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

• developed by Murata, Komatsu et al. [80]. In this approach, C60 or C70 fullerenes are modified stepwise towards an open-cage derivative in order to encapsulate small molecules such as H2 [81][82]. Eventually, the chemical modifications are reversed to close the hole and give an endohedral fullerene. As

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• pyridine rings, the naphthalene core at positions 5(8) and the CH2CH2 bridge (dehydrogenation) undergo chemical modifications under mild conditions, giving the corresponding acenaphthylenes. The latter can also be obtained in an unusual way by tele-elimination from 5,8-dibromodipyridoacenaphthene by

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling

• Elenilson F. da Silva,
• Krist Helen Antunes Fernandes,
• Denise Diedrich,
• Jessica Gotardi,
• Marcia Silvana Freire Franco,
• Carlos Henrique Tomich de Paula da Silva,
• Ana Paula Duarte de Souza and
• Simone Cristina Baggio Gnoatto

Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161

• glycyrrhizic acid, an oleanane, has demonstrated antiviral activity in the SARS-CoV-2 virus by inhibiting the ACE2 expression and SARS-CoV in vitro in Vero cells (IC50 = 365 μM), while chemical modifications to its backbone have been described which can enhance the potency of its antiviral activity [19][20

• interaction between the IMPDH protein and the derivative 8, indicating a probable mechanism of action. In summary, this study highlighted the importance of chemical modifications, in this case by linking a triazole ring to a triterpene backbone for the development of secure and efficient anti-RSV agents

Synthesis of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines and investigation of their fungistatic activity

• Anna V. Korotina,
• Svetlana G. Tolshchina,
• Rashida I. Ishmetova,
• Natalya P. Evstigneeva,
• Natalya A. Gerasimova,
• Natalya V. Zilberberg,
• Nikolay V. Kungurov,
• Gennady L. Rusinov,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2022, 18, 243–250, doi:10.3762/bjoc.18.29

• at C(3) allowed us to obtain 5 more derivatives exhibiting a high and moderate activity (MIC from 0.38 to 6.25 μg/mL) for one (3j, 5b) or several (4a, 5a, 5c) strains (Table. 1). Thus, the most promising compounds for chemical modifications aimed at the development of new fungistatics appear to be

(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

• 1980s, has led to the identification of the (phenylamino)pyrimidine (PAP) structure [5][6]. The addition of an additional pyridine ring to PAP raised its cellular activity, producing PAPP, which, after some more chemical modifications, culminated in imatinib (IMT) [7]. PAPP has been used to develop new

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• biosphere by structurally supporting plants, providing energy to animals, and regulating a variety of biological processes [1]. Their versatility and diversity result in a wide range of properties exploited for commercial purposes. Chemical modifications permit to broaden their applications even further

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• and diagnostics, and attempts to develop new PNA therapeutics. The discussion starts with a brief review of PNA’s binding modes and structural features, followed by the most impactful chemical modifications, PNA enabled assays and diagnostics, and discussion of the current state of development of PNA

• for innovative chemistry and biology to unlock the full potential of PNA in biomedical applications. Keywords: antisense; chemical modifications; diagnostics; peptide nucleic acid; PNA; Introduction Peptide nucleic acid (PNA) is a DNA mimic where the sugar–phosphate backbone of DNA is replaced with

• , many research groups have worked on chemical modifications to the backbone and nucleobases of PNA, as well as conjugating PNA to other biomolecules (e.g., cell-penetrating peptides) [4]. The present review summarizes the most significant efforts and achievements in optimizing various aspects of PNA

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• simplicity combined with the five natural bases, adenine (A), cytosine (C), guanine (G), thymine (T) and uracil (U, in RNA) belies the fact that both DNA and RNA are decorated with chemical modifications. For a catalogue of natural modifications in DNA, see https://dnamod.hoffmanlab.org/ [1], and in RNA, see

• improving metabolic stability, pairing properties (RNA affinity), protein binding and transport/cellular uptake are concerned, chemical modifications are a prerequisite for the discovery and development of oligonucleotide therapeutics [11][12][13][14][15]. Thus, the natural PS and 2'-OMe backbone

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

• Naohiro Horie,
• Takao Yamaguchi,
• Shinji Kumagai and
• Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

• , Fujisawa, Kanagawa 251-8555, Japan National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan 10.3762/bjoc.17.54 Abstract Chemical modifications have been extensively used for therapeutic oligonucleotides because they strongly enhance

• data indicate that GuNA[Me] could be a useful modification for therapeutic antisense oligonucleotides. Keywords: artificial nucleic acid; duplex-forming ability; oligonucleotide synthesis; Introduction The efficacy and safety of therapeutic oligonucleotides can be controlled by chemical modifications

• . For applications in antisense technology, chemical modifications aimed at enhancing the duplex-forming ability toward a target RNA (i.e., a complementary single-stranded RNA) and improving the stability against enzymatic degradations are commonly utilized. For instance, antisense oligonucleotides

Computational tools for drawing, building and displaying carbohydrates: a visual guide

• Kanhaya Lal,
• Rafael Bermeo and
• Serge Perez

Beilstein J. Org. Chem. 2020, 16, 2448–2468, doi:10.3762/bjoc.16.199

• incrementally from drop-down menus. A useful feature of this tool is the real-time rendering of the carbohydrate image: each added monosaccharide and modified linkage is directly reported to the image as well as to a text (GRS) format. Option for numerous chemical modifications is also available. On the other

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• molecules, sumanene is more attractive as chemical modifications can be easily performed at both benzylic as well as peripheral aromatic carbons. Although, a handful of reports are available in the literature related to the selective functionalization at the benzylic carbons of the sumanene. In contrast

Efficient synthesis of piperazinyl amides of 18β-glycyrrhetinic acid

• Dong Cai,
• ZhiHua Zhang,
• Yufan Meng,
• KaiLi Zhu,
• LiYi Chen,
• ChangXiang Yu,
• ChangWei Yu,
• ZiYi Fu,
• DianShen Yang and
• YiXia Gong

Beilstein J. Org. Chem. 2020, 16, 798–808, doi:10.3762/bjoc.16.73

• structure of 18β-glycyrrhetinic acid offered numerous possibilities to chemical modifications, thereby leading to the formation of novel derivatives [7][8][9]. There are three functional groups at C-3, C-11 and C-30 in the structure of 18β-glycyrrhetinic acid amenable to chemical modifications. The

Combination of multicomponent KA² and Pauson–Khand reactions: short synthesis of spirocyclic pyrrolocyclopentenones

• Riccardo Innocenti,
• Elena Lenci,
• Gloria Menchi and
• Andrea Trabocchi

Beilstein J. Org. Chem. 2020, 16, 200–211, doi:10.3762/bjoc.16.23

• cyclopentenone ring [37], as this heterocycle is a powerful synthon for the synthesis of a variety of bioactive target molecules, due to the broad diversity of chemical modifications available for the enone structural motif [38]. The most common approach to access such chemotype is the Pauson–Khand (PK) reaction

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

• subject of extensive study since the mid-twentieth century [1]. Obtained from the base-catalyzed condensation of para-alkylated phenols and formaldehyde, calix[4]arenes have cyclic bowl-like structures which provide various sites for controlled chemical modifications. The versatility of calix[4]arenes has

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

• Victoria V. Lipson,
• Tetiana L. Pavlovska,
• Nataliya V. Svetlichnaya,
• Anna A. Poryvai,
• Nikolay Yu. Gorobets,
• Erik V. Van der Eycken,
• Irina S. Konovalova,
• Svetlana V. Shiskina,
• Alexander V. Borisov,
• Vladimir I. Musatov and
• Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

• the formation of both unexplored heterocyclic systems containing a free amino group open for chemical modifications and the corresponding hetarylpropanoic acids providing useful templates for the synthesis of some marine alkaloids or their analogues. In domino reactions of the 2-amino-4-arylimidazoles

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• these interfere with planned chemical modifications of NR+X− on the 5′-C-hydroxy moiety. The most common approaches convert the cis-2′,3′-hydroxy groups of NR+X− to an acetonide (i.e., 2′,3′-O-isopropylidene nicotinamide riboside 29; isopro-NR) in a reaction with 2,2-dimethoxypropane in the presence of

Synthesis of a tubugi-1-toxin conjugate by a modulizable disulfide linker system with a neuropeptide Y analogue showing selectivity for hY1R-overexpressing tumor cells

• Rainer Kufka,
• Robert Rennert,
• Goran N. Kaluđerović,
• Lutz Weber,
• Wolfgang Richter and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2019, 15, 96–105, doi:10.3762/bjoc.15.11

• strongly hampered in its cytotoxic activity, and the peptide moiety ensures the target-specific toxin delivery toward the diseased cells, while omitting (most) healthy cells. To assess the impact of the chemical modifications due to the linker-assisted peptide–toxin conjugation and toxin liberation on the

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

• several hurdles such as instability in biological fluids, low cell penetration, limited tissue distribution, and off-target effects. With this aim, many chemical modifications have been introduced into ONs definitively as a means of modifying and better improving their properties as gene silencing agents

• cells or tissues, off-target effects and toxicity hamper the path to success of ON-based therapeutics and need to be solved. Fortunately, various chemical modifications of ONs have been designed to address these issues [9]. The most common modification in AONs and siRNAs is the phosphorothioate (PS

• (2’-OMe), 2’-fluoro (2’-F), and 2’-O-(2-methoxyethyl) (MOE) [9][10]. Some examples of the combination of 2’-OMe and 2’-F modified nucleotides in siRNAs were reported, and the potency of the modified siRNA was increased compared to unmodified siRNA. Many chemical modifications have been introduced in

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• was shown to greatly enhance the adaptive immune responses [100]. Monophosphoryl lipid A (MPLA), an efficient and safe vaccine adjuvant registered for the use in Europe [59] is derived from the LPS of Salmonella minnesota R595 by following chemical modifications: elimination of the core

A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• to synthesize other rhamnose analogues. The structures of spinosad and spinetoram. Chemical modifications of spinosyn J and spinosyn L. Retrosynthetic analysis of 3'-O-ethyl-5,6-dihydrospinosyn J. Hydrolysis of spinosyn A and formation of the aglycone and D-forosamine. Synthesis of 3-O-ethyl-2,4-di-O

Synthesis of ergostane-type brassinosteroids with modifications in ring A

• Vladimir N. Zhabinskii,
• Darya A. Osiyuk,
• Yuri V. Ermolovich,
• Natalia M. Chaschina,
• Tatsiana S. Dalidovich,
• Miroslav Strnad and
• Vladimir A. Khripach

Beilstein J. Org. Chem. 2017, 13, 2326–2331, doi:10.3762/bjoc.13.229

• naturally occurring BS (e.g., epibrassinolide [8]) have found practical application in agriculture and thus are commercially available and a cheap source for further chemical modifications. As a part of our programme aimed at the study of BS biosynthesis, we focussed in the present investigation on the

Synthesis and photophysical properties of novel benzophospholo[3,2-b]indole derivatives

• Mio Matsumura,
• Mizuki Yamada,
• Atsuya Muranaka,
• Misae Kanai,
• Naoki Kakusawa,
• Daisuke Hashizume,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2017, 13, 2304–2309, doi:10.3762/bjoc.13.226

• may be associated with the low fluorescence quantum yields. Conclusion A series of novel indole-fused phospholes were synthesized by simple chemical modifications at the trivalent phosphorus center. These organophosphorus compounds generated a whole series of derivatives from only one precursor. The X

• ]indole 3. Chemical modifications of the phosphorus atom of 3. Selected bond length and angles. Absorption and fluorescence spectroscopy data.a Calculated HOMO and LUMO levels of phospholes. Supporting Information Supporting Information File 340: Experimental details, characterization data, and NMR

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

• Hao Wang,
• Cui Chen,
• Weibing Liu and
• Zhibo Zhu

Beilstein J. Org. Chem. 2017, 13, 2023–2027, doi:10.3762/bjoc.13.200

• applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules. Keywords: difunctionalization of alkenesiodine; iodination–peroxidation reaction; TBHP; Introduction Alkenes have attracted considerable interest in recent years as abundant, simple chemical

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• ]. However, chemical complementation with mycolactone restored the typical M. ulcerans pathology for mycolactone-deficient strains [35]. Some chemical modifications were performed on the purified extracts showing that peracetylation or exhaustive double bond saturation by hydrogenation resulted in a total