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Search for "complementarity" in Full Text gives 60 result(s) in Beilstein Journal of Organic Chemistry.
Diarylethene-modified nucleotides for switching optical properties in DNA
- Sebastian Barrois and
- Hans-Achim Wagenknecht
Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103
- polymerase-assisted PEX and PCR experiments, an absolutely critical issue regarding the application of single C–C bonds, or ethinyl or phenylene linkers is the question of whether the canonical base-recognition complementarity is effected by the chromophore modification [42][43]. Due to the strongest
Graphical Abstract
Scheme 1: Spiropyran as DNA base surrogate 1, DNA base modifications 2 and 3, and diarylethene-modified nucle...
Scheme 2: Synthesis of diarylethene-modified 2’-deoxyuridines 4 [30], 5 and 6.
Figure 1: Photoswitching properties of nucleosides 4–6 (each 20 mM in MeCN, rt). Top: Irradiation of 4 at 242...
Scheme 3: Synthesis of DNA building block 17 [30] and sequences of diarylethene-modified DNA1–DNA4.
Figure 2: Irradiation of dsDNA2 at 310 nm (A, left) and plot of kinetic trace of absorption changes at 450 nm...
Figure 3: UV–vis absorption spectra of ssDNA1–ssDNA4 (2.5 μM in 50 mM Na–Pi buffer, pH 7, 250 mM NaCl, rt).
Fifty years of oxacalix[3]arenes: A review
- Kevin Cottet,
- Paula M. Marcos and
- Peter J. Cragg
Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22
- complementarity between the arrangement of phenolic groups and the preferred coordination environment of Na+. Removal of the tert-butyl groups through a conventional AlCl3 driven retro-Friedel–Crafts de-tert-butylation reaction, as seen in other calixarenes, is unsuccessful in the case of oxacalixarenes
Graphical Abstract
Figure 1: Calixarenes and expanded calixarenes: p-tert-Butylcalix[4]arene (1), p-tert-butyldihomooxacalix[4]a...
Figure 2: Conventional nomenclature for oxacalix[n]arenes.
Scheme 1: Synthesis of oxacalix[3]arenes: (i) Formaldehyde (37% aq), NaOH (aq), 1,4-dioxane; glacial acetic a...
Figure 3: p-tert-Butyloctahomotetraoxacalix[4]arene (4a) [16].
Figure 4: X-ray crystal structure of 3a showing phenolic hydrogen bonding (IUCr ID AS0508) [17].
Scheme 2: Stepwise synthesis of asymmetric oxacalix[3]arenes: (i) MOMCl, Adogen®464; (ii) 2,2-dimethoxypropan...
Figure 5: X-ray crystal structure of heptahomotetraoxacalix[3]arene 5 (CCDC ID 166088) [21].
Scheme 3: Oxacalix[3]arene synthesis by reductive coupling: (i) Me3SiOTf, Et3SiH, CH2Cl2; R1, R2 = I, Br, ben...
Scheme 4: Oxacalix[3]naphthalene: (i) HClO4 (aq), wet CHCl3 (R = tert-butyl, 6a, H, 6b) [20].
Figure 6: Conformers of 3a.
Scheme 5: Origin of the 25:75 cone:partial-cone statistical distribution of O-substituted oxacalix[3]arenes (p...
Scheme 6: Synthesis of alkyl ethers 7–10: (i) Alkyl halide, NaH, DMF [24].
Scheme 7: Synthesis of a pyridyl derivative 11a: (i) Picolyl chloride hydrochloride, NaH, DMF [26,27].
Figure 7: X-ray crystal structure of partial-cone 11a (CCDC ID 150580) [26].
Scheme 8: Lower-rim ethyl ester synthesis: (i) Ethyl bromoacetate, NaH, t-BuOK or alkali metal carbonate, THF...
Scheme 9: Forming chiral receptor 13: (i) Ethyl bromoacetate, NaH, THF; (ii) NaOH, H2O/1,4-dioxane; (iii) S-P...
Figure 8: X-ray crystal structure of 16 (IUCr ID PA1110) [32].
Scheme 10: Lower rim N,N-diethylamide 17a: (i) N,N-Diethylchloroacetamide, NaH, t-BuOK or alkali metal carbona...
Scheme 11: Capping the lower rim: (i) N,N-Diethylchloroacetamide, NaH, THF; (ii) NaOH, H2O/1,4-dioxane; (iii) ...
Figure 9: X-ray crystal structure of 18 (CCDC ID 142599) [33].
Scheme 12: Extending the lower rim: (i) Glycine methyl ester, HOBt, dicyclohexycarbodiimide (DCC), CH2Cl2; (ii...
Scheme 13: Synthesis of N-hydroxypyrazinone derivative 23: (i) 1-[3-(Dimethylamino)propyl]-3-ethylcarbodiimide...
Scheme 14: Synthesis of 24: (i) 1-Adamantyl bromomethyl ketone, NaH, THF [39].
Scheme 15: Synthesis of 25 and 26: (i) (Diphenylphosphino)methyl tosylate, NaH, toluene; (ii) phenylsilane, to...
Figure 10: X-ray crystal structure of 27 in the partial-cone conformer (CCDC ID SUP 90399) [41].
Scheme 16: Synthesis of strapped oxacalix[3]arene derivatives 28 and 29: (i) N,N’-Bis(chloroacetyl)-1,2-ethyle...
Figure 11: A chiral oxacalix[3]arene [45].
Figure 12: X-ray crystal structure of asymmetric oxacalix[3]arene 30 incorporating t-Bu, iPr and Et groups (CC...
Scheme 17: Reactions of an oxacalix[3]arene incorporating an upper-rim Br atom with (i) Pd(OAc)2, PPh3, HCO2H,...
Scheme 18: Synthesis of acid 39: (i) NaOH, EtOH/H2O, HCl (aq) [47].
Figure 13: Two forms of dimeric oxacalix[3]arene 40 [47].
Scheme 19: Capping the upper rim: (i) t-BuLi, THF, −78 °C; (ii) NaBH4, THF/EtOH; (iii) 1,3,5-tris(bromomethyl)...
Figure 14: Oxacalix[3]arene capsules 46 and 47 formed through coordination chemistry [52,53].
Figure 15: X-ray crystal structure of the 3b-vanadyl complex (CCDC ID 240185) [57].
Scheme 20: Effect of Ti(IV)/SiO2 on 3a: (i) Ti(OiPr)4, toluene; (ii) triphenylsilanol, toluene; (iii) partiall...
Figure 16: X-ray crystal structures of oxacalix[3]arene complexes with rhenium: 3b∙Re(CO)3 (CCDC ID 620981, le...
Figure 17: X-ray crystal structure of the La2·3a2 complex (CSD ID TIXXUT) [60].
Figure 18: X-ray crystal structures of [3a∙UO2]− with a cavity-bound cation (CCDC ID 135575, left) and without...
Figure 19: X-ray crystal structure of a supramolecule comprising two [3g·UO2]− complexes that encapsulate a di...
Figure 20: X-ray crystal structure of oxacalix[3]arene 49 capable of chiral selectivity (CSD ID HIGMUF) [65].
Figure 21: The structure of derivative 50 incorporating a Reichardt dye [66].
Figure 22: Phosphorylated oxacalix[3]arene complexes with transition metals: (Left to right) 26∙Au, 26∙Mo(CO)3...
Figure 23: X-ray crystal structure of [17a·HgCl2]2 (CCDC ID 168653) [69].
Figure 24: X-ray crystal structures of 3f with C60 (CCDC ID 182801, left) [76] and a 1,4-bis(9-fluorenyl) C60 deri...
Figure 25: X-Ray crystal structure of 3i and 6a encapsulating C60 (CCDC ID 102473 and 166077) [23,79].
Figure 26: A C60 complexing cationic oxacalix[3]arene 51 [81].
Figure 27: An oxacalix[3]arene-C60 self-associating system 53 [87].
Scheme 21: Synthesis of fluorescent pyrene derivative 55: (i) Propargyl bromide, acetone; (ii) CuI, 1-azidomet...
Scheme 22: Synthesis of responsive rhodamine derivative 57: (i) DCC, CH2Cl2 [91].
Scheme 23: Synthesis of nitrobenzyl derivative 58: (i) 1-Bromo-4-nitrobenzyl acetate, K2CO3, refluxing acetone...
Figure 28: X-ray crystal structure of [Na2∙17a](PF6)2 (CCDC ID 116656) [97].
Ratiometric fluorescent probe for enantioselective detection of D-cysteine in aqueous solution
- Xiao-bo Zhou,
- Wing-Hong Chan,
- Albert W. M. Lee and
- Chi-Chung Yeung
Beilstein J. Org. Chem. 2011, 7, 1508–1515, doi:10.3762/bjoc.7.176
- health [32]. On the basis of multipoint electrostatic interactions and structure complementarity of the host–guest, we have rationally designed and synthesised a bis(spiropyran) as a fluorescence turn-on probe for selective binding of GSH [33]. We have also developed the first spiropyran–metal sensing
- enantioselectivity of 3.35 conferred by the chiral trans-1,2-diaminocyclohexane moiety for recognizing D-cysteine in 1% ACN/HEPES buffered solutions (pH 7.4) (Figure 5). Apparently, owing to the structure complementarity of the host–guest, D-cysteine outperforms its enantiomer in forming a more stable complex with
Graphical Abstract
Figure 1: Structures of biological active thiols.
Figure 2: The structure of ACAQ.
Figure 3: Emission spectra of (a) Zn2+–ACAQ or (b) Cd2+–ACAQ complex (5 μM) at increasing concentrations of C...
Figure 4: Job’s plot of Cd2+–ACAQ in 10 mM HEPES buffer (pH 7.4) at 298 K. The sum of the concentrations of t...
Figure 5: Fluorescence spectra of Cd2+–ACAQ (10 µm) upon the titration of (a) D-Cys and (b) L-Cys in buffer s...
Figure 6: Fluoresence emission change of Cd2+–ACAQ at 500 nm in response to the addition of 15 equiv amino ac...
Figure 7: Fluorescence spectra of (10 µm) Cd2+–ACAQ upon the titration of various amino acids in buffer solut...
Figure 8: UV spectra of Cd2+–ACAQ (25 µm) upon the titration of (a) D-Cys, (b) L-Cys (0–12 equiv) in buffer s...
Figure 9: Partial 1H NMR spectra (400 MHz) of ACAQ (5 mM) before and after the addition of Cd2+ and then incr...
Figure 10: Proposed binding model of Cd2+–ACAQ with cysteine.
Figure 11: Reversibility study. Emission spectra of Cd2+–ACAQ complex (5 μM) with 10 equiv L-Cys in buffer sol...
Supramolecular FRET photocyclodimerization of anthracenecarboxylate with naphthalene-capped γ-cyclodextrin
- Qian Wang,
- Cheng Yang,
- Gaku Fukuhara,
- Tadashi Mori,
- Yu Liu and
- Yoshihisa Inoue
Beilstein J. Org. Chem. 2011, 7, 290–297, doi:10.3762/bjoc.7.38
- non-covalent interactions in the ground state [4][5][6][7][8][9][10][11]. The geometrical and functional complementarity and the subsequent induced fit between chiral host and guest substrate should play a crucial role in determining the stereochemical fate of chiral photoreaction, and therefore the
Graphical Abstract
Scheme 1: Biphenyl-capped (5), naphthalene-capped (6), and naphthalene-appended γ-cyclodextrin (7).
Figure 1: UV–vis spectral changes of 0.2 mM AC upon increasing the concentration of 7 in pH 9 phosphate buffe...
Figure 2: Circular dichroism spectra of 7 (0.2 mM) in the presence of 0, 0.0083, 0.025, 0.048, 0.071, 0.093, ...
Figure 3: Circular dichroism spectra of 6 (0.2 mM) in the presence of 0, 0.0083, 0.025, 0.048, 0.071, 0.093, ...
Figure 4: UV–vis spectra of AC (black dashed line) and 7 (red dashed line) and fluorescence spectra of 7 (0.0...
Fluorometric recognition of both dihydrogen phosphate and iodide by a new flexible anthracene linked benzimidazolium-based receptor
- Kumaresh Ghosh and
- Debasis Kar
Beilstein J. Org. Chem. 2011, 7, 254–264, doi:10.3762/bjoc.7.34
- ][42][43][44][45]. Iodide binding induced quenching of emission is attributed to the i) complementarity in size of iodide with the pseudocavity formed by the receptor-binding site and ii) heavy atom effect of iodide, which is also true for Br−. But the small quenching of emission in the presence of Br
Graphical Abstract
Figure 1: Synthesized compounds 1 and 2.
Scheme 1: Synthesis of 1 and 2.
Figure 2: Energy optimized geometry of 1 with H2PO4− (E = 92.14 kcal/mol, a = 2.45 Å, b = 1.94 Å, c = 2.34 Å, ...
Figure 3: Change in fluorescence emission of 1 (c = 5.78 × 10−5 M) in the presence of 2 equiv of tetrabutylam...
Figure 4: Change in emission spectra of 1 (c = 5.78 × 10−5 M) in presence of increasing amounts of H2PO4− in ...
Figure 5: Suggested modes of binding of the H2PO4− ion into the cleft of 1.
Figure 6: Plot of change in emission of 1 at 420 nm vs the ratio of guest to host concentration in CH3CN.
Figure 7: Fluorescence Job plot of 1 with H2PO4−.
Figure 8: Change in fluorescence emission of 2 (c = 3.93 × 10−5 M) in the presence of 1 equiv of tetrabutylam...
Figure 9: Stern–Volmer plots for 1 (c = 5.78 × 10−5 M) with H2PO4−, F−, Br− and I− at 420 nm (up to the addit...
Figure 10: Change in UV–vis spectra of 1 (c = 5.78 × 10−5 M) in presence of increasing amounts of H2PO4− in CH3...
Figure 11: Change in fluorescence emission of 1 (c = 5.78 × 10−5 M) in the presence of 2 equiv of tetrabutylam...
Figure 12: Stern–Volmer plots for 1 (c = 5.78 × 10−5 M) with H2PO4−, F−, Br− and I− at 420 nm (up to the addit...
Figure 13: Fluorescence decays (at λmax = 420 nm) of receptor 1 upon the addition of H2PO4− ion ([H] = 5.78 × ...
Figure 14: Fluorescence decays (at λmax = 420 nm) of receptor 1 upon the addition of I− ion ([H] = 5.78 × 10−5...
Figure 15: Partial 1H NMR (300 MHz, CDCl3 containing 4% CD3CN) spectra of (a) 1 (c = 1.38 × 10−3 M), (b) 1:1 a...
Catalysis: transition-state molecular recognition?
- Ian H. Williams
Beilstein J. Org. Chem. 2010, 6, 1026–1034, doi:10.3762/bjoc.6.117
- of enzymes was due to structural complementarity with the TS rather than the reactant state of the substrate [3]: “enzymes are molecules that are complementary in structure to the activated complexes of the reactions they catalyse … [which] would thus lead to a decrease in its energy, and hence to a
- the TS and should cause an acceleration by forcing bound substrates to resemble the TS” [5]. However, the clear logical implications of the notion of TS complementarity for understanding the origins of enzyme catalytic power were described eloquently (but with a friendly tongue in cheek) by R. L
- present discussion. Recently, some authors have sought to go “beyond the Pauling paradigm” by noting that “enzymes enter into reactions with substrates and do not merely complement the transition states of the uncatalysed reactions” [9]. The implication seems to be that the notion of TS complementarity
Graphical Abstract
Figure 1: Free energy profiles for reactions of substrate S uncatalysed and catalysed by enzyme E, showing ho...
Scheme 1: SN2 methyl transfer from SAM to catechol catalysed by COMT.
Figure 2: Energetic analysis of the compression hypothesis for enzyme-catalysed methyl transfer.
Figure 3: Catalyst design for methyl transfer: (a) the reaction to be catalysed; (b) dipoles favourably align...
Scheme 2: SN2 methyl transfer (a) uncatalysed and (b) within a cryptand cavity.
Figure 4: Free energy analysis of COMT catalysis.
Scheme 3: Formation of glycosyl-enzyme covalent intermediate COV.
Figure 5: Conformational change of the xylose ring from chair (via envelope) with long OYHY…Oring hydrogen bo...
Figure 6: AM1/OPLS potentials of mean force for formation of glycosyl-enzyme covalent intermediate between 4-...
Figure 7: Hydrogen-bond distances HY…Oring (red) and HY…Onuc (blue) to boat conformer of RC, TS and glycosyl-...
Molecular recognition of organic ammonium ions in solution using synthetic receptors
- Andreas Späth and
- Burkhard König
Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32
- selective recognition of ammonium ions depends on steric and molecular complementarity and the pre-organization [17] of interacting functional groups. As far back as 1890, Fischer suggested that enzyme–substrate interactions function like a “lock and key” between an initially empty host and a guest that
- exhibit molecular complementarity [18]. Today studies of non-covalent interactions, mainly by artificial model structures and receptors, have led to a far better understanding of many biological processes. Moreover, they are often the inspiration for supramolecular research, including self-assembly
- interactions [23][24] and steric complementarity [25]. The crucial interaction mechanisms have been comprehensively summarized [26][27]; basic rules for receptors and design have been outlined [28][29]. As in nature, molecular recognition can either be static – a complexation reaction with defined
Graphical Abstract
Figure 1: Biologically important amines and quaternary ammonium salts: histamine (1), dopamine (2) and acetyl...
Figure 2: Crown ether 18-crown-6.
Figure 3: Conformations of 18-crown-6 (4) in solvents of different polarity.
Figure 4: Binding topologies of the ammonium ion depending on the crown ring size.
Figure 5: A “pseudorotaxane” structure consisting of 24-crown-8 and a secondary ammonium ion (5); R = Ph.
Figure 6: Typical examples of azacrown ethers, cryptands and related aza macrocycles.
Figure 7: Binding of ammonium to azacrown ethers and cryptands [111-113].
Figure 8: A 19-crown-6-ether with decalino blocking groups (11) and a thiazole-dibenzo-18-crown-6-ether (12).
Figure 9: 1,3-Bis(6-oxopyridazin-1-yl)propane derivatives 13 and 14 by Campayo et al.
Figure 10: Fluorescent azacrown-PET-sensors based on coumarin.
Figure 11: Two different pyridino-cryptands (17 and 18) compared to a pyridino-crown (19); chiral ammonium ion...
Figure 12: Pyridino-18-crown-6 ligand (21), a similar acridino-18-crown-6 ligand (22) and a structurally relat...
Figure 13: Ciral pyridine-azacrown ether receptors 24.
Figure 14: Chiral 15-crown-5 receptors 26 and an analogue 18-crown-6 ligand 27 derived from amino alcohols.
Figure 15: C2-symmetric chiral 18-crown-6 amino alcohol derivatives 28 and related macrocycles.
Figure 16: Macrocycles with diamide-diester groups (30).
Figure 17: C2-symmetric chiral aza-18-crown-6 ethers (31) with phenethylamine residues.
Figure 18: Chiral C-pivot p-methoxy-phenoxy-lariat ethers.
Figure 19: Chiral lariat crown ether 34.
Figure 20: Sucrose-based chiral crown ether receptors 36.
Figure 21: Permethylated fructooligosaccharide 37 showing induced-fit chiral recognition.
Figure 22: Biphenanthryl-18-crown-6 derivative 38.
Figure 23: Chiral lariat crown ethers derived from binol by Fuji et al.
Figure 24: Chiral phenolic crown ether 41 with “aryl chiral barriers” and guest amines.
Figure 25: Chiral bis-crown receptor 43 with a meso-ternaphthalene backbone.
Figure 26: Chromogenic pH-dependent bis-crown chemosensor 44 for diamines.
Figure 27: Triamine guests for binding to receptor 44.
Figure 28: Chiral bis-crown phenolphthalein chemosensors 46.
Figure 29: Crown ether amino acid 47.
Figure 30: Luminescent receptor 48 for bis-alkylammonium guests.
Figure 31: Luminescent CEAA (49a), a bis-CEAA receptor for amino acids (49b) and the structure of lysine bindi...
Figure 32: Luminescent CEAA tripeptide for binding small peptides.
Figure 33: Bis crown ether 51a self assembles co-operatively with C60-ammonium ion 51b.
Figure 34: Triptycene-based macrotricyclic dibenzo-[24]-crown-8 ether host 52 and guests.
Figure 35: Copper imido diacetic acid azacrown receptor 53a and the suggested His-Lys binding motif; a copper ...
Figure 36: Urea (54) and thiourea (55) benzo crown receptor for transport and extraction of amino acids.
Figure 37: Crown pyryliums ion receptors 56 for amino acids.
Figure 38: Ditopic sulfonamide bridged crown ether receptor 57.
Figure 39: Luminescent peptide receptor 58.
Figure 40: Luminescent receptor 59 for the detection of D-glucosamine hydrochloride in water/ethanol and lumin...
Figure 41: Guanidinium azacrown receptor 61 for simple amino acids and ditopic receptor 62 with crown ether an...
Figure 42: Chiral bicyclic guanidinium azacrown receptor 63 and similar receptor 64 for the enantioselective t...
Figure 43: Receptors for zwitterionic species based on luminescent CEAAs.
Figure 44: 1,10-Azacrown ethers with sugar podand arms and the anticancer agent busulfan.
Figure 45: Benzo-18-crown-6 modified β-cyclodextrin 69 and β-cyclodextrin functionalized with diaza-18-crown-6...
Figure 46: Receptors for colorimetric detection of primary and secondary ammonium ions.
Figure 47: Porphyrine-crown-receptors 72.
Figure 48: Porphyrin-crown ether conjugate 73 and fullerene-ammonium ion guest 74.
Figure 49: Calix[4]arene (75a), homooxocalix[4]arene (75b) and resorcin[4]arene (75c) compared (R = H, alkyl c...
Figure 50: Calix[4]arene and ammonium ion guest (R = H, alkyl, OAcyl etc.), possible binding sites; A: co-ordi...
Figure 51: Typical guests for studies with calixarenes and related molecules.
Figure 52: Lower rim modified p-tert-butylcalix[5]arenes 82.
Figure 53: The first example of a water soluble calixarene.
Figure 54: Sulfonated water soluble calix[n]arenes that bind ammonium ions.
Figure 55: Displacement assay for acetylcholine (3) with a sulfonato-calix[6]arene (84b).
Figure 56: Amino acid inclusion in p-sulfonatocalix[4]arene (84a).
Figure 57: Calixarene receptor family 86 with upper and lower rim functionalization.
Figure 58: Calix[6]arenes 87 with one carboxylic acid functionality.
Figure 59: Sulfonated calix[n]arenes with mono-substitution at the lower rim systematically studied on their r...
Figure 60: Cyclotetrachromotropylene host (91) and its binding to lysine (81c).
Figure 61: Calixarenes 92 and 93 with phosphonic acids groups.
Figure 62: Calix[4]arene tetraphosphonic acid (94a) and a double bridged analogue (94b).
Figure 63: Calix[4]arene tetraphosphonic acid ester (92c) for surface recognition experiments.
Figure 64: Calixarene receptors 95 with α-aminophosphonate groups.
Figure 65: A bridged homocalix[3]arene 95 and a distally bridged homocalix[4]crown 96.
Figure 66: Homocalix[3]arene ammonium ion receptor 97a and the Reichardt’s dye (97b) for colorimetric assays.
Figure 67: Chromogenic diazo-bridged calix[4]arene 98.
Figure 68: Calixarene receptor 99 by Huang et al.
Figure 69: Calixarenes 100 reported by Parisi et al.
Figure 70: Guest molecules for inclusion in calixarenes 100: DAP × 2 HCl (101a), APA (101b) and Lys-OMe × 2 HC...
Figure 71: Different N-linked peptido-calixarenes open and with glycol chain bridges.
Figure 72: (S)-1,1′-Bi-2-naphthol calixarene derivative 104 published by Kubo et al.
Figure 73: A chiral ammonium-ion receptor 105 based on the calix[4]arene skeleton.
Figure 74: R-/S-phenylalaninol functionalized calix[6]arenes 106a and 106b.
Figure 75: Capped homocalix[3]arene ammonium ion receptor 107.
Figure 76: Two C3 symmetric capped calix[6]arenes 108 and 109.
Figure 77: Phosphorous-containing rigidified calix[6]arene 110.
Figure 78: Calix[6]azacryptand 111.
Figure 79: Further substituted calix[6]azacryptands 112.
Figure 80: Resorcin[4]arene (75c) and the cavitands (113).
Figure 81: Tetrasulfonatomethylcalix[4]resorcinarene (114).
Figure 82: Resorcin[4]arenes (115a/b) and pyrogallo[4]arenes (115c, 116).
Figure 83: Displacement assay for acetylcholine (3) with tetracyanoresorcin[4]arene (117).
Figure 84: Tetramethoxy resorcinarene mono-crown-5 (118).
Figure 85: Components of a resorcinarene based displacement assay for ammonium ions.
Figure 86: Chiral basket resorcin[4]arenas 121.
Figure 87: Resorcinarenes with deeper cavitand structure (122).
Figure 88: Resorcinarene with partially open deeper cavitand structure (123).
Figure 89: Water-stabilized deep cavitands with partially structure (124, 125).
Figure 90: Charged cavitands 126 for tetralkylammonium ions.
Figure 91: Ditopic calix[4]arene receptor 127 capped with glycol chains.
Figure 92: A calix[5]arene dimer for diammonium salt recognition.
Figure 93: Calixarene parts 92c and 129 for the formation molecular capsules.
Figure 94: Encapsulation of a quaternary ammonium cation by two resorcin[4]arene molecules (NMe4+@[75c]2 × Cl−...
Figure 95: Encapsulation of a quaternary ammonium cation by six resorcin[4]arene molecules (NMe3D+@[130]6 × Cl−...
Figure 96: Structure and schematic of cucurbit[6]uril (CB[6], 131a).
Figure 97: Cyclohexanocucurbit[6]uril (CB′[6], 132) and the guest molecule spermine (133).
Figure 98: α,α,δ,δ-Tetramethylcucurbit[6]uril (134).
Figure 99: Structure of the cucurbituril-phthalhydrazide analogue 135.
Figure 100: Organic cavities for the displacement assay for amine differentiation.
Figure 101: Displacement assay methodology for diammonium- and related guests involving cucurbiturils and some ...
Figure 102: Nor-seco-Cucurbituril (±)-bis-ns-CB[6] (140) and guest molecules.
Figure 103: The cucurbit[6]uril based complexes 141 for chiral discrimination.
Figure 104: Cucurbit[7]uril (131c) and its ferrocene guests (142) opposed.
Figure 105: Cucurbit[7]uril (131c) guest inclusion and representative guests.
Figure 106: Cucurbit[7]uril (131c) binding to succinylcholine (145) and different bis-ammonium and bis-phosphon...
Figure 107: Paraquat-cucurbit[8]uril complex 149.
Figure 108: Gluconuril-based ammonium receptors 150.
Figure 109: Examples of clefts (151a), tweezers (151b, 151c, 151d) and clips (151e).
Figure 110: Kemp’s triacid (152a), on example of Rebek’s receptors (152b) and guests.
Figure 111: Amino acid receptor (154) by Rebek et al.
Figure 112: Hexagonal lattice designed hosts by Bell et al.
Figure 113: Bell’s amidinium receptor (156) and the amidinium ion (157).
Figure 114: Aromatic phosphonic acids.
Figure 115: Xylene phosphonates 159 and 160a/b for recognition of amines and amino alcohols.
Figure 116: Bisphosphonate recognition motif 161 for a colorimetric assay with alizarin complexone (163) for ca...
Figure 117: Bisphosphonate/phosphate clip 164 and bisphosphonate cleft 165.
Figure 118: N-Methylpyrazine 166a, N-methylnicotinamide iodide (166b) and NAD+ (166c).
Figure 119: Bisphosphate cavitands.
Figure 120: Bisphosphonate 167 of Schrader and Finocchiaro.
Figure 121: Tweezer 168 for noradrenaline (80b).
Figure 122: Different tripods and heparin (170).
Figure 123: Squaramide based receptors 172.
Figure 124: Cage like NH4+ receptor 173 of Kim et al.
Figure 125: Ammonium receptors 174 of Chin et al.
Figure 126: 2-Oxazolin-based ammonium receptors 175a–d and 176 by Ahn et al.
Figure 127: Racemic guest molecules 177.
Figure 128: Tripods based on a imidazole containing macrocycle (178) and the guest molecules employed in the st...
Figure 129: Ammonium ion receptor 180.
Figure 130: Tetraoxa[3.3.3.3]paracyclophanes 181 and a cyclophanic tetraester (182).
Figure 131: Peptidic bridged paraquat-cyclophane.
Figure 132: Shape-selective noradrenaline host.
Figure 133: Receptor 185 for binding of noradrenaline on surface layers from Schrader et al.
Figure 134: Tetraphosphonate receptor for binding of noradrenaline.
Figure 135: Tetraphosphonate 187 of Schrader and Finocchiaro.
Figure 136: Zinc-Porphyrin ammonium-ion receptors 188 and 189 of Mizutani et al.
Figure 137: Zinc porphyrin receptor 190.
Figure 138: Zinc porphyrin receptors 191 capable of amino acid binding.
Figure 139: Zinc-porphyrins with amino acid side chains for stereoinduction.
Figure 140: Bis-zinc-bis-porphyrin based on Tröger’s base 193.
Figure 141: BINAP-zinc-prophyrin derivative 194 and it’s guests.
Figure 142: Bisaryl-linked-zinc-porphyrin receptors.
Figure 143: Bis-zinc-porphyrin 199 for diamine recognition and guests.
Figure 144: Bis-zinc-porphyrin crown ether 201.
Figure 145: Bis-zinc-porphyrin 202 for stereodiscrimination (L = large substituent; S = small substituent).
Figure 146: Bis-zinc-porphyrin[3]rotaxane and its copper complex and guests.
Figure 147: Dien-bipyridyl ligand 206 for co-ordination of two metal atoms.
Figure 148: The ligand and corresponding tetradentate co-complex 207 serving as enantioselective receptor for a...
Figure 149: Bis(oxazoline)–copper(II) complex 208 for the recognition of amino acids in aqueous solution.
Figure 150: Zinc-salen-complexes 209 for the recognition tertiary amines.
Figure 151: Bis(oxazoline)–copper(II) 211 for the recognition of amino acids in aqueous solution.
Figure 152: Zn(II)-complex of a C2 terpyridine crown ether.
Figure 153: Displacement assay and receptor for aspartate over glutamate.
Figure 154: Chiral complex 214 for a colorimetric displacement assay for amino acids.
Figure 155: Metal complex receptor 215 with tripeptide side arms.
Figure 156: A sandwich complex 216 and its displaceable dye 217.
Figure 157: Lanthanide complexes 218–220 for amino acid recognition.
Figure 158: Nonactin (221), valinomycin (222) and vancomycin (223).
Figure 159: Monesin (224a) and a chiral analogue for enantiodiscrimination of ammonium guests (224b).
Figure 160: Chiral podands (226) compared to pentaglyme-dimethylether (225) and 18-crown-6 (4).
Figure 161: Lasalocid A (228).
Figure 162: Lasalocid derivatives (230) of Sessler et al.
Figure 163: The Coporphyrin I tetraanion (231).
Figure 164: Linear and cyclic peptides for ammonium ion recognition.
Figure 165: Cyclic and bicyclic depsipeptides for ammonium ion recognition.
Figure 166: α-Cyclodextrin (136a) and novocaine (236).
Figure 167: Helical diol receptor 237 by Reetz and Sostmann.
Figure 168: Ammonium binding spherand by Cram et al. (238a) and the cyclic[6]metaphenylacetylene 238b in compar...
Figure 169: Receptor for peptide backbone and ammonium binding (239).
Figure 170: Anion sensor principle with 3-hydroxy-2-naphthanilide of Jiang et al.
Figure 171: 7-bromo-3-hydroxy-N-(2-hydroxyphenyl)naphthalene 2-carboxamide (241) and its amine binding.
Figure 172: Naturally occurring catechins with affinity to quaternary ammonium ions.
Figure 173: Spiropyran (244) and merocyanine form (244a) of the amino acid receptors of Fuji et al.
Figure 174: Coumarin aldehyde (245) and its iminium species with amino acid bound (245a) by Glass et al.
Figure 175: Coumarin aldehyde appended with boronic acid.
Figure 176: Quinolone aldehyde dimers by Glass et al.
Figure 177: Chromogenic ammonium ion receptors with trifluoroacetophenone recognition motifs.
Figure 178: Chromogenic ammonium ion receptor with trifluoroacetophenone recognition motif bound on different m...
Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides
- Ana Maria Castilla,
- M. Morgan Conn and
- Pablo Ballester
Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5
- receptor converge toward the center of the macrocycle. The macrocycle is large enough to accommodate the threading dipeptide without incurring any substantial steric clashes. We also observed appropriate complementarity between the hydrogen-bonding groups of substrate and receptor (Figure 3). The analysis
Graphical Abstract
Figure 1: Schematic representation of the design of a host–guest complex based on antiparallel β-sheet geomet...
Figure 2: Molecular structures of the two designed receptors 1 and 2 having different relative orientations o...
Figure 3: CAChe minimized structures for the “endo” complexes formed between receptors 1 (a) and 2 (b) and th...
Scheme 1: Synthesis of tetraprotected bis(alanyl)benzophenones 3 from L-phenylalanine 7.
Scheme 2: Deprotection reactions of bis(alanyl)benzophenone units 3.
Scheme 3: Synthesis of the linear tetrapeptides 15 and 17 as mixtures of diastereoisomers.
Figure 4: a) Molecular structures of the two major diastereoisomers of the cyclic receptors obtained from the...
Figure 5: Reverse-phase HPLC chromatograms of the purified fraction obtained from macrocyclization reactions ...
Figure 6: Variable-temperature 1H NMR experiments of 1 in chloroform-d solution. The proton signals that appe...
Figure 7: Small fraction of the columnar arrangement observed in solid-state packing of receptor 1. Two adjac...
Figure 8: Molecular structures of the guests used in the binding experiments.
Figure 9: Selected region of the variable-concentration 1H NMR spectra acquired using chloroform-d solutions ...
Figure 10: a) Selected region of a series 1H NMR spectra acquired during titration of receptor 2 with n-C6H13-...
Figure 11: CAChe minimized structures for two possible binding geometries, a) exo and b) endo complexes formed...
Self-association of an indole based guanidinium-carboxylate-zwitterion: formation of stable dimers in solution and the solid state
- Carolin Rether,
- Wilhelm Sicking,
- Roland Boese and
- Carsten Schmuck
Beilstein J. Org. Chem. 2010, 6, No. 3, doi:10.3762/bjoc.6.3
- of directed, H-bond assisted salt-bridges is crucial. Zwitterion 1 combines in a near perfect fit geometrical self-complementarity with the possibility to form two salt-bridges assisted by a network of six H-bonds. The superior stability of 1·1 compared to analogous zwitterions based on other
Graphical Abstract
Figure 1: Self-assembly of zwitterion 1 to give dimer 1·1 and self-assembly of zwitterion 2 to give dimer 2·2...
Scheme 1: Synthesis of zwitterion 2.
Scheme 2: Synthesis of compound 2·H+.
Figure 2: 1H NMR spectra of zwitterion 2 (bottom) and its protonated form 2·H+ (top).
Figure 3: Part of the 1H NMR spectrum of 2 in [D6]DMSO showing the complexation-induced shifts of the indole ...
Figure 4: Representative binding isotherm of the aromatic proton d (left) and the indole NH proton (right).
Figure 5: Binding isotherm of the guanidinium NH2 protons.
Figure 6: Crystal structure of dimer 2·2 with hydrogen bond distances (Å) and dihedral angles.
Figure 7: Side view of dimer 2·2 in the solid state.
Figure 8: Part of the crystal lattice of zwitterion 2.
Scheme 3: An attractive H-bond in 1 (left) is replaced by a repulsive steric interaction in 2 (right).
Figure 9: Energy-minimized structure for dimer 2·2 with hydrogen bond distances (Å) and dihedral angles.
Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives
- Andrew Kennedy,
- Adam Nelson and
- Alexis Perry
Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2
- piperidines 22C and 22D are summarised in Figure 5. Two-directional synthesis of aza-C-linked disaccharide derivatives With the scope, limitations and complementarity of the dihydroxylations established, we turned to the two-directional synthesis of aza-C-linked disaccharide derivatives. The required starting
- outcome is different in each of the rings (syn to one hydroxyl group, and anti to the other). With a substituent in the 6-position of the piperidine ring, the complementarity between the alternative methods was lost. With the substrates 29, trans-27 and trans-33, dihydroxylation occurred anti to the
Graphical Abstract
Scheme 1:
Scheme 2:
Scheme 3:
Figure 1: Diastereoselective substitution of the N,O acetal 12
Scheme 4:
Figure 2: Diastereoselective Luche reduction of piperidinones
Scheme 5:
Figure 3: Diastereoselective dihydroxylation of unsaturated piperidines
Figure 4: Diagnostic nOe observations for the piperidine 22A
Figure 5: Diagnostic nOe observations for the piperidines 22C and 22D
Scheme 6:
Figure 6: Stereoselectivity of two-directional Luche reductions
Scheme 7:
Scheme 8:
Figure 7: Two-directional functionalisation by diastereoselective dihydroxylation
