Optically Active Helical Polymer From Anionic Polymerization of (S)-6-Acrylyl-2,2’-dimethoxy-1,1’-binaphthyl

(S)-6-Acrylyl-2,2’-dimethoxy-1,1’-binaphthyl (ADBN) was synthesized and anionically polymerized using n-BuLi as an initiator. The absolute value of specific optical rotation [α]²⁵₅₈₉ of poly-ADBN is ?118.0 and that is about 8 times that of the starting monomer ADBN. Poly-ADBN was confirmed to exist in the form of one-handed helical structure in solution by means of comparing the specific optical rotation, the CD and UV-Vis spectra with that of ADBN and the model compounds such as (S)-6-propionyl-2,2’-dimethoxy-1,1’-binaphthyl (PDBN) and (S)-6-heptanoyl-2,2’-dimethoxy-1,1’-binaphthyl (HDBN). This conclusion was also confirmed by the fact that the g-value of poly-ADBN is about 13 times as high as that of its monomer and model compounds     

Solvent-Free Acetylation of Thiols Under Catalysis of MgBr2·OEt2

Solvent-free protection of aromatic and aliphatic thiols with acetic anhydride was performed at room temperature under trace quantities of magnesium bromide ethyl etherate, affording rapid formation of various thiol esters in excellent yields.     

Synthesis and Properties of Poly(Aryl Ether Ketone) Copolymers with Trifluoromethyl‐Substituted Benzene in the Side Chain

The new monomer (4‐(4′‐trifluoromethyl)phenoxyphenyl)hydroquinone (TFPOPH) was synthesized in a three‐step synthesis. A series of poly(aryl ether ketone) copolymers were prepared by the reaction of (4‐(4′‐Trifluoromethyl)phenoxyphenyl)hydroquinone and hydroquinone (HQ) with 4,4′‐difluorobenzophenone (DFB) in the presence of potassium carbonate in tretramethylene sulfone (TMS). Thermal analyses of the fluorinated copolymers showed that the glass transition temperature and 5.0% weight loss temperature are similar with that of PEEK, and the crystallinity decreased with increasing of TFPOPH. For the copolymer synthesized with the molar fraction of TFPOPH in the diphenol monomers (TFPOPH, HQ) being over 0.2, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of TFPOPH being not higher than 0.2 is rhombic. The solubility in polar aprotic solvents of poly(aryl ether ketone)s copolymers increases and dielectric constant decreases step by step.     

Three New C19‐Diterpenoid Alkaloids from Aconitum forrestii

A further study of the alkaloid constituents of Aconitum forrestii led to the isolation of three new C₁₉‐diterpenoid alkaloids, named 14‐acetoxy‐8‐O‐methylsachaconitine ( 1 ), 14‐acetoxyscaconine ( 2 ), and 8‐O‐ethylcammaconine ( 3 ). Their structures were determined by UV, IR, and MS, 1D‐ and 2D‐NMR analyses.     

Deoxygenation of Aromatic Ketones Using Transfer Hydrogenolysis with Raney Nickel in 2-Propanol

Aryl ketones are readily deoxygenated to their corresponding aryl alkanes upon treatment with Raney nickel catalyst in boiling 2-propanol.

Polymer Composites with Plasma-Treated Fillers

A Large-volume Microwave Plasma (LMP) generator has been used to irradiate mica and ground-wood fibers in inert and active gas environments. Irradiated fillers were subsequently incorporated in a polypropylene matrix at solids levels of 10 and 20%. Calorimetrically measured heats of immersion showed that substantial changes in surface properties of fillers were effected by irradiation in ethylene, ammonia, and similar active gases. These surface changes are reflected In ultimate tensile and elongation properties of composites which show marked improvement over controls based on unirradiated fillers. Although no appreciable response in melt viscosity has been observed, surface treatment of fillers does seem to increase significantly melt elasticity of filled composites. The implications of improved performance motivate a more detailed study of the use potential of LMP in the fomulation of polymer composites.     

Oxidation of Poly(dimethylbutadiene) Popcorn Polymer

Poly(dimethylbutadiene) popcorn polymer oxidizes readily in the presence of oxygen at room temperature. Quantitative data are presented for the production of the major volatile product, 2,5-hexanedione, as well as for the secondary products: water, acetic acid, and acetaldehyde. Three reaction mechanisms formerly proposed for polyisoprene oxidation are considered for their applicability to poly(dimethylbutadiene) popcorn oxidation. Of these, one that assumes the formation of a Bevilacquatype peroxyalkoxy radical followed by hydrogen abstraction to form an alcohol group, double bond migration, formation of a peroxide radical adjacent to the alcohol, then elimination of a hydroxy radical and scission, can explain the experimental data.     

Transfer Hydrogenation of Ketones with 2‐Propanol and Raney® Nickel

Raney nickel in refluxing 2‐propanol containing a trace of HCl is an effective catalytic system for the reduction of ketones to secondary alcohols.     

Direct Oxidation of N‐Benzylamides to Aldehydes or Ketones by N‐Bromosuccinimide

A simple and efficient approach for the one‐pot transformation of N‐benzylamides to aldehydes or ketones under mild conditions was reported. All the 20 substrates gave moderate to excellent oxidative yields under the optimized conditions. Our study may provide a new approach for the one‐pot synthesis of aldehydes or ketones from the corresponding amides.     

Preparation and Characterization of Some Substituted Benzyl N-Nitrosocarbamates Containing an N-2-(Methylthio)ethyl or a Bis(2-aminoethyl)sulfide Functionality

The synthesis and characterization of some substituted benzyl N-nitrosocarbamates with an N-2-(methylthio)ethyl or a bis(2-aminoethyl)sulfide functionality is reported, as a part of a long-term goal to design and prepare novel photolabile structures that could be used as substances for controlled release of alkylating and/or crosslinking agents. The synthesis was accomplished by reaction of benzyl chloroformates with the corresponding amines, resulting in the preparation of carbamates. The latter were subsequently nitrosated, utilizing two different N-nitrosation methods, to yield the target structures.