Syntheses and characterizations of insecticidal sucrose esters

New types of sucrose esters have been synthesized and shown to be potent insecticides against sweet potato whiteflies. On the basis of the structures of natural sucrose esters isolated from various Nicotiana species and which were shown to be potent whitefly insecticides, it was decided to synthesize similar sucrose esters. Specific conditions were worked out for the reaction of acid chloride with sucrose to yield a series of mono-, di-, tri-, and tetraacyl sucroses. As the active sucrose esters of Nicotiana species contain mainly heptanoic and octanoic acids esterified to sucrose, C-6-C-12 aliphatic acid sucrose esters were prepared. Capillary gas chromatography of their TMS derivatives showed that distinct groups of isomers were produced. Separation by silicic acid chromatography produced fractions containing individual groups of monoacyl sucroses, diacyl sucroses, triacyl sucroses, etc. Evaluations of individual groups of the C-6-C-12 acid sucroses showed that diheptanoyl sucroses, dioctanoyl sucroses, and dinonanoyl sucroses were most active against whiteflies and aphids. Details of syntheses, separations, GC and NMR data, and whitefly assays are presented.