Copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters for synthesis of functionalized 2,3-allenoates

Herein,copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters have been developed.The enynic orthoesters as precursors of unstable enynic esters were applied to produce the functionalized 2,3-allenoate products.Meanwhile,the asymmetric 1,4-protosilylation of enynic orthoesters with Ph Me2Si-Bpin was also studied.The chiral monopyridine imidazoline ligand was efficient to provide the asymmetric 1,4-protosilylation products with high enantioselectivity.

Environmentally Benign Synthesis of Sugar Orthoesters Promoted by Anhydrous Sodium Acetate and Ultrasound

A convenient and alternative procedure for the synthesis of sugar orthoesters from glycosyl bromides with an- hydrous sodium acetate as base under ultrasound irradiation is described. Various sugar and sugar-sugar orthoesters were prepared in 70%-91% isolated yields.

A new route to the synthesis of thieno[2,3-d]pyrimidin-4(3H)-one derivatives catalyzed by 12-tungstophosphoric acid (H_3PW_(12)O_(40))

Heteropoly acid H3PW12040 （PW） has been used as an effective catalyst for the synthesis of thieno[2,3-d]pyrimidin-4（3H）-one derivatives. The present methodology offers several advantages, such as high yields, short reaction times, mild reaction condition and a recyclable catalyst with a very easy work up.

Properties of a New Dental Photocurable Matrix Resin with Low Shrinkage

In order to reduce the amount of volumetric shrinkage that occurs in dental composites as a result of curing,a new kind of dental matrix resin combining bisphenol-S-bis（3-meth acry late-2-hydroxy propyl）ether（BisS-GMA） with the expanding monomer unsaturated spiro orthoesters 2-methylene-1,4,6-trispiro[4,4] nonane （SOE） was prepared,with triethylene glycol dimethacrylate （TEGDMA） as diluent.CQ （camphorquinone） of 1wt% and DMAEMA （2-（dimethylamino） ethyl meth acrylate） of 2wt% were used as photoinitiation system to initiate the copolymerization of the matrix resins.The performance including volumetric shrinkage,degree of conversion and condition of the ring-opening reaction of SOE,as well as curing time and the tensile bond strength were investigated respectively by the dilatometer,Fourier transfer infrared,the universal testing machine,and so on.The ring-opening polymerization of SOE occurred.Meanwhile,the obtain copolymers were crosslinked.The matrix resin containing BisS-GMA and SOE showed a reduced amount of volumetric shrinkage at 1.52%,which is a promising strategy for obtaining a polymer with a low amount of volumetric shrinkage.Furthermore,the other properties were not compromised.

利用磁性可回收的Fe_3O_4纳米颗粒催化剂合成苯并咪唑的新方法(英文)

Magnetically recoverable Fe3O4 nanoparticles have been synthesized as a catalyst for the cyclocondensation of 1,2-phenylenediamines with orthoesters under solvent-free conditions.Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding benzimidazole derivative at 80 °C.This green method offers significant advantages in terms of its simplicity,low catalyst loadings,high product yields,and non-toxic nature.The Fe3O4 nanoparticles were characterized by X-ray diffraction,transmission electron microscopy,and Fourier transform infrared spectroscopy.

A Rapid Access to Novel and Known Benzimidazole Derivatives Using Silica Chloride as a Reusable Catalyst

A new application of silica chloride as an easily available and reusable solid acid catalyst for the synthesis of benzimidazole and its derivatives through the condensation of o-phenylenediamines and orthoesters under thermal and solvent-free conditions is described. This novel and eco-friendly method is very cheap and has many advan- tages including excellent yields, short reaction time, and simple work-up procedure.

Synthesis of Pyrazolo[3,4-d]pyrimidin-4-ones Catalyzed by Brensted-acidic Ionic Liquids as Highly Efficient and Reusable Catalysts

A convenient and efficient method for the synthesis of pyrazolo[3,4-d]pyrimidin-4-ones via heterocyclization reaction of 5-amino-lH-pyrazole-4-carboxamides with triethyl orthoesters using two BrCnsted-acidic ionic liquids, 3-methyl-l-（4-sulfonic acid）butylimidazolium hydrogen sulfate [MIM＋（CH2）4SO3H][ HSO4 ] or N-（4-sulfonic acid）butyl triethylammonium hydrogen sulfate [Et3N＋（CH2）4SO3H][ HSO4 ], as efficient homogeneous catalysts under solvent-free conditions is described.

KAI（SO4）2-12H2O （Alum） Catalyzed One-Pot Three-Component Synthesis of 2-Alkyl and 2-Aryl-4（3H）-quinazolinone under Microwave Irradiation and Solvent Free Conditions

Twenty 2,3-disubstituted-4（3H）-quinazolinones were synthesed by one-pot three-component method with isa- toic anhydride, orthoesters and amines as raw materials in the presence of KAI（SO4）2·12H2O （Alum） under micro- wave irradiation and solvent-free conditions. 6-Bromo-2-propyl-3-p-tolylquinazolin-4（3H）-one （4m）, 6-bromo-2- methyl-3-phenethylquinazolin-4（3H）-one （4n） and 6-bromo-2-ethyl-3-phenethylquinazolin-4（3H）-one （40） were characterized by IR, 1H NMR, 13C NMR and elemental analysis.

A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones

A new approach to the facile synthesis of 2-substituted-quinazolin-4（3H）-ones and its derivatives using the condensation reaction of substituted 2-aminobenzamide and orthoesters is reported.