Kelly M. Wiggins, Austin College, Sherman, TX and Andrew J. Carr, Austin College, Sherman, TX.
Bisurea organogelator molecules of the type [(3,5-OR)C6H3(CH2NHC(=O)NH)]2(C2H4)n (R= C12H25 and n= 3 or 6) have been shown to be efficient organogelators when the tail length is sufficiently long enough; typically ten carbons or more. The conventional synthesis of this family of gelators is limited due to several issues: the utilization of commercially available diisocyanato-compounds, the utilization of an azide intermediate and the need to reduce one of the intermediates with lithium aluminum hydride (LAH). In an attempt to make the synthesis of the organogelators more industrial friendly, we have devised an alternative synthetic route to the gelators that requires the isolation of fewer intermediates and avoids the use of azide and LAH. This route also allow for the utilization of commercially available diamines or polyamines to be used in the generation of the final bis/poly urea thus allowing for a broader study of linker effects on gelation. The new route employs the synthesis of a primary amide, which can be reduced with LAH to the amine or it can be dehydrated to form a nitrile. The nitrile is then reduced by catalytic hydrogenation with 5%-10% palladium on carbon in methanol with hydrochloric acid to the amine salt. Once the amine is isolated it is then converted to the isocyanate by treatment with triphosgene. The isocyanate then can be reacted with any diamine/polyamine to generate novel organogelators. Yields and synthetic protocols will be presented.