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Search for "diesters" in Full Text gives 58 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis and self-assembly of 1-deoxyglucose derivatives as low molecular weight organogelators
- Guijun Wang,
- Hao Yang,
- Sherwin Cheuk and
- Sherman Coleman
Beilstein J. Org. Chem. 2011, 7, 234–242, doi:10.3762/bjoc.7.31
- or less equally nucleophilic [39]. The amount of diester was significantly less than the amounts of the 2- and 3-esters. Diester formation mirrors the synthesis of the diesters of compound 1. The selection of the R groups used in this series was based on our previous results [34][35][36]. We
- results shown in Table 1, quite a few of the diesters were good gelators for the solvents tested. In hexane, only the two short chain terminal acetylene compounds 9A and 10A formed gels. Several diesters were effective gelators for ethanol, including the benzoate 15A and the long chain diacetylene
- compounds 17A and 18A. The two diaryl esters 15A and 16A were also able to form gels in aqueous DMSO solution. Compared to the diesters, the monoesters were not as effective as organogelators; only the 2-pentynoate 9B was able to gelate aqueous DMSO, and the 2-benzoate 15B was able to form a gel in ethanol
Graphical Abstract
Figure 1: Structures of three ester derivatives of compound 1.
Figure 2: Structures of ester analogs 5–7 and headgroup 8.
Scheme 1: Synthesis of a series of esters 9A–18C.
Figure 3: Optical micrographs of the gels formed by compound 9A in hexane at 15 mg/mL (A, B), 9B in DMSO/wate...
Figure 4: An ethanol gel formed by compound 18A at <10 mg/mL. a) A clear solution when heated above 70 °C; b)...
Figure 5: Optical micrographs under bright field (a, b) and scanning electron micrograph (c) of the gel forme...
Figure 6: The UV–vis absorption spectra of the polymerized gel formed by compound 18A in ethanol (10 mg/mL): ...
About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations
- Hatice Mutlu,
- Lucas Montero de Espinosa,
- Oĝuz Türünç and
- Michael A. R. Meier
Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131
- ADMET polymerizations were studied in detail. The isomerization reactions were investigated by degradation of the prepared polyesters via transesterification with methanol, yielding diesters. These diesters, representing the repeat units of the polyesters, were then quantified by GC-MS. Keywords: ADMET
- [30]. In all cases, continuous nitrogen purging was applied throughout the polymerizations and polymerizations were run in duplicate to obtain a reliable set of data. Moreover, the resulting ADMET polymers were transesterified with methanol to yield α,ω-diesters, which were subsequently analyzed by GC
- isomerization. As a result, the corresponding transesterified polymer yields a mixture of diesters with different chain lengths, since double bond isomerisation and olefin metathesis occur concurrently. The molecular weight of the isomerized diesters thus varies by multiples of 14 g/mol (one methylene group
Graphical Abstract
Figure 1: Olefin isomerization during ADMET polymerization.
Figure 2: Ru–indenylidene metathesis catalysts C1 and C2, “boomerang” complexes C3, and Hoveyda–Grubbs 2nd ge...
Figure 3: Representative scheme for the in situ generated Ru–indenylidene [38].
Figure 4: Synthesis of the studied α,ω-diene, its ADMET polymerization, and the strategy to evaluate isomeriz...
Figure 5: GPC traces of the polymerizations performed at 60, 80, 100 and 120 ºC in presence of a) 0.5 mol % C1...
Figure 6: GC-MS study of the acid-catalyzed degradation products of polymers P19, P20, P21, and P22.
Figure 7: GPC traces of polymerizations performed with C1 at 80, 100, and 120 ºC. Samples taken at 5 min (―–)...
Figure 8: DSC traces of ADMET polymers P11 and P12 (Table 1, entries 11 and 12, respectively).
Oxalyl retro-peptide gelators. Synthesis, gelation properties and stereochemical effects
- Janja Makarević,
- Milan Jokić,
- Leo Frkanec,
- Vesna Čaplar,
- Nataša Šijaković Vujičić and
- Mladen Žinić
Beilstein J. Org. Chem. 2010, 6, 945–959, doi:10.3762/bjoc.6.106
- modeling and XRPD studies of diasteroisomeric diesters (S,S)-1b/(S,R)-1b and diacids (S,S)-1b/(S,R)-1a, a basic packing model in their gel aggregates is proposed. The intermolecular hydrogen bonding between extended gelator molecules utilizing both, the oxalamide and peptidic units and layered organization
- ) and diesters (3b, 4b). It appears that the increased hydrogen bonding potential of terminal diamide derivatives provides somewhat more versatile gelators capable of gelating solvents of medium and low polarity where intermolecular hydrogen bonding is favored. TEM and DSC investigations As reported
Graphical Abstract
Scheme 1: Oxalyl retro-dipetide gelators; each b to a, (a) LiOH/MeOH, H2O; (b) H+; each b to c: (c) NH3/MeOH.
Figure 1: Chiral bis(amino acid)-(I) and bis(amino alcohol)-(II)-oxalamide gelators.
Figure 2: TEM images (PWK staining) of: (S,S)-1a H2O/DMSO gel.
Figure 3: TEM images (PWK staining) of: (S,R)-1a H2O/DMSO gel.
Figure 4: TEM images (PWK staining) of: (S,R)-1b toluene gel showing the presence of short tape like aggregat...
Figure 5: The concentration dependence of NH and C*H chemical shifts in (S,R)-1b toluene-d8 gel samples (conc...
Figure 6: The concentration dependence of NH and C*H chemical shifts in (S,S)-1b and its racemate (S,S)-1b/(R...
Figure 7: Temperature dependence of: a) oxalamide NH protons (▲), Leu-NH protons (Δ) and b) oxalamide-α-Leu-C...
Figure 8: Temperature dependent CD spectra of: a) (S,R)-1b decalin gel (c = 3.4·10−2 M); b) (S,S)-1b decalin ...
Figure 9: X-ray powder diffractograms of (a) (S,R)-1b and (b) (S,S)-1b xerogels prepared from their toluene g...
Figure 10: (a) Fully minimized the lowest energy conformations of (S,S)-1b (top) and (S,R)-1b generated by sys...
Figure 11: Schematic presentation of the proposed (S,S)-1b and (S,R)-1b basic packing model based on XRPD, 1H ...
Figure 12: X-ray powder diffraction (XRPD) diagram of (S,R)-1a water/DMSO xerogel.
Conjugated polymers containing diketopyrrolopyrrole units in the main chain
- Bernd Tieke,
- A. Raman Rabindranath,
- Kai Zhang and
- Yu Zhu
Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92
- step in high yield by the reaction of benzonitrile (or other aromatic nitriles) with succinic acid diesters. Numerous DPP derivatives have since been synthesized, their colours ranging from orange yellow via red to purple. Many DPP derivatives exhibit a high photostability in the solid state, weather
Graphical Abstract
Figure 1: Structure of 3,6-diphenyl-substituted 2,5-diketopyrrolo[3,4-c]pyrrole (DPP).
Scheme 1: Synthesis of DPP monomers.
Figure 2: Plot of current density and light intensity versus voltage of polymer light-emitting diode containi...
Scheme 2: Pd-catalyzed coupling reactions for preparation of DPP-containing polymers.
Figure 3: Optical properties of some diphenylDPP-based conjugated polymers.
Figure 4: Optical properties of copolymers P-21 and P-22 based on two isomeric diphenylDPP monomer units (fro...
Figure 5: Absorption spectroelectrochemical plots of P-25 and P-26 as thin films on ITO glass. Scan rate: 100...
Scheme 3: Thiophenyl-DPP-based polymers.
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...
Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues
- Aleksandra Jankowiak,
- Piotr Kaszynski,
- William R. Tilford,
- Kiminori Ohta,
- Adam Januszko,
- Takashi Nagamine and
- Yasuyuki Endo
Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83
- ] and also diesters 17 [2] provide an opportunity for further investigation of this interesting phenomenon. Therefore, we focused on series 14–16 to investigate the CH2O, COO, OOC connecting groups, and also on series 17–20 to study the CH2O, CH2CH2, COO, OOC groups. Here we describe the preparation of
- an isostructural series of diesters 16[6] and 18B, and also tetraesters 19 and 20, and a detailed comparative analysis focusing on the impact of the connecting group on mesogenic properties. The analysis is aided by molecular modeling of the pertinent molecular fragments. In addition, we report two
- homologues of 16A[6], diesters 16A[5] and 16A[7]. Results Synthesis Diesters 16[n] were prepared from diphenols 21 and appropriate carboxylic acid chlorides in the presence of a base as shown in Scheme 1. The requisite diphenols 21 were obtained in nearly quantitative yields by treating the corresponding
Graphical Abstract
Figure 1: The molecular structures of 1,12-dicarba-closo-dodecaborane (12-vertex p-carborane, A) and 1,10-dic...
Figure 2: The molecular structures of derivatives 1–20.
Scheme 1: Preparation of diesters 16[n].
Scheme 2: Preparation of esters 18–20.
Scheme 3: Preparation of phenol 24.
Figure 3: Partial DSC trace for 16D[6]. Heating rate 5 K/min.
Figure 4: Optical textures of 16D[6] obtained for the same region of the sample upon cooling: (a) SmA growing...
Figure 5: The change in the clearing temperature ΔTc upon substitution –OCH2– → –CH2CH2– in selected pairs of...
Figure 6: The change in the clearing temperature ΔTc upon replacing of the –OCH2– connecting group with anoth...
Figure 7: Equilibrium ground state geometries (B3LYP/6-31G(d)) for benzene derivatives: ethoxybenzene (25), p...
Phase- vanishing halolactonization of neat substrates
- Nicole Windmon and
- Veljko Dragojlovic
Beilstein J. Org. Chem. 2008, 4, No. 29, doi:10.3762/bjoc.4.29
- GC-MS analysis). Thus, formation of dibromo products decreased compared to 4-pentenoic acid. Interestingly, no dibromo derivatives at all were observed in bromolactonizations of diacid 14 and diesters 17 and 20 (Table 1, entries 3, 6 and 8). Iodine monochloride also worked very well on the same
- liquid and solid substrates. Although the diesters 17 and 20 are solids, their reactions proceeded through formation of melts [17] and gave the corresponding halolactones in high yields (Table 1, entries 6–9). However, stirring was necessary as the respective products were also solids and sometimes they
Graphical Abstract
Scheme 1: Bromolactonization of 4-pentenoic acid.
Scheme 2: Bromolactonization of 4-pentenoic acid in ethyl acetate.
Scheme 3: Iodolactonization of 4-pentenoic acid.
Scheme 4: Bromolactonization of 5-norbornene-2-carboxylic acid.
Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives
- Andrew Kennedy,
- Adam Nelson and
- Alexis Perry
Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2
- ] although the reducing agent still approaches the ketone from a pseudo-axial direction, the net stereochemical outcome is different (see Figure 6). The configuration of both alcohols in the bis-allylic alcohols trans-27 and cis-27 was cleanly inverted using a Mitsunobu reaction, and the resulting diesters
Graphical Abstract
Scheme 1:
Scheme 2:
Scheme 3:
Figure 1: Diastereoselective substitution of the N,O acetal 12
Scheme 4:
Figure 2: Diastereoselective Luche reduction of piperidinones
Scheme 5:
Figure 3: Diastereoselective dihydroxylation of unsaturated piperidines
Figure 4: Diagnostic nOe observations for the piperidine 22A
Figure 5: Diagnostic nOe observations for the piperidines 22C and 22D
Scheme 6:
Figure 6: Stereoselectivity of two-directional Luche reductions
Scheme 7:
Scheme 8:
Figure 7: Two-directional functionalisation by diastereoselective dihydroxylation
