Patent GB-918128-A (GB)
Title: Pyrazolino-benzimidazole colour couples
IPC: C07D487/04
Filed: 1959-06-19
Abstract: The invention comprises 1,5-pyrazolinobenzimidazoles-11,21 of formulae <FORM:0918128/IV (b)/1> and <FORM:0918128/IV (b)/2> in which: R1 is a hydrogen atom, a saturated or unsaturated aliphatic hydrocarbon group having 1-20 carbon atoms, an aralkyl or aryl group, an alkoxyphenyl group in which the alkyl radical has 1-20 carbon atoms, an aminophenyl, acylaminophenyl, alkylaminophenyl group, naphthyl or amino group (which amino group may be further substituted by a mono-or di-alkylamino group in which the alkyl radicals have 1-20 carbon atoms), a cycloalkylamino group, a substituted or unsubstituted amino group bonded at the 3-position to another 1,5-pyrazolino-benzimidazole-(11,21)-radical, an acylamino group, an esterified carboxylic acid group or an amide group which may be substituted by a saturated or unsaturated aliphatic, aromatic or heterocyclic group; R2 is a hydrogen atom; R3 is a hydrogen atom, halogen atom, a sulphonic acid group, a carboxylic acid group or an azo radical of the formula -N=N-R, in which R is an aromatic or heterocyclic radical; R4 represents a radical of formula =CH-R5, in which R5 represents an alkyl, aralkyl, a phenyl group, or a phenyl group substituted by a tertiary amino group; and S represents hydrogen, a halogen atom, a carboxylic acid group, a sulphonic acid group, a chlorsulphonyl group, a substituted or unsubstituted aminosulphonyl group, an alkyl, aralkyl, aryl, heterocyclic, alkoxy, hydroxyl or a substituted or unsubstituted amino group; or a benzene ring condensed with the benzene ring to which S is bonded.  These compounds may be prepared by heating the corresponding 1-(o-amino-phenyl)-pyrazol-5-one alone or in the presence of an aliphatic, araliphatic or aromatic amine, a heterocyclic nitrogen base or phosphoric acid to a temperature of 100-200 DEG C.  To produce a compound having an azo group in the 4-position the compound of formula <FORM:0918128/IV (b)/3> is diazotised; if a sulphonic group is desired in the 4-position then the same starting material is treated with concentrated sulphuric acid.  Examples are given of compounds of the first formula given above in which the substituents S, R1, R2 and R3 are hydrogen except for those specified as follows:- (a) R1 is COOH; (b) S is SO3H and R1 is C17H35; (c) and R2 are SO3H and R1 is C17H35; (d R1 is phenyl and S is SO3H; (e) R1 is phenyl; (f) S is SO3H and R1 is <FORM:0918128/IV (b)/4> (g) R1 is COOH and S is Cl or Br; (h) S is SO3H and R1 is <FORM:0918128/IV (b)/5> (j) R1 is COOH and R2 is Cl; (k) S is SO3H and R1 is C17H33; (l) S is SO3H and R1 i 2-amino-3-chlorophenyl; (m) S is SO3H and R1 is <FORM:0918128/IV (b)/6> (n) R1 is C17H35 and S is CISO2H; (o S is 3,5-dimethoxycarbonyl-phenylaminosulphonyl and R1 is C17H35; (p) S is 3,5-dicarboxyphenyl-aminosulphonyl and R1 is C17H35; (q) S is COOH and R1 is C17H35; (r) S is the two substituents Cl and NH2 and R1 is C17H35; (s) S is the two substituents phenylamino sulphonyl and chlorine and R1 is C17H35; (t) S is methoxy and R1 is C17H35; (u) S is the two substituents Cl and SO3H and R1 is C17H35; (v) S is chlorine; (w) R1 is methyloxycarbonyl and (x) R1 is aminocarbonyl. Specification 892,886 is referred to.ALSO:5-Amino-2-hydroxy-4-methylbenzoic acid is dissolved in hydrochloric acid and diazotised; the solution is neutralised and added to a solution of the compound of formula <FORM:0918128/IV (b)/1> in lithium hydroxide to give a yellow azo dye of formula <FORM:0918128/IV (b)/2> (Example 6).  4-(Dimethylamino)-benzaldehyde and the compound of formula <FORM:0918128/IV (b)/3> are dissolved in alcohol, the solution is brought to a pH of 9 by treatment with caustic soda and is then boiled and neutralised with hydrochloric acid to give an orange-red dye of formula <FORM:0918128/IV (b)/4> (Example 7).  Specification 892,886 is referred to.