The first 1,8-diheterocyclicnaphthalenes, the 1,8-bis(1′H-1′,2′,3′-triazolyl)naphthalenes (1a–i), have been synthesized by 1,3-dipolar cycloadditions of 1,8-diazidonaphthalene to acetylenic esters or enolates of acetoacetic esters, and have strained structures as revealed by comparison of their spectral properties with those of the corresponding 1-(1′H-1′,2′,3′-triazolyl)naphthalenes.
The first 1,8-diheteroaromatic naphthalenes, 1,1′-(1,8-naphthylene)di-1H-1,2,3-triazoles (1), were synthesized by 1,3-dipolar cycloadditions of 1,8-diazidonaphthalene to acetylenic esters. The spectral properties of these compounds were studied and compared with those of the corresponding 1-(1-naphthyl)-1H-1,2,3-triazoles (2). The two triazole rings at the peri-positions in 1 are in a face-to-face arrangement according to the results of 1H NMR spectra. The UV spectra of 1 are almost identical with each other and show a red shift from those of corresponding 2. No significant spectral differences between 1 and 2 were observed in the IR spectra. The fragment ion with two azirine groups at the peri-position in the naphthalene ring was observed in the MS spectra of 1.