Synthesis of Benzoxazoles Containing Allyl Crosslinking Sites via Claisen Rearrangements

by Hutson, Leslie K.

Hutson, Leslie K. M.S. Department of Chemistry, Wright State University, 1999. Synthesis of Benzoxazoles Containing Allyl Crosslinking Sites via Claisen Rearrangements. The reaction of diethyl 2,5-dihydroxyterephthalate with allyl bromide/K2CO3 in DMF followed by hydrolysis provided 2,5-di(allyloxy)terephthalic acid. The conversion of 2,5-di (allyloxy)terephthalic acid to 1,4-di(2-benzoxazolyl)-2,5-di(allyloxy)benzene in PPSE was unsuccessful. However, the reaction of 1,4-di(2-benzoxazolyl)-2,5- dihydroxybenzene with allyl bromide/K2CO3 provided 1,4-di(2-benzoxazolyl)-2,5- di(allyloxy)benzene. DSC analysis indicated that 1,4-di(2-benzoxazolyl)-2,5- di(allyloxy)benzene undergoes a Claisen rearrangement to the corresponding diallyl product. The synthesis of 2-allyloxy-1,4-di(2-benzoxazolyl)benzene was carried out using 2-hydroxy-1,4-di(2-benzoxazolyl)benzene as starting material. DSC analysis was inconclusive with respect to a Claisen rearrangement. The reaction of 2-allyloxybenzoic acid with 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane in PPSE was unsuccessful but the reaction of 2,2-bis(2-(2-hydroxyphenyl)-5-benzoxazolyl)-1,1,1,3,3,3-hexafluoropropane with allyl bromide/K2CO3 in DMF provided 2,2-bis(2-(2- allyloxyphenyl)-5-benzoxazolyl)-1,1,1,3,3,3-hexafluoropropane. DSC analysis of 2,2- bis(2-(2-allyloxyphenyl)-5-benzoxazolyl)-1,1,1,3,3,3-hexafluoropropane was inconclusive as to the presence of a Claisen rearrangement.