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Search for "lactones" in Full Text gives 159 result(s) in Beilstein Journal of Organic Chemistry.

Diastereoselective Mannich reactions of pseudo-C2-symmetric glutarimide with activated imines

  • Tatsuya Ishikawa,
  • Tomoko Kawasaki-Takasuka,
  • Toshio Kubota and
  • Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 2473–2477, doi:10.3762/bjoc.13.244

Graphical Abstract
  • lactones in good to excellent yields [4][5]. One of the most intriguing features of this protocol is the fact that the enantiomers at the lactone part were readily obtained only by the selection of the tertiary amines employed in the reaction. It is quite apparent that this success is, at least in part
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Published 21 Nov 2017

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

  • Alexey Yu. Dubovtsev,
  • Maksim V. Dmitriev,
  • Аndrey N. Maslivets and
  • Michael Rubin

Beilstein J. Org. Chem. 2017, 13, 2179–2185, doi:10.3762/bjoc.13.218

Graphical Abstract
  • tested their reactivity with pyrrolediones 9 (Scheme 6). Gratifyingly, this reasoning was correct, as we obtained the corresponding lactones 23 as the sole products in reasonable yields (Scheme 6). The crystal structure of compound 23aa (CCDC 1546064) depicted in Figure 4 confirmed the formation of this
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Published 19 Oct 2017

Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes

  • José Enrique Barquera-Lozada and
  • Gabriel Cuevas

Beilstein J. Org. Chem. 2017, 13, 1969–1976, doi:10.3762/bjoc.13.192

Graphical Abstract
  • possible explanation of the inhibition of Cope rearrangement by the lactone ring (proposed by Takeda) is that the lactone ring raises the Cope TS energy, as the lactone ring strains the germacrane ring. Contrary to what Takeda predicted, the relative energies of opened lactones, TS7-9 (50.8 kcal/mol) and
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Published 19 Sep 2017

Pd(OAc)2/Ph3P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

  • Dominik Kellner,
  • Maximilian Weger,
  • Andrea Gini and
  • Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

Graphical Abstract
  • structures that can be further transformed into interesting potential biologically active heterocyclic derivatives such as terpenoid pyranes, lactones, (hydro)chromenes or pyridines, among others [23][24][25][26]. Depending on the connection of the two isoprene units, four different kinds of dimers can be
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Published 29 Aug 2017

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

Graphical Abstract
  • control of a number of cytokines. Alternatively, lipopolysaccharide (endotoxin) is known as strong inducer of NO in macrophages. Since it is known that sesquiterpene lactones, Tg, Tb, as well as Tb derivatives [31], possess strong stimulating activity for NO production by immune cells [40][41], we
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Published 04 Jul 2017

A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE

  • Tue Heesgaard Jepsen,
  • Emil Glibstrup,
  • François Crestey,
  • Anders A. Jensen and
  • Jesper Langgaard Kristensen

Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98

Graphical Abstract
  • synthetic procedures are extremely scarce. Herein, we wish to provide different strategies used to synthesize the CD fragment of DHβE as a general and simple method for the construction of [6,6]-bicyclic lactones which includes a stereoselective synthesis of vinyl halides, a regio- and stereoselective
  • unfortunately this reaction proceeded without a trace of the desired lactone 9. Recently Szostak et al. have shown that 6-membered lactones undergo reduction with SmI2 [20] which may explain this result. However, upon treatment with sodium napthalenide lactone 7 was fully converted but all attempts to isolate
  • challenging [6,6]-bicyclic lactone fragment in general through an expedient regio- and stereoselective Mizoroki–Heck cyclization approach. This method enabled the synthesis of the elusive and volatile CD fragments ([6,6]-bicyclic lactones 9 and 26) of the Erythrina alkaloid DHβE. This allowed the
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Published 22 May 2017

Synthesis of D-manno-heptulose via a cascade aldol/hemiketalization reaction

  • Yan Chen,
  • Xiaoman Wang,
  • Junchang Wang and
  • You Yang

Beilstein J. Org. Chem. 2017, 13, 795–799, doi:10.3762/bjoc.13.79

Graphical Abstract
  • chain elongations of aldoses employing the Henry reaction, the aldol reaction, and the Wittig reaction for the preparation of ketoheptoses [20][21][22], sugar lactones were also often utilized for the synthesis of D-manno-heptulose via reactions with C-nucleophiles or conversion into exocyclic glycals
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Letter
Published 28 Apr 2017

Lipids: fatty acids and derivatives, polyketides and isoprenoids

  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2017, 13, 793–794, doi:10.3762/bjoc.13.78

Graphical Abstract
  • another important consequence for signaling compounds that travel with high speed in aqueous environments – an effect that is immediately recognizable if a drop of oil is spilled on a water surface. An impressive example is reported in this Thematic Series with the use of highly apolar lactones from the
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Editorial
Published 27 Apr 2017

Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

  • Matthew A. Horwitz,
  • Elisabetta Massolo and
  • Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

Graphical Abstract
  • nucleophile. Mild reaction conditions allow the formation of diversely functionalized fused bicyclic lactones. The products participate in facially selective additions from the convex surface, leading to allylic alcohol derivatives. Keywords: conjugate addition; cyclohexadienones; dearomatization
  • desymmetrizing intramolecular conjugate addition of a tethered dithiane moiety to para-cresol-derived cyclohexadienones. The substrates are easily accessible from cheap starting materials and the reaction provides functionalized bicyclic lactones as a single diastereomer. The products of the reaction were able
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Letter
Published 24 Apr 2017

Exploring endoperoxides as a new entry for the synthesis of branched azasugars

  • Svenja Domeyer,
  • Mark Bjerregaard,
  • Henrik Johansson and
  • Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2017, 13, 644–647, doi:10.3762/bjoc.13.63

Graphical Abstract
  • ready access to the two lactol isomers 29,30 in quantitative yield (≈1:1 ratio of isomers) [10][22][23]. Lactol isomers 29,30 could potentially serve as precursors for the formation of substituted piperidines via reductive amination or be oxidised to yield lactones or lactam derivatives. Conclusion
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Published 03 Apr 2017

Polyketide stereocontrol: a study in chemical biology

  • Kira J. Weissman

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

Graphical Abstract
  • unepimerized methyl configuration) to generate a hybrid PKS called TKS-AR1, and the stereochemistry of the resulting triketide lactones 15 and 16 established by NMR. This analysis showed that the methyl group arising from the hybrid 1/5 module was epimerized in 50% of the product 16 and that this change in
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Published 24 Feb 2017

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

Graphical Abstract
  • isoprenyl side chain is an influential factor of the group- (or species-) specific pheromonal activity [25]. Intriguingly, the same applies for group- (or species-) specificity in Gram negative bacteria because the chemical structure and length of the acyl side chain in acylhomoserine lactones, which are
  • in boldface and colored blue. (B) Chemical structures of acyl homoserine lactones. The acyl side chains are shown in boldface. (A) Schematic representation of the signal transduction cascade of quorum sensing stimulated by the ComX pheromone in B. subtilis. (B) Amino acid sequences of the aspartate
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Published 22 Feb 2017

The reductive decyanation reaction: an overview and recent developments

  • Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

Graphical Abstract
  • monodecyanated products 69a,b. Bicyclic lactones 70a,b are then obtained in 3 steps in 41% and 51% yields, respectively, from 69a,b. Later Curran’s group discovered that NHC-boryl radicals, generated from NHC-boranes (N-heterocyclic carbene boranes), abstracted the cyano group from various organic nitriles and
  • [106]. Synthesis of bicyclic lactones [119][120]. Reductive decyanation of malononitriles and cyanoacetates using NHC-boryl radicals (9 examples). For 74 and 75, isolated or NMR yields are given from 71 [121]. Proposed mechanism for the reduction by NHC-boryl radicals. The other possible pathway
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Published 13 Feb 2017

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

Graphical Abstract
  • , 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
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Published 13 Dec 2016

Radical polymerization by a supramolecular catalyst: cyclodextrin with a RAFT reagent

  • Kohei Koyanagi,
  • Yoshinori Takashima,
  • Takashi Nakamura,
  • Hiroyasu Yamaguchi and
  • Akira Harada

Beilstein J. Org. Chem. 2016, 12, 2495–2502, doi:10.3762/bjoc.12.244

Graphical Abstract
  • supramolecular polymerization catalyst capable of inserting the monomer between the active and binding sites can be designed. Based on this concept, we have reported that CDs can include and activate lactones to yield a polymer with a single CD at the end of the polymer chain [61][62][63][64]. Subsequently, we
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Published 22 Nov 2016

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

Graphical Abstract
  • 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
  • iteration on the first extension module of the PKS for the marginolactone azalomycin. Given the identical gene arrangement in the kanchanamycin gene cluster, we propose that iteration also operates there. The structures of marginolactones azalomycin and kanchanamycin, and of the β-lactones ebelactone A and
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Published 11 Oct 2016

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

Graphical Abstract
  • (B) is probably accompanied with decyclization (C) and dehydratation processes forming compound 2 (Scheme 3, path I). However, according to the literature, in most cases, the addition of water to the similar cyclic iminoethers leads to hydrolysis and formation of lactones [26][27]. Another probable
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Published 27 Sep 2016

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

Graphical Abstract
  • acetone are mainly produced by the Hock process, which is based on the rearrangement of cumene hydroperoxide. In 2003, phenol was produced to more than 95% by this oxidation process [52][53][54]. Another important application of organic peroxides is the synthesis of lactones from cyclic ketones via the
  • oxidation is widely used in organic synthesis for the preparation of esters and lactones and the Criegee reaction is applied to transform tertiary alcohols into ketones and aldehydes. The Hock rearrangement is a key step in the cumene (cumene–phenol) process and the Kornblum–DeLaMare is an important tool in
  • Smith rearrangements are of interest in allyl hydroperoxide transformations. 1.1 Baeyer–Villiger oxidation The BV reaction is the oxidation of ketones or aldehydes A under the action of hydrogen peroxide, hydroperoxides, Caro’s acid (H2SO5), or organic peracids to yield esters, lactones, or carboxylic
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Published 03 Aug 2016

Rh-Catalyzed reductive Mannich-type reaction and its application towards the synthesis of (±)-ezetimibe

  • Motoyuki Isoda,
  • Kazuyuki Sato,
  • Yurika Kunugi,
  • Satsuki Tokonishi,
  • Atsushi Tarui,
  • Masaaki Omote,
  • Hideki Minami and
  • Akira Ando

Beilstein J. Org. Chem. 2016, 12, 1608–1615, doi:10.3762/bjoc.12.157

Graphical Abstract
  • α,β-unsaturated lactones, similar β-lactams with anti-selectivities were obtained. Furthermore the yield and anti selectivity could be increased by adding Lewis acid, and we succeeded in achieving the effective synthesis of (±)-ezetimibe by using this reaction. Experimental General information 1H
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Published 27 Jul 2016

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

Graphical Abstract
  • their standard catalytic repertoire (Scheme 1). They transacylate the thioester of a PKS-bound polyketide onto a nucleophile. If the nucleophile is water, this leads to carboxylic acids. The reactions of backbone hydroxy groups or amines consequently give lactones and lactams. TE domains mostly form
  • 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
  • are biosynthesised in seven principal ways (Scheme 2). Those comprise nucleophilic addition of a hydroxy group to electrophiles like epoxides 4, carbonyl groups 6 or Michael acceptors 9, potentially followed by further processing (a–c in Scheme 2). Lactones 12 are formed by transacylation of a
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Published 20 Jul 2016

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

  • Bernardas Morkunas,
  • Balint Gal,
  • Warren R. J. D. Galloway,
  • James T. Hodgkinson,
  • Brett M. Ibbeson,
  • Yaw Sing Tan,
  • Martin Welch and
  • David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

Graphical Abstract
  • types of quorum sensing systems. Two of the QS signaling systems in P. aeruginosa utilise N-acylated-L-homoserine lactones (AHLs) as signalling molecules [20][21][22]. The rhl system utilises N-butanoyl-L-homoserine lactone (BHL) and it’s cognate receptor RhlR [20][21][22]. The las system utilises N-(3
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Published 11 Jul 2016

The EIMS fragmentation mechanisms of the sesquiterpenes corvol ethers A and B, epi-cubebol and isodauc-8-en-11-ol

  • Patrick Rabe and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2016, 12, 1380–1394, doi:10.3762/bjoc.12.132

Graphical Abstract
  • the actinobacterium Micromonospora aurantiaca [9] and more than 30 blastmycinones, a class of γ-lactones that depend on the antimycin biosynthetic gene cluster in several streptomycetes [10]. We have also recently developed structural proposals for a series of methylated monoterpenes from the 2
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Published 05 Jul 2016

Enantioselective carbenoid insertion into C(sp3)–H bonds

  • J. V. Santiago and
  • A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

Graphical Abstract
  • reaction. The catalyst 17c showed opposite enantioselectivity when compared to the catalysts 17a and 17b, with the S-enantiomer formed as the major product. In 1991, Doyle and coworkers published asymmetric synthesis of lactones from alkyl diazoacetates in high enantioselectivity by intramolecular rhodium
  • carbenoid insertion into C(sp3)–H [40]. In this work, the authors introduced the enantiomeric rhodium(II) carboxamides complexes (R)-18 and (S)-18 (Figure 4). The authors could observe the enantioselective formation of the lactones 20 with high enantiomeric excess (Table 2). The carbenoid formed by (S)-18
  • favored the S configuration at the generated stereogenic center for most of the prepared lactones. The opposite preference, R configuration at the new stereogenic center of 20, was reported to the use of the enantiomeric rhodium complex (R)-18. When substrate 19f reacts under catalysis of rhodium(II
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Published 04 May 2016

Indenopyrans – synthesis and photoluminescence properties

  • Andreea Petronela Diac,
  • Ana-Maria Ţepeş,
  • Albert Soran,
  • Ion Grosu,
  • Anamaria Terec,
  • Jean Roncali and
  • Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

Graphical Abstract
  • halogenated lactones having the 4a,9a-fused skeleton and an ester group at position 1. The cycloaddition reaction proceeded with moderate regio- and stereoselectivity. As reported in the literature, the inverse-electron demand Diels–Alder cycloaddition of unsymmetrical olefins and oxadiazinones [33][34][35
  • obtain photoluminescent compounds with higher performance, the dehydrogenation reaction of enol-lactones 2 and 3 was performed. Adapted from a procedure previously described [38], the oxidation of the isomeric mixture 2'a/3''a and 2'c/3'c, respectively, in the presence of 2,3-dichloro-5,6-dicyano-1,4
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Published 27 Apr 2016

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

  • Luíse Azevedo,
  • Larissa Faqueti,
  • Marina Kritsanida,
  • Antonia Efstathiou,
  • Despina Smirlis,
  • Gilberto C. Franchi Jr,
  • Grégory Genta-Jouve,
  • Sylvie Michel,
  • Louis P. Sandjo,
  • Raphaël Grougnet and
  • Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

Graphical Abstract
  • ) and the partition coefficient calculated for compounds 1 (16.20), 2 (2.77) and 3 (13.51) (Figure 1). Sesquiterpenes were previously reported from the genus Jungia [6][7][24][25][26]. Nevertheless, no glycosylated sesquiterpenes (and sesquiterpene lactones) were previously found in this genus. CPC has
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Published 12 Apr 2016
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