Synthesis and properties of poly(amic acid)s and polyimides based on 2,2′,6,6′‐biphenyltetracarboxylic dianhydride

Poly(amic acid)s (PAAs) having the high solution stability and transmittance at 365 nm for photosensitive polyimides have been developed. PAAs with a twisted conformation in the main chains were prepared from 2,2′,6,6′‐biphenyltetracarboxylic dianhydride (2,2′,6,6′‐BPDA) and aromatic diamines. Imidization of PAAs was achieved by chemical treatment using trifluoroacetic anhydride. Among them, the PAA derived from 2,2′,6,6′‐BPDA and 4,4′‐(1,3‐phenylenedioxy)dianiline was converted to the polyimide by thermal treatment. The heating at 300 °C under nitrogen did not complete thermal imidization of PAAs having glass‐transition temperatures (T_g)s higher than 300 °C to the corresponding PIs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6385–6393, 2006     

Über die Phosphidierung des Nickels durch Phosphortrichlorid

On the Phosphidation of Nickel by Phosphorus Trichloride The phosphidation of nickel sheets by phosphorus trichloride vapor of 30 and 50 Torr has been studied kinetically by gravimetric means in the temperature range of 400–650°C in hydrogen atmosphere. The phosphidation proceeded generally according to the parabolic rate law. The parabolic rate constant increased with an increase of temperature, and its temperature dependence yielded the activation energies of about 33 and 47 kcal/mole for 400–550 and 550–650°C, respectively. X-ray and electron microprobe analyses showed that surfaces of the specimens phosphidized are made up of mixtures of Ni₂P and Ni₆P₅, and that at the phosphide/metal interface the compound Ni₂P is formed. The experiments using argon as carrier gas resulted in the formation of both the phosphides and the chlorides, and this fact could be explained in terms of thermodynamics.     

Determination of sultopride and tiapride in serum by gas chromatography using a surface ionisation detector

A sensitive and selective method has been developed for the determination of sultopride and tiapride in serum using gas chromatography with a surface ionisation detector. No interfering peaks from endogenous substances were observed. The method showed good reproducibility and accuracy, and the standard curve was linear up to 2 micrograms/ml with a correlation coefficient of 0.999. This method is applicable to pharmacokinetic studies and therapeutic drug monitoring of sultopride and tiapride.     

A New Synthetic Route to (±)-Perhydrohistrionicotoxin

Starting from ethyl 2-cyclohexen-1-carboxylate ( 3 ) the total synthesis of the perhydrohistrionicotoxin intermediate 23 was achieved in 25% overall-yield. The two key steps involve a positionally specific addition of HOBr to the oxime-olefin 7 and the alkylation of bromooxime 17 with 1-lithio-1-butyne. The latter represents a novel method for stereospecific and position-specific introduction of a nucleophilic butyl equivalent in α-position to a ketonic carbonyl group.     

Synthesis of aromatic polyamides by 1-hydroxybenzotriazole-catalyzed polycondensation of active aromatic diesters with aromatic diamines

Catalytic actions of various additives were studied in the polycondensation of di(4-nitrophenyl) isophthalate with bis(4-aminophenyl) ether in N-methyl-2-pyrrolidone, and 1-hydroxybenzotriazole (HOBt) was found to be a highly effective catalyst that yielded high-molecular-weight polyamide. In addition to the polycondensation of the 4-nitrophenyl ester, the polymerization of negatively substituted phenyl esters like di(2,4,5-trichlorophenyl) isophthalate was also accelerated by HOBt. For the HOBt-catalyzed aminolysis of esters a bifunctional concerted mechanism that involves an eight-membered transition state was proposed.