6690-12-6Relevant academic research and scientific papers
A novel synthetic approach to the bicyclo[5.3.1]undecan-11-one framework of vinigrol
Wang, Xian-Lei,Lu, Yun-Yu,Wang, Jie,Wang, Xuan,Yao, He-Quan,Lin, Guo-Qiang,Sun, Bing-Feng
, p. 3562 - 3566 (2014)
The first synthetic attempt commencing from an eight-membered ring to approach the [5.3.1] bicyclic core of vinigrol has demonstrated the feasibility of using the conformational bias of the cyclooctane-ring system to realize highly diastereoselective reactions. The synthetic potential of the newly disclosed access to in/out isomerism may stimulate broader interests. This journal is the Partner Organisations 2014.
Vanadyl β-tetrabromoporphyrin: Synthesis, crystal structure and its use as an efficient and selective catalyst for olefin epoxidation in aqueous medium
Dar, Tawseef Ahmad,Tomar, Reshu,Mian, Rasel Mohammad,Sankar, Muniappan,Maurya, Mannar Ram
, p. 10405 - 10413 (2019/04/10)
We hereby report the synthesis, characterization and catalytic applications in the epoxidation of alkenes by a vanadyl porphyrin having bulky bromo substituents at the β-positions viz. vanandyltetrabromotetraphenylporphyrin (1). The synthesized porphyrin was characterized by various spectroscopic techniques like UV-visible, FT-IR, EPR, MALDI-TOF mass spectrometry and single crystal X-ray analysis. Porphyrin 1 has a nonplanar structure as indicated by its X-ray structure, DFT and electrochemical studies. 1 was analyzed for its catalytic application in the epoxidation of various alkenes. The catalytic reactions were carried out in CH3CN/H2O mixture in 3:1 (v/v) ratio. 1 displayed good efficiency in terms of mild reaction conditions, lower reaction temperature and minimal catalyst amount consumption. 1 exhibited excellent selectivity, high conversion efficiency and huge TOF (7600-9800 h-1) in a significantly low reaction time of 0.5 h. Catalyst 1 was regenerated at the end of various catalytic cycles making it reusable and industrially important.
MULTIPLE CYCLOADDITION REACTIONS FOR LABELING OF MOLECULES
-
Paragraph 0800-0801, (2016/12/12)
The present invention relates to methods for linking tetrazines with dienophiles to establish at least two linkages by sequentially performing at least two cycloaddition reactions. The methods in particular allow establishing multi-labeling strategies. In particular, the invention relates to methods for forming linkages by cycloaddition reactions, wherein the method comprises reacting a first alkyl-substituted tetrazine with a first dienophile comprising a irans-cyclooctenyl group followed by reacting a second tetrazine with a second dienophile comprising a cyclooctynyl group, wherein the reaction of the first tetrazine with the first dienophile proceeds in the presence of the second dienophile.
Efficient and shortcut syntheses of some novel eight-membered ring cyclitols starting from cycloocta-1,3-diene
Ecer, Kadriye,Salamci, Emine
, p. 8389 - 8396 (2015/03/05)
Cyclooctane-1,2,3,4-tetraols, aminocyclooctanetriol, and chlorocyclooctanetriol were synthesized starting from cis,cis-1,3-cyclooctadiene by a concise and efficient method. Cyclooctene endoperoxide and cyclooctene epoxide obtained by photooxygenation and epoxidation, respectively, of cis,cis-1,3-cyclooctadiene were used as the key intermediates. The other oxygen, nitrogen, and chloro functionalities were introduced via epoxidation of the remaining double bond, ring-opening of epoxide, and cis-hydroxylation reactions.
Minimal tags for rapid dual-color live-cell labeling and super-resolution microscopy
Nikic, Ivana,Plass, Tilman,Schraidt, Oliver,Szymanski, Jedrzej,Briggs, John A. G.,Schultz, Carsten,Lemke, Edward A.
supporting information, p. 2245 - 2249 (2014/03/21)
The growing demands of advanced fluorescence and super-resolution microscopy benefit from the development of small and highly photostable fluorescent probes. Techniques developed to expand the genetic code permit the residue-specific encoding of unnatural amino acids (UAAs) armed with novel clickable chemical handles into proteins in living cells. Here we present the design of new UAAs bearing strained alkene side chains that have improved biocompatibility and stability for the attachment of tetrazine-functionalized organic dyes by the inverse-electron-demand Diels-Alder cycloaddition (SPIEDAC). Furthermore, we fine-tuned the SPIEDAC click reaction to obtain an orthogonal variant for rapid protein labeling which we termed selectivity enhanced (se) SPIEDAC. seSPIEDAC and SPIEDAC were combined for the rapid labeling of live mammalian cells with two different fluorescent probes. We demonstrate the strength of our method by visualizing insulin receptors (IRs) and virus-like particles (VLPs) with dual-color super-resolution microscopy. Copyright
A heterogenized vanadium oxo-aroylhydrazone catalyst for efficient and selective oxidation of hydrocarbons with hydrogen peroxide
Monfared, Hassan Hosseini,Abbasi, Vahideh,Rezaei, Adineh,Ghorbanloo, Massomeh,Aghaei, Alireza
experimental part, p. 85 - 92 (2012/08/28)
A hydrazone Schiff base ligand derived from salicylaldehyde and benzhydrazide has been synthesized and reacted with vanadium(IV) leading to the corresponding vanadium(V) complex. The complex has been anchored on the surface of functionalized silica gel by N,O-coordination to the covalently Si-O bound modified salicylaldiminato ligand. The supported complex has been evaluated as a catalyst for hydrocarbon oxidation with hydrogen peroxide in acetonitrile. The heterogeneous system proved to be an efficient catalyst and was able to activate hydrogen peroxide toward the oxidation of alkenes, alkanes, benzene, and alkylaromatic compounds with more than 2,500 h-1 activity. Springer Science+Business Media B.V. 2011.
A new efficient iron catalyst for olefin epoxidation with hydrogen peroxide
Mikhalyova, Elena A.,Makhlynets, Olga V.,Palluccio, Taryn D.,Filatov, Alexander S.,Rybak-Akimova, Elena V.
supporting information; experimental part, p. 687 - 689 (2012/02/01)
A new aminopyridine ligand derived from bipiperidine (the product of full reduction of bipyridine, bipy) coordinates to iron(ii) in a cis-α fashion, yielding a new selective catalyst for olefin epoxidation with H 2O2 under limiting substrate conditions.
The catalytic function of a silica gel-immobilized Mn(II)-hydrazide complex for alkene epoxidation with H2O2
Ghorbanloo, Massomeh,Monfared, Hassan Hosseini,Janiak, Christoph
experimental part, p. 12 - 20 (2011/10/05)
An efficient and highly selective heterogeneous catalyst was developed by immobilization of a manganese complex on an inorganic support to yield (silica gel)-O2(EtO)Si-L1-Mn(HL2) [(L1) - modified salicylaldiminato and H2L2(E)- N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide]. Mn(II) has been anchored on the surface of functionalized silica by means of N,O-coordination to the covalently Si-O bound modified salicylaldiminato Schiff base ligand. The prepared material (silica gel)-O2(EtO)Si-L1-Mn(HL 2), was characterized by elemental and thermogravimetric analyses (TGA and DTA), UV-vis and FT-IR spectroscopy. This new material is demonstrated to be a very active catalyst in clean epoxidation reactions using a combined oxidant of aqueous hydrogen peroxide and actonitrile in the presence of aqueous sodium hydrogencarbonate. The effects of reaction parameters such as solvent, NaHCO3 and oxidant in the epoxidation of cis-cyclooctene were investigated. Cycloalkenes were oxidized efficiently to their corresponding epoxide with 87-100% selectivity in the presence of this catalyst. This catalytic system showed also good activities in the epoxidation of linear alkenes. The obtained results show that this catalyst is a robust and stable heterogeneous catalyst which can be recovered quantitatively by simple filtration and reused multiple times without loss of its activity.
Iron-catalyzed epoxidation of olefins using hydrogen peroxide
Hasan, Kamrul,Brown, Nicole,Kozak, Christopher M.
experimental part, p. 1230 - 1237 (2011/06/27)
A practical method of olefin epoxidation was developed by combining FeCl3·6H2O and 1-methylimidazole in acetone using H2O2 as the terminal oxidant. This system showed very good reactivity toward epoxidation of both terminal and substituted alkenes. The use of tridentate and tetradentate amine-bis(phenolate) ligands as additives was also examined. Modest improvement in selectivity was achieved if a bulky tridentate ligand was used. Generally, however, the simple catalyst system involving ferric chloride, 1-methylimidazole and dilute H2O 2 in acetone proved most successful in achieving good to excellent yields of epoxide products for a number of substrates, including aromatic and aliphatic alkenes.
Highly selective olefin epoxidation with the bicarbonate activation of hydrogen peroxide in the presence of manganese(III) meso-tetraphenylporphyrin complex: Optimization of effective parameters using the Taguchi method
Monfared, Hassan Hosseini,Aghapoor, Vahideh,Ghorbanloo, Massomeh,Mayer, Peter
experimental part, p. 209 - 216 (2011/02/16)
A MnIII-porphyrin-based catalytic system was explored for olefin epoxidations under mild reaction conditions using sodium bicarbonate-hydrogen peroxide as an oxidant. The Mn(TPP)OAc/imidazol/NaHCO3 system efficiently catalyzed the epoxidation of olefins with H2O2. Cyclic olefins were transformed in excellent yield (80-100%) and selectivity (87-100%), the obtained selectivity and yields being much better than those observed in the absence of bicarbonate. In the presence of an excess of substrate, the turnover number 4286 was obtained with the Mn(TPP)OAc/Im/NaHCO3/H2O2 system after 2 h. The bicarbonate-activated oxidation system is a simple, inexpensive, and relatively nontoxic alternative to other oxidants and peroxyacids, and it can be used in a variety of oxidations where a mild, neutral pH oxidant is required. Due to the various factors, such as solvent, reaction temperature, stoichiometric ratio of imidazole/NaHCO3/H2O2, influencing the oxidation of olefins, the Taguchi method of system optimization was used to determine the percent of contribution (%P) of each factor. It was found that the solvent had the most influence on the oxidation (30.051%) and the imidazole amount stood in second place (22.286%).
