Patent GB-949091-A (GB)
Title: Aminopyrazoles
Inventor: DICKINSON CLIFFORD LEE
Filed: 1961-07-19
Abstract: The invention comprises aminopyrazoles having the general formula: <FORM:0949091/C2/1> in which R is hydrogen, carbamyl, N-substituted carbamyl, N,N-di (lower alkyl) carbamyl, thiocarbamyl, substituted or unsubstituted arylsulphonyl containing not more than 10 carbon atoms, substituted or unsubstituted aroyl, the aroyl group containing not more than 11 carbon atoms, guanyl or substituted or unsubstituted n-alkanoyl, the alkanoyl group containing not more than 9 carbon atoms, and X and Y are monovalent radicals containing not more than 7 carbon atoms, one of which is cyano and the other is halogen, hydrocarbon sulphonyl free of aliphatic unsaturation, lower alkylthio or piperidino. (The expressions "lower alkyl" and "lower alkylthio" refer respectively to alkyl and alkylthio groups containing from 1 to 4 carbon atoms.)  The invention also comprises (a) the preparation of the aminopyrazoles in which R has the above stated meaning excluding hydrogen by reacting a hydrazide of the formula R.NH. NH2, in which R has the above stated meaning excluding hydrogen, with a tetra-substituted ethylene of the formula <FORM:0949091/C2/2> where X and Y have the above stated meaning and Z is the same group as that substituent X or Y that is not a cyano group, in the presence of an inert diluent or solvent, the molar proportions of the reactants being from 1.5:1 to 1:1.5, and (b) the preparation of the aminopyrazoles in which R is hydrogen by reacting semicarbazide or a salt thereof with a substituted ethylene as defined in (a) above under the same conditions as specified in (a), and then hydrolysing the product of the reaction to remove the N-carbamyl substituent thereof without affecting any other substituent in the product. (The reaction product obtained in the above processes is a mixture of the 5-amino -3, 4- disubstituted-pyrazole and 3-amino -4, 5- disubstituted-pyrazole and although the novel compounds are referred to herein as 5-aminopyrazoles only it is to be understood that the invention relates also to the isomeric 3-aminopyrazoles.) Many novel pyrazoles are specified, typical examples being 5-amino -3- cyano -1, 4- bis (p-toluenesulphonyl) pyrazole (obtained from p-toluenesulphonyl-hydrazide and 1, 2-dicyano -1, 2- bis (p-toluenesulphonyl) - ethylene, the latter being obtained by treating dichlorofumaronitrile with sodium p-toluenesulphinate), 5-amino -3- cyano -4-ptoluenesulphonyl -1- carbamylpyrazole, obtained by treating 5-amino -3- cyano -4- p-toluenesulphonyl pyrazole with isocyanic acid, 5-amino -3- cyano -4- methane-sulphonyl -1- carbamylpyrazole (obtained by reacting semicarbazide with dichlorofumaronitrile and potassium methyl sulphinate) and also obtained by reacting isocyanic acid with 5-amino -3- methanesulphonyl -4- cyano-purazole which is itself obtained by the H2O2 oxidation of 5-amino -3- methylthio -4-cyano -1- carbamyl-pyrazole, 5-amino -1- (5, 8-dichloro -2- naphthoyl)-3- chloro -4- cyanopyrazole, 5-amino -1- p-nitrophenylacetyl -3-chloro -4- cyanopyrazole, 5-amino -1- w-cyanopelargonyl -3- chloro -4- cyanopyrazole, 5-amino -1- (b -indole -a - aminopropionyl) -3-chloro -4- cyanopyrazole, 5-amino -3- cyano -4-p-toluenesulphonyl -1- thiocarbamylpyrazole, obtained by reacting 5-amino -3- cyano -1-guanyl -4- p-toluene-sulphonylpyrazole with H2S, 5-amino -3- cyano -4- p-toluenesulphonyl -1- [(3)-camphorylcarbamyl] - pyrazole and 5-amino -4- cyano -1- carbamyl -3- piperidinopyrazole, obtained by reacting isocyanic acid with 5-amino -4- cyano -3- piperidinopyrazole which is itself obtained by reacting hydrazine with 1,1,2-tricyano -2- piperidinoethylene. Either or both of the hydrogens of the 5-amino group of the pyrazoles, can be replaced by reacting the novel pyrazoles with an acylating or alkylating agent. Thus, reaction of 5-amino -3- chloro-4- cyano -1- p-toluenesulphonlpyrazole with a molar proportion of p-toluenesulphonyl chloride yields 3-chloro -4- cyano -5- p-toluenesulphonylamino -1- p-toluene-sulphonylpyrazole. Similarly, a hydrogen of the 5-amino group can be replaced by an acetyl, benzoyl, naphthoyl, carbamyl, p-acetamidobenzenesulphonyl, thioacetyl or thiocarbamyl group.  Furthermore, the 5-amino group of the pyrazoles can be reacted with aliphatic or aromatic aldehydes such as butyraldehyde, benzaldehyde and naphthaldehyde or with cyclohexanone to form Schiff's base type condensation products which can be employed as dyes (see Division C4), and these condensation products can be reduced, e.g. with H2 and a platinum catalyst, to give secondary amines, i.e. compounds wherein one of the hydrogen atoms of the 5-amino group is replaced by an aliphatic, cyclohexyl or aromatic radical.ALSO:Dyes are obtained by reacting novel amino pyrazoles (see Division C2) having the general formula <FORM:0949091/C3/1> in which R is hydrogen, carbamyl, N-substituted carbamyl, N,N-di-(lower alkyl) carbamyl, thiocarbamyl, substituted or unsubstituted arylsulphonyl containing not more than 10 carbon atoms, substituted or unsubstituted aroyl, the aroyl group containing not more than 11 carbon atoms, guanyl or substituted or unsubstituted n-alkanoyl, the alkanoyl group containing not more than 9 carbon atoms, and X and Y are monovalent radicals containing not more than 7 carbon atoms, one of which is cyano and the other is halogen, hydrocarbonsulphonyl free of aliphatic unsaturation, lower alkylthio or piperidino (where in the above the expressions "lower alkyl" and "lower alkylthio" refer respectively to alkyl and alkyltio groups containing from 1 to 4 carbon atoms, and although the pyrazoles are shown to have the formula corresponding to 5-amino-3,4-disubstituted pyrazoles it is to be understood that the invention relates also to the 3-amino-4,5-disubstituted isomers) with (a) an aliphatic or aromatic aldehyde, e.g. butyraldehyde, benzaldehyde or naphthaldehyde, or cyclohexanone to form Schiff's base type condensation products (i.e. the carbonyl compound reacts with the 5-amino group of the pyrazole); or (b) with nitrosylsulphuric acid (prepared from sodium nitrite and sulphuric acid) and then coupling with b -naphthol to form an orange dye.  In an example, 5-amino-1 - carbamyl - 3 - cyano - 4 - p - toluenesulphonylpyrazole is heated with p-dimethylaminobenzaldehyde in the presence of p-toluenesulphonic acid and the 5-p-dimethylaminobenzalamino compound obtained is used as a yellow dye for wool and silk fabrics.