Phillips Duphar

Since the introduction of diflubenzuron by Phillips-Duphar in the mid 1970 s there has been considerable interest in the benzoyl-ureas. Current information suggests that they exert their effect on Insects by interfering with the formation of chitin, the primary structural component of the arthropod exoskeleton. The biochemical process that is responsible for chitin formation is shown in Figure... 

The synthesis of enynes is of interest in the chemistry of certain natural products. Terminal enynes occur in several natural products such as histrionicotoxin and laurencin, and the internal enyne unit is found along with polyacetylenes and allenes in natural products from Compositae and Umbelliferae. Both internal Z-and. E-enynes are also useful as precursors to stereochemically define d dienes on their partial reduction. A group from Phillips-Duphar has described an efficient synthesis of the functionalized enyne (95), which serves as the C5 synthon for the convergent synthesis of vitamin A. The l,3-dichloro-2-ether (94) is dechlorinated, substituted, and isomerized in one step on reaction with two molar equivalents of sodium acetylide in liquid ammonia, giving (95) with an E Z ratio... 

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