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Search for "cobalt" in Full Text gives 137 result(s) in Beilstein Journal of Organic Chemistry.
An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals
- Marcus Baumann,
- Ian R. Baxendale,
- Steven V. Ley and
- Nikzad Nikbin
Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57
Graphical Abstract
Figure 1: Structures of atorvastatin and other commercial statins.
Figure 2: Structure of compactin.
Scheme 1: Synthesis of pentasubstituted pyrroles.
Scheme 2: [3 + 2] Cycloaddition to prepare 5-isopropylpyrroles.
Scheme 3: Regiospecific [3 + 2] cycloaddition to prepare the pyrrole scaffold.
Scheme 4: Formation of the pyrrole core of atorvastatin via [3 + 2] cycloaddition.
Scheme 5: Formation of pyrrole 33 via the Paal–Knorr reaction.
Scheme 6: Convergent synthesis towards atorvastatin.
Figure 3: Binding pocket of sunitinib in the TRK KIT.
Scheme 7: Synthesis of sunitinib.
Scheme 8: Alternative synthesis of sunitinib.
Scheme 9: Key steps in the syntheses of sumatriptan and zolmitriptan.
Scheme 10: Introduction of the N,N-dimethylaminoethyl side chain.
Scheme 11: Japp–Klingemann reaction in the synthesis of sumatriptan.
Scheme 12: Synthesis of the intermediate sulfonyl chlorides 62 and 63.
Scheme 13: Alternative introduction of the sulfonamide.
Scheme 14: Negishi-type coupling to benzylic sulfonamides.
Scheme 15: Heck reaction used to introduce the sulfonamide side chain of naratriptan.
Scheme 16: Synthesis of the oxazolinone appendage of zolmitriptan.
Scheme 17: Grandberg indole synthesis used in the preparation of rizatriptan.
Scheme 18: Improved synthesis of rizatriptan.
Scheme 19: Larock-type synthesis of rizatriptan.
Scheme 20: Synthesis of eletriptan.
Scheme 21: Heck coupling for the indole system in eletriptan.
Scheme 22: Attempted Fischer indole synthesis of elatriptan.
Scheme 23: Successful Fischer indole synthesis for eletriptan.
Scheme 24: Mechanistic rationale for the Bischler–Möhlau reaction.
Scheme 25: Bischler-type indole synthesis used in the fluvastatin sodium synthesis.
Scheme 26: Palladium-mediated synthesis of ondansetron.
Scheme 27: Fischer indole synthesis of ondansetron.
Scheme 28: Optimised Pictet–Spengler reaction towards tadalafil.
Figure 4: Structures of carvedilol 136 and propranolol 137.
Scheme 29: Synthesis of the carbazole core of carvedilol.
Scheme 30: Alternative syntheses of 4-hydroxy-9H-carbazole.
Scheme 31: Convergent synthesis of etodolac.
Scheme 32: Alternative synthesis of etodolac.
Figure 5: Structures of imidazole-containing drugs.
Scheme 33: Synthesis of functionalised imidazoles towards losartan.
Scheme 34: Direct synthesis of the chlorinated imidazole in losartan.
Scheme 35: Synthesis of trisubstituted imidazoles.
Scheme 36: Preparation of the imidazole ring in olmesartan.
Scheme 37: Synthesis of ondansetron.
Scheme 38: Alternative route to ondansetron and its analogues.
Scheme 39: Proton pump inhibitors and synthesis of esomeprazole.
Scheme 40: Synthesis of benzimidazole core pantoprazole.
Figure 6: Structure of rabeprazole 194.
Scheme 41: Synthesis of candesartan.
Scheme 42: Alternative access to the candesartan key intermediate 216.
Scheme 43: .Medicinal chemistry route to telmisartan.
Scheme 44: Improved synthesis of telmisartan.
Scheme 45: Synthesis of zolpidem.
Scheme 46: Copper-catalysed 3-component coupling towards zolpidem.
Figure 7: Structure of celecoxib.
Scheme 47: Preparation of celecoxib.
Scheme 48: Alternative synthesis of celecoxib.
Scheme 49: Regioselective access to celecoxib.
Scheme 50: Synthesis of pazopanib.
Scheme 51: Syntheses of anastrozole, rizatriptan and letrozole.
Scheme 52: Regioselective synthesis of anastrozole.
Scheme 53: Triazine-mediated triazole formation towards anastrozole.
Scheme 54: Alternative routes to 1,2,4-triazoles.
Scheme 55: Initial synthetic route to sitagliptin.
Figure 8: Binding of sitagliptin within DPP-IV.
Scheme 56: The process route to sitagliptin key intermediate 280.
Scheme 57: Synthesis of maraviroc.
Scheme 58: Synthesis of alprazolam.
Scheme 59: The use of N-nitrosoamidine derivatives in the preparation of fused benzodiazepines.
Figure 9: Structures of itraconazole, ravuconazole and voriconazole.
Scheme 60: Synthesis of itraconazole.
Scheme 61: Synthesis of rufinamide.
Scheme 62: Representative tetrazole formation in valsartan.
Figure 10: Structure of tetrazole containing olmesartan, candesartan and irbesartan.
Scheme 63: Early stage introduction of the tetrazole in losartan.
Scheme 64: Synthesis of cilostazol.
Figure 11: Structure of cefdinir.
Scheme 65: Semi-synthesis of cefdinir.
Scheme 66: Thiazole syntheses towards ritonavir.
Scheme 67: Synthesis towards pramipexole.
Scheme 68: Alternative route to pramipexole.
Scheme 69: Synthesis of famotidine.
Scheme 70: Efficient synthesis of the hyperuricemic febuxostat.
Scheme 71: Synthesis of ziprasidone.
Figure 12: Structure of mometasone.
Scheme 72: Industrial access to 2-furoic acid present in mometasone.
Scheme 73: Synthesis of ranitidine from furfuryl alcohol.
Scheme 74: Synthesis of nitrofurantoin.
Scheme 75: Synthesis of benzofuran.
Scheme 76: Synthesis of amiodarone.
Scheme 77: Synthesis of raloxifene.
Scheme 78: Alternative access to the benzo[b]thiophene core of raloxifene.
Scheme 79: Gewald reaction in the synthesis of olanzapine.
Scheme 80: Alternative synthesis of olanzapine.
Figure 13: Access to simple thiophene-containing drugs.
Scheme 81: Synthesis of clopidogrel.
Scheme 82: Pictet–Spengler reaction in the preparation of tetrahydrothieno[3,2-c]pyridine (422).
Scheme 83: Alternative synthesis of key intermediate 422.
Figure 14: Co-crystal structures of timolol (left) and carazolol (right) in the β-adrenergic receptor.
Scheme 84: Synthesis of timolol.
Scheme 85: Synthesis of tizanidine 440.
Scheme 86: Synthesis of leflunomide.
Scheme 87: Synthesis of sulfamethoxazole.
Scheme 88: Synthesis of risperidone.
Figure 15: Relative abundance of selected transformations.
Figure 16: The abundance of heterocycles within top 200 drugs (5-membered rings).
Achiral bis-imine in combination with CoCl2: A remarkable effect on enantioselectivity of lipase-mediated acetylation of racemic secondary alcohol
- K. Arunkumar,
- M. Appi Reddy,
- T. Sravan Kumar,
- B. Vijaya Kumar,
- K. B. Chandrasekhar,
- P. Rajender Kumar and
- Manojit Pal
Beilstein J. Org. Chem. 2010, 6, 1174–1179, doi:10.3762/bjoc.6.134
- acetylation of the (R)-isomer of a racemic benzylic secondary alcohol with 91% ees. The methodology was used for the preparation of the known drug rivastigmine. Keywords: acetylation; bis-imine; cobalt chloride; enantioselectivity; lipase; Introduction The development and use of newer synthetic methods for
Graphical Abstract
Scheme 1: Lipase-catalyzed acetylation of racemic benzylic secondary alcohol [(RS)-4] and its application.
Scheme 2: FeCl3-meditated synthesis of bis-imines.
Scheme 3: Preparation of racemic 3-(1-hydroxyethyl)phenyl ethyl(methyl)carbamate [(RS)-4]
Scheme 4: Proposed reaction mechanism of lipase-catalyzed acetylation of racemic alcohol 4.
Scheme 5: Complete synthesis of rivastigmine.
Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers
- Daniel Crespy and
- Katharina Landfester
Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130
- diacrylate to yield, after the transfer to water, stable microgels. Monodisperse latexes could be obtained with the poly(2-hydroxyethyl methacrylate) when water, methanol, ethanol, ethylene glycol, or water/ethanol mixtures were used as the dispersed phase in the presence of cobalt tetrafluoroborate [21
- ]. This approach is particularly interesting to encapsulate large amounts of metal salts. Indeed, up to 22.6 wt % of the cobalt salt compared to the monomer content could be encapsulated. Monodisperse latexes of silver–polymer particles were also obtained upon reduction of silver nitrate in the monomer
- polystyrene nanoparticles were synthesized in emulsion and miniemulsion by non-covalently immobilized metallocene catalysts [67]. The catalytic polymerization of butadiene with a cobalt catalyst was found to give highly crystalline 1,2-polybutadiene with a particle size of 150–200 nm [68]. The
Graphical Abstract
Figure 1: Copolymerization of 2 monomers A and B with different polarities in direct miniemlusions with the d...
Figure 2: Interfacial alternating radical copolymerization between dibutyl maleate and vinyl gluconamide for ...
Figure 3: Chemical structures of the surfmers for radical polymerization in miniemulsions: a: sodium vinylben...
Scheme 1: Synthesis of the macroinitiator for ROMP in direct miniemulsion [71].
Figure 4: Monomers used in ionic miniemulsion polymerization. a: octamethylcyclotetrasiloxane [9,74], b: 1,3,5-tris...
Figure 5: Enzymatic reactions in miniemulsion droplets (reproduced with permission from [91]. Copyright (2003) Wi...
Figure 6: Chemical structure of a: polyaniline (leucoemeraldine), b: polypyrrole, c: poly(ethylene dioxythiop...
Figure 7: Transmission electron micrograph of polyurethane capsules synthesized by interfacial polyaddition i...
Figure 8: Schematics for the polycondensation reaction between hydrophobic alcohols and carboxylic acids surr...
Scheme 2: Polyimide from the reaction performed in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoro...
Figure 9: a: TEM micrograph of the cubic structures, b: proposed mechanism for the production of the nanocube...
Cross-metathesis of allylcarboranes with O-allylcyclodextrins
- Ivan Šnajdr,
- Zbyněk Janoušek,
- Jindřich Jindřich and
- Martin Kotora
Beilstein J. Org. Chem. 2010, 6, 1099–1105, doi:10.3762/bjoc.6.126
- (C88H126O5510B2B8Na2). Per-O-acetyl-2I-O-{4-{8,8’-μ-(sulfido)-[3,3’-commo-cobalt(III)-bis-(1,2-dicarbaundecaborate)]-8-yl}but-2-en-1-yl}-β-cyclodextrin (3ba). The compound was prepared from 2a (0.15 g, 0.07 mmol) and 1b (20 mg, 0.05 mmol). Column chromatography gave the title compound, 0.023 g (18%), as an orange
- , B-7’, B-9, B-9’, B-11, B-11’, B-12, B-12’), −14.68 (bs, 2 B, B-6, B-6’); MS (EI, m/z (rel.%)): 1214.4 (100), 1010.3 (10), 413.3 (68), 391.3 (10), 307.2 (52); HR-MS (ESI) calcd. for C90H135O5510B3B15CoNa2S: 1213.9194, found 1213.9233. Per-O-acetyl-6I-O-{4-{8,8’-μ-(sulfido)-[3,3’-commo-cobalt(III)-bis
- (bs, 2 B, B-6, B-6’); MS (EI, m/z (rel.%)): 1214.1 (100), 1010.3 (10), 414.3 (52), 360.3 (10), 307.2 (96); HR-MS (ESI) calcd. for C90H135O5510B3B15CoNa2S: 1213.9194, found 1213.9234. Per-O-acetyl-2I-O-{4-{8,8’-μ-(disulfido)-[3,3’-commo-cobalt(III)-bis-(1,2-dicarbaundecaborate)]-8-yl}but-2-en-1-yl}-β
Graphical Abstract
Figure 1: Starting allylcarboranes 1a–1c and O-allylcyclodextrins 2a–2c.
Scheme 1: Cross-metathesis of allylcarboranes 1 and O-allylcyclodextrins 2.
A perfluorocyclopentene based diarylethene bearing two terpyridine moieties – synthesis, photochemical properties and influence of transition metal ions
- Falk Wehmeier and
- Jochen Mattay
Beilstein J. Org. Chem. 2010, 6, No. 53, doi:10.3762/bjoc.6.53
- contrast to the iron(II) complex, the ditopic ligand seems to retain its photochromic properties in the cobalt(II) and nickel(II) complexes – synthesized from CoCl2 and [Ni(acac)2], respectively – although the photocyclisation takes much longer than with free 10a (about 5 minutes compared to ca. 30 seconds
- reversibility. It was shown that the presence of various transition metal ions significantly influences the photochromism of the bridging unit: While iron(II)-ions completely inhibit the photochromic reaction, cobalt(II) and nickel(II) appear to slow down the photoreaction considerably. Zinc(II)-ions, on the
- dissolved. The formation of the iron(II) and cobalt(II) complexes can be traced by the color change from colorless to blue (iron(II)) and red (cobalt(II)), respectively. UV–vis-spectra of 10a before (solid), after UV-irradiation (dashed) and after irradiation with vis light (dotted). UV–vis-spectra of 12
Graphical Abstract
Scheme 1: Synthesis of twofold iodinated bis(benzo[b]thiophenyl)perfluorocyclopentene 4.
Scheme 2: Synthesis of terpyridinyl boronic acids 9a and 9b.
Scheme 3: Synthesis of the bis(terpyridinyl)diarylethenes 10a and 10b.
Scheme 4: Photochromic reaction of the free ligand 10a.
Figure 1: UV–vis-spectra of 10a before (solid), after UV-irradiation (dashed) and after irradiation with vis ...
Scheme 5: Synthesis of the binuclear Ru(II)-complex 12.
Figure 2: UV–vis-spectra of 12 before (solid), after UV-irradiation (dashed) and after irradiation with vis l...
Figure 3: UV–vis-spectra of 12 before (dashed), after UV-irradiation (dotted), the difference (solid) and fre...
Figure 4: UV–vis-spectra of [Fe2+@10a] before (solid), after UV-irradiation (dashed) and after irradiation wi...
Figure 5: UV–vis-spectra of [Zn2+@10a] before (solid), after UV-irradiation (dashed) and after irradiation wi...
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...
Prediction of reduction potentials from calculated electron affinities for metal-salen compounds
- Sarah B. Bateni,
- Kellie R. England,
- Anthony T. Galatti,
- Handeep Kaur,
- Victor A. Mendiola,
- Alexander R. Mitchell,
- Michael H. Vu,
- Benjamin F. Gherman and
- James A. Miranda
Beilstein J. Org. Chem. 2009, 5, No. 82, doi:10.3762/bjoc.5.82
- [10] for both sets of metal-salens. Results and Discussion The 19 metal-salens comprising the training set are shown in Figure 1. The metals used in the training set include nickel, cobalt, copper, iron, zinc, and palladium. Included in the training set are the parent metal-salens (no substitution
- , cobalt, and copper were plotted on the graph due to the other metals (iron, zinc, and palladium) having only one point each in the training set. Negative Hammett parameters result from the presence of electron-donating groups and lead to smaller EAs. Positive Hammett parameters result from the presence
- of electron-withdrawing groups and lead to larger EAs. Figure 3 shows that there is a good linear correlation between the experimental reduction potential (Epc) and EA for each of nickel, cobalt, and copper. Iron, zinc, and palladium were again excluded due to having only one point each in the
Graphical Abstract
Figure 1: Training set of 19 metal-salens.
Figure 2: Correlation between electron affinity (EA) and Hammett σp parameter in the training set (R2 = 0.76,...
Figure 3: Correlation between Epc and EA for the Ni, Co, and Cu training set metal-salens (R2 = 0.93, 0.17 (0...
Figure 4: Comparison of experimental and predicted Epc for all training set metal-salens.
Figure 5: Test set of 14 metal-salens.
Preparation and Diels–Alder/cross coupling reactions of a 2-diethanolaminoboron- substituted 1,3-diene
- Liqiong Wang,
- Cynthia S. Day,
- Marcus W. Wright and
- Mark E. Welker
Beilstein J. Org. Chem. 2009, 5, No. 45, doi:10.3762/bjoc.5.45
- and Diels–Alder reactions of pyridine cobaloxime dienyl complexes over 15 years ago. Since that time, we have reported a number of synthetic routes to these and other related types of cobalt dienyl complexes as well as their subsequent cycloaddition and demetallation chemistry [3][4][5], and other
Graphical Abstract
Scheme 1: Synthesis of 2-diethanolaminoborate-1,3-butadiene.
Figure 1: Molecular structure of boron substituted diene 2.
Scheme 2: Diels–Alder reactions.
Scheme 3: Cross coupling reactions.
The first direct synthesis of β-unsubstituted meso- decamethylcalix[5]pyrrole
- Luis Chacón-García,
- Lizbeth Chávez,
- Denisse R. Cacho and
- Josue Altamirano-Hernández
Beilstein J. Org. Chem. 2009, 5, No. 2, doi:10.3762/bjoc.5.2
- catalyzed by a Brønsted-Lowry acid such as HCl or methanesulfonic acid, or a Lewis acid such as zeolites with aluminium or cobalt, BF3 or a bismuth salt [2][3][4][5]. The synthesis of calix[n]pyrroles where n > 4 has been reported for n = 5 or 6. The latter compounds have been synthesized via two routes: a
Graphical Abstract
Scheme 1: Products obtained by the reaction of pyrrole and acetone with bismuth(III).
Reactions of glycidyl derivatives with ambident nucleophiles; part 2: amino acid derivatives
- Gerald Dyker,
- Andreas Thöne and
- Gerald Henkel
Beilstein J. Org. Chem. 2007, 3, No. 28, doi:10.1186/1860-5397-3-28
- multifunctionalized heterocycles from a pyroglutamic acid derivative, glycidyl components and anilines by nucleophilic substitution and cobalt catalysis is presented. Introduction Recently we investigated the formation of 5- and 6-membered heterocycles from ethyl acetoacetate and glycidyl derivatives such as
- ) no cyclization products were obtained. Finally we succeeded in achieving a cyclization by a two-step procedure: the cobalt-catalyzed addition of electron-rich anilines 6 according to Iqbal [9] let to amino alcohols 7, which then cyclized in basic medium (NaH in DMF or THF), either to give 7-membered
- achieved the annulation reaction of amino acid derivatives with glycidyl compounds as functionalized C3 building blocks in combination with a cobalt-catalyzed addition of anilines to the epoxide functionality. This rather selective transition-metal catalysed step builds up the alcohol and the amino
Graphical Abstract
Scheme 1: Planned construction for morpholinones 3 from amino acid and glycidyl derivatives 1 and 2. R1, R3 =...
Scheme 2: Synthesis of pyrrolidinone-fused heterocycles from a glycidyl substituted pyroglutamic acid ester 5...
Figure 1: Structure of oxidation product 10a in the crystal.
Scheme 3: Special product conformers, by-products and intermediates of the transformation of 7.
The use of silicon- based tethers for the Pauson- Khand reaction
- Adrian P. Dobbs,
- Ian J. Miller and
- Saša Martinović
Beilstein J. Org. Chem. 2007, 3, No. 21, doi:10.1186/1860-5397-3-21
- consistent with the literature evidence and our previous results that the 5,7 systems are known not to be synthesised through the cobalt mediated methodology. The unsymmetrical acetal was recovered in near quantitative yield with no trace of any products of decomposition or hydrolysis. Therefore silyl acetal
Graphical Abstract
Scheme 1: Saigo's cycloisomerisation reaction under Pauson-Khand conditions.
Scheme 2: Pauson-Khand reaction and tether-cleavage in wet acetonitrile.
Scheme 3: Silyl-tethered allenic Pauson-Khand reaction reported by Brummond.
Scheme 4: Intramolecular Pauson-Khand reaction of allyldimethyl- and allyldiphenylsilyl propargyl ethers repo...
Scheme 5: Synthesis and attempted Pauson-Khand reactions of vinyldimethylsilyl- and vinyldiphenylsilyl ethers....
Figure 1: Functionalised acetylenes prepared and used in silyl ether-tethered Pauson-Khand reactions. Yields ...
Figure 2: Chain-functionalised acetylenes prepared and used in silyl ether-tethered Pauson-Khand reactions. Y...
Figure 3: Possible structure of THF-oxidation/insertion product.
Scheme 6: Model Pauson-Khand reaction of allyltrimethylsilane.
Scheme 7: Preparation of allyldiisopropylsilyl ethers.
Scheme 8: Pauson-Khand reaction of allyldiisopropylsilyl ethers.
Scheme 9: Preparation of allyldiisopropylsilanes.
Scheme 10: Attempted Mitsunobu reactions of diisopropylsilanols.
Scheme 11: Preparation of alkynic diisopropylsilanes.
Scheme 12: Preparation of allyldiisopropylsilyl ethers.
Scheme 13: Preparation of acetals from dichlorodiphenylsilane.
Scheme 14: Attempted Pauson-Khand reaction of allylpropargyldiphenylsilyl acetal.
Scheme 15: Proposed diisopropylsilyl acetal formation.
Scheme 16: Attempted allylpropargyldiisopropylsilyl acetal formation.
Scheme 17: Attempted allylpropargyldiisopropylsilyl acetal formation.
Scheme 18: Preparation of silicon-tethered Pauson-Khand precursors.
Scheme 19: Failed Pauson-Khand reaction of a silicon-tethered substrate.
Cobalt(II) chloride catalyzed one-pot synthesis of α-aminonitriles
- Surya K. De
Beilstein J. Org. Chem. 2005, 1, No. 8, doi:10.1186/1860-5397-1-8
- synthesis of α-aminonitriles. In continuation of our work to develop new organic transformations, [11][12][13][14][15][16][17] I report herein that cobalt(II) chloride which acts as a mild Lewis acid might be a useful and inexpensive catalyst for the synthesis α-aminonitrile. Although cobalt(II) chloride
- has been extensively used as a mild catalyst for a plethora of organic transformations, [18][19][20] there are no examples of the use of cobalt(II) chloride as catalyst for the synthesis of α-aminonitriles. Results and discussion The treatment of benzaldehyde and aniline with KCN in the presence of a
- , efficient, and practical method for the synthesis of α-aminonitriles through a one-pot three component coupling of aldehydes, amines, and potassium cyanide using a catalytic amount of cobalt(II) chloride. The major feature of this method is that it is truly a one-pot protocol that does not need a separate
