Fluorocyclisation via I(I)/I(III) catalysis: a concise route to fluorinated oxazolines

• Felix Scheidt,
• Christian Thiehoff,
• Gülay Yilmaz,
• Stephanie Meyer,
• Constantin G. Daniliuc,
• Gerald Kehr and
• Ryan Gilmour

Beilstein J. Org. Chem. 2018, 14, 1021–1027, doi:10.3762/bjoc.14.88

• siderophore antibiotic D-fluviabactin, the cytotoxic agent westiellamide, the antifungal macrodiolide leupyrrin A1 and the antitumour compound BE-70016 (Figure 1). In addition, synthetic polymers based on the 2-oxazoline building block constitute versatile platforms for a range of biomedical applications

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• . The general architecture of PDCs consists of three building blocks: the tumor-homing peptide, the cytotoxic agent and the biodegradable connecting linker. The aim of the current review is to provide a spherical perspective on the basic principles governing PDCs, as also the methodology to construct

• intervention, radiation and chemotherapy. Drugs used for this purpose are inevitably cytotoxic in order to eliminate cancer cells, but they lack selectivity that could be developed through targeting malignant cells (Figure 1). Due to the uncontrolled peripheral toxicity, anticancer drugs usually kill healthy

• , occurring via urine. Therefore, most conventional cytotoxic agents applied in chemotherapy lack optimum pharmacokinetic properties (ADME) and thus are not very effective to treat malignancies. Moreover, despite the intensive research to construct new cytotoxic drugs, survival rates in most cancers remain

Development of novel cyclic NGR peptide–daunomycin conjugates with dual targeting property

• Andrea Angelo Pierluigi Tripodi,
• Szilárd Tóth,
• Kata Nóra Enyedi,
• Gitta Schlosser,
• Gergely Szakács and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 911–918, doi:10.3762/bjoc.14.78

• selectivity to CD13+ cells. However, the cellular uptake and cytotoxic effect of Dau=Aoa-GFLGK(c[NleNGRE]-GG-)-NH2 was higher in comparison to the control especially on HT-29 cells. Therefore, this conjugate is more suitable for drug targeting with dual targeting property. Keywords: antitumor activity; drug

• characterization of novel cyclic NGR peptides and their corresponding NGR-drug conjugates. Special attention was paid on the chemostability and in vitro biological activity of the compounds [17][18]. Daunomycin (Dau) was used as cytotoxic agent, attached to the NGR-derivatives via oxime linkage. The prepared

• conjugates revealed substantial in vitro cytostatic/cytotoxic effects. Our results indicated that the conjugates had an antitumor effect against both CD13+ HT-1080 cells and CD13− (but integrin receptor positive) HT-29 human colon cancer cells. Moreover, we showed that the toxicity and the selectivity of the

Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

• Sabine Schuster,
• Beáta Biri-Kovács,
• Bálint Szeder,
• Viktor Farkas,
• László Buday,
• Zsuzsanna Szabó,
• Gábor Halmos and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 756–771, doi:10.3762/bjoc.14.64

• , 9Pro-EA] and triporelin [6D-Trp], which are used as pharmaceutical peptides to treat inter alia hormone dependent prostate and/or breast cancer [7]. Since the mid-1980s cytotoxic GnRH-I derivatives were developed and investigated to treat tumor cells [4][5][8][9]. Anthracyclines such as doxorubicin

• cellular uptake and the subcellular localization of the drug or the drug bioconjugates [13][14]. It is well known from the literature that anthracyclines accumulate in the nucleus, in that manner they also act as DNA stains [14][15]. The first cytotoxic GnRH-I derivative, which was investigated in

• the release of the cytotoxic agent within the tumor cell. During clinical trials, only mild side effects were observed which are caused by premature drug release [17]. The receptor mediated uptake of zoptarelin has been investigated by blockage of GnRH receptors using an excess of the GnRH-I

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• active zwitterionic species via an o-QM intermediate. Dimmock et al. subsequently examined the cytotoxic activity of phenolic azobenzene Mannich bases [92]. Correlations were found between structures and activities against murine P388DI and L1210 cells, human T-lymphocyte cell lines and, in some cases

• , mutagenous properties were also shown. Freccero et al. examined the photogeneration by laser flash photolysis and reactivity of naphthoquinone methides as well as their activity as purine selective DNA alkylating agents [93]. Farrell et al. studied the mechanism of the cytotoxic action of naphthoquinone

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

• cellular internalization in Vero cells. These data support that both 3-(N,N-dimethylamino)propyl and fma groups are required for optimal internalization in the three cell lines. Of special interest was the absence of cytotoxic effects in Vero cells at a 50 μM extracellular ON concentration for 72 h

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting

• Lizeth Bodero,
• Paula López Rivas,
• Barbara Korsak,
• Torsten Hechler,
• Andreas Pahl,
• Christoph Müller,
• Daniela Arosio,
• Luca Pignataro,
• Cesare Gennari and
• Umberto Piarulli

Beilstein J. Org. Chem. 2018, 14, 407–415, doi:10.3762/bjoc.14.29

• group (-CH2NH2) as a handle for conjugation to cytotoxic drugs (Figure 2, ligands 2 and 4) [28][29][30]. Conjugates of the functionalized ligands 2 and 4 with paclitaxel (PTX) via a 2’-carbamate with a self-immolative spacer and the lysosomally cleavable Val-Ala linker [31] were synthesized (Figure 2

• ) proved less potent than α-amanitin in all cell lines (see Table 3, cf. entry 1 with entries 2–4). In general, one can conclude that the “uncleavable” compounds 7 and 8 are much less cytotoxic than free α-amanitin, while the lysosomally cleavable compounds 9–11 show variable results, with RGD compound 9

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• concentrations (1 µM and 5 µM) of these compounds. The data (treated cells and untreated controls) were plotted together to compare the results (Figure 2). Shibata reagents 1 and 2a were not very cytotoxic at 5 μM. Perfluorinated phenylthio reagent 2b and perfluorinated phenyl reagent 3a showed similar, but

• moderate (45.3%), but low at 1 μM (17.9%). The non-fluorinated diphenyl iodonium salt 3o, on the other hand, was weakly cytotoxic at both concentrations (1 μM, 7.5%; 5 μM, 10.1%). Analysis of the perfluorinated phenyl reagent 4a with a triisopropylphenyl ligand displayed strong cytotoxicity (93.7%) at 5 μM

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• in the presence of LiI. A subsequently deprotection of this product by treatment with TFA led to the expected naturally occurring cytotoxic macrolide epothilone D. It must be noted that this novel highly convergent and stereocontrolled total synthesis of epothilone D clearly differed from other

• , cebulactam A1, and ansamacrolactams. In addition, novel total syntheses of prostaglandin E2, the cytotoxic agent epothilone D, and protein inhibitor ABT-737 along with formal syntheses of the protein inhibitor tedanolide C, the neprilysin inhibitor sacubitril, the antiproliferative agent jatrophane diterpene

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• ). Interestingly, high yields of the corresponding pyrazolo[3,4-b]pyridines 34 were obtained when reactions were carried under solvent-free microwave irradiation. The synthesized pyrazolo[3,4-b]pyridines have shown potential cytotoxic activity against cervical HeLa and prostate DU 205 cancer cell lines. A similar

• screened for their cytotoxic activity against human colon carcinoma (Colo-205) cell lines (Scheme 35). Buriol et al. [92] described the reaction of 5-aminopyrazole 16 with 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones 129 to yield pyrazolo[1,5-a]pyrimidine derivatives 130 in acetic acid and ethanol using

• (pyridin-3-yl)methanone (piperazinyl derivatives, 135) with 134 which were evaluated for their cytotoxic potential against MCF-7, HeLa, IMR 32 and SiHa cancer cell lines. Pyrazolo[1,5-a]pyrimidinyl amide derivatives 136 having piperazinyl derivatives, R1 = H, R2 = F and OCH3, R3 = H and OCH3, respectively

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• natural product is 6-nonyl-2H-pyran-2-one. The antimicrobial and cytotoxic effects of the synthetic volatiles are also reported. Keywords: enantioselective synthesis; gas chromatography; mass spectrometry; natural products; volatiles; Introduction A large variety of volatile organic compounds from

• products so far. Biological characterisation of compounds Three of the volatile metabolites identified from D. clavata (compounds 9, 14 and 17) were evaluated for antimicrobial and cytotoxic activities using a standard panel of fungi and bacteria, as well as the murine cell line L929 (Table 3). The 2

• -pyrone 17 exhibited a moderate antifungal and weak antibacterial effect, while the lactone 9 was moderately cytotoxic, but devoid of significant antimicrobial activity. The chlorinated aromatic compound 14 only weakly inhibited the sensitive test organisms Chromobacterium violaceum and Mucor hiemalis

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

• ulcerans, which exhibit cytotoxic, immunosuppressive and analgesic properties. As the virulence factor of M. ulcerans, mycolactones are central to the pathogenesis of the neglected disease Buruli ulcer, a chronic and debilitating medical condition characterized by necrotic skin ulcers. Due to their complex

• and mechanisms of action Although Buruli ulcer is associated with extensive fat cell necrosis at the sites of infection, the ulcers are typically accompanied by minimal pain or inflammatory response. These macroscopic observations reflect the cytotoxic [32], immunosuppressive [35][77] and analgesic

• might be crucial for Buruli ulcer pathogenesis [35][81]. With increasing concentrations, the cytotoxic effects of mycolactone become more prominent. These are typically accompanied by a profound structural change in the cytoskeleton followed by cell cycle arrest in the G0/G1 phase. Ultimately, cell

A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines

• Benedikt C. Melzer and
• Franz Bracher

Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156

• methylation protocol, we explored diazomethane, but no conversion was observed at all. Finally, all of the synthesized alkaloids were tested for their cytotoxic potential in a MTT assay on the HL-60 cell line. Except for menisporphine (2) and bianfugecine (6, both IC50 values > 50 µM), all of the described

• oxoisoaporphine alkaloids and the isomers 18 and 19 showed significant cytotoxic activity. IC50 values of alkaloid 3 and of compounds 18 and 19 are ranging from 3–6 µM. Very strong cytotoxicity was determined for 6-O-demethylmenisporphine (4) with an IC50 value of 0.06 µM and for dauriporphinoline (5) with 0.23

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide

• Ludmila Škorpilová,
• Silvie Rimpelová,
• Michal Jurášek,
• Miloš Buděšínský,
• Jana Lokajová,
• Roman Effenberg,
• Petr Slepička,
• Tomáš Ruml,
• Eva Kmoníčková,
• Pavel B. Drašar and
• Zdeněk Wimmer

Beilstein J. Org. Chem. 2017, 13, 1316–1324, doi:10.3762/bjoc.13.128

• active construct 6 from the liposomes. Further tests are necessary to confirm this hypothesis. Conclusion In summary, in order to develop a drug delivery system for potential theranostic applications, we prepared a submicron liposome-based formulation of a cytotoxic agent, sesquiterpene lactone

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydroanhydrocycloheximides

• Li Yang,
• Ping Wu,
• Jinghua Xue,
• Huitong Tan,
• Zheng Zhang and
• Xiaoyi Wei

Beilstein J. Org. Chem. 2017, 13, 1039–1049, doi:10.3762/bjoc.13.103

• 2 and 3 was observed and verified and the possible reaction path and mechanism were proposed by theoretical computations. The antifungal and cytotoxic activities of 1–6 were evaluated and suggested that 2,3-dehydrogenation results in the loss of the activities and supported that the OH-α is

• findings suggested that these cycloheximide derivatives possibly exert the antifungal and cytotoxic activities via a similar mode of action. Conclusion Three new (1–3) and three known (4–6) cycloheximide congeners were obtained from the cultures of Streptomyces sp. SC0581. The structure elucidation of the

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• cytotoxic activity toward lymphoma cells, resulting active at a very low micromolar range [101]. With the aim to activate the human immune system against self-tumor cells, Schlecht and co-workers designed the synthesis of AuNPs functionalized with Mucin1(MUC1)-glycopeptide antigens [102]. Mucins are a

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• (±)-oxomaritidine (gas–liquid–solid reaction) Baxendale et al. have developed a multistep synthesis for (±)-oxomaritidine, a cytotoxic alkaloid of the amaryllidaceae family of natural products [9] (Scheme 4). The process involved seven reaction steps out of which the first two reactions were carried out in parallel

Use of costic acid, a natural extract from Dittrichia viscosa, for the control of Varroa destructor, a parasite of the European honey bee

• Kalliopi Sofou,
• Demosthenis Isaakidis,
• Apostolos Spyros,
• Anita Büttner,
• Athanassios Giannis and
• Haralambos E. Katerinopoulos

Beilstein J. Org. Chem. 2017, 13, 952–959, doi:10.3762/bjoc.13.96

• -α and IFN-γ-stimulated chemokine production [48]. Costic acid exhibited selective cytotoxic effects to Spodoptera littoralis-derived Sf9 cells [49]. In spite of the diversity in biological activity, however, no acaricidal activity of either costic acid or D. viscosa extracts against V. destructor

• ) was measured according to the test protocol. Costic acid was not cytotoxic at concentrations of up to 230 micromolar (μM). Mortality of V. destructor (number of mites) after 12 h treatment with 20, 60, or 100 μL dose of acaricide. The number in parenthesis indicates the microliters of solution used in

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems

• Katarina Kemper,
• Max Hirte,
• Markus Reinbold,
• Monika Fuchs and
• Thomas Brück

Beilstein J. Org. Chem. 2017, 13, 845–854, doi:10.3762/bjoc.13.85

• stereoselective synthesis of (1R,3E,7E,11S,12S)-3,7,18-dolabellatriene, a bicyclic diterpene (Scheme 2). Dollabellanes derive mostly from marine organisms and display bioactivities such as antiviral and cytotoxic effects [59]. Dolabellatriene from a reprogrammed CotB2 contribute with antimicrobial activity

• process generally involves selection of the carbon source, media composition and in situ or post-fermentational product removal. Some terpene products have cytotoxic effects against the production host and separation from the cells is recommended already during fermentation. Ajikumar et al. also reported

New approach toward the synthesis of deuterated pyrazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]pyridines

• Aleksey Yu. Vorob’ev,
• Vyacheslav I. Supranovich,
• Gennady I. Borodkin and
• Vyacheslav G. Shubin

Beilstein J. Org. Chem. 2017, 13, 800–805, doi:10.3762/bjoc.13.80

• treating asthma and post-stroke patients [16]. 1,2,4-Triazolo[1,5-a]pyridines show antifungal [17], antitumor [18], and cytotoxic [19] activities. Both types of heterocyclic cores are readily available from N-aminopyridium salts and related pyridinium-N-imines via 1,3-cycloaddition reaction [20] or

Membrane properties of hydroxycholesterols related to the brain cholesterol metabolism

• Malte Hilsch,
• Ivan Haralampiev,
• Peter Müller,
• Daniel Huster and
• Holger A. Scheidt

Beilstein J. Org. Chem. 2017, 13, 720–727, doi:10.3762/bjoc.13.71

• domains and an attenuated phospholipid condensation effect was found. These properties, which depend on the molecular position of the hydroxy group, were correlated with cytotoxic effects of the respective molecules [22][23]. In the current study, the influence of hydroxycholesterols on membrane

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

• being excited with visible light, the PS – while reverting to the ground state – transfers the energy of its lowest excited triplet state to nearby molecular oxygen. This leads to an in situ generation of singlet oxygen (1O2), which is the main responsible species for cytotoxic reactions in cells [6

• systems in combined phototherapies. This approach has recently led to self-assembled systems based on a porphyrin–β-CD conjugate and a tailored nitric oxide photoreleaser forming a strong inclusion complex with the β-CD cavity [9]. This supramolecular nanoassembly simultaneously releases cytotoxic 1O2 and

• nitric oxide under illumination with visible light, resulting in amplified cancer-cell mortality [9]. By attaching porphyrin to γ-CD and dimeric β-CD, which are both able to form inclusion complexes with cytotoxic drug molecules such as doxorubicin and paclitaxel, nanocarriers with multimodal therapeutic

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• the synthesis of kinamycin 9 derivatives, which exhibited a strong cytotoxic and anticancer activity (Scheme 4) [15]. Propionic acid derivatives are also useful substrates in syntheses of 1-indanones and isocoumarins [16]. These latter are essential reagents for the synthesis of bioactive compounds

• keto-oximes 179 and 2-amino derivatives 180 are β2-adrenergic agonists tested for bronchodilating activity. The pterosin family are sesquiterpenoids naturally occurring in bracken fern (Pteridium aquilinum), some of them exhibit antibacterial and cytotoxic activity. A practical synthesis of pterosin A

Revaluation of biomass-derived furfuryl alcohol derivatives for the synthesis of carbocyclic nucleoside phosphonate analogues

• Bemba Sidi Mohamed,
• Christian Périgaud and
• Christophe Mathé

Beilstein J. Org. Chem. 2017, 13, 251–256, doi:10.3762/bjoc.13.28

• . However, none of them showed significant antiviral or cytotoxic activities. The absence of biological activity may be attributed to various factors, such as inability to enter cells or to behave as substrates for intracellular enzymes catalyzing phosphorylation, as well as a lack of inhibition of viral

Synthesis and evaluation of anti-oxidant and cytotoxic activities of novel 10-undecenoic acid methyl ester based lipoconjugates of phenolic acids

• Naganna Narra,
• Shiva Shanker Kaki,
• Rachapudi Badari Narayana Prasad,
• Sunil Misra,
• Koude Dhevendar,
• Venkateshwarlu Kontham and
• Padmaja V. Korlipara

Beilstein J. Org. Chem. 2017, 13, 26–32, doi:10.3762/bjoc.13.4

• calorimetry (DSC). The prepared compounds were also screened for their cytotoxic activity against five cell lines. It was observed that the lipoconjugates of caffeic acid, sinapic acid, ferulic acid, and coumaric acid displayed anticancer and anti-oxidant properties. The anticancer properties of these

• due to different media used for the assays; the DPPH assay is conducted in a polar medium but the linoleic acid oxidation study is conducted in a non-polar environment. Cytotoxic activity As there were studies reported on the cytotoxicity of phenolic lipids, we have further screened the prepared