Search results
Search for "pyrene" in Full Text gives 107 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of (−)-julocrotine and a diversity oriented Ugi-approach to analogues and probes
- Ricardo A. W. Neves Filho,
- Bernhard Westermann and
- Ludger A. Wessjohann
Beilstein J. Org. Chem. 2011, 7, 1504–1507, doi:10.3762/bjoc.7.175
- reagent, to yield the designed probe prototype 10 in 80% yield (from 8). Pyrene derivative 10 exhibited strong blue luminescence in both solution and solid phase. This probe may be used for tracking the (−)-julocrotine in biological systems, in particular in promastigote and amastigote forms of protozoan
Graphical Abstract
Figure 1: Retrosynthetic scheme for (−)-julocrotine (1).
Scheme 1: Reactions and conditions: (a) DCC, NHS, DMF 80 °C, 18 h, 76%. (b) Ph(CH2)2Br, K2CO3, acetone, r.t.,...
Scheme 2: Reactions and conditions: (a) (CH2O)n, MeOH, r.t., 2 h then, RCOOH and t-BuNC, r.t., 18 h.
Scheme 3: Reactions and conditions: (a) (CH2O)n, MeOH, r.t., 2 h then, (S)-2-methylbutanoic acid and 7, r.t. ...
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
- ]. Fluorescent particles of polystyrene were created in miniemulsion by copolymerizing styrene, the cationic polymerizable surfactant N,N-dimethyl-N-n-dodecyl-N-2-methacryloyloxyethyl ammonium bromide, and eventually the polymerizable dye 1-pyrenylmethyl methacrylate [60]. The pyrene dye encapsulated in the
- particles displayed an excitation lifetime 17 times longer than pyrene dissolved in THF. Metal-catalyzed polymerizations At the end of the last century, many groups focused their research on the production of polyolefins in aqueous media. Ethylene as one of the most industrially relevant monomers was
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...
Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission
- Ritesh Nandy and
- Sethuraman Sankararaman
Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112
- state rendering its fluorescence emission sensitive to environment and solvent polarity [20][21][22]. Pyrene is a prototypical example of a fluorophore and its monomer emission occurs around 380 nm. It has been shifted to as high as 600 nm by multiple substitution by groups that extend the conjugation
- and also by substituting donor-acceptor groups along the conjugation [23][24][25]. In addition, pyrene also exhibits excimer emission at a longer wavelength compared to monomer emission which can be used in sensing applications [26][27][28][29][30]. The pyrene chromophore can act as a donor or as an
- acceptor depending upon the substituent. Pyrene- π spacer-donor and pyrene- π spacer-acceptor type molecules have been widely studied and they have been used in sensing, photo and electro-luminescence applications [31][32][33][34][35][36]. Unlike pyrene, the triphenylene chromophore has not been widely
Graphical Abstract
Scheme 1: Structures of 2-phenylethynyltriphenylene derivatives.
Scheme 2: Synthesis of 2-ethynyltriphenylene (4).
Scheme 3: Synthesis of phenylethynyltriphenylene derivatives 1a–g.
Figure 1: Absorption spectra of 1a–g in cyclohexane and acetonitrile (10−5 M).
Figure 2: Fluorescence emission spectra of 1a–g in cyclohexane and DMSO (10−5 M), λex = 335 nm.
Figure 3: Fluorescence emission spectra of 1e and 1g in various solvents (10−5 M). CH – cyclohexane (λex = 33...
Figure 4: Effect of binary solvent system (cyclohexane-isopropyl alcohol) on the fluorescence emission of 1g ...
Figure 5: Lippert–Mataga plot showing Stokes shift as a function of solvent orientation polarizibility (Δf).
Figure 6: Correlation of Stokes shift with ET(30) scale.
Figure 7: HOMO and LUMO surfaces of 1c and 1g according to DFT calculations.
Synthesis and crossover reaction of TEMPO containing block copolymer via ROMP
- Olubummo Adekunle,
- Susanne Tanner and
- Wolfgang H. Binder
Beilstein J. Org. Chem. 2010, 6, No. 59, doi:10.3762/bjoc.6.59
- addition of cold ethyl vinyl ether. The polymer was isolated by column chromatography (SiO2) (eluent: DCM). Kinetic experiments A pyrene stock solution was prepared from 70 mg of pyrene dissolved in 2 ml of CDCl3. Monomer A 7 (20.83 mg, 0.099 mmol) dissolved in CDCl3 (0.2 ml) was first introduced into the
- NMR tube and then the pyrene stock solution (0.2 ml) was added. Before adding the initiator solution, the ratio of the monomer to the internal standard was determined by NMR. On the basis of this value, the monomer concentration at t = 0 was determined. A solution of the catalyst U3 (1.48 mg, 0.0019
- was monitored by integrating the resonance peaks at 6.27 and 6.07 ppm. For determination of the monomer concentration at t = 0 and the monomer consumption, the corresponding signals at 6.27 and 6.07 ppm from monomer A 7 compared with the one at 8.20 ppm from the internal standard pyrene were
Graphical Abstract
Scheme 1: Grubbs G1–G3 and Umicore U1–U3 catalyst.
Scheme 2: Synthetic pathway to BCP-AnTm using Grubbs’ (1–3) and Umicore (4–6) type catalysts.
Figure 1: 1H NMR spectrum of the homopolymer A50 synthesized with the catalyst U3.
Figure 2: 13C NMR spectrum of the homopolymer A50 synthesized with catalyst U3.
Figure 3: Kinetic progress monitored via 1H NMR spectroscopy of the polymerization of monomer A 7 with cataly...
Figure 4: Kinetic progress monitored via 1H NMR spectroscopy of the polymerization of 7 with catalyst U3; [7]...
Figure 5: ln([M]0/[M]t) vs. time (t) plot obtained from 1H NMR spectra for homopolymer-A50 using catalyst U3;...
Figure 6: Mn vs. time (t) kinetic plot and Mw/Mn (PDI) of the polymerization of monomer T 9 with catalyst U3;...
Figure 7: GPC trace of the block copolymer A25T25 synthesized with catalyst U3.
Figure 8: MALDI-TOF mass spectra of homopolymer A25 4 synthesized with catalyst U3: (a) full spectrum, (b) ex...
Figure 9: MALDI-TOF mass spectrum of BCP-A25T1 synthesized with catalyst U3.
Figure 10: MALDI-TOF mass spectrum of BCP-A25T2 13 synthesized with catalyst U3.
Figure 11: MALDI-TOF mass spectrum of BCP-A25T25 synthesized with catalyst U3.
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...
Aroylketene dithioacetal chemistry: facile synthesis of 4-aroyl- 3-methylsulfanyl- 2-tosylpyrroles from aroylketene dithioacetals and TosMIC
- H. Surya Prakash Rao and
- S. Sivakumar
Beilstein J. Org. Chem. 2007, 3, No. 31, doi:10.1186/1860-5397-3-31
- of the cannabinoids. [14] In continuation, and by following the method presently developed, the trisubstituted pyrrole 7 having pyrenoyl substituent was synthesized from AKDTA 6 (Scheme 3). Initially, 1-acetylpyrene 5 was transformed to hitherto unknown pyrene based AKDTA 6 by reaction with carbon
- disulfide and sodium tert-butoxide followed by alkylation with dimethyl sulfate. The reaction of TosMIC 2 with AKDTA 6 provided the trisubstituted pyrrole 7 in excellent yield. As anticipated, the 1H NMR spectrum of pyrenoylpyrrole 7 exhibited a doublet for C2'-H of pyrene unit as a doublet at δ 8.37 ppm
Graphical Abstract
Scheme 1: Cycloaddition of TosMIC to AKDTAs provide 2,3,4-trisubstituted pyrroles 3 and imidazole 4.
Scheme 2: Base induced dimerization of TosMIC to furnish imidazole 4.
Figure 1: Structure of 2,3,4-trisubstituted pyrroles 3a-g synthesized in this study.
Scheme 3: Synthesis of AKDTA 6 and it's further transformation to pyrrole 7.
Scheme 4: Regio-selectivity in the reaction of TosMIC with 8.
Scheme 5: Competition experiments involving one mmol each of TosMIC with AKDTA 1a and phenyl vinyl ketone 10 ...
Hydrogen bonding patterns in the cocrystals of 5-nitrouracil with several donor and acceptor molecules
- Reji Thomas,
- R. Srinivasa Gopalan,
- G. U. Kulkarni and
- C. N. R. Rao
Beilstein J. Org. Chem. 2005, 1, No. 15, doi:10.1186/1860-5397-1-15
- ,[19] who reported the formation of pyrene nanorods within a supramolecular framework. 5-nitrouracil, I, is an interesting molecule which can be crystallized in centric and non-centric structures. [21][22] The centric structure obtained by crystallizing I from water, exhibits tapes of nitrouracil
Graphical Abstract
Scheme 1: Hydrogen bonding patterns of I commonly found in its cocrystals with other molecules. Cyclic N-H......
Figure 1: Dioxane molecules held between the zig-zag rows of I, viewed (a) perpendicular and (b) parallel to ...
Figure 2: Cocrystal of I and piperazine: (a) A molecular layer showing alternating tapes of I and piperazine....
Figure 3: Cocrystal of I and N,N'-dimethylpiperazine: (a) A molecular layer showing alternating chains of I a...
Figure 4: Cocrystal of I and pyridine: A molecular layer showing alternating rows of I and pyridine.
Figure 5: Cocrystal of I and formamide: A molecular layer showing tapes of mixed composition,I and formamide,...
Figure 6: Cocrystal of I, ethanol and water: (a) A molecular layer showing tapes of mixed compositions- tapes...
Figure 7: Cocrystal of I and 3-aminopyridine: Stacks of molecular tapes arranged in alternating parallel and ...
Figure 8: Cocrystal of I and DABCO: A view along the diagonal of the ab plane showing the supramolecular asse...
Figure 9: (a) Tetrahedral pentamers of water in the ab plane forming a nearly square arrangement (b) Hydrogen...
Figure 10: A tetrahedron pentamer of water. The O...O distances and H-O-H angles are indicated in the inset.
