Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study

• Valya K. Nikolova,
• Cristina V. Kirkova,
• Silvia E. Angelova and
• Todor M. Dudev

Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131

• cations (La3+) a supramolecular approach with explicit solvent treatment has been applied in the study of the effect of metal hydration on the complexation process. The La3+ binding to the p-sulfonatocalix[4]arene host molecule (now in the metal’s second coordination shell) is still exergonic as evidenced

• of p-sulfonatocalix[4]arene and some inorganic and organic cations in aqueous solution [32]. The predicted ΔG value (relative Gibbs energy) of the complexation between the host calixarene molecule and hydrated La3+ cation (with an average coordination number of water molecules in the first hydration

• metal hydration (i.e., explicit solvent treatment method) on the complexation process was studied here by employing a supramolecular approach for one representative of the metal species from the series, La3+ cation. A hydration number of 9 and initial tricapped trigonal prismatic arrangement of the

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• -glycosylated compounds were observed. Preparation of vesicles upon hydration of a thin film of phospholipids and glycolipids Once synthesized, the compounds 5 and 8 bearing GlcNAc residues were used to produce giant vesicles (GVs) upon hydration with PBS (pH 7.4) by modifying reported procedures [28][29][30

• hydration temperature was 25 °C. Three volumes of the thus obtained GVs were diluted with one volume of an aqueous isotonic buffer solution termed “O-solution” (composed of 200 mM glucose in 50 mM of PBS buffer, pH 7.4) and centrifuged at 5,000 rpm for 10 minutes in a bench-top Eppendorf mini-centrifuge

• and 6. a) Spectrum of pure 1b; b) through d) crude reaction mixture after 0, 30 and 60 minutes of irradiation, respectively. Micrographs of giant vesicles and lipid aggregates obtained from the gentle hydration (in PBS, pH 7.4) of compounds 8 and 5, alone and in binary and ternary mixtures with POPC

LCST phase behavior of benzo-21-crown-7 with different alkyl chains

• Yan Deng,
• Xing Li,
• Qiao Zhang,
• Zheng Luo,
• Chengyou Han and
• Shengyi Dong

Beilstein J. Org. Chem. 2019, 15, 437–444, doi:10.3762/bjoc.15.38

• ethers with urea-based linkers show higher water solubility (5a–e), compared to crown ethers with carbamate-based linkers (3a–e). As amide groups are more hydrophilic compared with ester groups, it is reasonable that 5a–e show stronger hydration effects and exhibit a larger water-accessible surface area

Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• accordance to what was reported by the Dilman group [40]. The α,α-difluoroketone 3 rapidly underwent hydration in a reversible way to form the gem-diol 4. The stereochemistry of compound 4 could be assessed indicating the selective formation of the β-nucleoside with the addition of the iodine at the 7

Cobalt bis(acetylacetonate)–tert-butyl hydroperoxide–triethylsilane: a general reagent combination for the Markovnikov-selective hydrofunctionalization of alkenes by hydrogen atom transfer

• Xiaoshen Ma and
• Seth B. Herzon

Beilstein J. Org. Chem. 2018, 14, 2259–2265, doi:10.3762/bjoc.14.201

• of 3a were lower (see Supporting Information File 1, Table S1, entries 13–15). Mukaiyama and co-workers’ pioneering Markonikov-selective alkene hydration reaction [5][49][50][51][52][53][54] proceeds using dioxygen as the oxygen atom source. Exposure of the alkene 3a to similar conditions provided

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• -solubilizing group. Although its pKa may not be optimal for deprotonation at neutral or physiological pH, its small size and relatively high free energy of hydration (−373 kJ mol−1) ensure that ion-pairing effects are not strong. This was further confirmed by 1H NMR spectroscopy (Supporting Information File 1

• solution of crystalline alkali halides and the difference between the absolute free energy (or heat) of hydration of the corresponding anion and cation [27][28]. As a result, in the words of Fajans, “in the case of alkali halides, the solubility in a number of salts with the same cation (anion) and

• different anions (cations) is at a minimum when the cation and anion are approximately equal and increases with increasing difference of the ionic radii” [29]. This has been built upon by Collins who proposed that the difference in heats of hydration of a cation and anion is a surrogate for the extent of

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• film hydration method. To identify an optimal calixarene–AEPCDA ratio a series of PDA vesicles containing 1, 5, 10, 50 mol % of 10b was prepared. Polymerization of AEPCDA–calixarene vesicles was performed under UV irradiation using 254 nm light in quartz cuvettes of 1 cm path length. The absorbance

Synthesis of pyrimido[1,6-a]quinoxalines via intermolecular trapping of thermally generated acyl(quinoxalin-2-yl)ketenes by Schiff bases

• Svetlana O. Kasatkina,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev,
• Ivan G. Mokrushin and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2018, 14, 1734–1742, doi:10.3762/bjoc.14.147

• reaction (Table 1) was not detected. The most likely way of the formation of quinoxalinone 4a is hydration of the ketene with subsequent decarboxylation (Scheme 2); more careful drying the reaction vials and solvents easily reduced the amount of compound 4a. The formation of pyrido[1,2-a]quinoxaline 5a can

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• the cation (2). The formation of the structures (1) or (2) was correlated to the hydration energies (ΔHM) of the cations. Highly charged species with a high ΔHM like Li+ were considered more likely to form structure (2), because the cation–OHads interaction is stronger than for cations with a low ΔHM

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• small molecules comprise various heterocyclic and/or aromatic hydrocarbon rings with limited rotational freedom and torsion, allowing these drugs to fit into major/minor grooves of DNA by displacing water molecules from the spine of hydration as shown in the Figure 2 [25][26][27]. These molecules bind

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• DNA and RNA isolation The lack of free-volume within double-stranded DNA at low hydration levels leads to limited ice formation even under cooling in liquid air [57]. In contrast, cold denaturation of globular proteins at such temperatures is almost ubiquitous [58]. Furthermore, large conformational

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• absence of a satisfactory mechanistic proposal for the hydration reaction, we considered the possibility of a metal–vinylidene type activation mode, as it is well established for ruthenium-based alkyne hydration catalysts with anti-Markovnikov regioselectivity. To validate the hypothesis, the

• regioselectivity of tungsten-catalyzed alkyne hydration of a terminal, higher alkyne had to be determined. However, complex 1 was not a competent catalyst for the hydration of 1-octyne under the conditions tested. Furthermore, we could not observe the earlier reported hydration activity of complex 1 towards

• acetylene. A critical assessment of, and a possible explanation for the earlier reported results are offered. The title question is answered with "no". Keywords: acetylene hydratase; alkynes; catalytic hydration; enzyme models; tungsten complexes; Introduction In 1985, the enzyme acetylene hydratase

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• conducted on the freeze-dried samples. The elemental analysis data are in agreement with the values calculated for a 1:1 stoichiometry, i.e., the empirical formula C48H80O40·C15H10O6·20H2O. Note also the remarkable increase in the hydration status, from 7 water molecules per host molecule in γ-CD to 20

• and C4 carbons, multiplicity is associated with differences in the conformation about the α(1→4) linkages, while carbons positioned closer to the rims, such as is the case for C6, are more sensitive to ambient changes arising from hydration water molecules and the hydrogen-bonding network [33][34

• . 280 °C, after which the charred residue undergoes a slow thermal oxidation from 330 °C until its complete combustion at 520 °C [38]. The thermal decomposition trace of the physical mixture is quite similar to that of γ-CD, having approximately the same number of hydration water molecules. Remarkably

Remarkable functions of sn-3 hydroxy and phosphocholine groups in 1,2-diacyl-sn-glycerolipids to induce clockwise (+)-helicity around the 1,2-diacyl moiety: Evidence from conformation analysis by ¹H NMR spectroscopy

• Yoshihiro Nishida,
• Mengfei Yuan,
• Kazuo Fukuda,
• Kaito Fujisawa,
• Hirofumi Dohi and
• Hirotaka Uzawa

Beilstein J. Org. Chem. 2017, 13, 1999–2009, doi:10.3762/bjoc.13.196

• hydration occurring around the carbonyl groups in the 1,2-diacyl moiety triggers the dynamics of the molecular alignments in liposomes. Probably, an analogous phenomenon related to the solvation around sn-3 OH was observed. Thus, solvation is thought to play a key role in the dynamic conformation change

Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz–Fritsch–Bobbitt reaction with non-activated and moderately-activated systems

• Marco Mottinelli,
• Mathew P. Leese and
• Barry V. L. Potter

Beilstein J. Org. Chem. 2017, 13, 1871–1878, doi:10.3762/bjoc.13.182

• rearrangement product 13 would then lead to the isolated compound 11 upon hydration, either during the reaction or the work-up. However, the precise mechanism for the formation of 11 has yet to be explored and efforts to unravel it lay outside the scope of this work. The addition of 6 M HCl led to the

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

• deprotonation with occasional hydration at the C8 position of the carbocation intermediate which yields hydroxylated diphosphate products [62]. MvCPS1, however, catalyzes a C9–C8 hydride shift preceding hydration resulting in the labdane-type diterpene precursor for the antidiabetic marrubiin [63]. Double

Formose reaction accelerated in aerosol-OT reverse micelles

• Makoto Masaoka,
• Tomohiro Michitaka and
• Akihito Hashidzume

Beilstein J. Org. Chem. 2016, 12, 2663–2667, doi:10.3762/bjoc.12.262

• a layer of water molecules with restricted mobility, because of hydration of the hydrophilic group of the surfactant (i.e., the surfactant head) [22][23]. It is likely that the thickness of the layer of restricted water is approximately several nm [24][25]. The water molecules in the interfacial

• layer are more polar than those in the bulk water phase because of polarization caused by hydration of the surfactant head. Since Rw of AOT reverse micelles is practically proportional to w (Figure S1 in Supporting Information File 1), the fraction of water molecules in the interfacial layer increases

A self-assembled cyclodextrin nanocarrier for photoreactive squaraine

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248

• solution in a round bottom flask. Hydration and extrusion with a Liposofast extruder and membranes with 100 nm pore size yield bilayer vesicles of an approximate size of 100 nm. CDVs were decorated with AdSq by simple addition of the AdSq to the aqueous dispersion of the CDVs. Interestingly, the

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• , catalytic hydration of cyclohexene, or catalytic air oxidation of cyclohexane. However, as an intellectual exercise and proof of principle, we may be able to use the results described for integer partitioning to devise creative syntheses for cyclohexanone which involve actual ring construction via 2

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

• presence thereof, but all acids promote only the iminolactone decyclization process without traces of lactone derivative 4 (Table 2). It is also important to note that during the reaction pathway (Scheme 3) a carbonyl-assisted carbonitrile hydration effect (CACHE) was occured. The carbonyl group, through

Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst

• Lubabalo Mafu,
• Ben Zeelie and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193

• further hydrogenated over a metal-supported catalyst to yield the cis and trans isomers of menthol 2 (Scheme 1) [4]. Alternatively the acid-catalysed hydration of citronellal (1) results in the synthesis of the cis and trans isomers of para-menthane-3,8-diol (3, Scheme 2). This chemical derivative is well

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

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

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• from complexes. According to the TG analysis, the water content is 4.1–6.4% lower than for the β-CD. This observation supports the formation of the inclusion compound by partial replacement of the hydration water from the CD cavity by the guest compounds (FA glycerides). Studies on the evaluation of

• support the conclusion of formation of the β-CD/FA glyceride inclusion complex by means of water behavior. Hydration water is easier released from the β-CD/ASO complexes obtained at a 3:1 molar ratio. Both DSC and KFT analyses demonstrate this finding with a lower peak temperature and lower “strongly

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

• Adrián Gómez-Suárez,
• Yoshihiro Oonishi,
• Anthony R. Martin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

• as 10% of acetophenone, the corresponding hydration product. Furthermore, the formation of a new gold species, which was characterised as the previously reported σ,π-digold–acetylide species could also be observed. This diaurated species can be formed by reaction of [{Au(IPr)}2(µ-OH)][BF4] with