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Search for "energy balance" in Full Text gives 8 result(s) in Beilstein Journal of Organic Chemistry.
Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules
- Hendrik V. Schröder and
- Christoph A. Schalley
Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190
- dimer interaction was observed in the case of [4]rotaxane 22. This discrepancy can be explained by a simple energy balance. For a mixed-valence interaction, at least two TTF/TTF●+ units need to be free. Thus, after one-electron oxidation which liberates one TTF●+ from the cavity of 3, still the energy
Graphical Abstract
Figure 1: The two one-electron oxidation reactions of tetrathiafulvalene (TTF, 1) and the corresponding prope...
Figure 2: UV–vis spectra and photographs of TTF 2 in its three stable oxidation states (black line = 2, orang...
Figure 3: Structure and conformations of two TTF dimers in solution, the mixed-valence and the radical-cation...
Figure 4: (a) The isomerism problem of TTF. (b)–(d) Major synthetic breakthroughs for the construction of TTF...
Figure 5: (a) Host–guest equilibrium between π-electron-poor cyclophane 3 and different TTFs with their corre...
Figure 6: TTF complexes with different host molecules.
Figure 7: Stable TTF (a) radical-cation and (b) mixed-valence dimers in confined molecular spaces.
Figure 8: A “three-pole supramolecular switch”: Controlled by its oxidation state, TTF (1) jumps back and for...
Figure 9: Redox-controlled closing and opening motion of the artificial molecular lasso 12.
Figure 10: Graphical illustration how a non-degenerate TTF-based shuttle works under electrochemical operation....
Figure 11: The first TTF-based rotaxane 13.
Figure 12: A redox-switchable bistable molecular shuttle 14.
Figure 13: The redox-switchable cyclodextrin-based rotaxane 15.
Figure 14: The redox-switchable non-ionic rotaxane 16 with a pyromellitic diimide macrocycle.
Figure 15: The redox-switchable TTF rotaxane 17 based on a crown/ammonium binding motif.
Figure 16: Structure and operation of the electro- and photochemically switchable rotaxane 18 which acts as po...
Figure 17: (a) The redox-switchable rotaxane 19 with a donor–acceptor pair which is stable in five different s...
Figure 18: Schematic representation of a molecular electronic memory based on a bistable TTF-based rotaxane. (...
Figure 19: Schematic representation of bending motion of a microcantilever beam with gold surface induced by o...
Figure 20: TTF-dimer interactions in a redox-switchable tripodal [4]rotaxane 22.
Figure 21: (a) A molecular friction clutch 23 which can be operated by electrochemical stimuli. (b) Schematic ...
Figure 22: Fusion between rotaxane and catenane: a [3]rotacatenane 24 which can stabilize TTF dimers.
Figure 23: The first TTF-based catenane 25.
Figure 24: Electrochemically controlled circumrotation of the bistable catenane 26.
Figure 25: A tristable switch based on the redox-active [2]catenane 27 with three different stations.
Figure 26: Structure of catenane-functionalized MOF NU-1000 [108] with structural representation of subcomponents. ...
Figure 27: (a) [3]Catenanes 29 and 30 which can stabilize mixed-valence or radical-cation dimers of TTF. (b) S...
A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds
- Claudia Lar,
- Adrian Woiczechowski-Pop,
- Attila Bende,
- Ioana Georgeta Grosu,
- Natalia Miklášová,
- Elena Bogdan,
- Niculina Daniela Hădade,
- Anamaria Terec and
- Ion Grosu
Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115
- of 2 in the case of the cryptand–anthracene complex is +11.44 kcal/mol and +17.41 kcal/mol for the corresponding pyrene complex. Since the anthracene molecule enters the cavity of the cryptand with its longitudinal direction the deformation energy of the cryptand becomes lower and the energy balance
Graphical Abstract
Figure 1: Cryptands with 1,3,5-triphenylbenzene (1) and 2,4,6-triphenyl-1,3,5-triazine (2) aromatic reference...
Scheme 1: Synthesis of cryptand 2.
Figure 2: NMR spectra of cryptand 2: top, 1H NMR; bottom, 13C NMR.
Figure 3: Chemical shift changes of the reference signal (belonging to the more deshielded protons of the p-p...
Figure 4: The equilibrium geometry structure of cryptand 2 having 2,4,6-triphenyl-1,3,5-triazine caps.
Figure 5: The equilibrium geometry structures of the cryptand–anthracene (a) and cryptand–pyrene (b) host–gue...
Figure 6: The equilibrium geometry structure of the cryptand 2–1,5-dihydroxynaphthalene host–guest complex.
Figure 7: The inclusion dynamics of the anthracene in the cavity of the cryptand for different constrained di...
Self-optimisation and model-based design of experiments for developing a C–H activation flow process
- Alexander Echtermeyer,
- Yehia Amar,
- Jacek Zakrzewski and
- Alexei Lapkin
Beilstein J. Org. Chem. 2017, 13, 150–163, doi:10.3762/bjoc.13.18
- segment, which was assumed to behave as a batch reactor, as samples were taken in the dispersion-free centre of the segment. For the purpose of calculating the cost associated with heating the system, a steady state energy balance, Equation 9, was established. were ηheat denotes an overall efficiency of
Graphical Abstract
Figure 1: A framework of closed-loop or self-optimisation combining smart DoE algorithms, process analytics, ...
Scheme 1: Catalytic reaction scheme showing C–H activation of an aliphatic secondary amine 1 to form the azir...
Scheme 2: A simplified reaction mechanism based on literature [21], showing intermediate B and the side reaction ...
Figure 2: Schematics of the automated continuous-flow system used for model development and ‘black-box’ seque...
Figure 3: Results of experiments from the MBDoE in Table 2, conducted for parameter estimation, and their correspond...
Figure 4: Results of in silico iterations of the multi-objective active learner (MOAL) algorithm [26]. Each itera...
Figure 5: Results of the optimisation driven by a statistical algorithm and in the absence of a physical proc...
3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells
- Wei Li,
- Munechika Otsuka,
- Takehito Kato,
- Yang Wang,
- Takehiko Mori and
- Tsuyoshi Michinobu
Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134
- structure [38]. As an efficient HTM for the PSCs, p-type polymers should have a good energy balance with the perovskite layer [39]. Most importantly, the highest occupied molecular orbital (HOMO) energy level should be close to the valence band of the perovskite. The HOMO levels of 3,6-Cbz-EDOT and 2,7-Cbz
Graphical Abstract
Scheme 1: Synthesis of 3,6-Cbz-EDOT and 2,7-Cbz-EDOT by Stille polycondensation.
Figure 1: (a) Normalized UV–vis absorption of Cbz-EDOT polymers in CH2Cl2 measured at 10−5 M repeat unit−1 an...
Figure 2: Energy level diagram of PSC components including P3HT, 3,6-Cbz-EDOT, and 2,7-Cbz-EDOT.
Figure 3: (a) Current density–voltage curves and (b) incident photon to current conversion efficiency (IPCE) ...
Figure 4: Impedance spectroscopy characterization of the PSCs with different HTMs over the frequency range fr...
Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands
- Julia Wappel,
- Roland C. Fischer,
- Luigi Cavallo,
- Christian Slugovc and
- Albert Poater
Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17
- Hoveyda catalyst II, which can be obtained by 2bV through coordination of the isopropoxy group. The overall energy balance for the transformation of 2b to II is 33.1 kcal/mol down in energy. Similar energy profiles, corresponding to the transformation of 2aIH+, 2aIIH+, and 2bIH+ into II are reported in
Graphical Abstract
Scheme 1: Synthesis of 1-4; only the isolated and characterized complexes are shown.
Figure 1: Solid state structure of complexes 2a and 2b as retrieved from single crystal X-ray diffraction.
Figure 2: Time/conversion plot for the polymerization of 5 by preinitiators 1–4 in the presence of HCl ([5]:[...
Figure 3: 1H NMR spectrum in the low-field region of the active species for complexes 4 and M32.
Scheme 2: Energetics of 2a and 2b protonation in kcal/mol.
Figure 4: Reaction pathway of the transformation of 2b to HovII (energies in kcal/mol; main distances in Å).
Figure 5: DTA-TGA measurements for polymerizations of DCPD with catalysts 1b and 2b; Reaction conditions: [ca...
CO2 Chemistry
- Thomas E. Müller and
- Walter Leitner
Beilstein J. Org. Chem. 2015, 11, 675–677, doi:10.3762/bjoc.11.76
- Thomas E. Muller Walter Leitner CAT Catalytic Center, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany Lehrstuhl für Technische Chemie und Petrolchemie, ITMC, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany 10.3762/bjoc.11.76 Keywords: CO2 utilization; energy balance
Graphical Abstract
Figure 1: The carbon dioxide molecule.
Figure 2: Examples of highly reactive molecules that are isoelectronic to carbon dioxide.
Figure 3: Threefold reactivity of carbon dioxide and examples for different activation modes for CO2 involvin...
Continuous flow nitration in miniaturized devices
- Amol A. Kulkarni
Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38
- reactions. A control of the residence time supports the avoidance of byproducts from sequential reactions. This observation is common for all systems and thus it is necessary to optimize the energy balance in the system depending on the heat transfer rates, the heat of the reaction and the inlet flow rates
Graphical Abstract
Figure 1: Analysis of the literature on aromatic nitration over the last 50 years. Numbers next to each nitra...
Figure 2: Schematic of a typical experimental setup for aromatic nitration. The circular segment shown inside...
Scheme 1: Nitration of substituted pyrazole-5-carboxylic acid 1. T = 90 °C, residence time = 35 min, yield: 7...
Scheme 2: Nitration of 2-methylindole (4). T = 3 °C, residence time = 48 s, yield: 70%. [27].
Scheme 3: Nitration of pyridine-N-oxide (6), T = 120 °C, residence time = 80 min, yield: 78% (72% in the flas...
Scheme 4: Nitration of toluene (8). Method 1: H2SO4/HNO3, T = 65 °C, residence time = 15 min. Method 2: Ac2O/H...
Figure 3: Graphical presentation of a microreactor used for double nitration and the schematic of the experim...
Scheme 5: Nitration of 2-amino-6-chloro-4-pyrimidinol (14) [25].
Scheme 6: Nitration of benzaldehyde (16) [35].
Scheme 7: Nitration of salicylic acid (19) [30].
Scheme 8: Nitration of phenol (22) yielding mono-nitro isomers 23 and 24 as main products, hydroquinone (25),...
Scheme 9: Synthesis of 3-methyl-4-nitropyrazole (29) and 3,5-dimethyl-4-nitropyrazole (31) [31].
Figure 4: Photograph of the experimental setup for the synthesis of alkyl-nitropyrazoles. IMM’s SIMM-V2 micro...
Scheme 10: Nitration of chlorobenzene (33) [23].
Figure 5: Continuous flow nitration of chlorobenzene (33) with nitric acid in a sequence of continuously stir...
Scheme 11: Nitration of 2-isopropoxybenzaldehyde (36) by using red fuming nitric acid [37].
Figure 6: Silicon-glass microreactor by Knapkiewicz et al. [37]. (A) Layout of the microreactor with a built-in m...
Scheme 12: Synthesis of nitropyridine (40) [39].
Figure 7: Schematic of the experimental setup involving a pressure based charging system [39]. Reproduced with pe...
Scheme 13: Nitration of p-difluorobenzene (42) [40].
Figure 8: Schematic of the flow reactor arrangement. Reproduced with permission from [40]. Copyright 2013 The Ame...
Scheme 14: Nitration of naphthalene (47) [34].
Figure 9: Structure of the microreactor. (A) Top view (1, 2 – inlets, 3 – mixing points, 4 – outlet). (B) Lat...
Scheme 15: Nitration of 2-nitropropane (52) [38].
Figure 10: Schematic of the continuous nitration system reported in CN103044261A [56].
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
- -methylpiperidine (1.21) using zeolites and easily aromatised by catalytic dehydrogenation to 3-picoline in 78% overall yield (Scheme 4) [26]. The overall processing sequence is highly energy-efficient (coupling of the endothermic cyclisation with the exothermic dehydration gives a reasonable energy balance). In
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.
