Patent GB-340495-A (GB)
Title: Manufacture of condensation products from cyclohexyiamines
IPC: C09B51/00
Filed: 1929-09-30
Abstract: N-Aryl-cyclohexylamines.-Cyclohexylamine or a homologue thereof is condensed with a nitro derivative of the aromatic series which contains a reactive halogen atom, whereby hydrochloric acid is split off and N-nitroaryl-cyclohexylamines produced.  The condensation is preferably carried out in the presence of acid binding agents and a carrier, such as copper or a salt thereof, and in some cases pressure is advantageous.  These nitro derivatives can be converted to the corresponding amino compounds by reduction.  An advantageous method of reduction is by first acylating the N-cyclohexylnitroarylamines, and then reducing, the acyl groups being split off from the products if desired.  Those nitro or amino derivatives which also contain one or more sulphonic acid groups may be wholly or partially desulphonated by heating with a mineral acid.  According to examples (1) Cyclohexylamine is condensed with (i) 1-chloro2,4-dinitrobenzene; the product dyes acetate silk yellow shades and on treatment with acetic anhydride yields 1-N-acetylcyclohexylamino-2,4-dinitrobenzene, (ii) 1,4-dichloro-2-nitrobenzene, (iii) 1-chloro-2,4-dinitronaphthalene, (iv) 1-chloro-4-nitrobenzene-2-carboxylic acid, (v) 1-chloro-2,4-dinitrobenzene-6-sulphonic acid; the product dyes wool and silk reddish-yellow shades, (vi) 1-chloro-2,6-dinitrobenzene-4-sulphonic acid; the product dyes wool yellow shades, (vii) 1-chloro-2-nitrobenzene-4-sulphonic acid; the product dyes wool and silk brilliant yellow shades, (viii) 1-chloro-4-nitrobenzene-2-sulphonic acid; the product dyes wool and acetate silk yellow shades: (2) The last-named product, N-cyclohexylamine-4-nitro-benzene-2-sulphonic acid is (i) reduced to the amino derivative by cauterized iron in neutral solution, (ii) treated with acetic anhydride whereby N-acetylcyclohexylamino-4-nitrobenzene-2-sulphonate is obtained, and this is reduced to the amino derivative with iron and acetic acid or zinc and ammonia, (iii) desulphonated by boiling with aqueous sulphuric acid (or hydrochloric or other mineral acid); the product is converted to N-acetylcyclohexylamino-4-nitrobenzene by treatment with acetic anhydride, and this reduced with iron and acetic acid; this amino derivative may be diazotized and coupled with the usual azo components, and on heating with aqueous hydrochloric acid (or other saponifying agent) yields N-cyclohexylamino-4-aminobenzene; alternatively the desulphonated product N-cyclohexylamino-4-nitrobenzene may be aroylated with benzoyl chloride or with 2,5-dichlorobenzoyl chloride, or with 3-nitrobenzoyl chloride and these products reduced to the corresponding amino derivatives by means of iron and acetic acid: (3) The above desulphonation process can be applied to the products of (1) which contain sulpho groups to obtain N-cyclohexylamino-2-nitrobenzene and N-cyclohexylamino-2,4-dinitro-benzene: (4) reduction of N-acetyl-o- and p-methylcyclohexylamino-4-nitrobenzenes by means of iron and acetic acid yields the corresponding amino derivatives: (5) N-cyclohexylamino-2-nitrobenzene-4-sulphonic acid is treated with acetic anhydride and the acyl derivative reduced with iron and acetic acid; the N-acetylcyclohexylamino-2-aminobenzene 4-sulphonic acid thus obtained yields a diazo compound capable of coupling with an azo-component.  The further condensation of N-cyclohexylamino-4-aminobenzene-2-sulphonic acid with 1-chloro-2,4 dinitrobenzene or the similarly substituted naphthalene derivative to produce acid wool dyestuffs is also mentioned.  It is stated that the N-acylcyclohexylamino-arylamines are stable to oxidizing agents as distinct from the corresponding non-hydrogenated aromatic amino derivatives, and that they can be diazotized and coupled with azo-components.  Specification 329,960, [Class 15 (ii), Dyeing, Processes &c. for], is referred to.