New dyestuffs for synthetic fibres, benzimidazo-thioxantheno-isoquinolin-ones

Abstract

Condensation of 3-and Cbromo-or nitro-7H-benzimidazo[2,1-a]benz[d,e]iso-quinolin-7-ones with 2-aminobenzenethiol, followed by Pschorr cyclisation of the resultant product, afforded the isomer mixture of the new heterocycles benzimidazo[l,t-b~thioxantheno[2,1,9-d,e,~soquinolin-7-one and benzimidaz0[2.l-a]thioxantheno[2,1 ,Bd,e,f,]isoquinolin-8-one. Separation of these ismers and their characterisation by unambiguous synthesis is reported. Small amounts of analogous 5-membered sulphur heterocycles were also formed by cyclisation in the 8-position of the naphthalene ring. These new heterocycles dye synthetic fibres in fluorescent orange and yellow shades, showing excellent fastness to light and sublimation. Principal mass spectra features of the compounds are given.

New Intermediates and Dyes for Synthetic‐polymer Fibres. Benzimidazothioxanthenoisoquinolinone Dioxides and Sulphones of 7H‐Benzimidazo (2, 1‐a) benz(d, e) isoquinolin‐7‐one

“…The isomers were separable to some extent by chromatographic methods and characterisation of each isomer was confirmed by alternative synthesis. Thus 3and 4-nitro-7H-benzimidazo(2,l-a)benz(d,e)isoquinolin- 7-ones have been previously described [151, together with their conversion into benzimidazo(l,2-b)thioxantheno-(2,1,9-d,e,f)isoquinolin-7-one (V) and benzimidazo(2,l-althioxantheno (2,1,9-d,ef)isoquinolin-8-one (Vl) [5]. On oxidation these gave Vlll (A, , , 425 nm) and IX ( A, , , 438 nm) respectively, identical with the components separated chromatographically from the isomer mixture.…”

“…The alkylthioethers had only poor to moderate light fastness on the acetate fibres, the ethylthio (1.1-1.3) and j3-hydroxyethylthio derivatives (11.1-11.3) giving values in the 2-3 region. The phenylthio derivatives (111.1-111.3) were considerably faster (5)(6) and can be considered satisfactory dyes for these substrates.…”