Avibactam, sodium (2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]octan-6-yl sulfonate,
Avibactam Sodium Salt (1)
Avibactam, sodium (2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]octan-6-yl sulfonate,
Avibactam Sodium Salt (1)
Structural modifications in the β-enamino diketone system allied to the Lewis acid carbonyl activator BF3 were strategically employed for this control. Also a one-pot method for the preparation of 3,5-disubstituted 4-hydroxymethyl-N-arylpyrazole derivatives from the β-enamino diketone and arylhydrazine substrates is described.
3-(Ethoxycarbonyl)-4-formyl-5-(4-nitrophenyl)-1-phenyl-1H-pyrazole (3a)
A sustainable procedure for the synthesis of various alkyl arylacetates from benzyl alcohols has been developed. With palladium as the catalyst and organic carbonates as the green solvent and in situ activator, benzyl alcohols were carbonylated in an efficient manner without any halogen additives.
Ethyl 2-phenylacetate
1H NMR (300 MHz, Chloroform-d) δ 7.32 – 7.08 (m, 5H), 4.08 (q, J = 7.1 Hz, 2H), 3.54 (s, 2H), 1.18 (t, J = 7.1 Hz, 3H).
13C NMR (75 MHz, CDCl3) δ 171.61, 134.17, 129.24, 128.54, 127.03, 60.85, 41.45, 14.18.
AMISELIMOD
UNII-358M5150LY; CAS 942399-20-4; 358M5150LY; MT-1303; Amiselimod, MT-1303
Molecular Formula: | C19H30F3NO3 |
---|---|
Molecular Weight: | 377.448 g/mol |
2-amino-2-[2-[4-heptoxy-3-(trifluoromethyl)phenyl]ethyl]propane-1,3-diol
Phase II Crohn’s disease; Multiple sclerosis; Plaque psoriasis
Amiselimod, also known as MT1303, is a potent and selective immunosuppressant and sphingosine 1 phosphate receptor modulator. Amiselimod may be potentially useful for treatment of multiple sclerosis; inflammatory diseases; autoimmune diseases; psoriasis and inflammatory bowel diseases. Amiselimod is currently being developed by Mitsubishi Tanabe Pharma Corporation
Mitsubishi Tanabe is developing amiselimod, an oral sphingosine-1-phosphate (S1P) receptor antagonist, for treating autoimmune diseases, primarily multiple sclerosis, psoriasis and inflammatory bowel diseases, including Crohn’s disease.
EU states expire 2026, and
Expire in the US in June 2030 with US154 extension.
Inventors | Masatoshi Kiuchi, Kaoru Marukawa, Nobutaka Kobayashi, Kunio Sugahara |
Applicant | Mitsubishi Tanabe Pharma Corporation |
In recent years, calcineurin inhibitors such as cyclosporine FK 506 have been used to suppress rejection of patients receiving organ transplantation. While doing it, certain calcineurin inhibitors like cyclosporin can cause harmful side effects such as nephrotoxicity, hepatotoxicity, neurotoxicity, etc. For this reason, in order to suppress rejection reaction in transplant patients, development of drugs with higher safety and higher effectiveness is advanced.
[0003] Patent Documents 1 to 3 are useful as inhibitors of (acute or chronic) rejection in organ or bone marrow transplantation and also useful as therapeutic agents for various autoimmune diseases such as psoriasis and Behcet’s disease and rheumatic diseases 2 aminopropane 1, 3 dioly intermediates are disclosed.
[0004] One of these compounds, 2-amino-2- [2- (4-octylphenel) propane] 1, 3 diol hydrochloride (hereinafter sometimes referred to as FTY 720) is useful for renal transplantation It is currently under clinical development as an inhibitor of rejection reaction. FTY 720 is phosphorylated by sphingosine kinase in vivo in the form of phosphorylated FTY 720 [hereinafter sometimes referred to as FTY 720-P]. For example, 2 amino-2-phosphoryloxymethyl 4- (4-octafil-el) butanol. FTY720 – P has four types of S1 P receptors (hereinafter referred to as S1 P receptors) among five kinds of sphingosine – 1 – phosphate (hereinafter sometimes referred to as S1P) receptors It acts as an aggroove on the body (other than S1P2) (Non-Patent Document 1).
[0005] It has recently been reported that S1P1 among the S1P receptors is essential for the export of mature lymphocytes with thymus and secondary lymphoid tissue forces. FTY720 – P downregulates S1P1 on lymphocytes by acting as S1P1 ghost. As a result, the transfer of mature lymphocytes from the thymus and secondary lymphatic tissues is inhibited, and the circulating adult lymphocytes in the blood are isolated in the secondary lymphatic tissue to exert an immunosuppressive effect Has been suggested (
Non-Patent Document 2).
[0006] On the other hand, conventional 2-aminopropane 1, 3 dioly compounds are concerned as transient bradycardia expression as a side effect, and in order to solve this problem, 2-aminopropane 1, 3 diiori Many new compounds have been reported by geometrically modifying compounds. Among them, as a compound having a substituent on the benzene ring possessed by FTY 720, Patent Document 4 discloses an aminopropenol derivative as a S1P receptor modulator with a phosphate group, Patent Documents 5 and 6 are both S1P Discloses an amino-propanol derivative as a receptor modulator. However, trihaloalkyl groups such as trifluoromethyl groups are not disclosed as substituents on the benzene ring among them. In any case, it is currently the case that it has not yet reached a satisfactory level of safety as a pharmaceutical.
Patent Document 1: International Publication Pamphlet WO 94 Z 08943
Patent Document 2: International Publication Pamphlet WO 96 Z 06068
Patent Document 3: International Publication Pamphlet W 0 98 z 45 429
Patent Document 4: International Publication Pamphlet WO 02 Z 076995
Patent document 5: International public non-fret WO 2004 Z 096752
Patent Document 6: International Publication Pamphlet WO 2004 Z 110979
Non-patent document 1: Science, 2002, 296, 346-349
Non-patent document 2: Nature, 2004, 427, 355-360
Reference Example 3
5 bromo 2 heptyloxybenzonitrile
(3- 1) 5 Synthesis of bromo-2 heptyloxybenzonitrile (Reference Example Compound 3- 1)
1-Heptanol (1.55 g) was dissolved in N, N dimethylformamide (24 ml) and sodium hydride (0.321 g) was added at room temperature. After stirring for 1 hour, 5 bromo-2 fluoborosyl-tolyl (2.43 g) was added and the mixture was further stirred for 50 minutes. The reaction solution was poured into water, extracted with ethyl acetate, washed with water, saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. After eliminating the 5 bromo 2 fluconate benzonitrile as a raw material, the reaction was carried out again under the same conditions and purification was carried out by silica gel column chromatography (hexane: ethyl acetate = 50: 1 to 5: 1) to obtain the desired product (3.10 g ) As a colorless oil.
– NMR (CDCl 3) δ (ppm): 0.89 (3H, t, J = 6.4 Hz), 1.24-1.35 (6H, m
J = 8.8 Hz), 1.48 (2H, quint, J = 7.2 Hz), 1.84 7.59 (1 H, dd, J = 8.8, 2.4 Hz), 7.65 (1 H, d, J = 2.4 Hz).
Example 1
2 Amino 2- [2- (4-heptyloxy-3 trifluoromethylph enyl) propane-1, 3-diol hydrochloride
(1 – 1) {2, 2 Dimethyl 5- [2- (4 hydroxy 3 trifluoromethylfuethyl) ethyl] 1,3 dioxane 5 mercaptothenylboronic acid t butyl ester (synthesis compound 1 1)
Reference Example Compound 2-5 (70.3 g) was dissolved in tetrahydrofuran (500 ml), t-butoxycallium (13.Og) was added, and the mixture was stirred for 1 hour. To the mixed solution was dropwise added a solution of the compound of Reference Example 1 (15.Og) in tetrahydrofuran (100 ml) under ice cooling, followed by stirring for 2 hours under ice cooling. Water was added to the reaction solution, the mixture was extracted with ethyl acetate, washed with water, saturated brine, dried with anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane: ethyl acetate = 3: D to obtain 31. Og of a pale yellow oily matter.) The geometric isomer ratio of the obtained product was (E : Z = 1: 6).
This pale yellow oil was dissolved in ethyl acetate (200 ml), 10% palladium carbon (3.00 g) was added, and the mixture was stirred under a hydrogen atmosphere at room temperature for 7 hours. After purging the inside of the reaction vessel with nitrogen, the solution was filtered and the filtrate was concentrated. The residue was washed with diisopropyl ether to obtain the desired product (2.2 g) as a colorless powder.
1 H-NMR (CDCl 3) δ (ppm): 1. 43 (3H, s), 1.44 (3H, s), 1. 47 (9H, s), 1
(2H, m), 91- 1. 98 (2H, m), 2. 50-2.66 (2H, m), 3. 69 (2H, d, J = Il. 6 Hz), 3. 89 J = 8.2 Hz), 7. 22 (1 H, dd J = 8 Hz), 5. 02 (1 H, brs), 5. 52 . 2, 1. 7 Hz), 7. 29 (1 H, d, J = l. 7 Hz).
(1-2) {2,2 Dimethyl-5- [2- (4heptyloxy-3 trifluoromethyl) ethyl] 1,3 dioxane 5-mercaptobutyric acid t-butyl ester Synthesis (compound 1 2)
Compound 1-1 (510 mg) was dissolved in N, N dimethylformamide (10 ml), potassium carbonate (506 mg) and n-heptyl bromide (0.235 ml) were added and stirred at 80 ° C. for 2 hours. Water was added to the reaction solution, the mixture was extracted with ethyl acetate, washed with water and saturated brine, dried with anhydrous sulfuric acid
The resultant was dried with GENSCHUM and the solvent was distilled off under reduced pressure to obtain the desired product (640 mg) as a colorless oil.
– NMR (CDCl 3) δ (ppm): 0.89 (3H, t, J = 6.8 Hz), l.30-1.37 (6H, m
(2H, m), 1.91-1.98 (2H, m), 1.42-1.50 (2H, m), 1.42 (3H, s), 1.44 (3H, s), 1.47 J = 16.6 Hz), 4.00 (2H, t, J = 6.4 Hz), 4.9 8 (2H, d, J = 11.6 Hz), 3.69 1 H, brs), 6.88 (1 H, d, J = 8.5 Hz), 7.26 – 7.29 (1 H, m), 7.35 (1 H, d, J = 1.5 Hz).
(1-3) Synthesis of 2-amino-2- [2- (4heptyloxy 3 trifluoromethyl) ethyl] propane 1, 3 diol hydrochloride (Compound 1- 3)
Compound 12 (640 mg) was dissolved in ethanol (15 ml), concentrated hydrochloric acid (3 ml) was caught and stirred at 80 ° C. for 2 hours. The reaction solution was concentrated, and the residue was washed with ethyl ether to give the desired product (492 mg) as a white powder.
MS (ESI) m / z: 378 [M + H]
– NMR (DMSO-d) δ (ppm): 0.86 (3H,
6 t, J = 6.8 Hz), 1.24 – 1.39 (6
(4H, m), 3.51 (4H, d, J = 5. lHz), 4.06 (2H, m), 1.39-1.46 (2H, m), 1.68-1.78 (4H, m), 2.55-2.22 , 7.32 (2H, t, J = 5.1 Hz), 7.18 (1 H, d, J = 8.4 Hz), 7.42 – 7.45 (2 H, m), 7.76 (3 H, brs;).
PATENT
WO 2009119858
JP 2011136905
WO 2017188357
PATENT
WO-2018021517
Patent Document 1: WO2007 / 069712
[Chemical formula 3]
PATENTS
////////////AMISELIMOD, Phase II, Crohn’s disease, Multiple sclerosis, Plaque psoriasis, MT-1303, MT1303, MT 1303, Mitsubishi Tanabe Pharma Corporation, Mitsubishi , JAPAN, PHASE 2
CCCCCCCOC1=C(C=C(C=C1)CCC(CO)(CO)N)C(F)(F)F
A series of (−)-nornuciferidine derivatives was synthesized and the non-natural enantiomer of the aporphine alkaloid was discovered to be a potent β1– and β2-adrenergic receptor ligand that antagonized isoproterenol and procaterol induced cyclic AMP increases from adenylyl cyclase, respectively. Progressive deconstruction of the tetracyclic scaffold to less complex cyclic and acyclic analogues revealed that the conformationally restricted (6a-R,7-R)-7-hydroxyaporphine 2 (AK-2-202) was necessary for efficient receptor binding and antagonism.
(6aR,7R)-1,2-Dimethoxy-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinolin-7-ol (2) To a solution of S2 (10 mg, 0.031 mmol) in THF (2 mL) was added 2 N NaOH(aq) (1 mL), and the mixture was stirred at 70 oC for 2 days. After being quenched with H2O (10 mL), the aqueous layer was extracted with EtOAc (2 × 20 mL). The combined organic extracts were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by column chromatography on silica gel (CH3OH/CH2Cl2, 5:95 to 10:90) to afford 2 (7.6 mg, 82%) as a pale yellow solid; mp 89−91 oC; [] 24 D +78 (c 0.58, CHCl3); 1H NMR (CDCl3, 500 MHz) 8.37−8.35 (1 H, m), 7.73−7.72 (1 H, m), 7.38−7.33 (2 H, m), 6.65 (1 H, s), 4.55 (1 H, d, J = 11.5 Hz), 3.88 (3 H, s), 3.67 (1 H, d, J = 11.5 Hz), 3.64 (3 H, s), 3.40−3.37 (1 H, m), 3.10−3.03 (1 H, m), 2.98 (1 H, td, J = 11.5, 3.5 Hz), 2.73 (1 H, d, J = 16.0 Hz); 13C NMR (CDCl3, 125 MHz) 152.5, 145.1, 139.0, 130.2, 129.4, 128.1, 127.8, 127.4, 125.9, 124.3, 123.1, 111.8, 72.0, 60.3, 59.0, 55.9, 42.0, 28.9; HRMS (ESI/Q-TOF) m/z [M + H]+ calculated for C18H20NO3 298.1438; found 298.1440
SIMILAR IN LIT
7-Oxygenated aporphines 1–6 possessing anti-configurations have previously been reported. In order to explore their bioactivities, a synthesis was established by utilizing a diastereoselective reductive acid-mediated cyclization followed by palladium-catalyzed ortho-arylations. Moderate XPhos precatalyst loading (10 mol %) and short reaction times (30 min) were sufficient to mediate the arylations. Alkaloids 1–5 were successfully prepared, while (−)-artabonatine A was revised to syn-isomer 30. Consequently, (−)-artabonatine E likely also has a syn-configuration (31).
///////////AK-2-202,
* Corresponding authors
Professor of Enzymology and Biophysical Chemistry
The construction of biocatalytic cascades for the production of chemical precursors is fast becoming one of the most efficient approaches to multi-step synthesis in modern chemistry. However, despite the use of low solvent systems and renewably resourced catalysts in reported examples, many cascades are still dependent on petrochemical starting materials, which as of yet cannot be accessed in a sustainable fashion. Herein, we report the production of the versatile chemical building block cinnamyl alcohol from the primary metabolite and the fermentation product L-phenylalanine. Through the combination of three biocatalyst classes (phenylalanine ammonia lyase, carboxylic acid reductase and alcohol dehydrogenase) the target compound could be obtained in high purity, demonstrable at the 100 mg scale and achieving 53% yield using ambient temperature and pressure in an aqueous solution. This system represents a synthetic strategy in which all components present at time zero are biogenic and thus minimises damage to the environment. Furthermore we extend this biocatalytic cascade by its inclusion in an L-phenylalanine overproducing strain of Escherichia coli. This metabolically engineered strain produces cinnamyl alcohol in mineral media using glycerol and glucose as the carbon sources. This study demonstrates the potential to establish green routes to the synthesis of cinnamyl alcohol from a waste stream such as glycerol derived, for example, from lipase treated biodiesel.
(R)-3-amino-3-(3-fluorophenyl)propanoic acid (1c) 1H NMR (CDCl3): δ 7.16-7.31 (m, 5H, ArH), 6.50-6.54 (d, 1H, J = 16 Hz, C=CH), 6.23-6.30 (dt, 1H, J = 16, 8 Hz, C=CHCH2 ), 4.21-4.23 (dd, 2H, J = 8, 4 Hz, C=CHCH2); 13C NMR (CDCl3): 136.70, 131.09, 128.60, 128.54, 127.69, 126.48, 63.65.
////////////cinnamyl alcohol, biocatalytic, metabolic engineering
A persulfurated coronene, a molecule dubbed a “sulflower” for its resemblance to a sunflower, bloomed this year. It’s the first fully sulfur-substituted polycyclic aromatic hydrocarbon and only the second member of a new class of circular heterocyclic carbon sulfide compounds, after the synthesis of octathio[8]circulene a decade ago.
Chemists hope to create other class members, including the simplest one, persulfurated benzene, for use in battery cathodes and other electronic materials.
A team led by Xinliang Feng of Dresden University of Technology and Klaus Müllen of the Max Planck Institute for Polymer Research created the sulflower (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.6b12630).
http://pubs.acs.org/doi/abs/10.1021/jacs.6b12630
Synthesis of persulfuratedcoronene (5, PSC)
5 (82 mg) as dark red solid in 61% yield. HR-MS (HR-MALDI-TOF) m/z: Calcd. for C24S12: 671.6629; Found 671.6648 [M]+; Elem. Anal. calcd. for C24S12: C, 42.83; S, 57.17. Found: C, 42.87; S, 57.13.
We report the first synthesis of a persulfurated polycyclic aromatic hydrocarbon (PAH) as a next-generation “sulflower.” In this novel PAH, disulfide units establish an all-sulfur periphery around a coronene core. The structure, electronic properties, and redox behavior were investigated by microscopic, spectroscopic and electrochemical methods and supported by density functional theory. The sulfur-rich character of persulfurated coronene renders it a promising cathode material for lithium–sulfur batteries, displaying a high capacity of 520 mAh g–1 after 120 cycles at 0.6 C with a high-capacity retention of 90%
Research Group Leader
Renhao received his PhD in Physical Chemistry from Shandong University in 2013. Since 01/2017, he is a research group leader at the Chair for Molecular Functional Materials in TUD. His current research interest focuses on synthesis of organic 2D crystals (2D polymers/COFs/MOFs) and their applications in electronics and energy technology.
Phone: +49 – 351 / 463-40401 or -34932
Email: renhao.dong@tu-dresden.de
Xinliang Feng received his Bachelor’s degree in analytic chemistry in 2001 and Master’s degree in organic chemistry in 2004. Then he joined Prof. Klaus Müllen’s group at the Max Planck Institute for Polymer Research for PhD thesis, where he obtained his PhD degree in April 2008. In December 2007 he was appointed as a group leader at the Max-Planck Institute for Polymer Research and in 2012 he became a distinguished group leader at the Max-Planck Institute for Polymer Research.
His current scientific interests include graphene, two-dimensional nanomaterials, organic conjugated materials, and carbon-rich molecules and materials for electronic and energy-related applications. He has published more than 370 research articles which have attracted more than 25000 citations with H-index of 75.
He has been awarded several prestigious prizes such as IUPAC Prize for Young Chemists (2009), Finalist of 3rd European Young Chemist Award, European Research Council (ERC) Starting Grant Award (2012), Journal of Materials Chemistry Lectureship Award (2013), ChemComm Emerging Investigator Lectureship (2014), Highly Cited Researcher (Thomson Reuters, 2014, 2015 and 2016), Fellow of the Royal Society of Chemistry (FRSC, 2014). He is an Advisory Board Member for Advanced Materials, Journal of Materials Chemistry A, ChemNanoMat, Energy Storage Materials, Small Methods and Chemistry -An Asian Journal. He is also one of the Deputy Leaders for European communitys pilot project Graphene Flagship, Head of ESF Young Research Group “Graphene Center Dresden”, and Working Package Leader of WP Functional Foams & Coatings of GRAPHENE FLAGSHIP.
Nature, Science, Nature Materials, Nature Nanotechnology, Nature Chemistry, Journal of the American Chemical Society, Angewandte Chemie International Edition, Nano Letters, Advanced Materials, Chemical Society Reviews, ACS Nano, Small, Chemical Communications, Chemistry of Materials, Organic Letters, Journal of the Organic Chemistry, Chemistry – A European Journal, ChemSusChem, ChemPhysChem, Macromolecular Rapid Communications, Journal of Material Chemistry, New Journal of Chemistry, Chemistry – An Asian Journal, ACS Applied Materials & Interfaces, Energy & Environmental Science, Organic Electronics and so on
Referee for research grants in NSF, US Department of Energy, ESF, ISF and Fondazione Cariparo and Fondazione CariModena.
Click to open publications list
Phone: +49 351 / 463-43251
Fax: +49 351 / 463-43268
Email: sabine.strecker@tu-dresden.de
Research into energy technologies and electronic devices is strongly governed by the available materials. We introduce a synthetic route to graphenes which is based upon the cyclodehydrogenation (“graphitization”) of well-defined dendritic (3D) polyphenylene precursors. This approach is superior to physical methods of graphene formation such as chemical vapour deposition or exfoliation in terms of its (i) size and shape control, (ii) structural perfection, and (iii) processability (solution, melt, and even gas phase). The most convincing case is the synthesis of graphene nanoribbons under surface immobilization and in-situ control by scanning tunnelling microscopy.
Columnar superstructures assembled from these nanographene discs serve as charge transport channels in electronic devices. Field-effect transistors (FETs), solar cells, and sensors are described as examples.
Upon pyrolysis in confining geometries or “carbomesophases”, the above carbon-rich 2D- and 3D- macromolecules transform into unprecedented carbon materials and their carbon-metal nanocomposites. Exciting applications are shown for energy technologies such as battery cells and fuel cells. In the latter case, nitrogen-containing graphenes serve as catalysts for oxygen reduction whose efficiency is superior to that of platinum.
Müllen, K., Rabe, J.R., Acc. Chem. Res. 2008, 41, (4), 511-520;
Wang, X., Zhi, L., Müllen, K. Nano. Lett. 2008, 8, 323-327;
Feng, X.; Chandrasekhar, N.; Su, H. B.; Müllen, K., Nano. Lett. 2008, 8, 4259.;
Pang, S.; Tsao, H. N.; Feng, X.; Müllen, K., Adv. Mater. 2009, 31, 3488;
Feng, X., Marcon, V., Pisula, W., Hansen, M.R., Kirkpatrick, I., Müllen, K., Nature Mater. 2009, 8, 421;
Cai, J., Ruffieux, P., Jaafar, R., Bieri, M., Braun, T., Blankenburg, S., Muoth, M., Seitsonen, A. P., Saleh, M., Feng, X., Müllen, K., Fasel, R., Nature 2010, 466, 470-473;
Yang, S., Feng, X., Zhi, L., Cao, Q., Maier, J., Müllen, K., Adv. Mater. 2010, 22, 838; Liu, R., Wu, D., Feng, X., Müllen, K., Angew. Chem. Int. Ed. 2010, 49, 2565;
Käfer, D., Bashir, A., Dou, X., Witte, G., Müllen, K., Wöll, C., Adv. Mater. 2010, 22, 384;
Diez-Perez, I., Li, Z., Hihath, J., Li, J., Zhang, C., X., Zang, L., Dai, Y., Heng, X., Müllen, K., Tao, N. J. Nature Commun. 2010, DOI: 10.1038.
Prof. Dr. Klaus Müllen
joined the Max-Planck-Society in 1989 as one of the directors of the Max-Planck Institute for Polymer Research. He obtained a Diplom-Chemiker degree at the University of Cologne in 1969 after work with Professor E. Vogel. His Ph.D. degree was granted by the University of Basel, Switzerland, in 1972 where he undertook research with Professor F. Gerson on twisted pi-systems and EPR spectroscopic properties of the corresponding radical anions. In 1972 he joined the group of Professor J.F.M. Oth at the Swiss Federal Institute of Technology in Zürich where he worked in the field of dynamic NMR spectroscopy and electrochemistry. He received his habilitation from the ETH Zürich in 1977 and was appointed Privatdozent. In 1979 he became a Professor in the Department of Organic Chemistry, University of Cologne, and accepted an offer of a chair in Organic Chemistry at the University of Mainz in 1983. He received a call to the University of Göttingen in 1988.
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S1Sc6c8c1c9SSc%10c2SSc%13c2c%11c4c3c%13SSc3c%12SSc7c%12c4c(c5c7SSc56)c8c%11c9%10
http://pubs.acs.org/doi/abs/10.1021/jacs.6b12630
A derivatisation agent selection guide
The study reported herein is aimed at the greenness assessment of 267 derivatisation agents that are frequently applied in analytical chemistry and related disciplines. Multicriteria decision analysis allowed obtaining three rankings of derivatisation agents applied in liquid chromatography, gas chromatography and chiral analysis. The criteria of assessment included the safety information obtained from material safety data sheets and physicochemical and environmental parameters predicted with relevant models. As for some of the agents predicted data were not available, these agents were assessed with a smaller number of criteria, within the ranking of low confidence. The results of the study will help to apply greener derivatisation agents, wherever the green chemistry principle of avoiding derivatisation cannot be fulfilled.
The present study provides an assessment, in terms of greenness, of 267 LC, GC and chiral derivatisation agents typically used in analytical chemistry and related fields. The preference rankings were performed for each group of derivatisation agents by means of MCDA according to the best relevant criteria that are available. In all three cases fine rankings were obtained for high and low confidence assumptions. For more informative assessment, it would be beneficial to include toxicological endpoints and more information about environmental persistence among assessment criteria. Incorporating valuable greenness indicators of synthesis processes such as carbon footprint or energy needs during production of each chemical as assessment criteria would be worthwhile. Unfortunately, these values are not easily available in the literature for a satisfactory number of derivatisation agents. Furthermore, recovery of derivatisation agents is another important issue that influences the greenness of derivatisation reactions, so its inclusion as assessment criterion would also be desirable. However, it is dependent on reaction specific conditions – not only the kind of derivatisation agent matters, but also analytes to be determined and solvents employed. The greenness of derivatisation agents is very rarely considered during analytical method development. The main criteria for selection of derivatisation agents are their rapidity and efficiency, but greenness should be also considered. This study allows selecting less problematic derivatisation agents for analytical method development while some clues can also be deduced for other than analytical applications.
Gdańsk University of Technology
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Catalytic C-H amination at its limits: challenges and solutions
Catalytic C–H amination reactions enable direct functionalization of non-activated C(sp3)–H bonds with high levels of regio-, chemo- and stereoselectivity. As a powerful tool to unlock the potential of inert C–H bonds, C–H amination chemistry has been applied to the preparation of synthetically challenging targets since major simplification of synthetic sequences are expected from this approach. Pushing C–H amination to its limits has led to a deeper understanding of the reaction mechanism and scope. In this review, we present a description of the specific challenges facing catalytic C–H amination in the synthesis of natural products and related compounds, as well as innovative tactics created to overcome them. By identifying and discussing the major insights gained and strategies designed, we hope that this review will stimulate further progress in C–H amination chemistry and beyond.
Conclusion Since the seminal works of Du Bois in the early 2000s, the pace of discovery in the field of metal-catalysed C–H amination has been breath-taking. Not surprisingly, this synthetic tool has been applied to the total synthesis of many compounds of interest, given the high prevalence of the amino group in natural products and synthetic pharmaceuticals.67 Chemist’s confidence in the high potential of the C–H amination methodology to unlock inert C–H bonds has been demonstrated by its application to more and more challenging substrates. This has been a powerful drive for progress in the field. New valuable insights have been gained allowing, for example, a better regiochemical control via stereoelectronic and/or conformational effects. Innovative strategies have been discovered to direct the insertion event in substrates bearing a large degree of attendant functionality. Solutions have spanned from the elegant exploitation of kinetic isotope effects to the tactical use of protecting groups with different sizes or electronic characteristics. Systematic exploration of different catalytic systems has been also performed leading to the opening of new possibilities in C–H amination technology. Manganese-based catalysts have thus given rise to nitrenoids that overcome the low reactivity of primary aliphatic C–H bonds without interfering with weaker secondary/tertiary C–H bonds. Despite these impressive achievements, much remains to be done. Counterintuitive selectivity and unexplained reactivity should serve as a reminder that further studies are highly needed to understand in depth catalytic C–H amination chemistry. Many challenges remain on the way, from basic to applied research. A clear mechanistic view based on definitive evidence concerning the details of the C–N bond forming process would undoubtedly facilitate the rational design of efficient catalytic systems leading to higher regio-, chemio- and stereoselectivity. In particular, the quest for site-selective C–H amination through catalyst control has to be pursued.10d,e In this context, the development of efficient intermolecular C–H amination process still represents a major challenge and upcoming advancements are expected to increase the impact of this technology in organic synthesis. Future progress made in the field of catalytic C–H amination chemistry might also lead to industrial-scale applications in the next decade. It is likely that total synthesis of synthetically challenging targets related to natural products will continue to be a powerful driving force towards this goal.
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Iridium complexes generated from Ir(I) precursors and PIB oligomer functionalized bpy ligands efficiently catalyzed the reactions of arenes with bis(pinacolato)diboron under mild conditions to produce a variety of arylboronate compounds. The activity of this PIB bound homogeneous catalyst is similar to that of an original non-recyclable catalyst which allows it to be used under milder conditions than other reported recyclable catalysts. This oligomer-supported Ir catalyst was successfully recovered through biphasic extraction and reused for eight cycles without a loss of activity. Biphasic separation after the initial use of the catalyst led to an insignificant amount of iridium leaching from the catalyst to the product, and no iridium leaching from the catalyst was observed in the subsequent recycling runs. Arylboronate products obtained after extraction are sufficiently pure as observed by 1H and 13C-NMR spectroscopy that they do not require further purification.
Texas A&M University at Qatar
David Bergbreiter
Professor
Contact
Department of ChemistryP: 979-845-3437
F: 979-845-4719
bergbreiter@chem.tamu.edu
Our group explores new chemistry related to catalysis and polymer functionalization using the tools and precepts of synthetic organic chemistry to prepare functional oligomers or polymers that in turn are used to either effect catalysis in a greener, more environmentally benign way or to more efficiently functionalize polymers. Often this involves creatively combining the physiochemical properties of a polymer with the reactivity of a low molecular weight compound to form new materials with new functions. These green chemistry projects involve undamental research both in synthesis and catalysis but has practical aspects because of its relevance to practical problems.
A common theme in our catalysis studies is exploring how soluble polymers can facilitate homogeneous catalysis. Homogeneous catalysts are ubiquitously used to prepare polymers, chemical intermediates, basic chemicals and pharmaceuticals. Such catalysts often use expensive or precious metals or expensive ligands or are used at relatively high catalyst loadings. The products often contain traces of these catalysts or ligands – traces that are undesirable for esthetic reasons or because of the potential toxicity of these impurities. Both the cost of these catalysts of these issues require catalyst/product separation – separations that often are inefficient and lead to chemical waste. These processes also use volatile organic solvents – solvents that have to be recovered and separated. Projects underway in our lab explore how soluble polymers can address each of these problems. Examples of past schemes that achieve this goal in a general way as highlighted in the Figure below.
We also use functional polymers to modify existing polymers. Ongoing projects involve molecular design of additives that can more efficiently modify polymers’ physical properties. We also use functional polymers in covalent layer-by-layer assembly to surface polymers’ surface chemistry. An example of this work is our use of ‘smart’ polymers that reversibly change from being water soluble cold to being insoluble and hydrophobic on heating. Such polymers’ have been used by us to prepare ‘smart’ catalysts, ‘smart’ surfaces and membranes, and to probe fundamental chemistry underlying temperature and salt-dependent protein solvation.
Title: Research Assistant Professor
Education: M.S., I.I.T. Roorkee
Ph.D., Panjab University Chandigarh (2008)
Visiting Fellow (w/ Prof. G. G. Balint-Kurti), Bristol University, UK
Postdoctoral Research Associate (w/ Prof. Svetlana Malinovskaya), Stevens Institute of Technology, Hoboken, NJ
Senior Postdoctoral Research Associate (w/ Prof. Seogjoo Jang), Queens College of CUNY, NY
Office: Chemistry 010
Phone: 806-742-3124
Email: praveen.kumar@ttu.edu
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