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

• -b]pyrans) are important photochromic compounds used for the fabrication of plastic lenses [12][13]. Their photochromic properties were improved through an extended conjugation through the fusion to an indeno group. Moreover, 2-alkyl-6-(4-(dimethylaminostyryl)-4H-pyran, 2,3-dihydro-1H-cyclopenta[3a

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• to fuse two ketoacyl moieties, as exemplified by CorB and MxnB. Another mechanism is the fusion of one ketoacyl moiety with one acyl moiety, as shown for PpyS-like KSs. All evolved from FabH-type KSs, but form different clades in phylogenetic analyses. PpyS-like enzymes show the conserved glutamate

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• guest might weaken the hydration water binding, as revealed in DSC experiments by the lower endothermic fusion peak, specific to a dehydration process. X-ray powder diffraction analysis finally confirmed the complex formation. All these studies proved that organophosphorus pesticides are able to

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• context of analyzing the vancomycin complex with D–Ala–D–Ala containing peptides, suggested the cost of freezing a free rotation to be between 0.4 to 0.9 kcal/mol – a value that is also close to what we had measured [25]. In Williams’ case, the value was derived from the entropy of fusion within a

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• the crystalline component 2ME. Consistent with this, no melting endotherm for 2ME was observed in DSC traces of these preparations, whereas the traces of the corresponding CD-2ME physical mixtures revealed fusion of 2ME at a peak temperature of 188 °C (reported mp 187 °C [9]). Definitive inclusion

• –105 °C (peak temperature 80 °C), and a sequence of two small endotherms, a large exotherm, and a small endotherm, all of them spanning the range ≈255–350 °C, attributed to final dehydration and the onset of complex decomposition. The absence of any endothermic effect for the fusion of pure 2ME was

• complex between 2ME and TRIMEB. PXRD subsequently confirmed the presence of a new crystalline phase. TGA indicated no significant mass loss over the interval 30–260 °C while the DSC trace displayed only an endotherm of fusion with a peak temperature of 170 °C. Finally, a 1:1 TRIMEB/2ME complex ratio was

Recent highlights in biosynthesis research using stable isotopes

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2015, 11, 2493–2508, doi:10.3762/bjoc.11.271

• acetate in PKS research deals with the fusion of the polycyclic aromatic pigment clostrubin A (12) from Clostridium beijerinckii, a strictly anaerobic bacterium [28]. The purple colored compound features a benzo[a]tetraphene skeleton, which is unique in known polyphenolic natural products. Moreover

Preparation of Pickering emulsions through interfacial adsorption by soft cyclodextrin nanogels

• Shintaro Kawano,
• Toshiyuki Kida,
• Mitsuru Akashi,
• Hirofumi Sato,
• Motohiro Shizuma and
• Daisuke Ono

Beilstein J. Org. Chem. 2015, 11, 2355–2364, doi:10.3762/bjoc.11.257

• is observed in the magnified image due to the fusion of CD nanogel particles (Figure 8B). The spherical CD nanogel particles are easily inter-penetrable [21] and may form a dense interconnected network (Figure 8B). The strong connectivity results in an interfacial layer, which effectively protects

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• systems [35] including incorporation within the conjugated backbone [36][37], as a pendant unit [38][39][40] and direct fusion to the π-conjugated system of the polymer [41][42]. Incorporation of a TTF unit into a PT architecture allows the creation of interesting hybrid redox systems with a wide range of

• . Conjugated OT systems with fused TTF units Synthesis of the monomer units Incorporation of a TTF unit into a PT architecture via fusion to the polymer backbone allows the realisation of highly diverse electroactive conjugated systems with different contributions to the properties from each of the components

• precursor. The retrosynthetic scheme for these monomers with direct fusion of the TTF unit to a thiophene 14a–c is shown in Scheme 5, with the key building block thieno[3,4-d][1,3]dithiole-2-one 15a–c. Where there is no substitution at the α-position of the thiophene monomer, e.g., 14a, triethylphosphite

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• monooxygenases are useful biocatalysts for C–H activation, and there is a need to expand the range of these enzymes beyond what is naturally available. A panel of 93 variants of active self-sufficient P450cam[Tyr96Phe]-RhFRed fusion enzymes with a broad diversity in active site amino acids was developed by

• ], phenacetin, ethoxyresofurin and chlorzoxazone to only name a few [16]. For the current investigation we sought to develop P450cam further to expand their substrate range in biocatalysis. Our starting point was a catalytically self-sufficient form of the enzyme, previously created by fusion with the reductase

• Escherichia coli (E. coli), variants of the fusion enzyme catalysed the efficient, highly selective hydroxylation of ionones without the need to supply expensive nicotinamide cofactors [20]. Given the previously demonstrated affinity of P450cam for hydrophobic substrates, we were interested to see if P450cam

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• in the fusion of aromatic rings, which makes this assignment a difficult task. An initial solution for structure determination might be to associate a single crystal X-ray structure to the NMR data. Unfortunately, the development of a suitable crystal for the crystallographic analysis is not an easy

Tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds

• Javier Miró,
• María Sánchez-Roselló,
• Álvaro Sanz,
• Fernando Rabasa,
• Carlos del Pozo and
• Santos Fustero

Beilstein J. Org. Chem. 2015, 11, 1486–1493, doi:10.3762/bjoc.11.161

• enyne metathesis protocols [29], was also unsuccessful in the present case (Table 1, entry 14). It is noteworthy that compound 3a was always obtained as a single diastereoisomer showing a cis fusion between the two cycles [30]. Next, the optimized conditions (heating at 90 °C for 48 h in the presence of

• -exo. After chromatographic separation, NOESY experiments indicated that 10b-endo shows two nOe correlations: one between H1 and H2 (which indicates the cis-fusion of the two cycles) and another one between H1 and the aromatic proton H3. These two nOe interactions, together with the absence of a

Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

• Lee Trollope,
• Dyanne L. Cruickshank,
• Terence Noonan,
• Susan A. Bourne,
• Milena Sorrenti,
• Laura Catenacci and
• Mino R. Caira

Beilstein J. Org. Chem. 2014, 10, 3136–3151, doi:10.3762/bjoc.10.331

• ). On DSC analysis, permethylated α-CD [(hexakis(2,3,6-tri-O-methyl)-α-CD; TRIMEA; TMA] yielded an endotherm of fusion only (Tpeak,m = 217.6(1) °C, ΔHm = 40(3) J g−1) (Figure 2, curve (b)). The physical mixture (PM) of TMA and RSV instead showed a new endothermic peak at ca. 175 °C, due to the melting

• oil and the DSC trace shows a corresponding broad endotherm accompanying the dehydration. However, a sharp endotherm subsequently developed, peaking at ca. 110 °C, interpreted as commencement of complex fusion which overlaps the dehydration process. This coincides with the melting observed in HSM at

• molecules per 1:1 complex unit. The endotherm observed over the range of 30–120 °C appears sharper than expected for solvent loss alone, suggesting simultaneous melting of the complex. The HSM photographs confirm that dehydration is accompanied by complex fusion, the latter spanning a wide temperature range

Modification of physical properties of poly(L-lactic acid) by addition of methyl-β-cyclodextrin

• Toshiyuki Suzuki,
• Ayaka Ei,
• Yoshihisa Takada,
• Hiroki Uehara,
• Takeshi Yamanobe and
• Keiko Takahashi

Beilstein J. Org. Chem. 2014, 10, 2997–3006, doi:10.3762/bjoc.10.318

• PL-MCD83 and 67, Tg decreases to approximately 60 °C; similar trends were observed for Tc and Tm. For PL-MCD50, Tg and Tc are higher than those of PL-MCD67 and 83, while their Tm is approximately equal. The enthalpies of fusion for PL-MCD50, 67, and 83 are approximately equal to the enthalpies of

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

• Fabrizio Chiodo,
• Marco Marradi,
• Javier Calvo,
• Eloisa Yuste and
• Soledad Penadés

Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136

• related to HIV envelope [18]. GNPs coated with oligomannosides of the gp120 (manno-GNPs) were able to inhibit the DC-SIGN-mediated HIV-1 trans-infection of human T-cells [19] and gold glyconanoparticles coated with sulfated ligands showed to interfere with the adhesion/fusion of HIV during its entry [20

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• Bivalirudin have been manufactured in multikilogram scale [10][19]. Enfuvirtide (T-20/ Fuzeon®), for example, is an efficient membrane fusion inhibitor for HIV treatment consisting of 36 amino acids [80]. The large-scale bulk production of Fuzeon® is performed by solution-phase fragment condensation from

• interaction, there is also the possibility to increase peptide stability by direct fusion with HSA. One example of this effect is the GLP-1 analog CJC-1131. It contains a covalently attached albumin moiety and a D-amino acid at a labile position to obtain increased metabolic stability [107]. PEGylation of

Triol-promoted activation of C–F bonds: Amination of benzylic fluorides under highly concentrated conditions mediated by 1,1,1-tris(hydroxymethyl)propane

• Pier Alexandre Champagne,
• Alexandre Saint-Martin,
• Mélina Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2013, 9, 2451–2456, doi:10.3762/bjoc.9.283

• all could be observed without the activating agent. It is important to mention for this entry that even if morpholine is the only liquid component at room temperature, a homogeneous solution is generated around 60 °C by the fusion of 1,1,1-tris(hydroxymethyl)propane (melting point 56–58 °C). Starting

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• complex, encompasses internally monosubstituted allenes, as well as disubstituted counterparts, offering a direct entry to 5,7 bicyclic systems including those with all-carbon quaternary stereocenters at the ring fusion. In contrast to the intramolecular counterpart, gold-catalyzed intermolecular

Hypervalent iodine/TEMPO-mediated oxidation in flow systems: a fast and efficient protocol for alcohol oxidation

• Nida Ambreen,
• Ravi Kumar and
• Thomas Wirth

Beilstein J. Org. Chem. 2013, 9, 1437–1442, doi:10.3762/bjoc.9.162

• . Both syringes were placed in a syringe pump (Fusion 100) and connected via a T-piece to a tubing reactor (PTFE, length: 4 m, internal diameter: 0.75 mm). The tubing reactor was immersed in a thermocontrolled water bath at 35 °C. The total flow rate was adjusted to 0.4 mL min–1 resulting in a residence

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• date has been [125I]IMPY ([125I]140e). Representative of this scaffold, the synthesis of [125I]140e used a fusion reaction between 2-amino-5-iodopyridine (143) and an α-bromoacetophenone 144 to form 140e, which was then radiolabeled (Scheme 10B) [90]. This preparation has since been improved by Kung et

Preparation and ring-opening reactions of N-diphenylphosphinyl vinyl aziridines

• Ashley N. Jarvis,
• Andrew B. McLaren,
• Helen M. I. Osborn and
• Joseph Sweeney

Beilstein J. Org. Chem. 2013, 9, 852–859, doi:10.3762/bjoc.9.98

• . Optimization studies We next sought to improve the yields of the vinyl aziridination and thus modified our experimental rubric by carrying out the fusion of ZnCl2 under vacuum, rather than at atmospheric pressure. Using this minor modification, the reaction of N-diphenylphosphinylbenzaldimine furnished vinyl

1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

• Astrid Hoppe,
• Faten Sadaka,
• Claire-Hélène Brachais,
• Gilles Boni,
• Jean-Pierre Couvercelle and
• Laurent Plasseraud

Beilstein J. Org. Chem. 2013, 9, 647–654, doi:10.3762/bjoc.9.73

• according to Equation 3 with ΔHc being the crystallization enthalpy, and ΔH' the enthalpy of fusion of PCL, ΔH' = 161.1 J·g−1) affects directly the melting temperature (Tm). Thus, a decrease of molecular weight causes a decrease of the Tm. Analysis of the crystallinity of the various polycaprolactones by

Synthesis of 2,3-dihydronaphtho[2,3-d][1,3]thiazole-4,9-diones and 2,3-dihydroanthra[2,3-d][1,3]thiazole-4,11-diones and novel ring contraction and fusion reaction of 3H-spiro[1,3-thiazole-2,1'-cyclohexanes] into 2,3,4,5-tetrahydro-1H-carbazole-6,11-diones

• Lidia S. Konstantinova,
• Kirill A. Lysov,
• Ljudmila I. Souvorova and
• Oleg A. Rakitin

Beilstein J. Org. Chem. 2013, 9, 577–584, doi:10.3762/bjoc.9.62

• ., ring contraction and fusion products. A plausible mechanism was proposed for the formation of the products. Keywords: anthracene-1,4-diones; 1H-carbazole-6,11-diones; fused thiazoles; fusion reaction; heterocycles; naphthoquinones; ring contraction; sulfur–nitrogen; Introduction The 1,4

• -ethyldiisopropylamine in the reaction of 2-(methylamino)anthracene-1,4-diones with sulfur monochloride was discovered and explained. 3H-Spiro(thiazol-2,1'-cyclohexanes) underwent a new ring contraction and fusion reaction resulting in the formation of tetrahydroindoles. Experimental Melting points were determined on a

Hydrophobic analogues of rhodamine B and rhodamine 101: potent fluorescent probes of mitochondria in living C. elegans

• Laurie F. Mottram,
• Safiyyah Forbes,
• Brian D. Ackley and
• Blake R. Peterson

Beilstein J. Org. Chem. 2012, 8, 2156–2165, doi:10.3762/bjoc.8.243

• Mitochondria undergo dynamic fusion and fission events that affect the structure and function of these critical energy-producing cellular organelles. Defects in these dynamic processes have been implicated in a wide range of human diseases including ischemia, neurodegeneration, metabolic disease, and cancer

• mitochondrial stains rhodamine 123, rhodamine 6G, and rhodamine B, as well as the structurally related fluorophores rhodamine 101, and basic violet 11, revealed that HRB and HR101 are the most potent mitochondrial probes, enabling imaging of mitochondrial motility, fusion, and fission in the germline and other

• ; fluorescence; fusion; imaging; in vivo; microscopy; mitochondria; model organisms; organelle; rhodamine; spectroscopy; Introduction Fluorescent molecular probes represent critical tools for studies of chemical biology [1]. These compounds allow the creation of sensitive enzyme substrates, sensors of a wide

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

• ring fusion of C4a–N8 (1, 3 and 4) or C8a–N5 atoms (2), and differ in the arrangement of the substitution pattern of the imidazotriazine framework (Figure 1). The structural variation of imidazo[1,2,4]triazine derivatives poses a significant challenge, particularly if a broad variety of substituents is

• time. We observed that the adding of molecular sieves (4 Å) to the reaction medium greatly improved the yields of condensed products 23–25. The regioselective two-step cyclization of 14 yielding imidazo[5,1-c][1,2,4]triazine-3,6-dione (24, pathway A) via an N5–C5 ring fusion is outlined in Scheme 4

• (HSQC and HMBC) in combination with 1H and 13C NMR, and additionally by LC/ESI-MS (m/z 287 [M + H]+/285 [M − H]− for 24, 355 [M + H]+/353 [M − H]− for 25). Molecular modelling was performed to calculate the respective geometries by using the MMFF95 force field [27] assuming an N1–C5 ring fusion during