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Abstract Benzoxazole compounds were prepared by reactants of
2-aminophenol and 4-hydroxy-3-nitrobenzoic acid (mole ratio
10:1) in the presence of condensing agent,phosphorus pentoxide/
methanesulfonic acid. The pruduct, 2-(4-hydroxy-3-nitrophenyl)
benzoxazole, was reduced by the catalyzer, NH2NH2(aq) -Pd/C, to
get the amino phenyl benzoxazole. it was reacted with the
derivativesof benzoic acid to obtain 2-phenyl-5-
benzoxazolybenzoxazoles. The compounds which contain double
benzoxazole rings had longer wavelength of UV absorption max.
and excitation max. than single benzoxazole ring compounds. The
derivatives of double benzoxazole rings had no or only weak
donor substitutent, shown fluorescent strength about twice as
strong as single benzoxazole ring. Otherwise, the derivatives of
double benzoxazole rings containing strong donor substitutent
shown weaker fluorescent strength than single benzoxazole ring.
The nitro benzoxazole compounds shown very weak fluorescent
strength. The fluorescent wavelength of the benzoxazole
compounds which without substitutent or with weak donor
substitutent, is equal to the vaule caculated by the Pestemer
rule(coefficient is 2.5). But fluorescent wathlength of the
benzoxazole compounds containing strong donor or aceptor
substitutent, did not fit the vaule (2.5). Therefore, Pestemer
rule is applied to the benzoxazole compounds which without
substitutent or with weak donor substitutent.
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