Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• was planned which would likewise set the labile C2–C5 diene and thus concomitantly stabilize this functionality by macrocyclic constraints. Menche’s total synthesis of archazolid A Synthesis of the north-eastern fragment As shown in Scheme 3, the construction of the north-eastern fragment 5 relied on

• deprotection step. The Menche group then had considerable difficulties in closing the macrocyclic ring using an HWE reaction. Finally, the macrocylization could be realised by using NaH as a strong non-nucleophilic base. It proved essential to perform this reaction in the presence of molecular sieves to remove

• synthesis. Accordingly, they applied a Heck macrocyclization strategy for the total synthesis of archazolid B. As shown in Scheme 7, this strategy could be successfully implemented and the macrocyclic core of the target compound was obtained in useful yields by coupling of 38, which in turn was accessible

Inclusion complexes of β-cyclodextrin with tricyclic drugs: an X-ray diffraction, NMR and molecular dynamics study

• Franca Castiglione,
• Fabio Ganazzoli,
• Luciana Malpezzi,
• Andrea Mele,
• Walter Panzeri and
• Giuseppina Raffaini

Beilstein J. Org. Chem. 2017, 13, 714–719, doi:10.3762/bjoc.13.70

• )° for 1 and 2, respectively, where the figures in parentheses give the standard errors. The β-CD macrocyclic rings appear slightly distorted upon inclusion of the guest molecule. In the crystal, the arrangement of the complexes formed by 1 and 2 with β-CD are similar, being stacked head-to-head to form

• and refined with a riding model. Both complexes were found to crystallize in the solid state in 1:1 host–guest ratio with many partially disordered water molecules distributed in the intermolecular space outside the macrocyclic cavities. Full molecular and crystal data, together with the structural

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• template for design of complex molecules has become increasingly popular in pharmacology, supramolecular chemistry and nanoscience over recent years [4][5]. Many macrocyclic dimeric derivatives of bile acid were described [6][7][8]. As a rule, a route to the majority of macrocyclic structures requires

Novel β-cyclodextrin–eosin conjugates

• Gábor Benkovics,
• Damien Afonso,
• András Darcsi,
• Szabolcs Béni,
• Sabrina Conoci,
• Éva Fenyvesi,
• Lajos Szente,
• Milo Malanga and
• Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

• property can be utilized to protect the guest molecules from oxidation and degradation, to enhance their solubility and bioavailability, or to use the CD host as a drug carrier [1]. The potential application of these macrocyclic sugars in such pharmaceutical formulations required the understanding of the

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

• Sophie Letort,
• Michaël Bosco,
• Benedetta Cornelio,
• Frédérique Brégier,
• Sébastien Daulon,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2017, 13, 417–427, doi:10.3762/bjoc.13.45

• study focusing on the impact of covalently bound functional groups to macrocyclic β-cyclodextrin that are involved in the OP hydrolysis. Four new derivatives 2–5 were prepared (Figure 3) for this purpose. Compared to analog 1, scavenger 2 has a longer linker between the iodosobenzoate group and the

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

• pathway via a diradical intermediate leading to the formation of the unusual macrocyclic dimer 9 by computational methods. First calculations were made for phenyl selenophen-2-yl thiocarbonyl S-methanide (8A), which can undergo a 1,3-dipolar electrocyclization (1,3-ring closure) to form the thiirane 3a

• of thiobenzophenone S-methanide 1 (Ar1 = Ar2 = Ph). On the other hand, in the hetaryl functionalized thiocarbonyl S-methanide 8 the lowest activation energy was found for the C–C bond formation between C(2) atoms of the selenophen-2-yl ring, leading to the twelve-membered macrocyclic product 9

Polyketide stereocontrol: a study in chemical biology

• Kira J. Weissman

Beilstein J. Org. Chem. 2017, 13, 348–371, doi:10.3762/bjoc.13.39

• synthesis [4]), which incorporate both high functional group density and rich stereochemistry. These features, coupled with the fact that the majority of reduced polyketides are macrocyclic, result in significant in-built conformational constraints. As a consequence, these molecules present their diverse

Posttranslational isoprenylation of tryptophan in bacteria

• Masahiro Okada,
• Tomotoshi Sugita and
• Ikuro Abe

Beilstein J. Org. Chem. 2017, 13, 338–346, doi:10.3762/bjoc.13.37

• unknown at this time. Kawaguchipeptins A and B are members of the cyanobactin family and are macrocyclic undecapeptides with the cyclic amino acid sequence of [WLNGDNNWSTP]. They are produced by Microcystis aeruginosa NIES-88 (Figure 6) [52][53]. Kawaguchipeptin A contains one D-leucine and two prenylated

Interactions between photoacidic 3-hydroxynaphtho[1,2-b]quinolizinium and cucurbit[7]uril: Influence on acidity in the ground and excited state

• Jonas Becher,
• Daria V. Berdnikova,
• Darinka Dzubiel,
• Heiko Ihmels and
• Phil M. Pithan

Beilstein J. Org. Chem. 2017, 13, 203–212, doi:10.3762/bjoc.13.23

• this ligand increase by about two to three orders of magnitude, respectively, when bound to CB[7]. Keywords: azoniahetarenes; cucurbit[7]uril; heterocycles; photoacids; supramolecular photochemistry; Introduction The complexation of ligands by macrocyclic host molecules, such as crown ethers

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

• Vinicius R. Campos,
• Ana T. P. C. Gomes,
• Anna C. Cunha,
• Maria da Graça P. M. S. Neves,
• Vitor F. Ferreira and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2017, 13, 195–202, doi:10.3762/bjoc.13.22

• fields, including medicine [1][2][3] , supramolecular chemistry [4][5][6] and catalysis [7][8][9][10]; their functionalization became a target for several research groups [11][12][13]. In particular, the insertion of functional groups into the macrocyclic core merits considerable attention due to the

Identification, synthesis and mass spectrometry of a macrolide from the African reed frog Hyperolius cinnamomeoventris

• Markus Menke,
• Pardha Saradhi Peram,
• Iris Starnberger,
• Walter Hödl,
• Gregory F.M. Jongsma,
• David C. Blackburn,
• Mark-Oliver Rödel,
• Miguel Vences and
• Stefan Schulz

Beilstein J. Org. Chem. 2016, 12, 2731–2738, doi:10.3762/bjoc.12.269

• , is usually not possible from an EI mass spectrum. In the article, we present the synthesis and for the first time elucidate the structure of macrolides from the frog family Hyperoliidae. Keywords: chemical communication; chiral gas chromatography; macrocyclic lactones; ring-closing metathesis

• ; pheromones; Introduction The lactone motif is found in many compounds that are used in chemical communication. Among them, macrocyclic lactones are an important class because of their biosynthetic availability and their inherent compound properties. During the biosynthesis of macrocyclic lactones, a fatty

• from Madagascar also use chemical cues. Macrocyclic lactones such as phoracantholide I (3), phoracantholide J (4) or gephyromantolide A (5), are released by males from femoral glands to serve as signals, often accompanied by secondary alcohols (Figure 1) [2][3][4]. Another frog family most likely using

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

• Artem N. Semakin,
• Aleksandr O. Kokuev,
• Yulia V. Nelyubina,
• Alexey Yu. Sukhorukov,
• Petr A. Zhmurov,
• Sema L. Ioffe and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2016, 12, 2471–2477, doi:10.3762/bjoc.12.241

• polyhydrazones. Thus, treatment of macrocyclic polyamines tacn (1,4,7-triazacyclononane), tacd (1,5,9-triazacyclododecane) and cyclam (1,4,8,11-tetraazacyclotetradecane) with 1a gave the corresponding tris- and tetra-hydrazones 7, 8 and 9, respectively, in high yields (methods C,D in Figure 2, a small excess of

• 1a was used to ensure complete alkylation). Macrocyclic polynitrogen ligands with several hydrazone arms may be of interest for the design of sensors [52] and contrast agents [53]. Unfortunately, alkylation of ethylenediamine with 4 equivalents of 1a led to an indecipherable mixture of products. In

A direct method for the N-tetraalkylation of azamacrocycles

• Andrew J. Counsell,
• Angus T. Jones,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

• deprotonate the macrocyclic amine NHs then introducing the appropriate alkyl bromide; however yields were low (35–40%) and the scope limited (in part by the harsh reaction conditions) [34]. Trabaud et al. have prepared a series of N-tetraalkyl ester and carboxylic acid derivatives using bromoester

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• macrocyclic core of teixobactin by Reddy et al.: In 2016, Reddy et al. reported their synthetic efforts towards teixobactin (17) with a solution-phase synthesis of the macrocyclic core 109 (Scheme 24) [73]. Their synthetic approach focused on the macrolactonisation of a linear precursor 110 differing from

• -hydroxyenduracididine 98. Total synthesis of mannopeptimycin α (12) and β (13). Synthesis of protected L-allo-enduracididine 102. The solid phase synthesis of teixobactin (17). Retrosynthesis of the macrocyclic core 109 of teixobactin (17). Synthesis of macrocycle 117. Acknowledgements The authors would like to thank

Evidence for an iterative module in chain elongation on the azalomycin polyketide synthase

• Hui Hong,
• Yuhui Sun,
• Yongjun Zhou,
• Emily Stephens,
• Markiyan Samborskyy and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2016, 12, 2164–2172, doi:10.3762/bjoc.12.206

• or module of enzymes. Examples of deviation from this paradigm, in which a module catalyses either multiple extensions or none are of interest from both a mechanistic and an evolutionary viewpoint. We present evidence that in the biosynthesis of the 36-membered macrocyclic aminopolyol lactones

• minor differences in the macrocyclic ring [50]. However in our hands azalomycins F3a (1a, minor) and F4a (1b, major) were produced. The HRMS of the marginolactone from DSM4137 was in agreement with that expected for 1b (calcd [M + H]+: 1082.6734, found 1082.6722). Targetted gene-disruption of the azl

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• monensin A, another well-known ionophore antibiotic, applying an oxidative cyclization approach using potassium permanganate [64]. Amphidinolide F Amphidinolide F (24) is a marine natural product isolated from the dinoflagellate Amphidinium sp. in 1991 [65]. The macrocyclic core of these highly cytotoxic

Diastereoselective synthesis of 3,4-dihydro-2H-pyran-4-carboxamides through an unusual regiospecific quasi-hydrolysis of a cyano group

• Mikhail Yu. Ievlev,
• Oleg V. Ershov,
• Mikhail Yu. Belikov,
• Angelina G. Milovidova,
• Viktor A. Tafeenko and
• Oleg E. Nasakin

Beilstein J. Org. Chem. 2016, 12, 2093–2098, doi:10.3762/bjoc.12.198

• influenza caused by influenza A and B viruses contain a 3,4-dihydro-2H-pyran fragment [5]. Moreover, dihydropyrans have been proven to be particularly useful in the preparation of cyclic components of macrocyclic antibiotics [6][7] and as precursors in the synthesis of C-glycosides [8]. Modern and

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• the respective heterocycles. We will not cover medium-sized and macrocyclic lactones and lactams, but concentrate on small heterocycles with ring sizes between 3 and 6 atoms (for a review about macrolactones see reference [12]). Review 1 Oxygen-containing heterocycles Oxygen-containing heterocycles

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• irradiation. Thus, the development of novel MCR based on phosphorous reagents would allow the synthesis of macrocyclic and medium or large-sized heterocyclic systems, substances which are currently underrepresented in the literature. Further, the design of new biocompatible scaffolds such as β-lactams and

Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides

• Andrew W. Truman

Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120

• identified [87][90]. The most well-studied member of the family is microcin J25 (Figure 7C) from E. coli AY25. Initial structural characterisation incorrectly identified microcin J25 as a conventional head-to-tail macrocyclic peptide [91], which was later revised to the lassoed structure by multiple groups

• peptides for each of these molecules. The sequence highlighted in blue in PatE corresponds to the core peptide for patellamide C, another macrocyclic RiPP that contains thiazoles and oxazolines. Formation of thiazoles and oxazoles in RiPPs. A) Biosynthesis of microcin B17. B) Mechanistic models for the

Towards the total synthesis of keramaphidin B

• Pavol Jakubec,
• Alistair J. M. Farley and
• Darren J. Dixon

Beilstein J. Org. Chem. 2016, 12, 1096–1100, doi:10.3762/bjoc.12.104

• intermolecular Diels–Alder reaction and a double late stage RCM reaction to close the two macrocyclic rings; albeit the last stage afforded 1 in 1% yield after separation of various oligomeric byproducts [4]. Our group has had a long-standing research program dedicated towards the total syntheses of the

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• . Substituents attached to the isatins and ketones had little effect on the yields and enantioselectivity, regardless of their electronic properties and positions. Amino alcohol catalysts In 2014, Evano and co-workers reported a concise synthesis of the macrocyclic core of TMC-95A using the asymmetrc aldol

Marine-derived myxobacteria of the suborder Nannocystineae: An underexplored source of structurally intriguing and biologically active metabolites

• Antonio Dávila-Céspedes,
• Peter Hufendiek,
• Max Crüsemann,
• Till F. Schäberle and
• Gabriele M. König

Beilstein J. Org. Chem. 2016, 12, 969–984, doi:10.3762/bjoc.12.96

• . Only recently it was recognized that members of this genus have a great potential as producers of metabolites with relevant biological activities. One striking example is the 2015 described nannocystin A (10, Figure 6), a macrocyclic compound of NRPS-PKS origin with strong antiproliferative properties

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• triazolophane’s rigidity and that preorganization may be crucial for the large binding affinity. To test this idea, we examined the macrocyclic effect using an oligomer (Figure 8a) that folds up around chloride [17]. The affinity decreased by four orders of magnitude to ≈100 M−1, perfectly consistent with

• ) Pyridyl triazolophane and (b) its high-fidelity sandwich around iodide (crystal). Adapted with permission from [20], copyright 2010 Royal Society of Chemistry. Testing the (a) macrocyclic effect, and (b) effect of rigidity against (c) the parent triazolophane. (a) Representations of the four equilibria