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Search for "lanthanide" in Full Text gives 32 result(s) in Beilstein Journal of Organic Chemistry.
Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines
- Jérôme Husson and
- Michael Knorr
Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41
- as N-donor ligands toward numerous main-group, transition-metal and lanthanide cations [3]. Coordination compounds LnM(tpy)m (n = 0–4; m = 1,2) ligated with terpyridine derivatives form stable assemblies due to the thermodynamic chelate effect. In the case of transition metal complexes, the σ-donor/π
- provide lanthanide complexes 56 and 57 (Scheme 10). The bromo-derivative 54 was further functionalised by cross-coupling reactions. Namely, the treatment of 54 with aminophenylacetylene in a Sonogashira reaction afforded terpyridine 58. The triple bond was then reduced by hydrogenation providing tpy 59
- . Finally, the hydrolysis of the ester moieties followed by complexation to Eu(III) yielded the lanthanide complex 65 (Scheme 12). This synthetic sequence was used to demonstrate the possibility to prepare labelled oligonucleotides starting from azido-functionalised ones and alkynyl-containing terpyridines
Graphical Abstract
Figure 1: Structure and atomic numbering of 2,2’:6’,2’’-terpyridines.
Scheme 1: Synthesis of furanyl-substituted terpyridines 12–14 by using Kröhnke’s method.
Scheme 2: Synthesis of terpyridines under solvent-free conditions.
Scheme 3: Preparation of 4,4′,4′′-trisubstituted terpyridine containing carboxylate moieties.
Scheme 4: Synthetic pathway for the preparation of a furanyl-functionalised quinquepyridine.
Scheme 5: Utilization of an iminium salt in the preparation of a furanyl-substituted tpy.
Figure 2: Chemical structure of U- and S-shaped isomers.
Scheme 6: Preparation of an asymmetric furanyl-substituted terpyridine.
Scheme 7: Synthesis of tpy by Stille cross-coupling reaction.
Scheme 8: Oxidation of the furan ring of furanyl-substituted terpyridines.
Scheme 9: Direct oxidation of a furan ring attached on Ru(II) tpy complexes.
Figure 3: Example of polyoxometalate frameworks functionalised with tpy ligands and tpy-complex (reprinted wi...
Scheme 10: Synthetic pathway to europium(III) and samarium(III) chelates 56 and 57.
Scheme 11: Synthetic pathway to prepare thiocyanato-functionalised tpys as potential biomolecule-labelling age...
Scheme 12: Synthetic sequence envisioned for biomolecules labelling by click-chemistry.
Figure 4: Structure of pyrrolyl (66), thienyl (67) and bithienyl (68)-substituted complexes analogous to comp...
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
- −1 for Na+, 0.32 M−1 for K+ and 0.11 M−1 for Li+ in the presence of 10 equiv of the triflate salts. However, those oxacalixarenes form stronger complexes with transition, lanthanide and uranyl cations. Cragg employed the quartz-crystal-microbalance technique to investigate binding by Na+, K+ and Ca2
- Re(CO)3 to two deprotonated phenolic oxygen atoms as shown in Figure 16. Reaction with ester derivative 3k at 85 °C resulted in decomposition of the macrocycle. 4.1.4 Lanthanide complexation: The first study of the binding affinities of lanthanides for oxacalix[3]arenes was in 1995 when Hampton
- also shows that ketone 24 is a weak extracting agent, with a slight preference for Ag+. This is in agreement with the higher basicity of the carbonyl oxygen in the amide group compared with the ketone group. 4.2.4 Lanthanides: Marcos investigated the lanthanide extraction by both 17a [70] and 24 [39
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].
Complete transfer of chirality in an intramolecular, thermal [2 + 2] cycloaddition of allene-ynes to form non-racemic spirooxindoles
- Kay M. Brummond and
- Joshua M. Osbourn
Beilstein J. Org. Chem. 2011, 7, 601–605, doi:10.3762/bjoc.7.70
- oxindoles into chiral non-racemic spirooxindoles containing an alkylidene cyclobutene moiety. The enantiomeric excesses were determined by chiral lanthanide shift NMR analysis and the transfer of chiral information from the allene to the spirooxindole was found to be greater than 95%. Keywords: alkylidene
- cyclobutene; allene; allenyloxindole; chiral lanthanide shift reagent; chiral transfer; Introduction The [2 + 2] cycloaddition reaction of allenes and alkynes provides rapid entry into synthetically challenging alkylidene cyclobutene ring systems. We, along with others, have demonstrated the intramolecular
Graphical Abstract
Scheme 1: Conversion of propargyl acetate 1 to spirooxindole 2 containing the core framework of welwitindolin...
Scheme 2: Preparation of enantiopure propargyl acetate 7 (R = Ac).
Figure 1: Chiral NMR shift analysis of propargyl acetate 7.
Figure 2: Chiral NMR shift analysis of allenyloxindole 8.
Scheme 3: Microwave irradiation of allenyloxindole 8.
Figure 3: Chiral NMR shift analysis of spirooxindole 9.
Figure 4: Thermally generated biradical intermediate 10.
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
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...
An enantiomerically pure siderophore type ligand for the diastereoselective 1 : 1 complexation of lanthanide(III) ions
- Markus Albrecht,
- Olga Osetska,
- Thomas Abel,
- Gebhard Haberhauer and
- Eva Ziegler
Beilstein J. Org. Chem. 2009, 5, No. 78, doi:10.3762/bjoc.5.78
- should be prototypes for further lanthanide(III) complexes with an enterobactine analogue binding situation. Keywords: CD spectroscopy; enterobactin; lanthanide; macrocycles; molecular modeling; Introduction The availability of metal ions for biological systems is essential for growth and function
- , leading to a bowl-shape structure which is preorganized for the uptake of the metal. Here we present the synthesis of a novel tripodal ligand, which mimics some features of enterobactin, but in contrast is specific for the binding of high coordinated lanthanide(III) ions. The backbone is based on an
- to be tridentate by addition of diethylamide to the 2-position. Recently 2-amido-8-hydoxyquinolines were shown to be good ligands for the 3 : 1 complexation of lanthanide(III)ions [34][35]. The aryl ether of 3 bears already the allylic unit for Claisen rearrangement as well as the chloride leaving
Graphical Abstract
Figure 1: Structural formula of the siderophore enterobactine.
Scheme 1: Preparation of the compound 1a-H3 by utilization of a multiple Claisen-rearrangement.
Figure 2: 1H NMR spectra (300 MHz, CDCl3) of the ether compound 4 (top) and the ligand 1a-H3 (bottom).
Figure 3: Positive ESI MS of [(1a)La] in chloroform showing the peaks of {K[(1a)La]}+ (m/z = 1600.8) as well ...
Figure 4: CD and UV absorption titration curves for complexation of ligand 1a-H3 with lanthanum(III)nitrate h...
Figure 5: Titration curve observed for ligand 1a-H3 upon addition of lanthanum(III) nitrate hexahydrate.
Figure 6: Molecular structures of the Λ2 (left) and Δ2 (right) isomers of complex 1b·La calculated by using B...
Figure 7: UV and CD spectra of the complex (Λ)-1·La. Blue and violet curve: experimentally determined spectra...
Asymmetric reactions in continuous flow
- Xiao Yin Mak,
- Paola Laurino and
- Peter H. Seeberger
Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19
- of benzaldehyde (1) catalyzed by lanthanide(III)-PyBox complexes was investigated using a T-shaped borosilicate microreactor and electroosmotic flow (Scheme 1) [12]. The reaction was initially screened with different lanthanide (III) complexes such as Ce(III), Yb(III) and Lu(III). Further efforts
Graphical Abstract
Scheme 1: Enantioselective addition of trimethylsilyl cyanide to benzaldehyde.
Scheme 2: Asymmetric catalytic hydrogenation in a falling-film microreactor.
Scheme 3: Aldol reaction catalyzed by 5-(pyrrolidine-2-yl)tetrazole.
Scheme 4: Enantioselective addition of diethylzinc to aryl aldehydes.
Scheme 5: Glyoxylate-ene reaction in flow.
Scheme 6: Asymmetric synthesis of ß-lactams.
Scheme 7: α-Chlorination of acid chlorides in flow.
Scheme 8: Asymmetric Michael reaction in continuous flow.
Scheme 9: Enantioselective addition of Et2Zn to benzaldehyde using monolithic chiral amino alcohol.
Scheme 10: Continuous-flow hydrolytic dynamic kinetic resolution of epibromohydrin (32).
Scheme 11: Continuous-flow asymmetric cyclopropanation.
Scheme 12: Continuous asymmetric hydrogenation of dimethyl itaconate in scCO2.
Scheme 13: Continuous asymmetric transfer hydrogenation of acetophenone.
Scheme 14: Asymmetric epoxidation using a continuous flow membrane reactor.
Scheme 15: Enzymatic cyanohydrin formation in a microreactor.
Scheme 16: Resolution of (R/S)- 54 with immobilized lipase in a continuous scCO2- flow reactor.
Scheme 17: Enantioselective separation of Acetyl-D-Phe in a continuous flow reactor.
Asymmetric aza-Diels- Alder reaction of Danishefsky's diene with imines in a chiral reaction medium
- Bruce Pégot,
- Olivier Nguyen Van Buu,
- Didier Gori and
- Giang Vo-Thanh
Beilstein J. Org. Chem. 2006, 2, No. 18, doi:10.1186/1860-5397-2-18
- ] ZnCl2,[5] or lanthanide triflates[6] and Brönsted acids, including HBF4 or TsOH[7] largely helped promote the reaction. Of late, catalytic asymmetric versions of the aza-Diels-Alder reaction have been explored and high stereoselectivities were reported. So far, a few catalyst systems have been quoted in
Graphical Abstract
Scheme 1: Asymmetric aza-Diels-Alder reaction of Danishefsky's diene 1 with imines 2.
Figure 1: Possible interactions of substrates or intermediate of the aza-Diels-Alder reaction with the chiral...
