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Search for "intermolecular" in Full Text gives 756 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates
Beilstein J. Org. Chem. 2020, 16, 3008–3014, doi:10.3762/bjoc.16.250
- intermediates (triplet aryl cations [28][29] or aryl radicals [30][31]). As for the former case, the intermolecular formation of a biaryl arose from the photoheterolysis of an Ar–N bond (in arene diazonium salts or their derivatives [32][33]), of an Ar–Cl bond [34][35], of an Ar–O bond (in aryl phosphates [36
Chiral anion recognition using calix[4]arene-based ureido receptors in a 1,3-alternate conformation
Beilstein J. Org. Chem. 2020, 16, 2999–3007, doi:10.3762/bjoc.16.249
- chain of calixarene molecules joined together by intermolecular hydrogen bonds between the ureido groups (the C=O···H–N distances were 2.293 and 2.048 Å). One of the ureido functions in the macrocycle also held acetone via a C=O···H–N hydrogen bond (2.085 Å) and via a C=O···H–C bond (2.670 Å) from the
Naphthalonitriles featuring efficient emission in solution and in the solid state
Beilstein J. Org. Chem. 2020, 16, 2960–2970, doi:10.3762/bjoc.16.246
- , internal conversion, intermolecular electron transfer, as well as excimer or exciplex formation and isomerization. These phenomena significantly limit the usability of luminogens for the abovementioned purposes. Several attempts were already made to prevent or restrict these non-radiative pathways by
- some intermolecular CH…π interactions between the C–H units of the residual tolyl group and the central ring of the naphthalonitrile bearing two nitrile groups with a CH/π-ring distance of 2.780 Å (Figure 2A). Even though the naphthalonitrile planes of two adjacent head-to-tail-arranged molecules are
- parallel (see Figure 2B), the centroid distance between the rings reaches up to 4.985 Å, suggesting that the intermolecular π–π interactions are absent. In addition to these interactions, there also exist weak supramolecular N–H interactions. Firstly, two Me units form dimeric structures that are connected
Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives
Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242
- angle of 64.5°. The intermolecular distances are situated in the range 2.3–2.6 Å disclosing the lack of intermolecular interactions in the crystal structure. Scanning electron microscopy (SEM) analysis Besides process intensification leading to a shorter reaction time, another advantage of the
UV resonance Raman spectroscopy of the supramolecular ligand guanidiniocarbonyl indole (GCI) with 244 nm laser excitation
Beilstein J. Org. Chem. 2020, 16, 2911–2919, doi:10.3762/bjoc.16.240
- presence of polar solvents like water. This makes GCPs promising binding partners for acidic residues such as carboxylates at the C-terminus of peptides and proteins. The intermolecular interactions upon recognition induce subtle changes in the molecular properties such as the electronic structure and bond
- -covalent, i.e., only weak intermolecular interactions present, one would expect a peak shift for the isolated supramolecular ligand. However, the GCI is dissolved in water and therefore already involved in hydrogen bonding to water molecules. Upon the addition of the RGD binding partner, the water
Using multiple self-sorting for switching functions in discrete multicomponent systems
Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233
- intermolecular complex [Cu(68)(69)]+. As a result the toggling arm in [Cu(68)]+ had to move to the zinc porphyrin station affording [Cu(68)(69)]+. Whereas the organocatalyst 70 was firmly attached to the zinc porphyrin moiety of [Cu(68)]+, in [Cu(68)(69)]+ it was expelled into solution unfolding its catalytic
- catalytic activity. In sum, this study demonstrated partial and full release/binding of the organocatalyst 75 during the walking of the biped. Rather recently, the Schmittel group described a precise intermolecular communication system, in which multiple self-sorting steps set up a catalytic AND gate
Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans
Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226
- ethene atmosphere were applied in the reaction. In contrast to G-I, the presence of an ethene atmosphere was highly detrimental for the RCEYM catalyzed by the more stable and active G-II and HG-II precatalysts, as this led to the intermolecular cross-metathesis between the triple bonds of the substrates
Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches
Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210
- only the cis isomer coordinates to the Ni(II) for steric reasons and 3. intermolecular coordination. At higher concentrations dimer formation or coordination oligomers between trans record player molecules occurs [35]. To compare the new molecules (1f–j) with previous systems (1a–d), the switching
- molar extinctions of both species were determined by adding a strong axial ligand such as piperidine (to achieve almost complete coordination) and acid (TFA) (protonation of the pyridine unit to prevent coordination, completely diamagnetic). At concentrations of ≈10 µM, intermolecular coordination is
- diamagnetic (or the paramagnetic) species in the two photostationary states. The intermolecular association constants of pyridines as axial ligands to Ni-porphyrins as a function of their para substituents usually follow the Hammett relationship [5][12]. Hence, the association constants should also be
Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes
Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209
- slow evaporation of a CH2Cl2/CH3CN solution. The structure of the exTTF unit does not exhibit any significant changes upon incorporation into the crown ether [48]. No intermolecular stacking between the exTTF units was observed in the crystal structure of exTTFC7 (Figure 2a and section 2 in Supporting
Comparative ligand structural analytics illustrated on variably glycosylated MUC1 antigen–antibody binding
Beilstein J. Org. Chem. 2020, 16, 2540–2550, doi:10.3762/bjoc.16.206
- (Figures S4 and S5 in Supporting Information File 1), the bound Tn-antigen is able to stay resident in the dominant conformation without regularly flipping to other conformations. Hydrogen bonding The specifics of intermolecular interactions can also be considered, and here we utilized a hydrogen-bonding
- responsible for maintaining the conformation of the Tn-antigen. The role of the sugar in excluding water was not investigated. A short-lived intermolecular hydrogen bond (0.15%) was observed between Tyr100 and GalNAc, and this is unlikely to be significant. These results correlated with the hypothesis put
Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors
Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202
- , especially when intermolecular and intramolecular reactions or homogenous and heterogeneous reactions are compared. Since the quantum yield of most photochemical reactions is not known, the PSTY still gives a good comparison between different reactor geometries. The PSTY especially gains importance when
Computational tools for drawing, building and displaying carbohydrates: a visual guide
Beilstein J. Org. Chem. 2020, 16, 2448–2468, doi:10.3762/bjoc.16.199
Recent developments in enantioselective photocatalysis
Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197
- (hydrogen atom transfer) catalysis to allow the use of alkenes as the alkylating agent either in an intermolecular process using aldehydes 10 and alkenes 11 or intramolecularly using aldehydes 12 (Scheme 2) [27]. The proposed mechanism again proceeds via the formation of an enamine intermediate 13 that then
- ][33]. When an alkylating agent containing an aryl ring 40 (e.g., phenacyl/benzyl bromides) is used, the enamine intermediate 41 forms a coloured electron-donor acceptor (EDA) complex that can absorb visible light via an intermolecular charge-transfer state (EDA route) [14][34]. Mechanistic
- enantioselectivities (7 examples, up to 97:3 er) (Scheme 28a) [81]. A lower energy wavelength irradiation was able to be used, which limited the amount of background reaction as the absorption spectra of photocatalyst and substrate were more clearly resolved. The first intermolecular process using these catalysts was
Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A
Beilstein J. Org. Chem. 2020, 16, 2332–2337, doi:10.3762/bjoc.16.194
- involve three main intermolecular forces: a hydrophobic effect, hydrogen bonding and ion–dipole interactions at the carbonyl portals [7][8][9]. The high thermal stability [10], ease of synthesis [11], general absence of cytotoxicity or toxicity [12][13] and their good molecular recognition and binding
Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners
Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186
- , since its first successful synthesis, a variety of functionalized sumanenes as well as heterosumanenes have been developed because of their unique physiochemical properties. For example, bowl-to-bowl inversion, bowl depth, facial selectivity, crystal packing, metal complexes, intermolecular charge
Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator
Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185
- involved in intra- or intermolecular stacking interactions. The excellent reproducibility of the UV–vis spectrum upon cooling back to room temperature (Figure S2, Supporting Information File 1) verified the chemical stability of the compound. The aqueous solution of the studied compound 4 was non
Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis
Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183
- -lived and can exist beyond the timeframe of diffusion, to be leveraged in photosensitization. Intermolecular energy transfer from T1{PS} to the substrate excites it from its ground singlet state S0{Sub} to its excited triplet state T1{Sub}. This intermolecular energy transfer process, known as TTET
Synthesis of 6,13-difluoropentacene
Beilstein J. Org. Chem. 2020, 16, 2136–2140, doi:10.3762/bjoc.16.181
- CD2Cl2 solution at room temperature within 2 h. A possible reaction pathway for this degradation in the presence of moisture is an intermolecular attack of water, leading to a fluorohydrine 14 (Scheme 3). In absence of water, this reaction might take place in an intramolecular manner. The fluorohydrine
Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst
Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179
- of sugars [6], enzyme mimics [7], and the utilization of intermolecular cooperative effects [8] are further applications of photoswitchable catalysis. Particularly interesting and close to our approach is an early work by Inoue et al. who achieved control of the transformation of CO2 and 1,2
- azopyridine unit, and 2. the coordination–decoordination process. Both switching processes are connected by the molecular design; however, they are not necessarily equally efficient because the cis isomer might not coordinate completely and there might be coordination in the trans state due to intermolecular
- very strong ligand with respect to axial coordination to Ni-porphyrins [25]. According to 1H NMR studies, however, the trans isomer exhibits concentration-dependent coordination, which clearly indicates intermolecular coordination. Again, this is due to the very strong coordination power of the DMAP
Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction
Beilstein J. Org. Chem. 2020, 16, 2073–2079, doi:10.3762/bjoc.16.174
- ,6R)-13b. Intermolecular N-methylation of reduction product 7. Synthesis of pyrrolidinyl phosphonic acids 11a–d. Synthesis of tetrahydropyranylphosphonates 13a–f via diastereoselective Henry/acetalyzation reaction. Synthesis of (3,4-dihydro-2H-pyran-5-yl)phosphonate 14. Optimization of the conditions
Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes
Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173
- and therefore, are candidates for polar Diels–Alder reactions [40][41]. The thermal cyclization of Diels–Alder adducts as shown in Scheme 2 and Scheme 3 appear to be the first intramolecular SE(Ar) reactions of an α-(trifluoromethyl)iminium functional group. Analogous intermolecular reactions of CF3
pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide
Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168
- structure (Figure 1a) [54][55][56]. To support the results obtained from CD spectroscopy, FTIR spectroscopy was performed in D2O (pH 7.4). The appearance of two intense peaks at 1629 and 1678 cm−1 in the amide I region (Figure 1b) suggested an intermolecular antiparallel β-sheet arrangement [57][58][59][60
- two peptides increases in twisted β-sheets, the H-bonding distances increase, weakening the intermolecular forces. At basic pH values, the carboxyl group of Glu is present as a negatively charged carboxylate species, thereby inducing weak electrostatic repulsions between Glu− residues, which may be
- 24 h, which suggested the formation of very stable conformations under the investigated conditions. Although the mechanism of transformation is not clear to us at this stage, we hypothesize that multiple intermolecular interactions may play an important role in the transformation. At high
A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates
Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165
- Olusesan K. Koleoso Matthew Turner Felix Plasser Marc C. Kimber School of Science, Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK Department of Pharmaceutical Technology, Moshood Abiola Polytechnic, Abeokuta, Nigeria 10.3762/bjoc.16.165 Abstract An intermolecular
- radical adds to the central carbon of the allene giving a conjugated N-acyliminium that undergoes nucleophilic addition by arylamines and alcohols. Keywords: allenamide; allene; intermolecular; N-acyliminium; photoredox; Introduction Allenamides (Scheme 1, 1) and their congeners have attracted
- innovative transformations, including cycloadditions [5][6][7][8][9], intramolecular cyclizations and intermolecular addition reactions [10][11][12][13][14][15][16][17][18], as well as the use of the allenamide building block in natural product synthesis [1]. Addition reactions of allenamides, which can also
Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination
Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163
- previously tested the reactivity of 8 in the intermolecular aldol addition to ethyl glyoxalate [62]. As these attempts met with failure, we have turned our attention to enantioselective fluorination reactions [63][64][65]. Specifically, we decided to explore the enantioselective electrophilic fluorination of
Selective preparation of tetrasubstituted fluoroalkenes by fluorine-directed oxetane ring-opening reactions
Beilstein J. Org. Chem. 2020, 16, 1936–1946, doi:10.3762/bjoc.16.160
- which depended on the nucleophile (methanol or bromide ion) (Scheme 4). In the presence of excess bromide ions, the direct intermolecular nucleophilic attack of the oxetane (path a) is preferred leading to bromoalcohol 9 (path a). On the other hand, in the presence of the weaker methanol nucleophile, an
- between fluorine and bromine limited the intermolecular ring-opening reaction by bromide in favor of a faster intramolecular reaction involving the ester group leading to 14. Indeed, a competitive cyclization reaction occurred forming 14 with HBr/AcOH and confirmed when the reaction was performed in the
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