GB427977A - Manufacture of dyestuffs of the oxazine series - Google Patents

Abstract

Dyestuffs of the oxazine series are obtained by heating in a high boiling solvent quinones of the formula <FORM:0427977/IV/1> wherein X is hydrogen, halogen or alkyl and R an aromatic radicle. The formation of the oxazine may be effected in the presence of a metallic chloride or oxidizing agent or both as in Specification 8886/12 or 313,094, [both in Class 2 (iii)], or the high boiling solvent may contain an acylating agent as in the process of Specification 420,683. By using a sulphonating agent to assist ring formation, sulphonation is simultaneously effected. The sulphonated dyes which may be used for dyeing cotton or silk yield insoluble salts suitable as pigments. The unsulphonated dyes may also be used as pigments for colouring rubber and caoutchouc. During sulphonation, the acylamino group, e.g. the toluenesulphamino group may be wholly or in part removed. In examples: (1) the condensation products of chloranil with monoacetyl-1 : 4- or -1 : 3-diaminobenzene, monobenzoyl-1 : 4-diaminobenzene or monoacetyl-4 : 4<1>-diaminodiphenyl are heated in nitrobenzene in the presence of benzoyl chloride or ferric chloride; (2) the products from trichlortoluquinone and monoacetyl-1 : 4-diaminobenzene and from quinone and monoacetyl-1 : 4-diaminobenzene are condensed as in the previous example; (3) the product from chloranil and monoacetyl-1 : 4-diaminobenzene is boiled in trichlorbenzene in the presence of sodium nitrite and benzotrichloride. Samples have been furnished under Sect. 2 (5) of the following dyestuffs: (a) the oxazine derived from chloranil and monoformyl-1 - 4-diaminobenzene; (b) the dyestuff obtained by sulphonating the oxazine (a); (c) the dioxazine derived from chloranil and 3-amino-6-acetylamino - N - ethylcarbazol; (d) the dyestuff obtained by sulphonating the dioxazine (c). 3 - Amino - 6 - acetylamino - N - ethylcarbazole may be prepared by nitrating N-ethylcarbazol, reducing, acetylating the resulting 3-nitro-6-amino-N-ethylcarbazol and reducing the product. Specification 367,389 also is referred to. The Specification as open to inspection under Sect. 91 comprises also the formation of oxazines from quinones having the above general formula in which X is aryl. In a further example, the condensation product from tetrabromquinone and monoacetyl-1 : 4-diaminobenzene is subjected to ring formation. Examples forming the subject-matter of samples (a) and (c) are also included. This subject-matter does not appear in the Specification as accepted.