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Search for "extrusion" in Full Text gives 85 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of mesomeric betaine compounds with imidazolium-enolate structure
- Nina Gonsior,
- Fabian Mohr and
- Helmut Ritter
Beilstein J. Org. Chem. 2012, 8, 390–397, doi:10.3762/bjoc.8.42
- end-groups on both sides of the chain. The specific O–C–C–C–O vibration band was found at 1541 cm−1 in the IR spectra. Thermogravimetric analyses are depicted in Figure 7. The weight losses of up to 10% at temperatures lower than 120 °C are due to the extrusion of water. At higher temperatures
- unidentified decomposition was obtained, since the extrusion of one component results in the destruction of the polymer backbone. However, further conclusions can be drawn from the thermal stability. Polymers 6a–c are stable up to 300 °C, while oligomers 7a and 7b decompose at temperatures between 200 and 220
Graphical Abstract
Scheme 1: Reaction of p-bromanil (1) with 1-butylimidazole (2).
Figure 1: 1H NMR spectrum of mesomeric betaine 3.
Figure 2: 13C NMR spectrum of dipole 3.
Figure 3: Solid-state molecular structure of compound 3. Selected bond distances [Å]: O(1)–C 1.228(4), O(2)–C...
Figure 4: Formation of molecular layers in the crystal packing.
Figure 5: Higuchi–Connors phase diagram of 3/m-β-CD complex.
Scheme 2: Mechanism of molecular association of the complex.
Figure 6: Classification of betaine 3.
Scheme 3: Synthesis of polymer 6 and oligomer 7 based on imidazolium-enolate structures.
Figure 7: Thermogravimetric analyses of polymer networks 6a–c and oligomers 7a,b.
Valence isomerization of cyclohepta-1,3,5-triene and its heteroelement analogues
- Helen Jansen,
- J. Chris Slootweg and
- Koop Lammertsma
Beilstein J. Org. Chem. 2011, 7, 1713–1721, doi:10.3762/bjoc.7.201
- due to the low activation barrier for sulfur extrusion [40][48][70], which occurs through a sequence of low-energy processes involving several sulfur-containing intermediates [71][72]. Thiepine (5) can be stabilized by Fe(CO)3 complexation (15; Figure 2) [73] or by decorating the seven-membered ring
Graphical Abstract
Scheme 1: Valence isomerization of cyclohepta-1,3,5-triene (1) and its heteroelement analogues.
Scheme 2: Conformational ring inversions.
Scheme 3: Rearrangements of the parent cycloheptatriene 1 and norcaradiene 2.
Figure 1: NICS(0) values of fluorinated heteropines.
Scheme 4: Reactivity of oxepine (3) and benzene oxide (4).
Figure 2: Stabilized thiepines 15–18.
Scheme 5: Valence isomerization of 1H-azepines.
Scheme 6: Reactivity of 1H-azepine.
Figure 3: Benzannulated azepines 27 and 28.
Figure 4: Reported phosphepines 29–32.
Scheme 7: Phosphinidene generation from metal-complexed benzophosphepine 33.
Use of mixed Li/K metal TMP amide (LiNK chemistry) for the synthesis of [2.2]metacyclophanes
- Marco Blangetti,
- Patricia Fleming and
- Donal F. O'Shea
Beilstein J. Org. Chem. 2011, 7, 1249–1254, doi:10.3762/bjoc.7.145
- possible explanation for this is the cumbersome methods required for their synthesis. Typical approaches have utilised Wurtz coupling, the oxidation and thermal (500–600 °C) extrusion of SO2 from dithia[3.3]cyclophanes or the photochemical ring contraction of diselena[3.3]cyclophanes [17][18][19][20][21
Graphical Abstract
Scheme 1: Selective benzylic metalation with LiNK conditions. DG = directing group.
Scheme 2: Iterative LiNK/oxidative coupling synthesis of [2.2]metacyclophanes.
Figure 1: Xylene substrates.
Figure 2: Metalation selectivity for 4e (arrows indicate potential metalation sites). 2H NMR spectrum in CH2Cl...
Figure 3: Di-metalation selectivity for 6f. 2H NMR spectrum in CH2Cl2. *CD2Cl2.
Figure 4: X-Ray structure of 8c with thermal ellipsoids drawn at 50% probability level.
The arene–alkene photocycloaddition
- Ursula Streit and
- Christian G. Bochet
Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61
- indeed involved was carried out by Reedich and Sheridan [29]: By incorporating a diazo group into the last formed bond of the cyclopropyl ring in the meta photocycloadduct [30], they would be able to see whether the biradical formed by the extrusion of nitrogen gave the same products as the meta
Graphical Abstract
Scheme 1: Photochemistry of benzene.
Scheme 2: Three distinct modes of photocycloaddition of arenes to alkenes.
Scheme 3: Mode selectivity with respect of the free enthalpy of the radical ion pair formation.
Scheme 4: Photocycloaddition shows lack of mode selectivity.
Scheme 5: Mechanism of the meta photocycloaddition.
Scheme 6: Evidence of biradiacal involved in meta photocycloaddition by Reedich and Sheridan.
Scheme 7: Regioselectivity with electron withdrawing and electron donating substituents.
Scheme 8: Closure of cyclopropyl ring affords regioisomers.
Scheme 9: Endo versus exo product in the photocycloaddition of pentene to anisole [33].
Scheme 10: Regio- and stereoselectivity in the photocycloaddition of cyclopentene with a protected isoindoline....
Scheme 11: 2,6- and 1,3-addition in intramolecular approach.
Scheme 12: Linear and angularly fused isomers can be obtained upon intramolecular 1,3-addition.
Scheme 13: Synthesis of α-cedrene via diastereoselective meta photocycloaddition.
Scheme 14: Asymmetric meta photocycloaddition introduced by chirality of tether at position 2.
Scheme 15: Enantioselective meta photocycloaddition in β-cyclodextrin cavity.
Scheme 16: Vinylcyclopropane–cyclopentene rearrangement.
Scheme 17: Further diversification possibilities of the meta photocycloaddition product.
Scheme 18: Double [3 + 2] photocycloaddition reaction affording fenestrane.
Scheme 19: Total synthesis of Penifulvin B.
Scheme 20: Towards the total synthesis of Lacifodilactone F.
Scheme 21: Regioselectivity of ortho photocycloaddition in polarized intermediates.
Scheme 22: Exo and endo selectivity in ortho photocycloaddition.
Scheme 23: Ortho photocycloaddition of alkanophenones.
Scheme 24: Photocycloadditions to naphtalenes usually in an [2 + 2] mode [79].
Scheme 25: Ortho photocycloaddition followed by rearrangements.
Scheme 26: Stable [2 + 2] photocycloadducts.
Scheme 27: Ortho photocycloadditions with alkynes.
Scheme 28: Intramolecular ortho photocycloaddition and rearrangement thereof.
Scheme 29: Intramolecular ortho photocycloaddition to access propellanes.
Scheme 30: Para photocycloaddition with allene.
Scheme 31: Photocycloadditions of dianthryls.
Scheme 32: Photocycloaddition of enone with benzene.
Scheme 33: Intramolecular photocycloaddition affording multicyclic compounds via [4 + 2].
Scheme 34: Photocycloaddition described by Sakamoto et al.
Scheme 35: Proposed mechanism by Sakamoto et al.
Scheme 36: Photocycloaddition described by Jones et al.
Scheme 37: Proposed mechanism for the formation of benzoxepine by Jones et al.
Scheme 38: Photocycloaddition observed by Griesbeck et al.
Scheme 39: Mechanism proposed by Griesbeck et al.
Scheme 40: Intramolecular photocycloaddition of allenes to benzaldehydes.
Rh-Catalyzed rearrangement of vinylcyclopropane to 1,3-diene units attached to N-heterocycles
- Franca M. Cordero,
- Carolina Vurchio,
- Stefano Cicchi,
- Armin de Meijere and
- Alberto Brandi
Beilstein J. Org. Chem. 2011, 7, 298–303, doi:10.3762/bjoc.7.39
- bond to form the intermediates C which can undergo metal hydride elimination or 1,3-hydride migration to the rhodium to give, respectively, the allyl- and alkylrhodium(III) hydride complexes D and F. Metal extrusion by reductive elimination leads to the observed dienes and regeneration of the catalyst
Graphical Abstract
Scheme 1: General approach to spirocyclopropanated tetrahydropyridones by 1,3-dipolar cycloaddition/thermal r...
Scheme 2: Synthesis of tetrahydrospiro[cyclopropane-1,1’(2’H,6’H)-pyrido[2,1-a]isoquinolin]-2’-one 8.
Scheme 3: Synthesis of 7’-oxohexahydro spiro[cyclopropane-1-8’(5’H)indolizines] 12.
Scheme 4: Olefination of spirocyclopropanated heterocyclic ketones 8, 12 and 16.
Figure 1: Key NOE interactions. 18: 11b-H/11-H, 11b-H/6-H, 11b-H/Ht, Hv/2-CH3; E-19: Hb/CH3, Hc/11b-H, Hc/11-...
Scheme 5: Rearrangement of VCPs 15 and 17 catalyzed by Rh(PPh3)3Cl.
Scheme 6: Mechanism of the rearrangement of heterocyclic VCPs catalyzed by Rh(PPh3)3Cl.
Reciprocal polyhedra and the Euler relationship: cage hydrocarbons, CnHn and closo-boranes [BxHx]2−
- Michael J. McGlinchey and
- Henning Hopf
Beilstein J. Org. Chem. 2011, 7, 222–233, doi:10.3762/bjoc.7.30
- expected it to be readily available by photolytic [2 + 2] cycloaddition of hypostrophene, 34, or by extrusion of nitrogen from either 35 or 36, as in Scheme 6 [17][18][19][20]; surprisingly, all these routes were found to be ineffective. Success was finally achieved via ring contraction of a
Graphical Abstract
Figure 1: Molecular analogues of the Platonic solids.
Figure 2: The structure of [Mo6Cl8]4+ demonstrates the reciprocal relationship between the cube and the octah...
Figure 3: The deltahedra corresponding to the structures of the closo-boranes [BxHx]2−.
Scheme 1: The first synthesis of a tetrahedrane 19 by Maier.
Scheme 2: The conversion of Dewar benzenes to [3]-prismanes.
Scheme 3: Synthesis of [3]prismane 9 by Katz.
Scheme 4: Synthesis of cubane 10 by Eaton.
Scheme 5: Synthesis of cubane 10 by Pettit.
Scheme 6: Failed routes to [5]-prismane 11.
Scheme 7: Synthesis of [5]prismane 11 by Eaton.
Scheme 8: Retrosynthetic analysis for several approaches to dodecahedrane 16.
Scheme 9: Paquette´s synthesis of dodecahedrane 16.
Scheme 10: Prinzbach´s synthesis of dodecahedrane 16.
Figure 4: The as yet unknown polyhedranes 12–15.
Figure 5: Coupling of two Dewar benzenes.
Scheme 11: A possible route to octahedrane 12.
Scheme 12: A possible route to nonahedrane 13.
Figure 6: Capping [4]peristylane with a four-membered ring system.
Scheme 13: A possible route to decahedrane 14.
Figure 7: A possible route to undecahedrane 15 (left: side view; right: top view).
Scheme 14: Synthetic routes to trigonal prismatic hexasilanes 71a and hexagermanes 71b.
Scheme 15: Synthetic routes to octasila- and octagerma-cubanes.
Scheme 16: Synthesis of an octastannacubane and a decastannapentaprismane.
Scheme 17: Synthesis of a heterocubane.
Figure 8: D3d symmetric C8H8, a bis-truncated cubane.
Intramolecular hydroxycarbene C–H-insertion: The curious case of (o-methoxyphenyl)hydroxycarbene
- Dennis Gerbig,
- David Ley,
- Hans Peter Reisenauer and
- Peter R. Schreiner
Beilstein J. Org. Chem. 2010, 6, 1061–1069, doi:10.3762/bjoc.6.121
- regarding the nature of the fascinating [1,2]H-tunneling mechanism in phenylhydroxycarbenes (with parent 3, Scheme 1), we sought to study the behavior of derivatives of 3 in Ar matrices at temperatures as low as 11 K. We attempted to generate novel o-methoxy-substituted carbene 5 by extrusion of carbon
Graphical Abstract
Scheme 1: Unimolecular reactivity of hydroxycarbenes under cryogenic conditions: [1,2]H-Tunneling of 1 and 3 (...
Scheme 2: A selection of heterocarbenes that undergo intramolecular C–H insertions.
Scheme 3: Attempted generation of 5 and d-5 as well as their corresponding insertion products.
Scheme 4: Proposed mechanism for the generation of 8 and 9. The [1,2]H-tunneling process apparently cannot co...
Figure 1: Unmodified matrix IR spectrum (Ar, 11 K) of the pyrolysis (600 °C) of 5. Traces of 9 are indicated ...
Figure 2: Unmodified matrix IR spectrum (Ar, 11 K) of the pyrolysis (600 °C) of d-5. Traces of 9 are indicate...
Scheme 5: Decay of the 2,3-dihydrobenzofuran-3-ol molecular radical cation (8+•).
Scheme 6: Attempted generation of 12 and the actual pyrolysis product 11.
Scheme 7: Unanticipated reaction of 6 upon heating in xylenes.
Scheme 8: Potential energy hypersurface of (o-methoxyphenyl)hydroxycarbene (5) (not drawn to scale; ZPVE incl...
Scheme 9: Acid-catalyzed generation of 7 by unreacted 6.
One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes
- Priyabrata Roy and
- Binay Krishna Ghorai
Beilstein J. Org. Chem. 2010, 6, No. 52, doi:10.3762/bjoc.6.52
- extrusion of water by treatment of 7a with DBU in refluxing toluene, gave the quinoxaline derivative 5a [36]. The stereochemistry of the adduct 7a was assigned as exo based on the chemical shift of HA and HB (<4 ppm) [27]. A similar reaction process using N-methylmaleimide (entry 2) as dienophile led to the
Graphical Abstract
Scheme 1: Synthetic plan towards quinoxaline derivatives.
Scheme 2: Preparation of o-alkynyl carbonyl derivatives 1. A: pyrazine series; B,C: quinoxaline series.
Scheme 3: Synthesis of quinoxaline derivative.
Scheme 4: Synthesis of azahydrophenanthrone derivatives.
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...
Mitomycins syntheses: a recent update
- Jean-Christophe Andrez
Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33
- enhancement of reactivity of the cyclic acylal 64 [72][73][74][75][76]. This methodology has seen application in the synthesis of diverse heterocycles, as exemplified by the reaction of aniline with 64 to form the 1,5-addition adduct 65, and finally the amide 66 by internal acylation and extrusion of acetone
Graphical Abstract
Scheme 1: Aziridine containing natural products.
Scheme 2: Mitomycin structures and nomenclature.
Scheme 3: Base catalysed epimerization of mitomycin B.
Scheme 4: Biosynthesis of mitomycin C (MMC) 7.
Scheme 5: Mode of action of mitomycin C.
Scheme 6: The N–C3–C9a disconnection.
Scheme 7: Danishefsky’s Retrosynthesis of mitomycin K.
Scheme 8: Hetero Diels–Alder reaction en route to mitomycins.
Scheme 9: Nitroso Diels–Alder cycloaddition.
Scheme 10: Frank azide cycloadddition.
Scheme 11: Final steps of mitomycin K synthesis. aPDC, DCM; bPhSCH2N3, PhH, 80 °C; cL-selectride, THF, −78 °C; ...
Scheme 12: Naruta–Maruyama retrosynthesis.
Scheme 13: Synthesis of a leucoaziridinomitosane by nitrene cycloaddition. aAlCl3-Et2O; bNaH, ClCH2OMe; cn-BuL...
Scheme 14: Thermal decomposition of azidoquinone 51.
Scheme 15: Diastereoselectivity during the cycloaddition.
Scheme 16: Oxidation with iodo-azide.
Scheme 17: Williams’ approach towards mitomycins.aDEIPSCl, Imidazole, DCM; bPd/C, HCO2NH4, MeOH; cAllocCl, NaH...
Scheme 18: Synthesis of pyrrolidones by homoconjugate addition.
Scheme 19: Homoconjugate addition on the fully functionalized substrate.
Scheme 20: Introduction of the olefin.
Scheme 21: Retrosynthesis of N–C9a, N–C3 bond formation.
Scheme 22: Synthesis of the pyrrolo[1,2]indole 82 using N-PSP activation.aAc2O, Py; bAc2O, Hg(OAc)2, AcOH, 90%...
Scheme 23: Synthesis of an aziridinomitosane. am-CPBA, DCM then iPr2NH, CCl4 reflux; bK2CO3, MeOH; cBnBr, KH; d...
Scheme 24: Oxidation products of a leucoaziridinomitosane obtained from a Polonovski oxidation.
Scheme 25: Polonovski oxidation of an aziridinomitosane. am-CPBA; bPd/C, H2; cDimethoxypropane, PPTS.
Scheme 26: The C1–C9a disconnection.
Scheme 27: Ziegler synthesis of desmethoxymitomycin A.aIm2C=O, THF; bNH3; cTMSOTf, 2,6-di-tert-butylpyridine, ...
Scheme 28: Transformation of sodium erythorbate.aTBDMSCl; bNaN3; cPPh3; d(Boc)2O, DMAP; eTBAF; fTf2O, Pyr.
Scheme 29: Formation of C9,C10-unsaturation in the mitomycins. am-CPBA, DCM; bO3, MeOH; cMe2S; dKHMDS, (EtO)3P...
Scheme 30: Fragmentation mechanism.
Scheme 31: Michael addition-cyclisation.
Scheme 32: SmI2 8-endo-dig cyclisation.
Scheme 33: Synthesis of pyrrolo[1,2-a]indole by 5-exo-dig radical cyclization.
Scheme 34: The C9–C9a disconnection.
Scheme 35: Intramolecular nitrile oxide cycloaddition.
Scheme 36: Regioselectivity of the INOC.
Scheme 37: Fukuyama’s INOC strategy.
Scheme 38: Synthesis of a mitosane core by rearrangement of a 1-(1-pyrrolidinyl)-1,3-butadiene.
Scheme 39: Sulikowski synthesis of an aziridinomitosene. aPd(Tol3P)2Cl2, Bu3SnF, 140; bH2, Pd/C; cTFAA, Et3N; d...
Scheme 40: Enantioselective carbene insertion.
Scheme 41: Parson’s radical cyclization.
Scheme 42: Cha’s mitomycin B core synthesis.
Scheme 43: The N-aromatic disconnection.
Scheme 44: Kishi retrosynthesis.
Scheme 45: Kishi synthesis of a starting material. aallyl bromide, K2CO3, acetone, reflux; bN,N-Dimethylanilin...
Scheme 46: Kishi synthesis of MMC 7. aLDA, THF, −78 °C then PhSeBr, THF, −78 °C; bH2O2, THF-EtOAc; cDIBAL, DCM...
Scheme 47: Acid catalyzed degradation of MMC 7.
Scheme 48: In vivo formation of apomitomycin B.
Scheme 49: Advanced intermediate for apomitomycin B synthesis.
Scheme 50: Remers synthesis of a functionalized mitosene. aTMSCl, Et3N, ZnCl2 then NBS; bAcOK; cNH2OH; dPd/C, H...
Scheme 51: Coleman synthesis of desmethoxymitomycin A. aSnCl2, PhSH, Et3N, CH3CN; bClCO2Bn, Et3N; cPPh3, DIAD,...
Scheme 52: Transition state and pyrrolidine synthesis.
Scheme 53: Air oxidation of mitosanes and aziridinomitosanes.
Scheme 54: The C9-aromatic disconnection.
Scheme 55: Synthesis of the aziridine precursor. aLHMDS, THF; bNaOH; c(s)-α-Me-BnNH2, DCC, HOBT; dDIBAL; eK2CO3...
Scheme 56: Synthesis of 206 via enamine conjugate addition.
Scheme 57: Rapoport synthesis of an aziridinomitosene.
Scheme 58: One pot synthesis of a mitomycin analog.
Scheme 59: Synthesis of compound 218 via intramolecular Heck coupling. aEtMgCl, THF, then 220; bMsCl, Et3N; cN...
Scheme 60: Elaboration of indole 223. aEt3N, Ac2O; bAcOH; cSOCl2, Et3N; dNaN3, DMF; eH2SO4, THF; fK2CO3, MeOH; ...
Scheme 61: C9-C9a functionalization from indole.
Scheme 62: Synthesis of mitomycin K. a2 equiv. MoO5.HMPA, MeOH; bPPh3, Et3N, THF-H2O; cMeOTf, Py, DCM; dMe3SiCH...
Scheme 63: Configurational stability of mitomycin K derivatives.
Scheme 64: Epimerization of carbon C9a in compound 227b.
Scheme 65: Corey–Chaykovsky synthesis of indol 235.
Scheme 66: Cory intramolecular aza-Darzens reaction for the formation of aziridinomitosene 239.
Scheme 67: Jimenez synthesis of aziridinomitosene 242.
Scheme 68: Von Braun opening of indoline 244.
Scheme 69: C9a oxidation of an aziridinomitosane with DDQ/OsO4.
Scheme 70: Synthesis of epi-mitomycin K. aNaH, Me2SO4; bH2, Pd/C; cMitscher reagent [165]; d[(trimethylsilyl)methyl...
Scheme 71: Mitomycins rearrangement.
Scheme 72: Fukuyama’s retrosynthesis.
Scheme 73: [2+3] Cycloaddition en route to isomitomycin A. aToluene, 110 °C; bDIBAL, THF, −78 °C; cAc2O, Py.; d...
Scheme 74: Final steps of Fukuyama’s synthesis.
Scheme 75: “Crisscross annulation”.
Scheme 76: Synthesis of 274; the 8-membered ring 274 was made using a crisscross annulation. a20% Pd(OH)2/C, H2...
Scheme 77: Conformational analysis of compound 273 and 275.
Scheme 78: Synthesis of a mitomycin analog. aNa2S2O4, H2O, DCM; bBnBr (10 equiv), K2CO3, 18-crown-6 (cat.), TH...
Scheme 79: Vedejs retrosynthesis.
Scheme 80: Formation of the azomethine ylide.
Scheme 81: Vedejs second synthesis of an aziridinomitosene. aDIBAL; bTPAP, NMO; c287; dTBSCl, imidazole.
Scheme 82: Trityl deprotection and new aziridine protecting group 300.
Scheme 83: Ene reaction towards benzazocinones.
Scheme 84: Benzazocenols via homo-Brook rearrangement.
Scheme 85: Pt-catalyzed [3+2] cycloaddition.
Scheme 86: Carbonylative lactamization entry to benzazocenols. aZn(OTf)2, (+)-N-methylephedrine, Et3N, TMS-ace...
Scheme 87: 8 membered ring formation by RCM. aBOC2O, NaHCO3; bTBSCl, Imidazole, DMF; callyl bromide, NaH, DMF; ...
Scheme 88: Aziridinomitosene synthesis. aTMSN3; bTFA; cPOCl3, DMF; dNaClO2, NaH2PO4, 2-methyl-2-butene; eMeI, ...
Scheme 89: Metathesis from an indole.
Scheme 90: Synthesis of early biosynthetic intermediates of mitomycins.
