Studies On The Phototcycloaddition Reaction Of Heteroaryl Acetylenes Containing Benzoxazole And Benzothiazole Groups

The photocycloaddition reactions of1-(2-benzoxazolyl)-2-(4-R-phenyl)acetylene and1-(2-benzothiazolyl)-2-(4-R-phenyl) acetylenederivatives (R=H, Cl, Br, CH3) were carried out in concentrated hydrochloricacid under the irradiation of high-pressure mercury lamp. Eight photodimmerswere isolated.All the eight dimmers are unreported new compounds and their structureswere determined by1H NMR,13C NMR and MS. The results showed that thephotodimmers were triaryl substituted naphthalene derivatives with thestructure of1,3-bis(2-benzoxazolyl)-2-phenylnaphthalene,1,3-bis(2-benzoxazolyl)-2-(4-chlorophenyl)naphthalene,1,3-bis(2-benzoxazolyl)-2-(4-bromophenyl)naphthalene,1,3-bis(2-benzoxazolyl)-2-(4-methylphenyl)naphthalene,1,3-bis(2-benzothiazolyl)-2-phenylnaphthalene,1,3-bis(2-benzothiazolyl)-2-(4-chlorophenyl)naphthalene,1,3-bis(2-benzothiazolyl)-2-(4-bromophenyl)naphthalene,1,3-bis(2-benzothiazolyl)-2-(4-methylphenyl)naphthalene.And one photodimmer’s structure was confirmed by single crystal X-raydiffraction method.The studies in this thesis expanded the scope of diarylacetylenephotocycloaddition, which revealed that diarylacetylene derivatives containingbenzoxazole and benzothiazole groups had the same photoactivities as thosecontaining pyrydinyl groups in acidic water solution under the irradiation ofUV light and led to the formation of triaryl naphthalenes.The photochemical property of1-phenyl-2-(4-pyridinyl)acetylene dimmerwas also carried out in ethyl acetate under the irradiation of UV light. A newproduct was isolated and the structure was determined by single crystal X-raydiffraction method. It was found that the2-phenyl group and3-(4-pyridinyl)group were transposed.The synthesis, spectra and photocycloaddition mechanism were analyzedin details.