Chloromethylation of Azoic Compounds. II

Chloromethylation of Azoic Compounds, obtained from Naphtol-AS Series Coupling Components

Abstract

Insoluble azo compounds were prepared from 2-methyl-5-chloroaniline (Fast Red KB base), 2-methyl-4-chloroaniline (Fast Red TR base), 2-meteoxy -5-chloroaniline (Fast Red RC base), 4-nitroaniline (Fast Red 2G base), 2-methoxy-5-: nitroaniline (Fast Scarlet R base), and 3-nitroaniline (Fast Orange R base) as diazo components and 3-hydroxy-2-naphtho-o-anisidide (Naphtol AS-OL) and 3-hydroxy-2-naplitho-o-phenetidide (Naphtol AS-PH) as coupling components, and chloromethylation of the azo compounds has been attempted. Chloromethylat-ion of the azo compounds was possible by treating the azo cornpounds in glacial acetic acid with dry hydrogen chloride and paraformaldehyde or dichloromethyl ether, using anhydrous zinc chloride or phosphoric acid as a catalyst.
Phosphoric acid was ineffective as a catalyst for formation of azo compounds from o-anisidine as a diazo comonent and 2-naphthol, 3-hydroxy-2-naphthanilide (Naphtol AS), acetoacetanilide, and 1-phenyl-3-methyl-5-pyrazolone as coupling components as reported in the first series of this report but the phosphoric acid was effective as a catalyst in the preparations of azo compounds in this report. Only one chloromethyl group was introduced in all cases and the position of its entrance was confirmed to be the para position of methoxy group in aryl ring of hydroxynaphtho-o-anisidide and para position of ethoxy group in aryl ring of hydroxymaphtho-o-phenetidide.