Symmetrically substituted bis(azolyl)methanes are often prepared from azoles in dichloromethane under PTC conditions [1]. Unsymmetrically substituted 1-benztriazolylmethanes can be prepared from 1-hydroxymethylbenzotriazole [2] via nucleophilic substitution with secondary amines, in this case, benzimidazole.
1-Hydroxymethylbenzotriazole (2.98 g, 20 mmol) was dissolved in warm ethanol (50 ml). Benzimidazole (2.36 g, 20 mmol) was then added and the mixture was heated at reflux temperature. The reaction was monitored by TLC. After the reaction had ended the reaction mixture was set aside at 5 deg.C overnight. The crystalline product was then collected, washed with cold ether and recrystallized from ethanol. Yield 4.18 g (84.0 %) of a white crystalline powder.
M.p. 92-93 deg.C.
TLC (EtOAc): Rf 0.30.
1H NMR (CDCl3): 8.28 (s, 1H, -CH=), 7.00-8.13 (m, 8H, Harom), 6.05 (s, 1H, CH2), 5.63 (s, 1H, CH2).
IR (cm-1, KBr): 3179, 3115, 3096, 3063, 3001, 2965, 2863, 2797, 2741, 1458, 1408, 1306, 1273, 1246, 1235, 1159, 1076, 783, 768, 747, 619.
UV (lmax/log ε, methanol): 244/3.03, 250/3.05, 272/3.09, 279/3.06.
Anal. calc. for C14H11N5 (249.0): C 67.47, H 4.42, N 28.10; found: C 67.17, H 4.30, N 27.84.
Supplementary materials
Supplementary File 1Supplementary File 2Acknowledgements
The authors would like to thank Slovak Grant Agency (financial support No. 95/5195/202).
References and Notes
- Julia, S.; Sala, P.; del Mazo, J.; Sancho, M.; Ochoa, C.; Elguero, J.; Fayet, J.P.; Vertut, M.C. N-Polyazo- lylmethanes. 1. Synthesis and NMR study of N,N-diazolylmethanes. J. Heterocycl. Chem. 1982, 19, 1141. [Google Scholar] [CrossRef]
- Fries, K.; Guterbock, H.; Kuhn, H. Untersuchungen in der Reihe des Azimidobenzols und des N-Methyl-Azimidobenzols. Ann. 1934, 511, 213. [Google Scholar] [CrossRef]
- Sample Availability: Available from the author, 2g.
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