Functional Polymers, XL. Syntheses of Mono- and Di(4-methoxy)benzotriazole-Substituted 2,4-Dihydroxyaceto(or benzo)phenones

Article abstract of DOI:10.1007/BF00810072

Eight benzotriazoles and (4-methoxy)benzotriazoles, mono- or di-substituted derivatives of 2,4-dihydroxyaceto(or benzo)phenone were synthesized by azo coupling of (4-methoxy)2-nitrobenzenediazonium chloride with 2,4-dihydroxyaceto(or benzo)phenone followed by reductive cyclization.Pure monosubstituted compounds were very difficult to prepare.Careful selection of the pH for the azo coupling and selection of the proper reagents for the reductive cyclization were essential.All compounds were characterized by their ultraviolet, infrared, 1H and 13C NMR spectra and theirelemental analysis.These compounds have both the 2(2-hydroxyphenyl)2H-benzotriazole unit and a 2-hydroxyaceto(or benzo)phenone unit in the same molecule and are effective and useful ultraviolet absorbers. - Keywords: Functional polymers; 2(2-Hydroxyphenyl)2H-benzotriazoles; 2-Hydroxyphenylaceto(benzo)phenones; Azo coupling; Reductive cyclization; Ultraviolet stabilizers