ONE-POT PROCESS FOR THE PREPARATION OF 5-SULFONYL-SUBSTITUTED BENZOTRIAZOLES

摘要

5-Sulfonyl substituted benzotriazole UV absorbers are prepared from the corresponding 5-chlorobenzotriazole in a two step, but one-pot process where the second step involves the oxidation of the non-isolated 5-thio substitute d benzotriazole using sodium tungstate, hydrogen peroxide and formic acid. The 5- sulfonyl substituted benzotriazoles exhibit enhanced absorption in the near- visible range (over 350 nm) thus providing effective protection to substrate s in this critical area of the spectrum.