Thioethers and sulphones of 7H‐benzimidazo(2,1‐a)benz‐(d,e)isoquinolin‐7‐one: Dyes for synthetic‐polymer fibres

Abstract

A series of 4-alkylthio and 4-arylthio-1, 8-naphthalic anhydrides was obtained either by reaction of 4-chloro-1.8-naphthalic anhydride with thiols or of 4mercapto-1 ,&naphthalic anhydride with halides; oxidation of these afforded the corresponding sulphones. Reaction of the thioethers and sulphones with ophenylenediamines gave bright orange-yellow and greenish-yellow dyes respectively; these compounds have excellent colouration and fastness properties on synthetic-polymer fibres. The dyes were also obtained by condensation of 3-and 4-halogeno-7H-benzimidazo(2,l-a)benz(d,e)isoquinolin-7-ones with the appropriate thiol. The colour of the dyes is discussed in relation to structural changes in the thioether and sulphone substituents and the influence of substitution in each of the phenyl rings of the naphthyl residue is compared from an unambiguous synthesis of selected 3-and 4-thioethers and sulphones of 7H-benzimidazo(2,1a)benz(d,e)isoquinolin-7-one.