active site residues highly conserved

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• direct access to cyclopeptides related to naturally occurring histone deacetylase (HDAC) inhibitors Cyl-1 and Cyl-2. Late stage modifications on the unsaturated amino acid side chain allow the introduction of functionalities which might coordinate to metal ions in the active center of metalloproteins

• ]. Three of these enzyme classes (I, II, and IV) contain Zn2+ within the active site, and therefore these enzymes can be affected by typical Zn2+-binding HDAC inhibitors. In cellular systems, an acetylated lysine of a histone is entering the cavity of the active site and gets coordinated to Zn2

• +. Subsequent attack of water forms a tetrahedral intermediate which results in a cleavage of the acetylated lysine. Most HDAC inhibitors act as substrate mimics and contain a zinc-binding motif. They competitively interact with the HDACs to form stable intermediates and therewith block the active site. Many

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• University of Technology in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic Institute of Organic Chemistry of the University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria 10.3762/bjoc.18.15 Abstract Paullone isomers are known as inhibitors of tubulin polymerase and cyclin dependent

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

• synthesis of a series of amino-N-methylated compounds 36 and phenoxy-1,2-naphthoquinones 35 with a carbon skeleton similar to β-lapachone (11), which could modulate hCE1 activity. Studies have shown that amino-N-methylated-1,2-naphthoquinones 36 are more selective and potent inhibitors than phenoxy-1,2

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

• malignant tumors, including platelet-derived growth factor receptor beta (PDGFR-β), vessel epidermal growth factor receptor (VEGFR-2), and epidermal growth factor receptor (EGFR) [5][6]. In addition, these compounds may act as vascular disrupting agents and tubulin polymerization inhibitors, contributing to

• apoptosis [7]. Figure 1 highlights the structures of three EGFR inhibitors approved by the United States Food and Drug Administration (FDA) and one known tubulin inhibitor: erlotinib (1), gefitinib (2), lapatinib (3), and MPC-6827 – verubulin (4) [5][7]. Given that 4-anilinoquinazolines are potential

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

• reaction proceeds via a radical mechanism (path iii) [77], although use of radical inhibitors had little impact on the success of the reaction. It seems unlikely a radical pathway is involved in the reaction mechanism; however, it cannot be categorically excluded. In 2021, the Koh group demonstrated the

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

• anti-inflammatory [9], antibacterial [10], antiarrythmic [11] activity; some representatives are CNS suppressors and poly-ADP ribose polymerase (PARP) inhibitors [12] (see Figure 1). Several approaches to obtain 2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-one derivatives of type 1 are known in the

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

• naturally occurring (−)-codonopsinol B (1) and its N-nor-methyl analogue 2 were found to be effective α-glucosidase inhibitors, their racemic forms showed no evident antiproliferative activities against the selected human cancer cell lines U87-MG, HepG2, JEG-3 and MOLM-13 as well as immortalized proximal

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• approved P-gp inhibitors are available in clinics [50]. Further, structurally related molecules, like the seco-analogues dauricine and daurisoline and the truncated bisbenzylisoquinoline muraricine (Supporting Information File 1, Figure S1) also show [51] P-gp inhibitory potential, so we investigated the

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• as zidovudine, didanosine, zalcitabine, stavudine, lamivudine (1), and abacavir (a carbanucleoside) for treating HIV infection, along with protease and nonnucleoside reverse transcriptase inhibitors (NNRTIs). Phosphorylation of 1,3-oxathiolane nucleosides, such as 3TC (1) and FTC (2), occurs in vivo

• to compete with natural deoxynucleotides for incorporation into (viral) DNA. Chain elongation via reverse transcriptase is thus inhibited. This class of drugs is referred to as nucleoside reverse transcriptase inhibitors (NRTIs). In NRTIs, 3TC (1) possesses chemical and biological properties, a

• inhibitors [26][27][28]. 3TC (1) has a β-ʟ-oxathiolane ring structure, instead of the ribose ring in the canonical nucleosides, and studies have shown that the triphosphate of 1 (i.e., 3TCTP) inhibits reverse transcriptase due to DNA chain termination [26][29][30]. In comparison to some of the other NRTIs

Strategies for the synthesis of brevipolides

• Yudhi D. Kurniawan and
• A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

• hydrogenated brevipolide derivative. It is interesting to note that all the brevipolides A–J (1–10) pose the conserved stereocenters and bear a cyclopropyl unit in the core structure, which are in agreement with the prior structural assignment of compounds 7–9, previously identified as unnamed inhibitors for

• ELISA NF-κB assay. Upon the mitochondrial transmembrane potential assay, three members demonstrated ED50 values in the nanomolar level [4]. Moreover, three of the members were identified as inhibitors of the chemokine receptor CCR5 [11]. Therefore, they are potential agents for treating human

Synthesis and antimicrobial activity of 1H-1,2,3-triazole and carboxylate analogues of metronidazole

• Satya Kumar Avula,
• Syed Raza Shah,
• Khdija Al-Hosni,
• Muhammad U. Anwar,
• Rene Csuk,
• Biswanath Das and
• Ahmed Al-Harrasi

Beilstein J. Org. Chem. 2021, 17, 2377–2384, doi:10.3762/bjoc.17.154

• materials, dyes, agrochemicals, photostabilizers, and corrosion inhibitors (copper alloys) [6]. Incorporation of the 1H-1,2,3-triazole moiety is well known to impact on the physical, chemical and biological potential properties of organic molecules. Due to this reason, many efforts have been exerted to

• metronidazole scaffolds are known to have a large range of biological activities including tumorhypxia agents [8], antiprotozoal activity [9], antimicrobial [10], antitumour [11], carbonic anhydrase IX inhibitors [12], trichomonas vaginalis activity [13], antileishmanial agents [14] (Figure 2). We have recently

(Phenylamino)pyrimidine-1,2,3-triazole derivatives as analogs of imatinib: searching for novel compounds against chronic myeloid leukemia

• Luiz Claudio Ferreira Pimentel,
• Lucas Villas Boas Hoelz,
• Henayle Fernandes Canzian,
• Frederico Silva Castelo Branco,
• Andressa Paula de Oliveira,
• Vinicius Rangel Campos,
• Floriano Paes Silva Júnior,
• Rafael Ferreira Dantas,
• Jackson Antônio Lamounier Camargos Resende,
• Anna Claudia Cunha,
• Nubia Boechat and
• Mônica Macedo Bastos

Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144

• 10.3762/bjoc.17.144 Abstract The enzyme tyrosine kinase BCR-Abl-1 is the main molecular target in the treatment of chronic myeloid leukemia and can be competitively inhibited by tyrosine kinase inhibitors such as imatinib. New potential competitive inhibitors were synthesized using the (phenylamino

• chromosome known as Philadelphia (Ph). Ph is the result of the reciprocal chromosomal conversion between the proto-oncogene Abl1 of chromosome 9 and the BCR gene on chromosome 22 [3][4]. Research activity on compounds able to act as protein tyrosine kinase inhibitors (TKIs), which has intensified since the

• TKIs that are even more potent than IMT, such as nilotinib [6][7]. These drugs act as inhibitors at the ATP binding site in the inactive form of BCR-Abl-1, preventing the binding of the protein to ATP in a competitive manner and resulting in the interruption of the substrate phosphorylation process and

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• for tryptophan metabolism in the human body. Thus, the inhibition of these enzymes may help in tumor immunotherapy [105][106][107]. Xu recently found indole-2-carboxylic acid derivatives as IDO1/TDO dual inhibitors. In their effort to synthesize the following bis(indol-4-yl)amine derivatives via a

• . Syntheses of bis(indol-2-yl)selanes. Syntheses of bis(indol-3-yl)selanes. Synthesis of bis(indol-2-yl)tellane 147. Synthesis of tris(indolyl)borane 154. Synthesis of bis(indol-4-yl)amines 159. Synthesis of bis(indol-5-yl)amines. Synthesis of 6,5’/6,6’-bis(indolyl)amines. Synthesis of potent HIV-inhibitors

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• acetylcholinesterase inhibitors [11][12][13], being LSPN223 the most potent compound (Figure 2). Furthermore, coumarin derivatives have been used as fluorescent probes, laser dyes, fluorescent chemosensors, light absorbers for solar cells, optical brighteners, and organic light emitting diodes (OLEDs) [14][15]. From a

• electron-donating and electron-withdrawing substituents. Additionally, the products were evaluated as acetylcholinesterase (AChE) inhibitors and compound 93d showed a promising activity. Gurubrahaman et al. developed a method for the synthesis of (Z)-2-methylenepyrans 96 through a conjugated addition of 4

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• in good yields (Scheme 39C). The authors used the same methodology to synthesize two 4H-benzo[d][1,3]oxazin-4-one derivatives that act as inhibitors of two enzymes (compounds 130 and 131 in Scheme 39D). The first one is the enzyme C1r serine protease, involved in both inflammation and renal scarring

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• , an immunoactivating natural product (substrate 37) [97][98]. In 2015, the diastereoselective synthesis of (E,S)-3-hydroxy-7-tritylthio-4-heptenoic acid 43, a key component of cyclodepsipeptide histone deacetylase (HDAC) inhibitors, was achieved in flow (Scheme 4) [99]. Acetyloxazolidinone 41 was used

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• alkaloids that were isolated in the mid-1990s from the Caribbean sponge bataella sp. From a biological point of view, the batzelladines have received attention due to their reported activity as inhibitors of HIV gp120-human CD4 binding. Chiral N-tert-butanesulfinyl aldimine (SS)-58 was used as a precursor

• -hydroxypipecolic acid 145 was reported recently by Zhang and Sun. Compound 145 is an intermediate for the synthesis of β-lactamase inhibitors. A key step in this synthesis was the hydrocyanation of chiral sulfinyl imine 141, prepared from commercially available and inexpensive ʟ-glyceraldehyde acetal, with

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

• synthesis has been recently reported by Loesche et al. [43]. The reaction between piperazine and different N-aryl-N’-cyanoguanidines in methanol at 120 °C afforded low to moderate yields for potential new cholinesterase inhibitors (Scheme 17A). Another example of microwave conditions has been provided by

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

• Rashmi Singh,
• Tomas Horsten,
• Rashmi Prakash,
• Swapan Dey and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79

• cancer cell lines [12][13]. Fluoroquinophenoxazines 2 have been used as telomerase inhibitors in anticancer research [14]. Furthermore, benzofuroisoindoles 3 were part of a kinase inhibitor study [15]. Photobiologically active psoralene (linear furocoumarin) dibenzofurans 1 and angular furanocoumarin

• ][21]. These compounds are presumably multitargeting drugs because of the diverse applications as insulin-like growth factor 1 receptor (IGF-1R) inhibitors [22], selective GSK-3β inhibitors important in Alzheimer's disease [23][24], and cyclin-dependent kinase (CDK) inhibitors [25][26][27]. Lastly, the

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

• ] reported the potential of naphthopyrans as non-purine xanthine oxidase inhibitors. They explored a silicated fluoroboric acid-catalyzed three-component cycloaddition involving acyclic 1,3-diketones 54, β-naphthol (55) and aldehyde 5 for the synthesis of substituted naphthopyrans 56 under microwave

• irradiation under solvent-free conditions. The library of compounds proved to be active as xanthine oxidase inhibitors with the most potent molecule showcasing IC50 = 4 μM (Scheme 21). 5 Pyrroles Pyrroles are five-membered heterocycles consisting of four carbon atoms and a nitrogen atom. The pyrrole ring is

• phenanthroline. 6 Pyrimidines/fused pyrimidines 6.1 Pyrimidines Pyrimidines are six-membered aromatic heterocycles containing two nitrogen atoms at positions 1 and 3. These are an important class of compounds depicting a wide range of biological activities such as COX inhibitors, anti-inflammatory, anticancer

β-Lactamase inhibition profile of new amidine-substituted diazabicyclooctanes

• Zafar Iqbal,
• Lijuan Zhai,
• Yuanyu Gao,
• Dong Tang,
• Xueqin Ma,
• Jinbo Ji,
• Jian Sun,
• Jingwen Ji,
• Yuanbai Liu,
• Rui Jiang,
• Yangxiu Mu,
• Lili He,
• Haikang Yang and
• Zhixiang Yang

Beilstein J. Org. Chem. 2021, 17, 711–718, doi:10.3762/bjoc.17.60

• -lactamase inhibitors. As part of our efforts, we have synthesized a series of DBO derivatives A1–23 containing amidine substituents at the C2 position of the bicyclic ring. These compounds, alone and in combination with meropenem, were tested against ten bacterial strains for their antibacterial activity in

• MIC from <0.125 mg/L to 2 mg/L, and is comparable to avibactam against both E. coli strains with a MIC value of <0.125 mg/L. Keywords: amidine; antibacterial activity; β-lactamase inhibitors; diazabicyclooctane; synthesis; Introduction Survival stress posed by antimicrobial agents triggers multiple

• , sulbactam and tazobactam [13] evolved as the BLIs of class A, B and few of class D β-lactamases [14]. These inhibitors were advantageous to clavulanic acid due to their lack of chromosomal induction of AmpC but found susceptible to a few of class A enzymes such as TEM type [10] and CTX-M (ESBL), identified

Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

• Emine Salamci and
• Yunus Zozik

Beilstein J. Org. Chem. 2021, 17, 705–710, doi:10.3762/bjoc.17.59

• have become important structural components for drug development with a modifying action as inhibitors of glycosidases [4][5][6][7][8][9][10]. Aminocyclitols are amino polyhydroxy cycloalkanes [2] formally derived from cyclitols [11][12][13][14][15], which are polyhydroxylated cycloalkanes, via

• of the most important conduramines 4 is valienamine (3) [17], which is found as a building block in several aminoglycoside antibiotics [2]. Furthermore, conduramines 4 and their derivatives are used as both inhibitors of glycosidases and useful intermediates in organic synthesis [18]. Halocyclitols

• inhibitors of α-glycosidases [11][19]. Recent reviews report on the latest synthetic methodologies for aminocyclitols and related compounds [1][2][3][16]. Many methods have been previously reported for the synthesis of aminocyclitols containing five- and six-membered rings, along with their diverse

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• analogs are an interesting group of pharmacologically active heterocycles [1][2], many of which possess, e.g., antimicrobial [3][4], antifungal [5], antidepressant [6][7], and antihistaminic [8][9][10] properties. Amino- and amidophthalazine derivatives have been examined, e.g., as inhibitors of PGE2

• ][14] and PDE-10 [15] for a potential use in the treatment of chronic pain and neurodegenerative or psychiatric disorders. Some of these derivatives are known to possess anti-inflammatory (p38 MAP kinase inhibitors, Figure 1) [16], cardiotonic [17], and anticancer (Aurora-A kinase inhibitors