Synthesis of benzotriazoles
A [3 + 2] cycloaddition of azides to benzynes affords a rapid and easy entry to a variety of substituted, functionalized benzotriazoles under mild conditions.
F. Shi, J. P. Waldo, Y. Chen, R. C. Larock, Org. Lett., 2008, 10, 2409-2412.
A 1,7-palladium migration-cyclization-dealkylation sequence for the regioselective synthesis of benzotriazoles proceed in excellent yields with high regioselectivities. The mechanism of the reaction has also been investigated.
J. Zhou, J. He, B. Wang, W. Yang, H. Ren, J. Am. Chem. Soc., 2011, 133, 6868-6870.
C-H activation of aryl triazene compounds followed by intramolecular amination in the presence of a catalytic amount of Pd(OAc)2 provides 1-aryl-1H-benzotriazoles at moderate temperature.
R. K. Kumar, M. A. Ali, T. Punniyamurthy, Org. Lett., 2011, 13, 2102-2105.
A cyclocondensation of 2-(arylamino)aryliminophosphoranes enables the synthesis of 1-aryl-1,2,3-benzotriazoles under mild conditions. The reaction involves a three-step, halogen-free route starting from simple nitroarenes and arylamines.
E. Łukasik, Z. Wróbel, Synlett, 2014, 25, 1987-1990.
A convenient reaction of carboxylic acids with 1H-benzotriazole provides N-acylbenzotriazoles in good yields in the presence of only 0.35 equivalent of trichloroisocyanuric acid and 1.2 equivalents of PPh3.
M. Singh, A. S. Singh, N. Mishra, A. K. Agrahari, V. K. Tiwari, Synthesis, 2019, 51, 2183-2190.
The combination of 2,2′-dipyridyl disulfide and PPh3 enables the conversion of carboxylic acids into the corresponding N-acylbenzotriazoles in the presence of 1H-benzotriazole. This base-free reaction offers mild conditions, short reaction time, and wide substrate scope.
A. S. Singh, A. K. Agrahari, N. Mishra, M. Singh, V. K. Tiwari, Synthesis, 2019, 51, 470-476.