An asymmetric 5-endo chloroetherification of homoallylic alcohols is successfully developed that employs an easily available quaternary ammonium salt derived from cinchonine as a conventional organocatalyst. This approach provides ready access to β-chlorotetrahydrofurans in high enantioselectivities.

The structure of the title salt, NH(4) (+)·C(7)H(5)O(3) (-), is stabilized by substantial hydrogen bonding between ammonium cations and salicylate anions that links the components into a two-dimensional array.

A novel A2-B3-type supramolecular hyperbranched polymer was prepared based on the benzo-21-crown-7/secondary ammonium salt recognition motif. The resulting supramolecular polymer exhibited a reversible disassembled-assembled process by adding or removing potassium ions.

Two series of rosin quaternary ammonium salts (QAS) were synthesized using the same path. The structure of the target products was characterized by HPLC, MS, IR, and 1 HNMR, and the bioactivity was determined by filter paper method using Trametes versicolor (white-rot fungus) and Gloeophyllum trabeum (brown-rot fungus), which are two kinds of general wood decay fungi in nature. The results show...

Organoboron catalysts including an ammonium salt separated by a few carbon–carbon bonds to boron center were designed and synthesized. Borinane-based organoboron exhibited highest activity for the copolymerization of CO 2 epoxides.

Background and Aims: In this study we improved the purification of immunoglobulins from equine antiserum raised against the venom of 6 types of scorption species. Caprylic acid (octanoic acid), a fatty acid, was found to have no effect on the activity of the enzymes pepsin, which is used in antivenom purification to digest Fc fragment of immunoglobulins to obtain F(ab´)2. Materials and Methods...

We have obtained further insights into the CBD growth mechanisms of ZnS thin ®lms using an aqueous medium containing an ammonium salt. At room temperature the optimum concentration of this salt has enabled us to increase the thickness of the ®lm by more than 400%. The optical transmission below the band edge of our best ®lm is also found to be excellent. q 1999 Elsevier Science S.A. All rights ...

The values of the albumin and total globulin of serum determined with 22.4 per cent sodium sulfate by the method of Howe (1) are better correlated with the values of one fraction containing the albumin and QIglobulin and of another containing the pand r-globulins (2). However, 19 per cent sodium sulfate seems to separate these fractions more efficiently, since it yields results which agree very...