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Search for "bicyclic ring" in Full Text gives 34 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis, characterization and DNA interaction studies of new triptycene derivatives
- Sourav Chakraborty,
- Snehasish Mondal,
- Rina Kumari,
- Sourav Bhowmick,
- Prolay Das and
- Neeladri Das
Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130
- ; ethynyl; pUC19 plasmid; triptycene tripod; Introduction Triptycene is the simplest member of the class of compounds called iptycenes. Structurally, iptycenes have a number of arene rings joined together to form the bridges of [2.2.2]bicyclic ring systems. In triptycene, the bicyclic ring is decorated
Graphical Abstract
Scheme 1: Synthesis of TETs 1 and 2 and TATs 3 and 4.
Scheme 2: Synthesis of triptycenetripropiolic acid (TPA) 5 and 6.
Scheme 3: Synthesis of triphosphinotriptycenes (TPT) 7 and 8.
Figure 1: Nuclease activities of the triptycene derivatives 1–8. Agarose gel (top) shows results of the incub...
Figure 2: Effect of triptycene derivatives on the restriction endonuclease activity of HindIII and BamHI enzy...
Figure 3: (A) Oligomer duplex sequence that was used to study the effect of triptycene derivatives on the aba...
Figure 4: UV–vis spectra showing the hyperchromic effect after addition of ctDNA (20 μM) to 5 and 6 (80 μM).
Figure 5: UV–vis absorption spectra of (A) 2,6,14-trisubstituted triptycene derivatives 1, 3, 5 and 7 in DMSO...
An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles
- Marcus Baumann and
- Ian R. Baxendale
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
- bicyclic ring system of the highly substituted aromatic 1.104 (Scheme 19). A SNAr reaction is then used to introduce the saturated piperidinopyrrolidine appendage 1.105 to furnish the desired structure [57][58][59][60]. In order to obtain a high yield for the substitution reaction a one-pot procedure was
Graphical Abstract
Scheme 1: Scaled industrial processes for the synthesis of simple pyridines.
Scheme 2: Synthesis of nicotinic acid from 2-methyl-5-ethylpyridine (1.11).
Scheme 3: Synthesis of 3-picoline and nicotinic acid.
Scheme 4: Synthesis of 3-picoline from 2-methylglutarodinitrile 1.19.
Scheme 5: Picoline-based synthesis of clarinex (no yields reported).
Scheme 6: Mode of action of proton-pump inhibitors and structures of the API’s.
Scheme 7: Hantzsch-like route towards the pyridine rings in common proton pump inhibitors.
Figure 1: Structures of rosiglitazone (1.40) and pioglitazone (1.41).
Scheme 8: Synthesis of rosiglitazone.
Scheme 9: Syntheses of 2-pyridones.
Scheme 10: Synthesis and mechanism of 2-pyrone from malic acid.
Scheme 11: Polymer-assisted synthesis of rosiglitazone.
Scheme 12: Synthesis of pioglitazone.
Scheme 13: Meerwein arylation reaction towards pioglitazone.
Scheme 14: Route towards pioglitazone utilising tyrosine.
Scheme 15: Route towards pioglitazone via Darzens ester formation.
Scheme 16: Syntheses of the thiazolidinedione moiety.
Scheme 17: Synthesis of etoricoxib utilising Negishi and Stille cross-coupling reactions.
Scheme 18: Synthesis of etoricoxib via vinamidinium condensation.
Figure 2: Structures of nalidixic acid, levofloxacin and moxifloxacin.
Scheme 19: Synthesis of moxifloxacin.
Scheme 20: Synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane 1.105.
Scheme 21: Synthesis of levofloxacin.
Scheme 22: Alternative approach to the levofloxacin core 1.125.
Figure 3: Structures of nifedipine, amlodipine and clevidipine.
Scheme 23: Mg3N2-mediated synthesis of nifedipine.
Scheme 24: Synthesis of rac-amlodipine as besylate salt.
Scheme 25: Aza Diels–Alder approach towards amlodipine.
Scheme 26: Routes towards clevidipine.
Figure 4: Examples of piperidine containing drugs.
Figure 5: Discovery of tiagabine based on early leads.
Scheme 27: Synthetic sequences to tiagabine.
Figure 6: Structures of solifenacin (2.57) and muscarine (2.58).
Scheme 28: Enantioselective synthesis of solifenacin.
Figure 7: Structures of DPP-4 inhibitors of the gliptin-type.
Scheme 29: Formation of inactive diketopiperazines from cis-rotameric precursors.
Figure 8: Co-crystal structure of carmegliptin bound in the human DPP-4 active site (PDB 3kwf).
Scheme 30: Improved route to carmegliptin.
Figure 9: Structures of lamivudine and zidovudine.
Scheme 31: Typical routes accessing uracil, thymine and cytosine.
Scheme 32: Coupling between pyrimidones and riboses via the Vorbrüggen nucleosidation.
Scheme 33: Synthesis of lamivudine.
Scheme 34: Synthesis of raltegravir.
Scheme 35: Mechanistic studies on the formation of 3.22.
Figure 10: Structures of selected pyrimidine containing drugs.
Scheme 36: General preparation of pyrimidines and dihydropyrimidones.
Scheme 37: Synthesis of imatinib.
Scheme 38: Flow synthesis of imatinib.
Scheme 39: Syntheses of erlotinib.
Scheme 40: Synthesis of erlotinib proceeding via Dimroth rearrangement.
Scheme 41: Synthesis of lapatinib.
Scheme 42: Synthesis of rosuvastatin.
Scheme 43: Alternative preparation of the key aldehyde towards rosuvastatin.
Figure 11: Structure comparison between nicotinic acetylcholine receptor agonists.
Scheme 44: Syntheses of varenicline and its key building block 4.5.
Scheme 45: Synthetic access to eszopiclone and brimonidine via quinoxaline intermediates.
Figure 12: Bortezomib bound in an active site of the yeast 20S proteasome ([114], pdb 2F16).
Scheme 46: Asymmetric synthesis of bortezomib.
Figure 13: Structures of some prominent piperazine containing drugs.
Figure 14: Structural comparison between the core of aplaviroc (4.35) and a type-1 β-turn (4.36).
Scheme 47: Examplary synthesis of an aplaviroc analogue via the Ugi-MCR.
Scheme 48: Syntheses of azelastine (5.1).
Figure 15: Structures of captopril, enalapril and cilazapril.
Scheme 49: Synthesis of cilazapril.
Figure 16: Structures of lamotrigine, ceftriaxone and azapropazone.
Scheme 50: Synthesis of lamotrigine.
Scheme 51: Alternative synthesis of lamotrigine (no yields reported).
Figure 17: Structural comparison between imiquimod and the related adenosine nucleoside.
Scheme 52: Conventional synthesis of imiquimod (no yields reported).
Scheme 53: Synthesis of imiquimod.
Scheme 54: Synthesis of imiquimod via tetrazole formation (not all yields reported).
Figure 18: Structures of various anti HIV-medications.
Scheme 55: Synthesis of abacavir.
Figure 19: Structures of diazepam compared to modern replacements.
Scheme 56: Synthesis of ocinaplon.
Scheme 57: Access to zaleplon and indiplon.
Scheme 58: Different routes towards the required N-methylpyrazole 6.65 of sildenafil.
Scheme 59: Polymer-supported reagents in the synthesis of key aminopyrazole 6.72.
Scheme 60: Early synthetic route to sildenafil.
Scheme 61: Convergent preparations of sildenafil.
Figure 20: Comparison of the structures of sildenafil, tadalafil and vardenafil.
Scheme 62: Short route to imidazotriazinones.
Scheme 63: Alternative route towards vardenafils core imidazotriazinone (6.95).
Scheme 64: Bayer’s approach to the vardenafil core.
Scheme 65: Large scale synthesis of vardenafil.
Scheme 66: Mode of action of temozolomide (6.105) as methylating agent.
Scheme 67: Different routes to temozolomide.
Scheme 68: Safer route towards temozolomide.
Figure 21: Some unreported heterocyclic scaffolds in top market drugs.
Development of peptidomimetic ligands of Pro-Leu-Gly-NH2 as allosteric modulators of the dopamine D2 receptor
- Swapna Bhagwanth,
- Ram K. Mishra and
- Rodney L. Johnson
Beilstein J. Org. Chem. 2013, 9, 204–214, doi:10.3762/bjoc.9.24
- -receptor-modulating activity [42]. As in the lactam series, the biological activity of the bicylic derivatives was enhanced by incorporating hydrophobic moieties of the bicyclic ring system that would be in a position to access the hydrophobic pocket believed to be interacting with the leucyl side chain of
Graphical Abstract
Figure 1: PLG peptidomimetic design approach. The Φ2, ψ2, Φ3, and ψ3 torsion angles define the postulated β-t...
Figure 2: Lactam-based PLG peptidomimetics.
Figure 3: Lactam-based photoaffinity ligands of the PLG modulatory site.
Figure 4: Bicyclic PLG peptidomimetics.
Figure 5: Spiro-bicyclic PLG peptidomimetics.
Scheme 1: Synthesis of α-alkylaldehyde proline derivatives by Seebach's “self-regeneration of chirality” meth...
Scheme 2: Synthetic approaches to the spiro-bicyclic scaffolds.
Figure 6: Prolyl PLG analogues.
Figure 7: (A) Type VI β-turn mimics. An ethylene bridge connection in 43 and 45 between the α-carbon of the s...
Scheme 3: Synthesis of spiro-bicyclic type VI β-turn mimic 48.
Scheme 4: Biproline formation from Seebach’s oxazolidinone.
Figure 8: Positive and negative allosteric modulators of the D2 dopamine receptor based on the 5.6.5 spiro-bi...
Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes
- Jan-Christoph Kehr,
- Douglas Gatte Picchi and
- Elke Dittmann
Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191
- Claisen-type cyclization step to form the characteristic bicyclic ring structure of anatoxin while the growing chain is tethered to the AnaF ACP domain. Experimental evidence for this suggestion is currently lacking. Finally, the bicyclic thioester is suggested to be transferred to the polyketide synthase
Graphical Abstract
Figure 1: Cyanobacteria proliferate in diverse habitats. A) Bloom-forming freshwater cyanobacteria of the gen...
Figure 2: Schematic representation of enzymatic domains in A) nonribosomal peptide synthetases (NRPS); B) pol...
Figure 3: Structures of NRPS and PKS products in freshwater cyanobacteria.
Figure 4: A) Synthesis of the Adda ((2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-4,6-decadienoic...
Figure 5: Structures of NRPS and PKS products in marine cyanobacteria.
Figure 6: A) Formation of the trichloroleucyl starter unit of barbamide (7) synthesis through the non-heme ir...
Figure 7: Structures of NRPS and PKS products in terrestrial cyanobacteria.
Figure 8: Synthesis of the (2S,4S)-4-methylproline moiety of nostopeptolides A (13).
Figure 9: Structures of cyanobacterial peptides that are synthesized ribosomally and post-translationally mod...
Figure 10: Formation of ester linkages and ω-amide linkage in microviridins 17 by the ATP grasp ligases MvdD a...
Figure 11: Structures of cyanobacterial sunscreen compounds.
When cyclopropenes meet gold catalysts
- Frédéric Miege,
- Christophe Meyer and
- Janine Cossy
Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82
- could also be involved in intramolecular olefin cyclopropanation in order to access [n.1.0] bicyclic ring systems. Rather than examining the behaviour of cyclopropenes bearing an allylic chain at C3, and in order to avoid aryl-substituted cyclopropenes that have routinely been used as substrates
Graphical Abstract
Scheme 1: General reactivity of cyclopropenes in the presence of gold catalysts.
Scheme 2: Cationic organogold species generated from cyclopropenone acetals.
Scheme 3: Rotation barriers around the C2–C3 bond (M06 DFT calculations).
Scheme 4: Au–C1 bond length in organogold species of type D.
Scheme 5: Gold-catalyzed addition of alcohols or water to cyclopropene 8.
Scheme 6: Gold-catalyzed addition of alcohols to cyclopropene 10.
Scheme 7: Mechanism of the gold-catalyzed addition of alcohols to cyclopropenes.
Scheme 8: Synthesis of tert-allylic ethers from cyclopropenes and allenes.
Scheme 9: Oxidation of the intermediate gold–carbene with diphenylsulfoxide.
Scheme 10: Gold, copper and Lewis acid-catalyzed reactions of cyclopropene 18.
Scheme 11: Mechanism of the Lewis acid-catalyzed reactions of cyclopropene 18.
Scheme 12: Gold-catalyzed rearrangement of vinylcyclopropenes 25.
Scheme 13: Gold-catalyzed rearrangement of cyclopropenes 27 to indenes 28.
Scheme 14: Gold-catalyzed rearrangement of cyclopropenes 29 to indenes 30.
Scheme 15: Gold-catalyzed rearrangement of cyclopropenyl ester 34a.
Scheme 16: Gold-catalyzed reactions of cyclopropenyl esters 34b–34d.
Scheme 17: Gold-catalyzed reactions of cyclopropenylsilane 34e.
Scheme 18: Gold-catalyzed rearrangement of cyclopropenylmethyl acetates.
Scheme 19: Mechanism of the gold-catalyzed rearrangement of cyclopropenes 39.
Scheme 20: Gold-catalyzed cyclopropanation of styrene with cyclopropene 8.
Scheme 21: Representative reactions of carbene precursors on gold metal.
Scheme 22: Intermolecular olefin cyclopropanation with gold carbenes generated from cyclopropenes.
Scheme 23: Gold-catalyzed formation of trienes from cyclopropenes and furans.
Scheme 24: Gold-catalyzed formation of trienes from cyclopropenes and furans.
Scheme 25: Gold-catalyzed formation of trienes from cyclopropenes and furans.
Scheme 26: Gold-catalyzed cycloisomerization of cyclopropene-ene 59.
Scheme 27: Gold-catalyzed cycloisomerization of substituted allyl cyclopropenyl carbinyl ethers 62a–62f.
Scheme 28: Gold-catalyzed cycloisomerization of cyclopropene-enes.
Scheme 29: Gold-catalyzed cycloisomerization of cyclopropene-ynes.
Scheme 30: Formation of products arising from a double cleavage process in the gold-catalyzed cycloisomerizati...
Scheme 31: Gold-catalyzed cycloisomerization of cyclopropene-ynes involving a double cleavage process.
Scheme 32: Gold-catalyzed reaction of cyclopropene-ynes, cyclopropene-enes and cyclopropene-allenes.
Molecular rearrangements of superelectrophiles
- Douglas A. Klumpp
Beilstein J. Org. Chem. 2011, 7, 346–363, doi:10.3762/bjoc.7.45
- produce dication 84 and successive hydride shifts to give 85 which on ring closure affords the protonated lactone 80. A novel isomerization of a bicyclic ring system was described [29] for the 1,5-manxyl dication (87, Scheme 17). Ionization of the dichloride 86 in SbF5-SO2ClF gave the 1,5-manxyl dication
Graphical Abstract
Scheme 1: Superelectrophilic activation of the acetyl cation.
Scheme 2: Ring opening of diprotonated 2-oxazolines.
Scheme 3: AlCl3-promoted ring opening of isoxaolidine 16.
Scheme 4: Ring-opening reactions of cyclopropyl derivatives.
Scheme 5: Condensations of ninhydrin (28) with benzene.
Scheme 6: Rearrangement of 29 to 30.
Scheme 7: Superacid promoted ring opening of succinic anhydride (33).
Scheme 8: Reaction of phthalic acid (36) in FSO3H-SbF5.
Scheme 9: Ring expansion of superelectrophile 42.
Scheme 10: Reaction of camphor (44) in superacid.
Scheme 11: Isomerization of 2-cyclohexen-1-one (48).
Scheme 12: Isomerization of 2-decalone (51).
Scheme 13: Rearrangement of the acyl-dication 58.
Scheme 14: Reaction of dialkylketone 64.
Scheme 15: Ozonolysis in superacid.
Scheme 16: Rearrangement of 1-hydroxy-2-methylcyclohexane carboxylic acid (79) in superacid.
Scheme 17: Isomerization of the 1,5-manxyl dication 87.
Scheme 18: Energetics of isomerization.
Scheme 19: Rearrangement of dication 90.
Scheme 20: Superacid promoted rearrangement of pivaldehyde (92).
Scheme 21: Rearrangement of a superelectrophilic carboxonium ion 100.
Scheme 22: Proposed mechanism for the Wallach rearrangement.
Scheme 23: Wallach rearrangement of azoxypyridines 108 and 109.
Scheme 24: Proposed mechanism of the benzidine rearrangement.
Scheme 25: Superacid-promoted reaction of quinine (122).
Scheme 26: Superacid-promoted reaction of vindoline derivative 130.
Scheme 27: Charge migration by hydride shift and acid–base chemistry.
Scheme 28: Reactions of 1-hydroxycyclohexanecarboxylic acid (137).
Scheme 29: Reaction of alcohol 143 with benzene in superacid.
Scheme 30: Reaction of alcohol 148 in superacid with benzene.
Scheme 31: Mechanism of aza-polycyclic aromatic compound formation.
Scheme 32: Superacid-promoted reaction of ethylene glycol (159).
Scheme 33: Reactions of 1,3-propanediol (165) and 2-methoxyethanol (169).
Scheme 34: Rearrangement of superelelctrophilic acyl dication 173.
Novel tetracyclic structures from the synthesis of thiolactone-isatin hybrids
- Renate Hazel Hans,
- Hong Su and
- Kelly Chibale
Beilstein J. Org. Chem. 2010, 6, No. 78, doi:10.3762/bjoc.6.78
- in the tetracycles 4 was further sparked by the ease and simplicity of their preparation, and the novelty of their architecture as revealed by single X-ray crystal structure analysis. Attractive structural features of 4 include two vicinal quaternary stereocenters and a complex, bicyclic ring system
Graphical Abstract
Figure 1: Natural product and natural product-like hybrids.
Figure 2: Structures of thiolactomycin (1), isatin (2), the desired hybrid 3 and tetracycle 4.
Scheme 1: Reagents and conditions: (a) KOH, MeOH, 25 °C, 95–100% (b) 6, DMF, 60 °C, 9–36%.
Scheme 2: Proposed mechanism for the formation of tetracycles 4.
Figure 3: (a) Molecular structure of the tetracycle 4a. (b) Structure of the dimer of 4a showing the atomic n...
Figure 4: Molecular structure of (a) 4b and (b) 4c, with ellipsoidal model of probability level = 35%.
The C–F bond as a conformational tool in organic and biological chemistry
- Luke Hunter
Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38
- -generation catalyst for the Stetter reaction between aryl aldehydes (e.g. 47) and nitroalkenes (e.g. 48). Superficially, it seems that the bulky isopropyl group of 49 is solely responsible for the enantioselectivity of this reaction. However, the shape of the bicyclic ring system might also play a role and
Graphical Abstract
Figure 1: Conformational effects associated with C–F bonds.
Figure 2: HIV protease inhibitor Indinavir (17) and fluorinated analogues 18 and 19. In analogue 18 the gauche...
Figure 3: Cholesteryl ester transfer protein inhibitors 20 and 21. In the fluorinated analogue 21, nO→σ*CF hy...
Figure 4: HIV reverse transcriptase inhibitor 22 and acid-stable fluorinated analogues 23–25. The F–C–C–O gau...
Figure 5: Dihydroquinidine (26) and fluorinated analogues 27 and 28. Newman projections along the C9–C8 bonds...
Figure 6: The neurotransmitter GABA (29) and fluorinated analogues (R)-30 and (S)-30. Newman projections of (R...
Figure 7: The insect pheromone 31 and fluorinated analogues (S)-32 and (R)-32. The proposed bioactive conform...
Figure 8: Capsaicin (33) and fluorinated analogues (R)-34 and (S)-34.
Figure 9: Asymmetric epoxidation reaction catalysed by pyrrolidine 35. Inset: the geometry of the activated i...
Figure 10: The asymmetric transannular aldol reaction catalysed by trans-4-fluoroproline (41), and its applica...
Figure 11: The asymmetric Stetter reaction catalysed by chiral NHC catalysts 49–52. The ring conformations of ...
Figure 12: A multi-vicinal fluoroalkane.
Figure 13: X-ray crystal structures of diastereoisomeric multi-vicinal fluoroalkanes 55 and 56. The different ...
Figure 14: Examples of fluorinated liquid crystal molecules. Arrows indicate the orientation of the molecular ...
Figure 15: Di-, tri- and tetra-fluoro liquid crystal molecules 60–62.
Figure 16: Collagen mimics of general formula (Pro-Yaa-Gly)10 where Yaa is either 4(R)-hydroxyproline (63) or ...
Figure 17: Enkephalin-related peptide 64 and the fluorinated analogue 65. The electron-withdrawing trifluorome...
Figure 18: The C–F bond influences the conformation of β-peptides. β-Heptapeptide 66 adopts a helical conforma...
Figure 19: The conformations of pseudopeptides 69 and 70 are influenced by the α-fluoroamide effect and the fl...
A convenient allylsilane- N-acyliminium route toward indolizidine and quinolizidine alkaloids
- Roland Remuson
Beilstein J. Org. Chem. 2007, 3, No. 32, doi:10.1186/1860-5397-3-32
- nitrogen bicyclic ring systems. [6] This method represents an efficient and stereoselective strategy for the preparation of 5-substituted indolizidines. The source of chirality was the aminoester (R)-2 which was prepared according to Davies'methodology. [17] Synthesis of the indolizidine skeleton was
Graphical Abstract
Scheme 1: Allylsilane-N-acyliminium cyclisation.
Scheme 2: Enantioselective synthesis of (-)-indolizidine 167B by intramolecular allylsilane-N-acyliminium cyc...
Scheme 3: Synthesis of (±)-indolizidine 167B by intermolecular cyclisation of allylsilane-N-acyliminium cycli...
Scheme 4: Synthesis of 3,5-disubstituted indolizidines from L-pyroglutamic acid.
Scheme 5: Access to indolizidine precursors of dendroprimine starting from chiral 2-aminopropanoate.
Scheme 6: Access to (-)-dendroprimine by reduction with LiAlH4 of indolizidinones 26.
Scheme 7: Access to (-)-dendroprimine by catalytic hydrogenation of indolizidinones 26.
Scheme 8: Synthesis of (±)-myrtine and (±)-epimyrtine.
Scheme 9: Enantioselective synthesis of (+)-myrtine and (-)-epimyrtine.
Scheme 10: Synthesis of (±)-lasubines I and II and (±)-2-epilasubine II.
Scheme 11: Synthesis of (±)-lasubine I and II.
Scheme 12: Enantioselective synthesis of (-)-lasubines I and II and (+)-subcosine.
