1590-22-3Relevant articles and documents
Synthesis, properties, and two-dimensional adsorption characteristics of 5-amino[6]hexahelicene
Van Der Meijden, Maarten W.,Gelens, Edith,Quirs, Natalia Murillo,Fuhr, Javier D.,Gayone, J. Esteban,Ascolani, Hugo,Wurst, Klaus,Lingenfelder, Magal,Kellogg, Richard M.
, p. 1484 - 1492 (2016)
A convergent synthesis of racemic 5-amino[6]hexahelicene is described. Cross-coupling reactions are used to assemble a pentacyclic framework, and a metal-catalyzed ring-closure comprises the final step. The enantiomers were separated by means of chromatography and the absolute configurations were assigned by comparison of the CD spectra with hexahelicene. The t1/2 value for racemization at 210 °C was approximately 1 hour. Scanning tunneling microscopy (STM) measurements were carried out on enantiopure and racemic samples of aminohelicene on Au(111) under ultrahigh vacuum (UHV) conditions. Stairway to heaven? In a convergent synthesis of racemic 5-amino[6]hexahelicene (see figure), cross-coupling reactions assemble a pentacyclic framework, with a metal-catalyzed ring closure as the final step. The enantiomers are separated by means of chromatography and the absolute configurations assigned by comparison of the CD spectra with hexahelicene. Furthermore, scanning tunneling microscopy (STM) on Au(111) was performed under ultrahigh vacuum.
Chemistry of unique chiral olefins. 1. Synthesis, enantioresolution, circular dichroism, and theoretical determination of the absolute stereochemistry of trans- and cis-1,1',2,2',3,3',4,4'-Octahydro-4,4'- biphenanthrylidenes
Harada, Nobuyuki,Saito, Akira,Koumura, Nagatoshi,Uda, Hisashi,De Lange, Ben,Jager, Wolter F.,Wynberg, Hans,Feringa, Ben L.
, p. 7241 - 7248 (1997)
Unique chiral olefins, (E)-1,1',2,2',3,3',4,4'-octahydro-4,4'-biphenanthrylidene (1) and its (Z)-isomer 2, were synthesized. When these compounds are directly enantioresolved by using the HPLC Okamoto column with a chiral stationary phase, optically pure enantiomers were obtained. The CD spectra of these chiral olefins exhibit very intense Cotton effects in the 1B(b) transition region reflecting their strongly twisted π-electron systems. The CD and UV spectra of chiral olefins (M,M)-E-1 and (M,M)-(Z)-2 were theoretically calculated by the π-electron self-consistent field/configuration interaction/dipole velocity molecular orbital method. From the calculation results, the absolute stereostructures of these chiral olefins were theoretically determined to be [CD(+)239.0]-(M,M)-(E)-1 and [CD(+)238.1]-(M,M)-(Z)-2, respectively.
An efficient and novel method for the synthesis of β-aroylpropionic acids under solvent-free conditions
Mogilaiah,Reddy, N. Vasudeva,Reddy, G. Randheer
, p. 3109 - 3113 (2003)
A simple and rapid reaction of succinic anhydride with aromatic hydrocarbons is described. The reaction is conducted under Friedel-Crafts conditions in the absence of solvent at room temperature using aluminium chloride as catalyst.
Iron(II) and zinc(II) monohelical binaphthyl salen complexes
Wiznycia, Alexander V.,Desper, John,Levy, Christopher J.
, p. 4693 - 4695 (2005)
A new chiral binaphthyl salen ligand with rigid polyaromatic sidearms gives monohelical Complexes (FeII and ZnII) of predetermined handedness. The Royal Society of Chemistry 2005.
Cationic α-Diimine Nickel and Palladium Complexes Incorporating Phenanthrene Substituents: Highly Active Ethylene Polymerization Catalysts and Mechanistic Studies of syn/ anti Isomerization
Tran, Quan H.,Wang, Xiqu,Brookhart, Maurice,Daugulis, Olafs
, p. 4704 - 4716 (2020)
α-Diimine palladium complexes incorporating phenanthryl- and 6,7-dimethylphenanthrylimino groups have been synthesized and characterized. The (diimine)PdMeCl complexes prepared from 2,3-butanedione and acenaphthenequinone bearing the unsubstituted phenant
Synthesis, characterization and structural aspects of new haptens for PAHs
Li, Yi,Yang, Mingming,Liu, Yuanyuan,Wei, Rongqing,Liu, Xiaoning,Li, Fangshi
, p. 206 - 213 (2011)
Two new haptens for PAHs, 4-(naphthalen-2-yl)-4-oxobutanoic acid (I) and 4-(anthracen-1-yl)-4-oxobutanoic acid (II), were synthesized and confirmed by elemental analysis, IR, and 1H NMR. Single crystal X-ray structure showed that compound I crystallizes in the triclinic crystal system (space group = P-1). A classic hydrogen bonded dimer is formed by the carboxylic acid group from two molecules. The R22 (8) graph-set motif links the molecules into pairs around inversion centers in the unit cell. The O-H?O hydrogen-bonded interactions involving these pairs are very strong and stabilize molecular packing of these dimers into a unique assembly. Compound II crystallizes in the Monoclinic crystal system (space group = P21/c). Similarly to compound I, a classic hydrogen bonded dimer is formed by the carboxylic acid group from two molecules. The R22 (8) graph-set motif links the molecules into pairs around inversion centers in the unit cell. Besides, an intramolecular hydrogen bonding causes the formation of a planar six-membered ring, which is also coplanar with the adjacent anthracene ring. The geometries of the corresponding parts of the haptens are almost the same as those of naphthalene and anthracene. Ab initio Hartree-Fock computational calculation provided the supports that the size, shape (geometry) and electronic properties at the corresponding parts of the haptens did not change significantly, compared to those of naphthalene and anthracene. The haptens were coupled with bovine serum albumin (BSA) to make antigents. The coupling ratio of I-BSA was 1:20, and II-BSA 1:37, respectively. These results showed that the new haptens could be used to induce specific antibodies for PAHs.
Preparation method of light-driven molecular motor based on oxidized benzofuran structure
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Paragraph 0015; 0072-0073, (2022/01/04)
The present invention relates to a preparation method and application of a molecular motor containing oxidized benzofuran structure, belonging to the field of organic chemistry technology. The first motor is based on 3-methyl-2,3-dihydrofyl-4(1H)-ketone and 2-coumarinone as raw materials, the second motor is based on 3-methyl-2,3-dihydrophenanthrene-4(1H)-keto and naphthalene [1,2-b]furan-2(3H)-ketone as raw materials, the third motor with 3-methyl-2,3-dihydrophenanthin-4 (1H)-keto and 6-isopropylphenone-2(3H)-keto as raw materials, in the presence of titanium tetrachloride and 1,8-diazoacyclodo-unicyclic-7-ene, In anhydrous tetrahydrofuran solvents, nucleophilic addition reactions are prepared. The reaction conditions of the present invention are mild, there is no need to add strong acids and strong bases, the equipment requirements are low, the operating cost is reduced; the reaction process produces less waste, the degree of environmental pollution is low; the obtained product motor structure is novel and has potential application value in the field of molecular devices.
Direct Synthesis of Chiral NH Lactams via Ru-Catalyzed Asymmetric Reductive Amination/Cyclization Cascade of Keto Acids/Esters
Shi, Yongjie,Tan, Xuefeng,Gao, Shuang,Zhang, Yao,Wang, Jingxin,Zhang, Xumu,Yin, Qin
supporting information, p. 2707 - 2713 (2020/03/30)
Lactams with a stereogenic center adjacent to the N atom have existed in many medicinal agents and bioactive alkaloids. Herein we report a broadly applicable synthesis of enantioenriched NH lactams through a one-pot asymmetric reductive amination/cyclization sequence of easily available keto acids/esters. Such cascade processes alleviate the demand for protecting group manipulations as well as intermediate purification. This strategy is capable of constructing enantioenriched lactams and benzo-lactams of a five-, six-, or seven-membered ring in generally high yield and with excellent enantioselectivities (up to 97% ee). Scalable and concise syntheses of key drug intermediates have further displayed the importance of this methodology.
One-Pot Synthesis of 2,5-Disubstituted Furans through In Situ Formation of Allenes and Enolization Cascade
Bernhard, Yann,Gilbert, Joachim,Bousquet, Till,Favrelle-Huret, Audrey,Zinck, Philippe,Pellegrini, Sylvain,Pelinski, Lydie
supporting information, p. 7870 - 7873 (2019/12/24)
A one-pot synthesis of 2,5-disubstituted furans from γ-ketoacids is reported. In situ formation of allenoates by action of chloroformate on carboxylic acid following by enolization of ketone affords furan derivatives by cyclization. The reaction was extended to a wide scope of ketoacids and phosphonium salts. This methodology was applied on levulinic acid and derivatives, one of the biosourced platform chemicals.
Efficient Hydrogenation of Biomass Oxoacids to Lactones by Using NHC–Iridium Coordination Polymers as Solid Molecular Catalysts
Liu, Yaoqi,Sun, Zheming,Huang, Changyu,Tu, Tao
, p. 355 - 360 (2017/02/05)
A series of NHC–iridium coordination polymers have proven to be robust, efficient and recyclable solid molecular catalysts toward the hydrogenation of biomass levulinic acid (LA) to γ-valerolactone. Along with quantitative yields attained at 0.01 mol % catalyst loading under 50 atm of H2, the solid molecular catalyst was readily recovered and reused for 12 runs without obvious loss of the selectivity and activity. Remarkably, up to 1.2×105 TON, an unprecedented value could be achieved in this important transformation. In addition, a number of LA homologues, analogues and derivatives were well tolerated to deliver various intriguing and functional lactones in good to excellent yields, which further confirmed the feasibility of the solid molecular catalysts.
