摘要:
A facile synthesis of novel 1,4-phenylene bridged bis-isoxazolo-, pyrazolo-, and pyrano-fused tropone compounds (2-6) is described, involving the cyclization reaction of 3,3'-{1,4-phenylenebis[(1E)-3-oxoprop-1-ene-1,3-diyl]}bis(tropolone) (1) with hydroxylamine hydrochloride, aromatic hydrazine hydrochlorides, and I-2/DMSO/H2SO4 system, respectively. The substrate 1 was obtained via the Claisen-Schmidt condensation reaction between 3-acetyl-tropolone and terephthalaldehyde.