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Search for "2-pyrone" in Full Text gives 5 result(s) in Beilstein Journal of Organic Chemistry.
Anion–π catalysis on carbon allotropes
- M. Ángeles Gutiérrez López,
- Mei-Ling Tan,
- Giacomo Renno,
- Augustina Jozeliūnaitė,
- J. Jonathan Nué-Martinez,
- Javier Lopez-Andarias,
- Naomi Sakai and
- Stefan Matile
Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140
- preferred to maximize orbital overlap (Figure 4) [63]. For π-acidic surfaces, the exo transition state VII is more completely accessible (Figure 4). The 3-hydroxy-2-pyrone (24) was selected as representative diene for the anionic [4 + 2] cycloaddition with maleimide 25 as standard dienophile to afford endo
Graphical Abstract
Figure 1: (A) Anion–π catalysis: Stabilization of anionic transition states from substrate S to product P on ...
Figure 2: Bioinspired enolate addition chemistry to benchmark anion–π catalysts: Stabilization of “enol” inte...
Figure 3: Structure and activity of fullerene-amine dyads to catalyze the intrinsically disfavored but biolog...
Figure 4: Asymmetric anion–π catalysis of intrinsically disfavored exo-selective Diels–Alder reactions on ful...
Figure 5: Asymmetric anion–π catalysis to install remote stereogenic centers on fullerene catalyst 21, with n...
Figure 6: Primary anion–π autocatalysis on monofunctional fullerene 31, with catalytic and autocatalytic rate...
Figure 7: (A) Macrodipoles induced by anionic transition states account for anion–π catalysis on fullerenes. ...
Figure 8: Structure and activity of covalently and non-covalently modified SWCNTs and MWCNTs, with A/D ratios...
Figure 9: (A) Epoxide-opening ether cyclization on pristine carbon nanotubes occurs with (XVI) but not withou...
Figure 10: Electric-field-induced anion–π catalysis on MWCNTs 3 on graphite 76 in electrochemical microfluidic...
Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)
- Tao Wang,
- Kathrin I. Mohr,
- Marc Stadler and
- Jeroen S. Dickschat
Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9
- products so far. Biological characterisation of compounds Three of the volatile metabolites identified from D. clavata (compounds 9, 14 and 17) were evaluated for antimicrobial and cytotoxic activities using a standard panel of fungi and bacteria, as well as the murine cell line L929 (Table 3). The 2
- -pyrone 17 exhibited a moderate antifungal and weak antibacterial effect, while the lactone 9 was moderately cytotoxic, but devoid of significant antimicrobial activity. The chlorinated aromatic compound 14 only weakly inhibited the sensitive test organisms Chromobacterium violaceum and Mucor hiemalis
Graphical Abstract
Scheme 1: A selection of widespread fungal volatiles.
Figure 1: Total ion chromatogram of a representative headspace extract from Daldinia clavata MUCL 47436. Peak...
Scheme 2: Identified volatiles from Daldinia clavata MUCL 47436.
Figure 2: Mass spectra of volatiles from D. clavata that were identified by synthesis.
Scheme 3: Synthesis of manicone (10).
Scheme 4: Synthesis of a racemic mixture of all four diastereomers of 11.
Figure 3: Gas chromatographic analysis of 11 on a homochiral stationary phase. a) Synthetic mixture of all ei...
Scheme 5: Enantioselective synthesis of (4R,5S,6S)-11c and (4S,5R,6S)-11d.
Scheme 6: Epimerisations of (4R,5S,6S)-11c and (4S,5R,6S)-11d under basic conditions.
Figure 4: Gas chromatographic analysis of 11 on a homochiral stationary phase. a) Synthetic mixture of all ei...
Scheme 7: Proposed biosynthesis for (4R,5R,6S)-11a.
Figure 5: Mass spectra of a) 6-methyl-5,6-dihydro-2H-pyran-2-one (9), b) 6-propyl-5,6-dihydro-2H-pyran-2-one,...
Scheme 8: Synthesis of 6-methyl-5,6-dihydro-2H-pyran-2-one (9) and 6-nonyl-2H-pyran-2-one (17).
Biosynthesis of α-pyrones
- Till F. Schäberle
Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56
- -pyrones Dibenzo-α-pyrones (16) harbor the α-pyrone moiety in the middle part and consist of three ring structures (Figure 2). Aromatic rings are fused to edge c and e of the central 2-pyrone, yielding the basic structure of 16. Many dibenzo-α-pyrone-producing fungi have been described. However, it seems
- (2), tetraacetic acid lactone (3), and 6-pentyl-2-pyrone (29) also more complex systems, e.g., bufalin (31) [38], fusapyrones (32,33) [39], or the α-pyrone antibiotics corallopyronins (34,35) [40] and myxopyronins (36,37) [41], exist in the group of monocyclic α-pyrones (Figure 7). The bufadienolides
- . Structure of murayalactone, the only dibenzo-α-pyrone described from bacteria. Structures of the 6-pentyl-2-pyrone (29) and of trichopyrone (30). Only 29 showed antifungal activity. Selected monocyclic α-pyrones. Structures of the gibepyrones A–F. Structures of the phomenins A and B. Structures of
Graphical Abstract
Figure 1: Selected monocyclic and monobenzo α-pyrone structures.
Figure 2: The basic core structure of dibenzo-α-pyrones.
Figure 3: Selected dibenzo-α-pyrones.
Figure 4: Structure of ellagic acid and of the urolithins, the latter metabolized from ellagic acid by intest...
Figure 5: Structure of murayalactone, the only dibenzo-α-pyrone described from bacteria.
Figure 6: Structures of the 6-pentyl-2-pyrone (29) and of trichopyrone (30). Only 29 showed antifungal activi...
Figure 7: Selected monocyclic α-pyrones.
Figure 8: Structures of the gibepyrones A–F.
Figure 9: Structures of the phomenins A and B.
Figure 10: Structures of monocyclic α-pyrones showing pheromone (47) and antitumor activity (48), respectively....
Figure 11: Structures of 6-alkyl (alkoxy or alkylthio)-4-aryl-3-(4-methanesulfonylphenyl)pyrones.
Figure 12: Structures of kavalactones.
Figure 13: Strutures of germicins.
Figure 14: Structures of the pseudopyronines.
Figure 15: The structures of the monobenzo-α-pyrone anticoagulant drugs warfarin and phenprocoumon.
Figure 16: Structures of selected monobenzo-α-pyrones.
Figure 17: Hypothetical pathway of 29 generation from linoleic acid [34].
Figure 18: Proposed biosynthetic pathway of alternariol (modified from [77]). Malonyl-CoA building blocks are appl...
Figure 19: Structures of phenylnannolones and of enterocin, both biosynthesized via polyketide synthase system...
Figure 20: Pyrone ring formation. Examples for the three types of PKS systems are shown in A–C. In D the mecha...
Figure 21: Structures of csypyrones.
Figure 22: Schematic drawing of the T-shaped catalytic cavities of the related enzymes CorB and MxnB. The two ...
Figure 23: Stereo representation of the CorB binding situation (modified from [89]). The substrate mimic (dark vio...
Figure 24: Proposed mechanism for the CsyB enzymatic reaction. A) Coupling reaction of the β-keto fatty acyl i...
Figure 25: Proposed biosynthesis of photopyrone D (37) by the enzyme PpyS from P. luminescens (modified from [63])...
4-Hydroxy-6-alkyl-2-pyrones as nucleophilic coupling partners in Mitsunobu reactions and oxa-Michael additions
- Michael J. Burns,
- Thomas O. Ronson,
- Richard J. K. Taylor and
- Ian J. S. Fairlamb
Beilstein J. Org. Chem. 2014, 10, 1159–1165, doi:10.3762/bjoc.10.116
- , which are found embedded in a number of natural products. Keywords: heterocycles; Mitsunobu reaction; oxa-Michael addition; 2-pyrone; vinyl ethers; Introduction The 2-pyrone motif is a prevalent structural feature of many complex natural products and biologically active compounds [1][2]. Various
- is generally well-developed [7], efficient routes to these types of complex structural units are elusive, and the total synthesis of these and similar natural products remains a challenge [8]. Simple 2-pyrones such as 4-hydroxy-6-methyl-2-pyrone (triacetic acid lactone, 3a, Figure 1) are readily and
- methylating agents or simple alkyl or acyl halides. These often require heating with a base such as K2CO3 or DBU, and the available functionality is therefore limited to esters or simple primary alkyl groups [9][10][11]. Even in simple cases the yields obtained are variable as the 2-pyrone unit is prone to
Graphical Abstract
Figure 1: The phacelocarpus 2-pyrones 1 and 2.
Scheme 1: Generalised O-functionalisation of 6-alkyl-4-hydroxy-2-pyrones 3.
Scheme 2: Synthesis of alkylated 2-pyrones 3b–e.
Scheme 3: Michael addition of 3a to allene 8 and internal alkyne 10.
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
- sequence via the corresponding 2-pyrone (e.g. Scheme 9), which is converted to the 2-pyridone through an exchange with ammonia or an equivalent nitrogen source (NH4X; X = Cl, Br, I, OAc, OH). However, more conveniently the 2-pyrone precursor can be generated via the vacuum pyrolysis of coumalic acid (1.56
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.
