نتایج جستجو برای: benzoxazines

تعداد نتایج: 156  

Journal: :The Journal of organic chemistry 2005
Yong-Gui Zhou Peng-Yu Yang Xiu-Wen Han

Highly enantioselective hydrogenation of exocyclic enamides, (Z)-3-arylidene-4-acyl-3,4-dihydro-2H-benzoxazines, was achieved in up to 98.6% ee by using Rh/(R,R)-Me-Duphos complex as the catalytic system. The absolute configuration of the product was assigned as R by chemical interrelations.

2001
Ashok K. Prasad Najam A. Shakil Virinder S. Parmar

The capabilities of porcine pancreatic lipase (PPL), Candida antarctica lipase (CAL), and Candida rugosa lipase (CRL) were evaluated for enantioand/or regioselective acetylation/deacetylation of (±)-2,4-diacetoxyphenyl alkyl ketones, (±)-4-alkyl-3,4-dihydro3-hydroxyalkyl-2H-1,3-benzoxazines, and D-arabino and D-threo-polyhydroxyalkyltriazoles in organic solvents. PPL in tetrahydrofuran (THF) ex...

Journal: :Journal of Applied Polymer Science 2022

Abstract Benzoxazine monomers with high renewable content made from difuran diamine (DFDA) are presented. The benzoxazine were synthesized by reacting DFDA several bio‐based phenolic compounds and formaldehyde. These systems purified precipitation, depending on composition, the resulting solid powders melt at temperatures ranging between 50 150°C to form low viscosity liquids that can be used i...

2012
Magnus Rueping Teerawut Bootwicha Erli Sugiono

The asymmetric organocatalytic hydrogenation of benzoxazines, quinolines, quinoxalines and 3H-indoles in continuous-flow microreactors has been developed. Reaction monitoring was achieved by using an inline ReactIR flow cell, which allows fast and convenient optimization of reaction parameters. The reductions proceeded well, and the desired products were isolated in high yields and with excelle...

Journal: :Journal of the American Chemical Society 2012
Yi-Ming Wang Jeffrey Wu Christina Hoong Vivek Rauniyar F Dean Toste

A chiral anion phase-transfer system for enantioselective halogenation is described. Highly insoluble, ionic reagents were developed as electrophilic bromine and iodine sources, and application of this system to o-anilidostyrenes afforded halogenated 4H-3,1-benzoxazines with excellent yield and enantioselectivity.

2016
Jun Wang Ya Zhen Xu Ya Fei Fu Xiang Dong Liu

Latent curing systems are widely used in industrial thermosets in applications such as adhesion, coating, and composites. Despite many attempts to improve the practicality of this dormant reaction system, the majority of commercially available latent products still use particulate hardeners or liquid compounds with blocked active groups. These formulations generally lack fluidity or rapid react...

Journal: :Polymers 2021

To reveal the effect of chlorine substituents in ring aromatic amine on synthesis process benzoxazine monomer and its polymerization ability, as well to develop a fire-resistant material, previously unreported based 3,3′-dichloro-4,4′-diaminodiphenylmethane was obtained toluene mixture toluene/isopropanol. The resulting monomers were thermally cured for 2 h at 180 °C, 4 200 220 °C. A comparison...

Journal: :Chemical communications 2013
Zhuxiu Zhang Young Ran Ji Lukasz Wojtas Wen-Yang Gao Shengqian Ma Michael J Zaworotko Jon C Antilla

Two homochiral organocatalytic MOMs were prepared using tetra- and octa-carboxylate ligands, respectively. The nanoscopic channels in these MOMs are lined by organonocatalytic chiral phosphoric acid derivatives of binol and ocMOM-1 exhibited improved enantioselectivity over the parent ligand in the context of transfer hydrogenation of a series of benzoxazines.

2017
Augusto Rivera Jicli José Rojas Jaime Ríos-Motta Michael Bolte

The asymmetric unit of the title compound, C18H18I2N2O2, consists of one half-mol-ecule, completed by the application of inversion symmetry. The mol-ecule adopts the typical structure for this class of bis-benxozazines, characterized by an anti orientation of the two benzoxazine rings around the central C-C bond. The oxazinic ring adopts a half-chair conformation. In the crystal, mol-ecules are...

Journal: :Molecules 2017
Zi-Long Tang Lian Wang Jing-Zhao Tan Yi-Chao Wan Yin-Chun Jiao

A series of new 1-(carbamoylmethyl)-2-aryl-3,1-benzoxazines were prepared in moderate to good yields by BF₃·OEt₂-catalyzed reactions of aromatic aldehydes with 2-(N-substituted carbamoylmethylamino)benzyl alcohols. The structures of the target compounds were confirmed by IR, ¹H-NMR, 13C-NMR, and elemental analyses. The fungicidal activities of the target compounds against plant fungi were preli...

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