Date of Award
Mahesh K. Lakshman
Benzotriazoles are group of bicyclic heterocyclic compounds that contain three nitrogen atoms fused to a benzene ring. Along with their derivatives, they possess a wide range of properties. They are used in medical field, as they exhibit such properties as antibacterial,antiplasmoidal,antiprotozoal, antifungal and anti-inflammatory activities, among others. They are also used in various industries as herbicides, UV absorbers, deicing and antiicing agents and corrosion inhibitors, to list a few. Because of their wide range of applications, we designed a new two-step synthesis for the formation of N-1-aryl benzotriazoles. 1-Hydroxy-1H-benzotriazole N-oxides were synthesized using phenylboronic acid (PhB(OH)2), pyridine in CH2Cl2as the solvent. A wide range of aryl boronic acids showed good reactivity with 1-hydroxy-1H-benzotriazole as well as 6-chloro-1-hydroxy-1H-benzotriazole under established conditions and moderate to high yields of products were isolated. Obtained N-oxides were then deoxygenated using tetrahydroxydiboron (B2(OH)4) in MeCN, following previously established conditions. N-Oxides resulting from the reactions of 5,6-dichloro-1H-hydroxybenzotriazole were difficult to purify and prone to degradation. To alleviate the problem, a two-step one-pot reaction was designed. After N-arylation was complete and without any further purification, the reduction step was performed using B2(OH)4in MeCN. The method proved beneficial for the reaction with phenylboronic acid, and no significant improvement was observed in others. A reaction using 2-methoxypyrimidine-4-boronic acid showed that using established conditions, compounds with potential biological activity can be synthesized.
Andrzejewska, Magdalena R., "COPPER-MEDIATED N1-ARYLATION OF BENZOTRIAZOLES" (2019). CUNY Academic Works.