GB738585A - Improvements in or relating to tetrazolium compounds - Google Patents

Abstract

The invention comprises tetrazolium salts of the formula <FORM:0738585/IV (b)/1> where R1 is alkyl or aryl and R2 and R3 ar aryl, at least one of the latter being p-substituted by -N : N-aryl or -CH : CH-aryl. The aromatic nuclei may also carry halogen, nitro, hydroxyl, alkyl, acylamino, dialkylamino, quaternary ammonium, carboxyl or alkoxyl substituents. The compounds are made by oxidizing the corresponding formazans R2-NH-N=C(R1)-N=N-R3 (see Specification 738,632) and acidifying the reaction mixture; suitable oxidizing agents are lead tetra-acetate, mercuric oxide and isoamyl nitrite. In the examples the following substituted tetrazolium salts are prepared (chloride- or iodides):-2 : 5 - diphenyl - 3 - (p - phenylazophenyl), 2 : 5 - diphenyl - 3 - [p - (p - nitrophenylazo) - phenyl], 2 - (p - chlorophenyl) - 5 - phenyl - 3 - (p - phenylazophenyl), 2 - (p - acetamidophenyl) - 5 - phenyl - 3 - (p - phenylazophenyl), 2 : 5 - diphenyl - 3 - (41 - phenylazo - 11 - naphthyl), 2 - phenyl - 5 - methyl - 3 - (p - phenylazophenyl), 2 : 5 - diphenyl - 3 - [p - (p - chlorophenylazo) - phenyl], 2 : 5 - diphenyl - 3 - [p - (p - tolylazo) - phenyl], 2 - (p - carboxyphenyl) - 5 - phenyl - 3 - (p - phenylazophenyl), 2 : 5 - diphenyl - 3 - (21 : 51 - dimethyl - 41 - phenylazophenyl), 2 : 5 - diphenyl - 3 - [p - (p - hydroxyphenylazo) - phenyl], 2 : 5 - diphenyl - 3 - [p - (211 - chloro - 411 - hydroxyphenylazo) - phenylazo) - phenyl], 2 : 5 - diphenyl - 3 - [p - (311 - chloro - 411 - hydroxyphenylazo) - phenyl], 2 - phenyl - 5 - (p - hydroxyphenyl) - 3 - (p - phenylazophenyl), quaternary methochloride of 2 - phenyl - 5 - (p - dimethylaminophenyl) - 3 - [p - (p - hydroxyphenylazo) - phenyl], 2 : 5 - diphenyl - 3 - (p - styrylphenyl), 2 : 5 - diphenyl - 3 - [p - (p - acetamidostyryl) - phenyl], 2 : 5 - diphenyl - 3 - [p - (p - bromostyryl) - phenyl], 2 : 5 - diphenyl - 3 - [p - (p - hydroxystyryl) - phenyl], 2 - phenyl - 5 - (p - bromophenyl) - 3 - (p - styrylphenyl), 2 - phenyl - 5 - (p - methoxyphenyl) - 3 - (p - styrylphenyl), 2 : 5 - diphenyl - 3 - [p - (p - nitrophenyl) - phenyl], 2 - phenyl - 5 - methyl - 3 - (p - styrylphenyl), 2 - phenyl - 5 - methyl - 3 - [p - (p - nitrostyryl) - phenyl], 2 - (p - phenylazophenyl) - 5 - phenyl - 3 - (p - styrylphenyl), 2 - (p - phenylazophenyl) - 3 - (p - styrylphenyl) - 5 - (p - hydroxyphenyl) from p-acetoxy compound hydrolysed during the reaction, and 1 - (p - phenylazophenyl) - 3 - (p - carboxyphenyl-5-(p-styrylphenyl).