Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B

• Adwoa P. Nartey,
• Aboagye K. Dofuor,
• Kofi B. A. Owusu,
• Anil S. Camas,
• Hai Deng,
• Marcel Jaspars and
• Kwaku Kyeremeh

Beilstein J. Org. Chem. 2022, 18, 1763–1771, doi:10.3762/bjoc.18.185

• ]. The major secondary metabolic pathways, defense mechanisms, and intracellular transport processes vary widely among Bacillus depending on their natural habitats [4][5][6]. Although the majority of Bacillus species are non-pathogenic, the few well-studied and genome-sequenced pathogenic strains among

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• fundamentally different mechanisms have been proposed for the oxidation of alcohols [96] (Scheme 12). When using transition metals such as Cu(I) as co-catalyst, both aminoxyl radicals and metal ions serve as one-electron oxidants in a joint two-electron oxidation. In this system, primary aliphatic alcohols can

• processes [132][133][134]. Fluorinated substituents in the ketone molecule are used to achieve higher electrophilicity and reactivity. Both radical and ionic mechanisms were reported for CH-functionalization reactions [134][135]. An example of an oxidative hydroxylation involving aliphatic C(sp3)–H bonds is

• chiral copper complex. An extraordinary example of an asymmetric difluorination of alkenes with the migration of aryl or methyl groups was shown using a chiral aryl iodide catalyst [149][150] (Scheme 35). Depending on the nature of the migrating group, two mechanisms are possible that determine the

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• potent and significant drugs containing imidazole moieties. The formation of imidazole derivatives can be achieved using imidazole N-oxide as starting material. In this review, the scope of substrates and reaction mechanisms of various synthetic approaches using imidazole N-oxides as substrates are

• is a new emerging research area and which offers a lot of room for further development. In this review, several research procedures were discussed with their substrate scope and proposed reaction mechanisms. We hope that this review can be helpful to the researchers and the chemists for the future

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

• , Figure 1), is one of the few licensed drugs for treating RSV infections [8][9]. Although there are many suggested mechanisms of action, the main mechanisms for RBV involve the inhibition of the enzymes RNA-dependent RNA polymerase and inosine monophosphate dehydrogenase (IMPDH). IMPDH is required for the

• ). One of the main known mechanisms of action of RBV is the depletion of intracellular GTP pools via the inhibition of cellular IMPDH induced by the 5-monophosphate metabolite of RBV [44]. Thus, our finding based on these results is that compound 8 may act similarly to IMPDH inhibitors and the active

Molecular and macromolecular electrochemistry: synthesis, mechanism, and redox properties

• Shinsuke Inagi and
• Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 1505–1506, doi:10.3762/bjoc.18.158

• macromolecular electrochemistry. The scope of this interdisciplinary issue ranges from synthetic aspects (such as electrosynthesis and reaction mechanisms) to materials science (including redox properties and devices). Shinsuke Inagi and Mahito Atobe Yokohama, October 2022

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d₂)

• Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

• structure into first-generation non-nitrogen-containing BPs (non-NBPs) and into second- and third-generation nitrogen-containing BPs (NBPs). Some examples of NBPs are alendronate, risedronate, and zoledronate (Figure 1) [9]. NBPs and non-NBPs have different mechanisms of action, and NBPs have been shown to

Supramolecular approaches to mediate chemical reactivity

• Pablo Ballester,
• Qi-Qiang Wang and
• Carmine Gaeta

Beilstein J. Org. Chem. 2022, 18, 1463–1465, doi:10.3762/bjoc.18.152

• of the capsules by means of intermolecular interactions. The most intriguing aspect of catalysis in confined spaces [5][6][7][8][9][10][11][12][13][14] is that the reactions can take place through unusual mechanisms. This is mainly due to the conformational control of the substrates, steric

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• than the 1CT state (2.60 eV), while 3CT remains slightly lower in energy (2.57 eV). This has some important consequences on the TADF mechanisms. Table 5 lists spin–orbit couplings matrix elements (SOCMEs) between 1CT, 3LE, and 3CT states. The SOCMEs between 1CT and 3CT are small, 0.03 cm−1 at most

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme

• Jia-Hua Huang,
• Jian-Ming Lv,
• Liang-Yan Xiao,
• Qian Xu,
• Fu-Long Lin,
• Gao-Qian Wang,
• Guo-Dong Chen,
• Sheng-Ying Qin,
• Dan Hu and
• Hao Gao

Beilstein J. Org. Chem. 2022, 18, 1396–1402, doi:10.3762/bjoc.18.144

• whether 2 was generated by A. oryzae NSAR1. The result showed that the heterologous host indeed converts 1 to talaro-7,13-dien-19-ol (2, Scheme 1A; Supporting Information File 1, Figure S18). Mechanistic characterization of TadA So far, cyclization mechanisms of FC-type diterpenes afforded by PaFS [18

• monitored at 254 nm. Biosynthesis of FC-type diterpenoids. A) The biosynthetic pathway of 1, 2 and 4. B) Cyclization mechanisms of 1 and reported FC-type diterpenes. Supporting Information Supporting Information File 328: Experimental methods, nucleotide sequence, tables, and figures. Acknowledgements We

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• PPK2. They are structurally unrelated and use different catalytic mechanisms. PPK1 enzymes prefer the usage of adenosine 5'-triphosphate (ATP) for polyphosphate (polyP) synthesis while PPK2 enzymes favour the reverse reaction. With the emerging use of PPK enzymes in biosynthesis, a deeper understanding

• reaction where the terminal phosphate dissociates from the polyP chain before being attacked by the nucleotide [18]. Both mechanisms could proceed without a phosphate group transfer onto an amino acid side chain of the enzyme as in PPK1: here, the enzyme structure generates proximity and polarisation of

• the different reaction mechanisms. The thermodynamic equilibrium of the PPK reaction is not as close to the product side as in other ATP regenerating systems, which corresponds to the phosphate transfer potential of the different phosphate donors. This raises the question if PPK/polyP based systems

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• compared to 10ab-v2. Moreover, CH3NH2 approaches 4a/4a’ at the opposite side of the C–C6H5 sites to form IS3/IS5 and finally 10ab-v2/10ab . The reaction mechanisms in the gas phase and in the solvents model are only slightly different. Experimental General experimental methods NMR spectra were acquired on

Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

• Md Azadur Rahman,
• Kana Kuroda,
• Hirofumi Endo,
• Norihiko Sasaki,
• Tomoaki Hamada,
• Hiraku Sakai and
• Toshiki Nokami

Beilstein J. Org. Chem. 2022, 18, 1133–1139, doi:10.3762/bjoc.18.117

• (T2) on the yield of oligosaccharides. Influence of temperatures of anodic oxidation (T1) and glycosylation (T2). MALDI–TOF MS spectra of oligosaccharides. Proposed structures of byproducts of electrochemical polyglycosylation. Proposed mechanisms of electrochemical polyglycosylation. Oxidative

Enzymes in biosynthesis

• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1131–1132, doi:10.3762/bjoc.18.116

• as Escherichia coli or Saccharomyces cerevisiae. Besides in vitro studies with purified enzymes, heterologous expressions of whole pathways for the production of compounds is possible [6]. Enzyme mechanisms can be addressed through structure-based site-directed mutagenesis, which may also lead to

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• , Supporting Information File 1). Other plant polyketides, such as anthraquinones 19 and 20 and phenylpropanoids 21–24, failed to be dimerized. The reaction mechanism of P450-mediated phenol dimerization is believed to involve oxidative radical–radical coupling, though other mechanisms, such as radical

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• of their biosynthetic mechanisms. Keywords: biosynthesis; methyltransferase; natural azoxides; reactivity-based screening; Streptomyces; Introduction Azoxy natural products are a rare yet intriguing class of natural products with various beneficial biological properties, such as antibacterial

• macrozamin [4]. Although the N2H4 generation is an advantageous reactivity of an azoxy group, to the best of our knowledge, it has not been applied for the detection of azoxy bonds in the context of natural products discovery. The azoxy bond is biosynthesized by two distinct mechanisms. The first is the

• enzyme VlmA [18]. This intermediate is hypothesized to be transformed into the azoxy bond-containing intermediate via an intramolecular rearrangement accompanied by a concomitant oxidation [18]. Although the exact mechanisms of azoxy bond formation remain unclear, VlmH and VlmA cooperate to biosynthesize

Understanding the competing pathways leading to hydropyrene and isoelisabethatriene

• Shani Zev,
• Marion Ringel,
• Ronja Driller,
• Bernhard Loll,
• Thomas Brück and
• Dan T. Major

Beilstein J. Org. Chem. 2022, 18, 972–978, doi:10.3762/bjoc.18.97

• reference environment for terpene synthases [10][11][12][15][16][21][22][23][24][25]. The proposed reaction mechanisms yielding HP and IE and are presented in Scheme 1, while the reaction free energy profile is presented in Figure 2. Here, we modeled the transformations A→I (HP) and A’→E’ (IE). The gas

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• attracting much attention, since bioactive compounds possessing these structures are known. This method has the potential to be applied to synthesize bioactive 2-cyanonaphthalen-1-ols [8][9] and 3-substituted phthalides [12][13][14][15][16]. The reaction mechanisms of the electroreductive coupling of 1 with

• by cyclic voltammetry (Table 3) and acceptors 2 revealed no reduction peaks from 0 to −2.00 V vs SCE [5][6]. Therefore, this electroreductive coupling is initiated by the reduction of compounds 1. There are two possible reaction mechanisms for the reductive coupling of 1 with 2a as illustrated in

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• [1][2][3]. In OLEDs photons are mainly generated by radiative recombination in the emitting layer [4]. Therefore, the development of efficient luminescent materials and the exploration of new luminescent mechanisms are one of the core tasks in academic research. The most common luminescent materials

• ) [6][7]. In 2012, Adachi et al. first reported purely organic thermally activated delayed fluorescent (TADF) materials, which achieved nearly 100% exciton utilization via reverse intersystem crossing (RISC) [8]. Meanwhile, novel materials based on new luminescence mechanisms such as hybridized local

• brand new luminescent properties. In this mini-review, we summarize unique electron donor and acceptor materials which regulate luminescent properties via Lewis acid–base interactions and briefly explain the exploration of their chemical nature and interaction mechanisms. Review Lewis acids as electron

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• 2-methylisoborneol from (S)-2-Me-LPP may be explained by isomerization to 2-Me-GPP and then to (R)-2-Me-LPP. Keywords: biosynthesis; enantioselective synthesis; enzyme mechanisms; gas chromatography; terpenoids; Introduction After its first discovery from Streptomyces [1][2], it has been

Structural basis for endoperoxide-forming oxygenases

• Takahiro Mori and
• Ikuro Abe

Beilstein J. Org. Chem. 2022, 18, 707–721, doi:10.3762/bjoc.18.71

• attention in the field of natural products and organic synthesis. In this review, we summarize the structural analyses, mechanistic investigations, and proposed reaction mechanisms of endoperoxide-forming oxygenases, including cyclooxygenase, fumitremorgin B endoperoxidase (FtmOx1), and the asnovolin A

• reduced to produce PGH2. PGH2 is metabolized by downstream enzymes to yield a series of prostaglandins, which play important roles in inflammatory responses [35][36][37]. Although the active site architectures of COX-1 and COX-2 are not completely identical, the reaction mechanisms and catalytic residues

• enzymes, COX, FtmOx1, and NvfI, indicated that these enzymes employ distinct reaction mechanisms, suggesting that the enzymatic endoperoxide formation reactions individually evolve in a substrate-dependent manner. This fact makes it difficult to identify the endoperoxide-forming enzymes by a sequence

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• Theoretical background of electromagnetic induction To better understand the mechanisms of inductive heating, some basic physical principles are first explained. This type of heating depends on various structural, morphological, chemical, and physical properties of the materials to be heated. When a suitable

Tri(n-butyl)phosphine-promoted domino reaction for the efficient construction of spiro[cyclohexane-1,3'-indolines] and spiro[indoline-3,2'-furan-3',3''-indolines]

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

Beilstein J. Org. Chem. 2022, 18, 669–679, doi:10.3762/bjoc.18.68

• to give selectively spiro[indoline-3,2'-furan-3',3''-indolines] in satisfactory yields. The relative configuration of the complex spirooxindoles was confirmed by determination of several single crystal structures. Also, plausible reaction mechanisms have been proposed. This reaction has the

Rapid gas–liquid reaction in flow. Continuous synthesis and production of cyclohexene oxide

• Kyoko Mandai,
• Tetsuya Yamamoto,
• Hiroki Mandai and
• Aiichiro Nagaki

Beilstein J. Org. Chem. 2022, 18, 660–668, doi:10.3762/bjoc.18.67

• operation of the gas–liquid oxidation even with air in the flow reactor definitely paved the way for a green and fast oxidation process. Based on the mechanisms reported in the literature [11][31], we hypothesized the plausible reaction mechanism in our flow system as shown in Scheme 2. Firstly, the peracid

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• quenched due to aggregation-caused quenching (ACQ) [10]. Generally, the restriction of intermolecular π–π interactions in highly planar compounds plays a key role in aggregate structures exhibiting fluorescence [5][6][10]. In addition, intramolecular mechanisms, such as intramolecular rotation (RIR

• ), intramolecular charge transfer, and twisted intramolecular charge transfer (TICT) are involved in AIEE [20][21][22]. Various AIEE-based luminogens have been developed based on these mechanisms; however, many of them are high-molecular-weight compounds (MW > 500) with bulky substituents, which limits their

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• was kept around 10%, whereas in the case of doubly donor-substituted compound POZ-DBPHZ, the EQE dropped below 10% [17]. Theoretical calculations We performed electronic structure calculations on both the D–A (1) and D–A–D (POZ-DBPHZ) compounds to understand better their respective TADF mechanisms and

• ) luminance–current density characteristics. Schematics of the TADF mechanisms along with NTOs for the relevant electronic states for a) D–A compound 1 and b) D–A–D compound POZ-DBPHZ. Synthesis of compound 1. Summary of steady-state photophysical data of diluted solutions of 1.a Summary of the general