engleski

Synthesis of naphthoxazoles by photocyclization of 4-/5-(phenylethenyl)oxazoles

Promising test results on biological activity of our previously described naphtho[1, 2- d]oxazoles and heterobenz[1, 2-d]oxazoles, obtained by photochemical cyclization of 5- phenylethenyl- and 5-heteroarylethenyloxazoles, prompted us to continue with the photochemical synthesis of diverse substituted naphtho[1, 2- d]oxazoles and extend the photochemical cyclization to naphtho/heterobenz[2, 1- d]oxazoles going from 4- (aryl/heteroarylethenyl)oxazoles. Required p- and o-phenyl-substituted 5-arylethenyloxazoles were prepared from the corresponding α, β- unsaturated aldehydes and the TosMIC reagent by Van Leusen reaction. For the preparation of the substituted 4-(aryl/heteroarylethenyl)oxazoles the Wittig reaction was used starting from the selected diverse phosphonium salts and the 2- H/methyl-4-oxazolecarbaldehydes.

polycyclic oxazoles ; photocyclization ; biological activity ; Van Leusen ; Wittig reaction

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