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We have recently reported that condensation of 5-azido-4-cyano-1-substituted 1,2,3-triazoles with active methylene nitriles in the presence of a strong base yields bis [l,2,3] The structure of the diazo form 2 was established unambiguously by spectral methods (IR, ' H and 13C NMR), whereas the ring-closed form was assumed to have the angular structure 1 rather than the linear structure 3 which has an unfavourable ortho-quinoid arrangement. The angular structure was also postulated by Tennant' and Westerlund3 for similar systems. the benzyl methylene proton absorptions at 6 6.33, 5.80 and 5.95 respectively. The low field absorption at 6 6.33 is attributed to structure 4 where there is a deshielding effect of a substituent in the peri coupled with an anisotropic effect of the triazole ring.The deshielding effect of the peri-substituent is also observed in the 13C NMR spectrum with a CH2 absorption at 6 54.1 for 5 and 51.1 for 5. tion of 6 (6 9.88) is deshielded with respect to that of 5 (6 9.3), whereas 5 absorbs at 6 This is deduced from the 'H NMR spectra by integration of A s expected, the ring proton at the 4-posi-9.35.6-679 -

ChemInform Abstract Reaction of the azidotriazoles (III) with the active methylene nitriles (V) yields the tricyclic products (VI) instead of the previously reported compounds (IV). Structure (VI) is confirmed by 1H and 13C NMR spectroscopy as well as by X-ray analysis of the methylation product (VIIIb) (space group: P1).

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