91165-92-3Relevant academic research and scientific papers
Photolysis of 1-Aryl-1,2,3-triazoles; Rearrangement via !H-Azirines
Mitchell, Glynn,Rees, Charles W.
, p. 413 - 422 (2007/10/02)
The preparation and photolysis of a series of 1-(1-naphthyl)-1,2,3-triazoles, (2)-(5), and of 1-(2-methyl-1-naphthyl)-1,2,3-triazoles, (6)-(9), with and without electron-withdrawing groups (CO2R, CONH2, CN, CHO, COPh) in the triazole ring, are described.In the first series, triazoles (3) with two electron-withdrawing groups, and triazoles (4) with one such group at C-4, mostly give good yields of the expected benzindoles (10) and 11 respectively.Triazoles (5) with the electron-withdrawing group at C-5 also give benzindoles but these are now mixtures of the expected (12) and rearranged indoles (11).Photolysis of the 1-phenyltriazoles (21) and (22) follows the same pattern, those with the electron-withdrawing group at C-5 rearranging to give mixtures of indoles (23) and (24).This is explained by a mechanism (Scheme 3) in which the less stable carbene intermediate (13) rearranges to the more stable carbene (15) via the 1H-azirine (14), in competition with its direct cyclisation.This provides the first evidence for antiaromatic 1H-azirines as intermediates in a photochemical reaction.Photolysis of the 2-methylnaphthyl compounds follows a different path: diester (7b) and dinitrile (7d) give high yields of the deeply coloured 9-methyl-1H-benzoquinoline derivatives (25a) and (25b) respectively, the first stable examples of this ring system to be isolated.Photolysis of the nitrile (8c) gives 9b-methyl-9bH-benzindole-3-carbonitrile (28), a rare example of a stable indole with a ring junction substituent. 1,2-Shifts in the carbenes are only observed with the bis(trimethylsilyl)triazoles (2d) and (6f), in keeping with the known rapid migration of trimethylsilyl groups to carbene centres.
Synthesis and Spectroscopic Studies of 1,1'-(1,8-Naphthylene)di-1H-1,2,3-triazoles
Nagawa, Yoshinobu,Honda, Koichi,Nakanishi, Hiroshi
, p. 2931 - 2936 (2007/10/02)
The first 1,8-diheteroaromatic naphthalenes, 1,1'-(1,8-naphthylene)di-1H-1,2,3-trizoles (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.
Syntheses and Spectroscopic Studies of 1,8-Bistriazolylnaphthalenes
Honda, Koichi,Nakanishi, Hiroshi,Nagawa, Yoshinobu,Yabe, Akira
, p. 450 - 451 (2007/10/02)
The first 1,8-diheterocyclic naphthalenes, 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.
