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Search for "amino acid derivatives" in Full Text gives 84 result(s) in Beilstein Journal of Organic Chemistry.
Homoallylic amines by reductive inter- and intramolecular coupling of allenes and nitriles
- Peter Wipf and
- Marija D. Manojlovic
Beilstein J. Org. Chem. 2011, 7, 824–830, doi:10.3762/bjoc.7.94
- of the Boc-protected aminopyran ring in 21. One-pot hydrozirconation-reductive coupling of allene 2 and nitrile 7. Cyclization of allenylnitrile 18. Proposed chelated transition state model. Conversion of homoallylic amines to β-amino acid derivatives. Reaction of N-aluminoimines with
Graphical Abstract
Scheme 1: One-pot hydrozirconation-reductive coupling of allene 2 and nitrile 7.
Scheme 2: Cyclization of allenylnitrile 18.
Figure 1: Coupling constant analysis of the Boc-protected aminopyran ring in 21.
Scheme 3: Proposed chelated transition state model.
Scheme 4: Conversion of homoallylic amines to β-amino acid derivatives.
Anthracene appended pyridinium amide–urea conjugate in selective fluorometric sensing of L-N-acetylvaline salt
- Kumaresh Ghosh,
- Tanmay Sarkar and
- Asoke P. Chattopadhyay
Beilstein J. Org. Chem. 2010, 6, 1211–1218, doi:10.3762/bjoc.6.139
- to the charge–charge interaction and formation of unconventional hydrogen bonds with the anionic guests [27]. In order to explore this binding site for a wide range of substrates, especially for amino acid derivatives, we report here the design and synthesis of a new fluororeceptor 1 where anthracene
Graphical Abstract
Figure 1: Synthesized compounds 1 and 2.
Scheme 1: Syntheses of 1 and 2.
Figure 2: Change in 1H NMR of (A) 1 (400 MHz, CDCl3 containing 0.4% d6-DMSO; c = 2.80 × 10−3 M) and in the pr...
Figure 3: Change in fluorescence ratio of 1 upon addition of one equivalent of anions (c = 4.31 × 10−5 M) at ...
Figure 4: Change in emission of 1 (c = 4.31 × 10−5 M) upon gradual addition of tetrabutylammonium salts of (a...
Figure 5: Suggested modes of binding of the amino acid salts into the open cleft of 1.
Figure 6: Fluorescence titration curves for 1 (c = 4.31 × 10−5 M) at 492 nm.
Figure 7: Fluorescence decays (at λmax = 420 nm) of receptor 1 upon the addition of 1 equiv of L-N-acetylvali...
Figure 8: Change in absorbance of 1 (c = 4.31 × 10−5 M) upon gradual addition of tetrabutylammonium salts of ...
Figure 9: DFT optimized geometry of the complex of 1 with L-N-acetylvaline carboxylate salt [a = 1.93 Å, b = ...
En route to photoaffinity labeling of the bacterial lectin FimH
- Thisbe K. Lindhorst,
- Michaela Märten,
- Andreas Fuchs and
- Stefan D. Knight
Beilstein J. Org. Chem. 2010, 6, 810–822, doi:10.3762/bjoc.6.91
- scaffold molecule in two different ways in order to allow fine-tuning of the spacing between the mannoside ligand and the photoactive group. Thus, the amino acid derivatives Fmoc-Asp-OtBu and Fmoc-Asp(OtBu)-OH were employed in two analogous synthetic pathways, starting with peptide coupling to the known 2
Graphical Abstract
Figure 1: The photoaffinity technique allows the identification of ligand binding sites of a receptor protein...
Figure 2: a) Three known photolabile α-D-mannosides that differ in the nature of the photoactive functional g...
Scheme 1: Synthesis of photoactive glycoamino acids 11 and 12. i) Fmoc-Asp-OtBu (for 7), Fmoc-Asp(OtBu)-OH (f...
Scheme 2: Photo-crosslinking experiments with the model peptide angiotensin II and the photoactive mannosides ...
Figure 3: Affino dot–blot with FimHtr and photoactive mannosides applied to nitrocellulose disks. It was irra...
Figure 4: MS/MS spectra of angiotensin II (a) and of angiotensin II, photo-crosslinked with diazirine 2 (b), ...
Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective
- Norio Shibata,
- Andrej Matsnev and
- Dominique Cahard
Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65
- the synthesis of sugar and amino acid derivatives. Reagents 35 and 37 have been identified as mild and efficient trifluoromethylating reagents for primary and secondary aryl- and alkylphosphines. Both reacted with equal efficiency at −78 °C to rt without any added base since the reagents generate base
Graphical Abstract
Scheme 1: Preparation of the first electrophilic trifluoromethylating reagent and its reaction with a thiophe...
Scheme 2: Synthetic routes to S-CF3 and Se-CF3 dibenzochalcogenium salts.
Scheme 3: Synthesis of (trifluoromethyl)dibenzotellurophenium salts.
Scheme 4: Nitration of (trifluoromethyl)dibenzochalcogenium salts.
Scheme 5: Synthesis of a sulphonium salt with a bridged oxygen.
Scheme 6: Reactivity of (trifluoromethyl)dibenzochalcogenium salts.
Scheme 7: Pd(II)-Catalyzed ortho-trifluoromethylation of heterocycle-substituted arenes by Umemoto’s reagents....
Scheme 8: Mild electrophilic trifluoromethylation of β-ketoesters and silyl enol ethers.
Scheme 9: Enantioselective electrophilic trifluoromethylation of β-ketoesters.
Scheme 10: Preparation of water-soluble S-(trifluoromethyl)dibenzothiophenium salts.
Scheme 11: Method for large-scale preparation of S-(trifluoromethyl)dibenzothiophenium salts.
Scheme 12: Triflic acid catalyzed synthesis of 5-(trifluoromethyl)thiophenium salts.
Scheme 13: Trifluoromethylation of β-ketoesters and dicyanoalkylidenes by S-(trifluoromethyl)benzothiophenium ...
Scheme 14: Synthesis of chiral S-(trifluoromethyl)benzothiophenium salt 18 and attempt of enantioselective tri...
Scheme 15: Synthesis of O-(trifluoromethyl)dibenzofuranium salts.
Scheme 16: Photochemical O- and N-trifluoromethylation by 20b.
Scheme 17: Thermal O-trifluoromethylation of phenol by diazonium salt 19a. Effect of the counteranion.
Scheme 18: Thermal O- and N-trifluoromethylations.
Scheme 19: Method of preparation of S-(trifluoromethyl)diphenylsulfonium triflates.
Scheme 20: Reactivity of some S-(trifluoromethyl)diarylsulfonium triflates.
Scheme 21: One-pot synthesis of S-(trifluoromethyl)diarylsulfonium triflates.
Scheme 22: One-pot synthesis of Umemoto’s type reagents.
Scheme 23: Preparation of sulfonium salts by transformation of CF3− into CF3+.
Scheme 24: Selected reactions with the new Yagupolskii reagents.
Scheme 25: Synthesis of heteroaryl-substituted sulfonium salts.
Scheme 26: First neutral S-CF3 reagents.
Scheme 27: Synthesis of Togni reagents. aYield for the two-step procedure.
Scheme 28: Trifluoromethylation of C-nucleophiles with 37.
Scheme 29: Selected examples of trifluoromethylation of S-nucleophiles with 37.
Scheme 30: Selected examples of trifluoromethylation of P-nucleophiles with 35 and 37.
Scheme 31: Trifluoromethylation of 2,4,6-trimethylphenol with 35.
Scheme 32: Examples of O-trifluoromethylation of alcohols with 35 in the presence of 1 equiv of Zn(NTf2)2.
Scheme 33: Formation of trifluoromethyl sulfonates from sulfonic acids and 35.
Scheme 34: Organocatalytic α-trifluoromethylation of aldehydes with 37.
Scheme 35: Synthesis of reagent 42 and mechanism of trifluoromethylation.
Scheme 36: Trifluoromethylation of β-ketoesters and dicyanoalkylidenes with 42.
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
- crown macrocycles have been developed by Lee et al. [154] who studied their enantiomeric recognition properties towards a number of amino acid derivatives and chiral organic ammonium salts using UV–vis and NMR methods. The macrocycles were found to be strong chelating agents for primary organic ammonium
- values with triamine 45c. Based on this phenolphthalein skeleton, the host was later further developed for use in visual enantiomeric discrimination [185] (Figure 28). Various types of chiral host molecules were examined for their enantioselective color effect in complexation with chiral amino acid
- derivatives in methanol solution. The methyl substituted compound (S,S,S,S)-46a showed a particularly prominent selectivity for the alanine amide derivatives with 1,5-pentane diamine and 1,6-hexane diamine: A combination of methyl substituted host (S,S,S,S)-46a with the R-enantiomers developed a purple color
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...
Fused bicyclic piperidines and dihydropyridines by dearomatising cyclisation of the enolates of nicotinyl-substituted esters and ketones
- Heloise Brice,
- Jonathan Clayden and
- Stuart D. Hamilton
Beilstein J. Org. Chem. 2010, 6, No. 22, doi:10.3762/bjoc.6.22
- scope of the dearomatisation can be extended to much less reactive nucleophiles with a more electron deficient aromatic acceptor [39][40][41]. Thus enolates of glycine esters 1 carrying isonicotinoyl or nicotinoyl N-substituents cyclise readily to yield bicyclic amino acid derivatives 2 (Scheme 1a for
Graphical Abstract
Scheme 1: Dearomatising cyclisations (a) of enolates; (b) of electron-rich heteroaromatics.
Scheme 2: Synthesis of ketone 7.
Scheme 3: Dearomatising cyclisation to a 5-benzoylhexahydroisoquinoline.
Scheme 4: Synthesis of ester 12.
Scheme 5: Dearomatising cyclisation of ester 12.
Figure 1: Coupling constants (Hz) in the major diastereoisomer of 15.
Scheme 6: Synthesis of esters 18.
Scheme 7: Dearomatising cyclisation to form tetrahydrofurans.
Figure 2: Determination of the stereochemistry of 20b. Arrows indicate nuclear Overhauser enhancements.
Enantioselective synthesis of tricyclic amino acid derivatives based on a rigid 4-azatricyclo[5.2.1.02,6]decane skeleton
- Matthias Breuning,
- Tobias Häuser,
- Christian Mehler,
- Christian Däschlein,
- Carsten Strohmann,
- Andreas Oechsner and
- Holger Braunschweig
Beilstein J. Org. Chem. 2009, 5, No. 81, doi:10.3762/bjoc.5.81
- -C2 side chain, has been developed. A key intermediate was the chiral, N-Boc-protected ketone (1R,2S,6S,7R)-4-azatricyclo[5.2.1.02,6]decan-8-one, available from inexpensive endo-carbic anhydride in five steps and 47% yield. The rigid scaffold makes these amino acid derivatives promising candidates for
- ][8] are embedded in peptidomimetics (Figure 1). Enantioselective organocatalysis [9][10][11][12][13][14][15][16][17] is another field of application for conformationally rigid amino acid derivatives. In this context, focus was also put on derivatives in which the activating acidic group is anchored
- reactions. Our studies targeted the chiral, tricyclic amino acid derivatives 7 and 8 (Figure 2), which possess a central norbornane framework equipped with a 2-endo,3-endo-annelated pyrrolidine ring. Due to the constrained, bowl-shaped backbone, these compounds may possess high potential as β-turn-inducing
Graphical Abstract
Figure 1: The conformationally rigid amino acid derivatives 1–3 (β-turn-inducing building blocks) and 4–6 (su...
Figure 2: The targeted tricyclic amino acid derivatives 7 and 8, and the key intermediate 9.
Scheme 1: Synthesis of the racemic ketone rac-9. i) NH4OAc, HOAc, Δ, 4 d, 100%; ii) LiAlH4, THF, Δ, 1 d, 87% [24]...
Scheme 2: Enantioselective hydrosilylation/oxidation of 11. i) HSiCl3, [Pd(C3H5)Cl]2 (0.06 mol %), (R)-MOP (0...
Figure 3: X-ray crystal structure of 9. X-ray data have been deposited with the Cambridge Crystallographic Da...
Scheme 3: Initial route to the aldehyde rac-15. i) MePPh3+Br−, t-BuOK, toluene, Δ, 7 h, 77% or Mg, TiCl4, CH2...
Scheme 4: Assembly of the amino acid 7a•HCl and the N-tosylamide 7b•HCl. i) MeOCH2PPh3+Cl−, t-BuOK, toluene/T...
Scheme 5: Preparation of the amino acid 8a•HCl and the N-tosylamide 8b•HCl. i) TMSCH2CO2Et, LDA, THF, −78 °C ...
Figure 4: X-ray crystal structure of 8a•MeOH. X-ray data have been deposited with the Cambridge Crystallograp...
The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines
- Matthew J. McGrath and
- Carsten Bolm
Beilstein J. Org. Chem. 2007, 3, No. 33, doi:10.1186/1860-5397-3-33
- aryl-alkylsulfoximines are generally prepared by resolution with camphorsulfonic acid but this method is not applicable to dialkyl sulfoximines. [5][6][7] Imination of enantioenriched sulfoxides and derivatisation of sulfoximines with enantiomerically pure amino acid derivatives also provide
Graphical Abstract
Scheme 1: Desymmetrisation of N-trialkylsilyldimethylsulfoximines using chiral bases
Scheme 2: Preparation of N-trialkylsilyl dimethyl sulfoximine derivatives
Figure 1: The diamine (-)-sparteine and three chiral lithium amide bases.
Scheme 3: Preparation of vinyl sulfoximines
Figure 2: Selected NMR Characteristics of sulfoximine amides 12, 13 and 14.
Scheme 4: Preparation of O-methyl mandelamide derivatives (S,R)-12 and (R,R)-12
Scheme 5: The influence of (S,S)-bis(1-phenylethyl)amine on the ee of 1b
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
- 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.
