Synthesis of some 4‐substituted‐2‐( o ‐halogenophenyl)‐1,2,3‐triazoles

Mesoaldehyde 1,3‐dioxime was treated with either 2,4,6‐trichlorophenyl‐ (a), o ‐fluorophenyl‐ (b), or o ‐bromophenyl‐ (c) hydrazine to give the corresponding mesoaldehyde 1,3‐dioxime‐2‐halogenophenylhydrazones (1a,b,c). The latter were O ‐acetylated with acetic anhydride, and cyclized to triazole 4‐oximes (3b, c) or triazole 4‐ O ‐acetyloximes ( 6a,b,c ) with cesium carbonate, then converted to nitriles ( 7a,b,c ) by refluxing with acetic anhydride followed by pyrolysis, or to aldehydes ( 4a,b,c ) by hydrolysis. The nitriles ( 7a,b,c ) were also converted to acids ( 9a,b,c ), esters ( 10a,b,c ), amides ( 8a,c ), an alcohol (11a), and an amine ( 12a ). In addition, tetrazoles of two types were prepared. The first ( 13d,e ) were obtained from the acid chlorides by the action of 5‐aminotetrazole, whereas the second ( 14f ) was produced from the respective nitrile by the action of ammonium azide.