The Friedel-Crafts Acylation of Substituted Benzene with 2 - Phenylfuran-3, 4-dicarboxylic Acid Anhydride

2-Phenylfuran-3,4-dicarboxylic acid anhydride reacted with seven aromatic compounds, of which five gave keto acids in yields of 94%-63%. The structure of the keto acid was elucidated by reducing it to hydroxy acid and analyzing with NMR technique.

Narasaka reaction:Desilylative acylation of 1-alkenylsilanes with acid anhydrides

Recent advances in the desilylative acylation of 1-alkenylsilanes with acid anhydrides under transition metal catalysis are summarized.This catalytic desilylative acylation of 1-alkenylsilanes provides an efficient route toα,β-unsaturated ketones by using rhodium or iridium as the catalyst.Moreover,various one pot sequence reactions have been developed,which can synthesizeα,β-unsaturated ketones from simple starting materials in an economic way.Additionally,this approach is applied to the asymmetric synthesis of atropisomers possessing silanol groups with excellent enantioselectivity.

The UV Aging Properties of Maleic Anhydride Esterified Starch/Polylactic Acid Composites

Esterified starch/polylactic acid（ES/PLA） blending composite was prepared by melting extrusion with maleic anhydride esterified starch and PLA as the raw materials. The composite was accelerated aging by using UV aging box, and its properties were characterized by Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM）, X-ray diffraction（XRD）, thermo gravimetric analysis（TGA） and mechanical testing machine. FT-IR and SEM results show that the infrared absorption peak intensities of C-O, C-H, and C=O in aged samples decrease gradually with increasing aging time. The damage degree of surface and internal of aged samples increases gradually. XRD analysis results show that after aging treatment, the crystalline diffraction peak of thermoplastic esterified starch at 2θ = 21° disappears and the diffraction peaks of PLA at 2θ = 16.5° appear, indicating that the hydrolysis rate of esterified starch is greater than that of PLA. The crystallinity of PLA in aged sample shows an increasing trend at first followed by a decreasing one along with the increasing time of aging treatment, suggesting that the hydrolysis of amorphous regions of PLA is more preferential than its crystalline regions. Because of the influence of crystal structure and the change of composition structure, the initial decomposition temperature of aging test specimen gradually increases with the extension of aging time. The maximum decomposition rate temperature and residual mass increases at first, and then decrease after the aging time extending to 1600 h. As the aging time increases, the damage degree of combination interface between esterification starch and PLA is exacerbated, resulting in the tensile strength and bending strength of aged specimen decreasing gradually.

A NOVEL COPOLYMER-BOUND CIS-DICARBONYLRHODIUM COMPLEX FOR THE CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE

A series of porous microspheres of linear and ethylene diacrylate (M') cross-linked copolymers of 2-vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol-acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.

Novel Chemical Strategy for the Synthesis of RGDCySS Tetrapeptide

A new route was described to synthesize Arg-Gly-Asp-X（RGDX,X=amino acid） tetrapeptide.To better understand the method,the tetrapeptide Arg-Gly-Asp-CySS（RGDCySS） was chosen as a model target for X.First,GDCySS was obtained in four steps,comprising the chloroacetylation of L-aspartic acid（ClCH2COAsp）,synthesis of chloroacetyl L-aspartic acid anhydride[ClCH2COAsp（CO）2O],formation of ClCH2COAsp-CySS and ammonolysis of ClCH2COAsp-CySS.Second,preparation of Arg-NCA,which was coupled with GDCySS to synthesize RGDCySS by the NCA method（Leuchs＇ anhydrides method,NCA：N-carboxy-a-amino acid anhydride）.The purity of the product was analyzed by the high performance liquid chromatography（HPLC）.Molecular weights of the peptide products were confirmed by mass spectroscopy.In the developed approach,less protected amino acids were used compared to conventional solid-phase synthesis.The new route offers advantages of low cost,simplicity and rapid synthesis with a reasonable yield of 63.0％（calculated according to arginine content）.