The paper describes the following items ; (a) the construction of orb-web, (b) the chemical composition of secretions and the adhesive materials, (c) the toxin of spider, (d) the courtship and ferromon, (e) the thermal properties of spider's drag line, (f) the change in color of drag line. For example, the toxin of spider contains spermine whose existence is detected in human semen. The DSC curve between room temperature and 600°C shows that the spider's thread should be at least stable up to 200°C. The color of drag line changes from white to yellow with changing seasons from summer to autumn. The fact suggests a possibility that the color of spider's thread protects the spider from foreign invaders.
In a last decade, various important antibiotics containing higher-carbon carbohydrates, such as tunicamycin, anthelmycin (hikizimycin), mildiomycin, ezomycin, octosyl acid, apramycin, lincomycin etc., have been discovered in fermentation broths of Streptomyces species. Synthetic studies on higher-carbon carbohydrates of these antibiotics are reviewed
Synthetic chemistry of the plant growth-promoting steroids is reviewed with 80 references. Various syntheses of brassinolide, dolicholide, homodolicholide and other brassinosteroids are analyzed. The structure-activity relationship among these and related steroids is briefly discussed.
The cycloaddition containing a desilylation process is one of the recently progressive area in the chemistry of organosilicon compounds. Especially, the 1, 3- cycloadditions via azomethine ylides derived from trimethylsilylmethylamine derivatives have been developed. In this article authors explain these 1, 3-cycloadditions via azomethine ylides, the thiocarbonyl ylide or trimethylenemethane-Pd complex and 1, 4-cycloaddition, leading to syntheses of useful heterocycles and naturally occurring compounds.
Characteristic functions of arene·Cr (CO) 3 complexes as catalysts for the hydrogenation of multiple bonds such as 1, 3-dienes (to internal monoenes), alkynes (to cis-alkenes), and α, β-unsaturated carbonyl compounds (to saturated analogs) are reviewed. Application of these hydrogenation reactions to highly stereoselective syntheses of biologically significant substances such as carbacyclins and pheromone are also described.
Oxalic acid is the simplest dicarboxylic acid formed by oxidation of organic compounds. Oxalic acid has been prepared by several methods in countries, because the industrial process depends on natural resouces, economical demands of the country, and chemical technology. This paper deals with its advantage and view points of each process ; oxidation of carbohyrates with nitric acid, thermal decomposition of sodium formate, two step oxidation of propylene, one step oxidation of ethyleneglycol, and the CO-coupling process, respectively.