Preparation of saturated and unsaturated fatty acid hydrazides and long chain C-glycoside ketohydrazones

Abstract

A method is described to prepare both saturated and unsaturated fatty acid acyl hydrazides using a lipase as a catalyst. Hydrazides were generated from fatty acid methyl esters as well as directly from vegetable oils, and an organic co-solvent was not needed to maintain the integrity of the unsaturated fatty acids. Both C. antarctica lipase immobilized on acrylic resin and immobilized M. miehei lipase were used to catalyze the reaction, and they provided the desired acyl hydrazides with similar yields of 82.8% and 84.6%, respectively. Analysis of the products by MALDI-TOF-MS and GC-MS fragmentation pathways shows pure products free of starting methyl esters or triacylglycerols. These hydrazide molecules have been used, in conjunction with carbohydrate C-glycoside ketones, to prepare long chain C-glycoside ketohydrazones. This preparation does not require protecting groups or anomeric activation, and various C-glycoside ketohydrazones that retain the closed ring conformation of the parent sugars are described. These compounds have potential as renewable, sugar-based detergents in which the sugar moiety serves as the polar head group while the hydrazide alkyl chain is the non-polar component.