• Notably, sacidumlignan A ( 1 ) can be also efficiently synthesized in only 7 steps with 25% overall yield, where acid triggered tandem reaction starting from analogous Ueno-Stork cyclization product 27 played an important role. (rsc.org)
  • When the Lawesson s reagent mediated cyclization of various 1,4-dicarbonyl compounds is performed under microwave irradiation conditions in a conventional microwave oven, high yields of the desired S -heterocycles are obtained, little or no byproduct is formed, reaction times are extremely short, and no solvent is needed for the reaction. (organic-chemistry.org)
  • The use of high-quality enzymes and optimized Buffer significantly reaction efficiency, enabling the entire cyclization and digestion process to be completed in less than 30 minutes. (yeasen.com)
  • A new internal, base-mediated redox-cyclisation reaction has been discovered and developed. (mpg.de)
  • While at first most efforts were aimed at establishing the diradical nature of the thermal process and to derive therefrom efficient protocols for synthetic schemes, recent evidence has disclosed the C-2-C-6 cyclization as a unique reaction heavily influenced by nonstatistical dynamic effects. (itu.edu.tr)
  • This step results from an intramolecular cyclization reaction in which the carbonyl (C=O) group that was a part of the original isocyanate group (-N=C=O), is effectively extracted to yield perimidone and the amine corresponding to the original isocyanate species. (cdc.gov)
  • Efficient synthesis of (±)-sacidumlignan D ( 4 ) has been successfully achieved employing Ueno-Stork radical cyclization of α-bromo acetal 21 as a key step. (rsc.org)
  • A connective Pummerer-type cyclisation has been developed for an approach to the synthesis of ecteinascidin 597.Several electron rich glyoxamide substrates have been prepared and conditions for the connective Pummerer-type cyclisation have been developed successfully. (manchester.ac.uk)
  • The synthesis consists of a tin-mediated tandem radical cyclization of appropriate precursors to form 2,3-disubstituted dihydroindoles, which in turn are oxidized to yield the corresponding 2-arylindoles. (uni-regensburg.de)
  • The first chapter includes the synthesis of functionalized 2-(phenylthio)benzoates, containing a halogenated side chain, by domino '[3+3] cyclization / Homo-Michael′ reactions of 1-trimethylsilyloxy-3-arylthio-1,3-butadienes with 1,1-diacylcyclopropanes. (uni-rostock.de)
  • In the second chapter, a regioselective synthesis of 2-(arylthio)benzoates by the first [3+3] cyclizations of 3-arylthio-1-silyloxy-1,3-butadienes with 3-alkoxy-2-en-1-ones is reported. (uni-rostock.de)
  • Tariq, M & Moran, WJ 2020, ' Design and synthesis of chiral urea-derived iodoarenes and their assessment in the enantioselective dearomatizing cyclization of a naphthyl amide ', Tetrahedron , vol. 76, no. 45, 131634. (hud.ac.uk)
  • Electrophilic cyclizations of alpha,beta-alkynic hydrazones by molecular iodine were investigated for the synthesis of 4-iodopyrazoles. (metu.edu.tr)
  • An efficient synthesis of fully aromatic, fused-ring, monoaza-acenes through a nucleophile initiated cascading cyclization is illustrated. (ncsu.edu)
  • Recently, significant advances have taken place in the use of SmI 2 for the synthesis of nitrogen heterocycles, enabled in large part by the unique combination of high reducing power of this reagent (E 1/2 of up to −2.8 V) with excellent chemoselectivity of the reductive umpolung cyclizations mediated by SmI 2 . (mdpi.com)
  • R. Martín, Cuenca, A. , and Buchwald, S. L. " Sequential Copper-Catalyzed Vinylation/Cyclization: An Efficient Synthesis of Functionalized Oxazoles " , Org. (mit.edu)
  • A novel Fourier transform infrared (FT-IR) microspectrophotometer equipped with differential scanning calorimetry (DSC) was used to investigate the kinetics of intramolecular cyclization of aspartame (APM) sweetener in the solid state under isothermal conditions. (unboundmedicine.com)
  • The results support that the intramolecular cyclization process in APM proceeded in three steps: the methoxyl group of ester was first thermolyzed to release methanol, then an acyl cation was attacked by the lone pair of electrons available on nitrogen by an S(N)1 pathway, and finally ring-closure occurred. (unboundmedicine.com)
  • The intramolecular cyclization of APM determined by this microscopic FT-IR/DSC system was found to follow zero-order kinetics after a brief induction period. (unboundmedicine.com)
  • The total activation energy of the DKP formation via intramolecular cyclization was 261.33 kJ/mol, calculated by the above summation of the bond energy of cleavage, conversion, and formation, which was near to the value determined by the DSC or TGA method. (unboundmedicine.com)
  • We discover one dominant mutation is sufficient to activate cyclization, and together with two additional residues comprise a network of strongly epistatic interactions that activate, suppress or reactivate cyclization. (sri.com)
  • But further tests revealed that it was pa r t of a network of three residues that together interact to activate, suppress or reactivate cyclisation. (chemistryworld.com)
  • Radical cyclization reactions are organic chemical transformations that yield cyclic products through radical intermediates. (wikipedia.org)
  • Radical cyclization reactions produce mono- or polycyclic products through the action of radical intermediates. (wikipedia.org)
  • Disadvantages: the relative rates of the various stages of radical cyclization reactions (and any side reactions) must be carefully controlled so that cyclization and trapping of the cyclized radical is favored. (wikipedia.org)
  • Side reactions are sometimes a problem, and cyclization is especially slow for small and large rings (although macrocyclizations, which resemble intermolecular radical reactions, are often high yielding). (wikipedia.org)
  • Cyclization of the homologous 6-heptenyl radical is still selective, but is much slower-as a result, competitive side reactions are an important problem when these intermediates are involved. (wikipedia.org)
  • 2) Cyclization reactions of vinyl, aryl, and acyl radicals are also known. (wikipedia.org)
  • The emergence of terpene cyclization was critical to the evolutionary expansion of chemical diversity yet remains unexplored. (sri.com)
  • Here we report the first discovery of an epistatic network of residues that controls the onset of terpene cyclization in Artemisia annua. (sri.com)
  • They usually proceed in three basic steps: selective radical generation, radical cyclization, and conversion of the cyclized radical to product. (wikipedia.org)
  • The radical cyclization step usually involves the attack of a radical on a multiple bond. (wikipedia.org)
  • Three conditions must be met for an efficient radical cyclization to take place: A method must be available to generate a radical selectively on the substrate. (wikipedia.org)
  • Radical cyclization must be faster than trapping of the initially formed radical. (wikipedia.org)
  • 5-hexenyl radicals are the most synthetically useful intermediates for radical cyclizations, because cyclization is extremely rapid and exo selective. (wikipedia.org)
  • Although the exo radical is less thermodynamically stable than the endo radical, the more rapid exo cyclization is rationalized by better orbital overlap in the chair-like exo transition state (see below). (wikipedia.org)
  • Stabilizing the initially formed radical with electron-withdrawing groups provides access to more stable 6-endo cyclization products preferentially. (wikipedia.org)
  • However, low concentrations of a radical scavenger establish thermodynamic control and provide access to 6-endo products-not via 6-endo cyclization, but by 5-exo cyclization followed by 3-exo closure and subsequent fragmentation (Dowd-Beckwith rearrangement). (wikipedia.org)
  • 103 those of analogous hydrocarbon radicals), whereas HFC hexenyl and heptenyl ethers exhibit lower cyclization reactivity, as do HFC 7-octenyl radical systems, which cyclize in an endo manner. (canada.ca)
  • When treated with molecular iodine in the presence of sodium bicarbonate, alpha,beta-alkynic hydrazones underwent electrophilic cyclization to afford 4-iodopyrazoles in good to high yields. (metu.edu.tr)
  • The transformation consists of a sequential copper-catalyzed amidation of vinyl halides followed by cyclization promoted by iodine. (mit.edu)
  • Finally, the use of elemental hydrogen as a terminal reductant in the rhodiumcatalyzed enantioselective reductive cyclization of 1,6-enynes is described. (utexas.edu)
  • Whereas 1,6- enynes containing 1,2-substituted alkenes fail to provide reductive cyclization products due to competitive cycloisomerization, related alkenes in the form of conjugated enones afford reductive cyclization products in good to excellent yield and enantioselection. (utexas.edu)
  • Cascade Cyclization To Produce a Series of Fused, Aromatic Molecules. (ncsu.edu)
  • Wang, Q & Pettitt, BM 2016, ' Sequence Affects the Cyclization of DNA Minicircles ', Journal of Physical Chemistry Letters , vol. 7, no. 6, pp. 1045-1046. (utmb.edu)
  • Remarkably, this epistatic network of equivalent residues also controls cyclization in a BFS homologue from Citrus junos. (sri.com)
  • They reasoned that the important parts of the enzyme enabling cyclisation would lie within the active site or nearby, and thus focused their attention on the residues within 6Å of this region. (chemistryworld.com)
  • Recently, cyclizations induced by halogen groups that allow the production of diverse targets and the structural reorganization of organic molecules have attracted significant attention from synthetic chemists. (preprints.org)
  • In the final phase of this investigations it was explored the use of chiral derivatives of the chiral pool molecule citronellal as well as an achiral analogue in an effort to afford novel chiral aldehydes for propargylation and cyclisation. (bl.uk)
  • These new chiral iodoarenes were assessed as catalysts in the dearomatizing cyclization of a naphthyl amide and provided moderate yields of product in some cases with low enantioselectivities. (hud.ac.uk)
  • Using competition kinetic methodology, rate constants for cyclizations of a series of hydrofluorocarbon (HFC) and ether 5-hexenyl, 6-heptenyl, and 7-octenyl radicals have been determined. (canada.ca)
  • The extended ladder polymer can also be easily prepared by our chemical cyclization method using a soluble precursor. (elsevierpure.com)
  • We study cyclization of polymer chains in which the reactive ends of the chains are initially in close proximity (ring initial conditions). (psu.edu)
  • C) Nucleotide alignment of cyclization sequence (D) Nucleotide alignment of upstream AUG region. (cdc.gov)
  • In addition, the connective Pummerer-type cyclisation has been used with simple aldehyde substrates for the first time.The tetrahydroisoquinoline AB system of ecteinascidin 597 has been prepared successfully using the connective Pummerer-type cyclisation. (manchester.ac.uk)
  • In many cases, exo cyclization is favored over endo cyclization (macrocyclizations constitute the major exception to this rule). (wikipedia.org)
  • When this 'gateway' mutation was transferred to wild-type BFS, it was enough to generate cyclisation. (chemistryworld.com)
  • It is initially biosynthesized by cyclization of oxidosqualene to lupeol. (bvsalud.org)
  • These unique cyclizations may possibly be used as efficient synthetic strategies with future advances. (preprints.org)
  • The bond cleavage energy (259.38 kJ/mol) of thermolysis for the leaving group of -OCH(3), the bond conversion energy (328.88 kJ/mol) for the amide II NH band to DKP NH band, and the CN bond formation energy (326.93 kJ/mol) of cyclization for the DKP in the APM molecule were also calculated from the Arrhenius equation. (unboundmedicine.com)
  • This graph shows the total number of publications written about "Cyclization" by people in this website by year, and whether "Cyclization" was a major or minor topic of these publications. (rush.edu)
  • We find a surprising general relation between cyclization with ring and equilibrium initial conditions, namely that ring (t) ∝ d/dt ring , where (t) is the survival fraction. (psu.edu)
  • Below are the most recent publications written about "Cyclization" by people in Profiles. (rush.edu)