Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• ] and the photoxenobactins [32]. A unifying theme in the biosynthesis of these natural products is the use of a thiotemplate-based assembly strategy [33]. The molecular building blocks that are needed for the biosynthesis are covalently bound via thioester bonds to multi-domain enzymes. The domains

• intermediate (1’). In massiliachelin biosynthesis this intermediate is further processed and elongated with another cysteine-derived thiazoline, which is eventually reduced [18]. A premature hydrolytic release of 1’ from the assembly line would give 1, which could be further modified to 2–5. Some corresponding

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via https://www.ccdc.cam.ac.uk/data_request/cif. Supramolecular assembly of TMeQ[6] and 1,2-bis(4-pyridyl)ethene (G). (a) UV–vis titration of G (3.0 × 10−5 mol·L−1, pH

Facile access to 3-sulfonylquinolines via Knoevenagel condensation/aza-Wittig reaction cascade involving ortho-azidobenzaldehydes and β-ketosulfonamides and sulfones

• Ksenia Malkova,
• Andrey Bubyrev,
• Stanislav Kalinin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 800–807, doi:10.3762/bjoc.19.60

• conditions reported previously, we began our investigation using o-azidobenzaldehyde (1a), 2-oxopropanesulfonamide 2a, triphenylphosphine, and diethylamine as reagents for the quinoline-3-sulfonamide assembly (Table 1). The reaction mixture was stirred in MeCN at 95 °C for 6 h which led to a mediocre yield

• synthesis of 3-sulfonyl-substituted quinolines (sulfonamides and sulfones). The approach is based on a Knoevenagel condensation/aza-Wittig reaction cascade for the quinoline core assembly. Hence, o-azidobenzaldehyde, ketosulfonamide or ketosulfone were utilized as key building blocks. The method devised

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• exposure to alkaline environmental stimuli at pH 10.4, and the assembly and disassembly processes were reversible (Scheme 1). The introduction of the TBTQ-C6 host significantly improved the dispersion of the aggregates formed after the collapse of the spherical nanoparticles under alkaline conditions. In

• TPE labelling degree. Self-assembly behavior of CS-TPE in water. To investigate the self-assembly behavior of CS-TPE in water, the critical aggregation concentrations (CACs) of CS-TPE were determined by measuring their optical transmittance at different concentrations (Figure S2, Supporting

• to observe the morphology of CS-TPE aggregates. At pH 5.3, CS-TPE with Rf = 2, 10 and 20 mol % assembled into homogeneous spherical nanoparticles with average diameters of 131 nm, 166 nm and 236 nm, respectively (Figure 3a–c). This assembly behavior is supposed to be caused by the amphiphilic nature

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• derived from glycine Schiff bases containing a source of chirality is the most convenient and widely used template for modification of the glycine fragment under mild conditions. The template can be easily obtained via self-assembly of the starting components in the presence of metal ions (commonly Ni(II

• )-benzylproline lead to (S)-N-(2-benzoyl-5-tert-butylphenyl)-1-benzylpyrrolidine-2-carboxamide (L7) in 73% yield with 96% ee (see Supporting Information File 1). The self-assembly of the three components L7, Ni(NO3)2, and glycine gave the corresponding (GlyNi)L7 complex which was isolated in 66% yield and fully

Asymmetric synthesis of a stereopentade fragment toward latrunculins

• Benjamin Joyeux,
• Antoine Gamet,
• Nicolas Casaretto and
• Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32

• oxidation in presence of DMP. The assembly of aldehyde 8 and methyl ketone 15 was envisaged through a stereoselective aldol reaction. After unsuccessful attempts of Mukaiyama aldol reactions with silyl enol ethers [28], we found that dicyclohexylboron enolate 20, made in situ from ketone 15 and Cy2BCl in

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

• formation of microtubules, which are important structures in the constitution of eukaryotic cells [74]. All tested compounds interfered with the polymerization of tubulin, and when compared to colchicine, classified as a destabilizing agent which prevents the microtubule assembly [55], the tested

• derivatives of compound 2 favor to various degrees the formation of microtubules, suggesting that the mechanism of this class of compound interacts with tubulin in a way to allow the microtubule assembly. The authors also observed that the introduction of higher polarity groups at the position of the double

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• cyclodextrin assembly. Recently, Nasri and co-workers [68] constructed the triazole-bridged meso-arylporphyrins 171a–c and 172a–c by using the CuAAC reaction in good yields (Scheme 37). Initially, the triazolo-linked compounds 170a–c were prepared by reacting 3-methoxy-4-(prop-2-ynlyloxy)benzaldehyde (168

• porphyrin 174 and stirred at room temperature for 24 h, solubilization occurred, resulting in a homogeneous solution. This is due to the formation of a supramolecular assembly in which the hydrophobic adamantane arms of 176b are sequestered by the β-CD arms of porphyrin 174, resulting in water solubility

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• of view [28]. Accordingly, Hoogenboom et al. investigated the CROP of 2-alkyl-2-oxazoline in sulfolane and investigated its effect on monomer distribution and self-assembly of the performed copolymer [30][31][32]. However, the degradability of sulfolane into acidic components, its relatively high

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• (hetero)aromatic building blocks. 1,4-Dithianes have as yet not been investigated to the same extent as their well-known 1,3-dithiane counterparts, but they do offer attractive transformations that can find good use in the assembly of a wide array of complex molecular architectures, ranging from lipids

• , and several excellent reviews have highlighted their synthetic versatility and utility in the assembly of complex target molecules [4][5][6]. Some recent examples of 1,3-dithiane-mediated short and efficient total syntheses of complex target products are shown in Scheme 1b [7], wherein the original

• products related to different competing reaction pathways. However, when suitable cation-stabilizing substituents are present, especially on the central carbon atom, very useful transformations can result for the rapid assembly of cycloheptanoid scaffolds [91]. Oxyallyl cations (when Z is an oxygen-based

Practical synthesis of isocoumarins via Rh(III)-catalyzed C–H activation/annulation cascade

• Qian-Ci Gao,
• Yi-Fei Li,
• Jun Xuan and
• Xiao-Qiang Hu

Beilstein J. Org. Chem. 2023, 19, 100–106, doi:10.3762/bjoc.19.10

• of 1,2-difunctionalized arenes with alkynes or carbon monoxide (Scheme 1b, III) [13][14][15][16], have been widely applied for the assembly of isocoumarins over the past decades. Recently, the transition-metal-catalyzed ortho C–H activation/annulation of benzoic acids has emerged as an attractive

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• , it is evident that the water molecules which occupy the interstitial spaces between the columns reinforce this assembly of complex units via multiple O–H···O hydrogen bonds. These depictions also indicate that there are four β-CD molecules in the unit cell, corresponding to two dimeric complex units

• spaces between the columns (Figure 12, viewed down the c-axis) and are thus also responsible for reinforcing the assembly of γ-CD complex columnar units via water–water and water–host hydrogen bonds. It should be noted that, since PXRD analyses indicated that the γ-CD·PRO and γ-CD·BES crystal structures

Navigating and expanding the roadmap of natural product genome mining tools

• Friederike Biermann,
• Sebastian L. Wenski and
• Eric J. N. Helfrich

Beilstein J. Org. Chem. 2022, 18, 1656–1671, doi:10.3762/bjoc.18.178

• biosynthetic concepts. NP biosynthesis follows two fundamentally different principles: NPs can either be produced in an assembly line-like fashion (Figure 2A) or by discrete, multi-enzymatic assemblies (Figure 2B). Discrete, multi-enzymatic assemblies utilize monofunctional enzymes for the consecutive build-up

• and decoration of a NP scaffold. In comparison to biosynthetic assembly lines, intermediates are not permanently covalently bound to carrier proteins in discrete, multi-enzymatic assemblies. In both biosynthetic principles, the NP backbone is first assembled by core enzymes and then further modified

• by tailoring enzymes that decorate the NP scaffold. Assembly line-like pathways are characterized by mega enzymes, which can be subdivided into modules. Each module is responsible for the incorporation (and/or processing) of one building block into the nascent product. A “textbook” extension module

Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• synthesized the necessary building blocks, we turned our attention to construct resin-bound peptide 5 (Scheme 4). The assembly of this hexapeptide started with the loading of Fmoc-ᴅ-Trp(Boc)-OH (6) onto 2-chlorotrityl resin with iPr2NEt, which was followed by piperidine treatment to liberate resin-bound amine

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• properties. Such switchable systems with conjugated organic fragments containing an FeII/FeIII system were used in organic electronics as molecular switches, optoelectronic materials and in biochemistry as photonic or redox devices [6]. A promising approach is the coordination self-assembly of multiferrocene

Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts

• Karen R. Winters and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154

• still be important in the assembly of a ternary complex and the enantioselectivity of the reaction. The evaluation of the catalysts is shown in Table 1. CPA 4 was completely ineffective at inducing chirality (Table 1, entry 1) and catalyst 2 was not much better (entry 2). Catalyst 3 on the other hand

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

• supramolecular nanostructures, displayed aggregation-induced emission (AIE) due to the restricted phenyl-ring rotation of m-TPEWP5 component. Inspired by natural photosynthesis and following an energy transfer process, the supramolecular nanorod assembly was employed as a nanoreactor for a photocatalytic

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• self-assembly reactions from simple precursors and easily functionalized through addition reactions at heteroatoms [15][16][17][18][19][20]. Some time ago, our group introduced 1,4,6,10-tetraazaadamantane (TAAD) as a promising molecular platform for the design of functional tripodal molecules (Figure

• cyclization of the corresponding tris-hydrazones, as well as the assembly of unsymmetrically substituted TAADs having both amino(amido) and hydroxy groups at bridge nitrogen atoms (2N,1O-TAADs and 1N,2O-TAADs) via a hitherto unknown co-trimerization of oxime and hydrazone units [35]. Also, structural studies

• , 21, and 21·HCl as well as the previously described 3O-TAADs 2 do not form such host–guest complexes, although water and methanol molecules are present in their crystal lattices. Thus, the presence of amide/carbamate groups is essential for the assembly of these supramolecular structures. The

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• interventions that could halt its production would be of significant value. Within the biosynthetic assembly of alginate there is a critical dependence upon the provision of one sugar nucleotide building block, GDP-mannuronic acid (GDP-ManA, 5). This material is sourced from the cytosolic metabolic pool

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

• blocks can reduce the number of steps in the total synthesis. However, it requires manipulation of the anomeric leaving groups and deprotection of the protected hydroxy group at the 4-position prior to glycosylation. Although automated electrochemical assembly, which is a one-pot iterative synthesis of

Enzymes in biosynthesis

• Jeroen S. Dickschat

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

• assembly line logic, with individual domains for each single step [2]. Furthermore, the domains are organized into modules, each of which is responsible for the incorporation of one extender unit into the growing polyketide or peptide chain. With our knowledge today, the function of these large enzyme

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• . Results and Discussion Reactor assembly and model reaction We started our investigations by preparing a packed-bed reactor using a glass column (6.6 mm i.d., 100 mm length) that can be used in a dedicated setup for heterogeneous flow photocatalysis carried out in a commercial photochemical flow reactor

• )-proline. Optimization of temperature and light intensity for the coupling of 4-iodobenzotrifluoride and sodium p-toluenesulfinate. Comparison of different reactors. Supporting Information Supporting Information File 104: Details of packed-bed assembly, experimental procedures, reaction optimization and

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

• ://www.geneious.com). Protein purification and biochemical assays The Streptomyces genome was extracted by TIANamp Bacteria DNA Kit (TIANGEN BIOTECH), and the P450 genes were amplified by PCR (Table S1, Supporting Information File 1) and cloned into a pET-28a(+) vector by the T5 exonuclease DNA assembly method [39

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

• Koichi Mitsudo,
• Haruka Inoue,
• Yuta Niki,
• Eisuke Sato and
• Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

• consists of a membrane called a membrane electrode assembly (MEA), which can act as supporting electrolyte, electrode, and heterogeneous catalyst. Therefore, the further addition of a supporting electrolyte is not necessary for the electrochemical reactions using a PEM reactor, which offers clean and