Lloyd M. Jones, 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= alkyl 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. This family of gelators is limited to alkane and ether containing tails due to the harsh reaction conditions typically employed in the synthesis (hydrolysis, reaction with thionyl chloride, reduction with lithium aluminum hydride). This route also has the disadvantage of having to be modified at each step depending on the solubility and behavior of the derivative being synthesized. We have developed an efficient synthetic route that employs a protecting group (benzyl ether) on the phenol positions of the starting material, methyl 3,5-dihydroxybenzoate. This protected material is then utilized in the multi-step synthesis of a bis-urea of the type above. The benzyl groups are then selectively cleaved by catalytic hydrogenation to generate a tetraphenol (94% yield). The tetraphenol can then be used as a common intermediate for the synthesis of known and novel gelators. Once the tetraphenol has been generated a mild alkylation reaction is employed to synthesis the desired gelator. Since the tails are added last many different functional groups can be incorporated into the final structure. Detailed experimental procedures and yields will be presented.