Synthesis of Novel Benzoylphenylurea Chitin Inhibitors from Chlorothalonil

Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30～50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis,hydrolysis, decarboxylation and acylation reactions.     

Synthesis of Novel Benzoylphenylurea Chitin Inhibitors From Chlorothalonil ( Ⅱ )

Six novel benzoylphenylurea chitin inhibitor derivatives were synthesized in the yields of 30%-50%from the readily available starting material chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis and acylation reactions.     

Synthesis of Novel Benzoylphenylurea Chitin Inhibitors From Chlorothalonil(Ⅱ)

IntroductionThe insecticidal activity of benzoylphenylurea( BPU ) analogues,discovered in the early1 970′s[1_ 4] ,is connected with the process ofmoult-ing and appears to affect the chitin synthesis of in-sects. The benzoylphenylurea class of insectgrowth regulators( IGRs) ,interfere with chitinsynthesis in target pests,causing death or abortivedevelopment and are considered to be the fourthgeneration of insecticides or novel materials for in-sect control.Benzoylphenylurea type insecticides…     

Bioactive Properties of Chitin/Chitosan—Calcium Phosphate Composite Materials

Calcium phosphate coating over phosphorylated derivatives of chitin/chitosan material was produced by a process based on phosphorylation, Ca(OH)₂ treatment and SBF (simulated body fluid solution) immersion. Chitin/chitosan phosphorylated using urea and H₃PO₄ and then soaked in saturated Ca(OH)₂ solution at ambient temperature, which lead to the formation of thin coatings formed by partial hydrolysis of the PO₄ functionalities, were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5 × SBF solution for as little as one day. The Ca(OH)₂ treatment facilitates the formation of a calcium phosphate precursor over the phosphorylated chitin/chitosan, which in turn encourages the growth of a calcium deficient apatite coating over the surface upon immersion in SBF solution. The bio-compatibility of calcium phosphate compound—chitin/chitosan composite materials was evaluated by cell culture test using L-929 cells. The initial anchoring ratio and the adhesive strength of L-929 cells for composites was higher than that for the polystyrene disk (LUX, control). The results of in-vitro evaluation suggested that the calcium phosphate—chitin/chitosan composite materials were suitable for cell carrier materials.     

Synthesis of Novel Benzoylphenylurea Chitin Inhibitors From Chlorothalonil （Ⅲ）

Six novel benzoylphenylurea chitin inhibitor derivatives were synthesized in the yields of 30%--50% from the readily available starting material chlorothalonil 1 via sequential fluorine exchange, aminolysis, hy-drolysis and acylation reactions.     

Preparation and Properties of Alginate/Water‐Soluble Chitin Blend Fibers

Water‐soluble chitin (half‐deacetylated chitin) was prepared from chitosan by N‐acetylation with acetic anhydride. Alginate/water‐soluble chitin blend fibers were prepared by spinning their mixture solution through a viscose‐type spinneret into a coagulating bath containing aqueous CaCl₂ and ethanol. The structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). structure analysis indicated good miscibility existed between alginate and water‐soluble chitin, due to the strong interaction from the intermolecular hydrogen bonds and electrostatic interactions. Best values for the dry tensile strength and breaking elongation were obtained when the water‐soluble chitin content was 30 wt%. The wet tensile strength and breaking elongation decreased with the increase of water‐soluble chitin content. The introduction of water‐soluble chitin in the blend fiber can improve the water‐retention properties of the blend fiber compared to pure alginate fiber. The fibers treated with aqueous solution of silver nitrate have good antibacterial activity to Staphylococcus aureus.     

Synthesis and Characterization of a Novel Liquid Crystalline Chitin — Quaternary Ammonium Chitosan Salt

N-Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much hiuher than that of the chitosan in the same solvent.     

Synthesis of Chitin Oligosaccharides Using Dried <Emphasis Type="Italic">Stenotrophomonas maltophilia</Emphasis> Cells Containing a Transglycosylation Reaction-Catalyzing β<Emphasis Type="Italic">-N-</Emphasis>Acetylhexosaminidase as a Whole-Cell Catalyst

Bacterial strain NYT501, which we previously isolated from soil, was identified as Stenotrophomonas maltophilia, and it was confirmed that this strain produces an intracellular β-N-acetylhexosaminidase exhibiting transglycosylation activity. Several properties of this enzyme were characterized using a partially purified enzyme preparation. Using N,N′-diacetylchitobiose (GlcNAc)₂ and N,N′,N″-triacetylchitotriose (GlcNAc)₃ as substrates and dried cells of this bacterium as a whole-cell catalyst, chitin oligosaccharides of higher degrees of polymerization were synthesized. (GlcNAc)₃ was generated from (GlcNAc)₂ as the major transglycosylation product, and a certain amount of purified sample of the trisaccharide was obtained. By contrast, in the case of the reaction using (GlcNAc)₃ as a substrate, the yield of higher-degree polymerization oligosaccharides was comparatively low.