Patent GB-916658-A (GB)
Title: A process for the production of hydrazones
IPC: G03C7/26
Filed: 1960-06-10
Abstract: Osazones are obtained by reacting a 4-azo5-pyrazolone with an alkali metal hydroxide or a strong organic base, whereby the pyrazolone ring is opened and the carbonyl group of the pyrazolone is split off.  The 4-azo-5-pyrazolone may be of the formula <FORM:0916658/IV (b)/1> in which R1 is an alkyl radical containing 1-18 carbon atoms, which may be substituted, or a cycloalkyl, aryl, or aralkyl radical, or a heterocyclic ring; R2 is a substituted or unsubstituted alkyl radical, a cycloalkyl, aryl, aralkyl, carboxyl, or esterified carboxyl radical, amino or carbonamide group; R3 is an alkyl, cycloalkyl, aryl, or aralkyl radical; and R4 is an aryl radical or heterocyclic ring. The reaction may be carried out at 0 DEG -60 DEG C.  Compounds having the formula <FORM:0916658/IV (b)/2> are obtained.  R1 may be heptadecyl, cyclohexyl, phenyl, naphthyl, benzyl, benzothiazolyl, pyridyl, pyrazolyl, oxazolyl, thiazolyl, or thiophenyl.  The radical R1 may also be substituted by -SO3H, -SO2-, ethoxy, phenoxy, cyano, halogen, or nitro groups, or by amino or carbonamide groups in which the NH2 groups may be substituted by alkyl, or -COOR groups where R is a monovalent hydrocarbon radical. The radical R2 may also be substituted by -SO3H, -SO2-, etherified hydroxyl, cyano, halogen, nitro, amino, or carbamide groups.  R3 may be similarly substituted. R4 may be phenyl, naphthyl, benzothiazolyl, pyridyl, pyrazolyl, oxazolyl, thiozolyl, or thiophenyl, and it may also contain -SO3H, -SO2-, etherified hydroxyl, cyano, halogen, nitro, amino, and carbamide groups.  In carrying out the process, a pyrazolone derivative, the methylene group of which is substituted in the 4-position, is coupled with a diazonium salt and the resulting product is treated with an alkali metal hydroxide or organic base so as to open the pyrazolone ring and form the osazone.  In an example, 3-aminobenzonitrile is diazotised and coupled with 1-(41-sulphophenyl) - 3 - heptadecyl-4-methyl-5-pyrazolone.  Sodium hydroxide solution is added to form and precipitate the osazone which in the form of the free acid has the formula <FORM:0916658/IV (b)/3> Many other examples are given.  Specification 916,657 is referred to.ALSO:4-azo-5-pyrazolones, used in the production of ozazones (see Group IV(b)), have the general formula <FORM:0916658/IV (b)/1> in which R1 is an alkyl radical of 1-18 carbon atoms, substituted or not, or a cycloalkyl, aryl, or aralkyl radical, or a heterocyclic ring; R2 is an alkyl, cycloalkyl, aryl, aralkyl, carboxyl, or esterified carboxyl radical, or an amino or carbonamide group; R3 is an alkyl, cycloalkyl, aryl, or aralkyl radical; and R4 is an aryl or heterocyclic ring. R1 may be heptadecyl, cyclohexyl, phenyl. naphthyl, benzyl, benzothiazolyl, pyridyl, pyrazolyl, oxazolyl, thiazolyl, or thiopheny,l and it may contain -SO3H, -SO2-, etherified hydroxyl, cyano, halogen, nitro, or amino or carbonamide groups in which the -NH2 groups may be substituted by hydrocarbon radicals or carboxylic acid or ester groups.  R2 and R3 may also contain such substituent groups.  R4 may be phenyl, naphthyl, or any of the heterocyclic radicals specified for R1.  In an example 3-aminobenzonitrile is diazotised and coupled with 1-(41-sulphonphenyl)- 3-heptadecyl- 4-methyl-5-pyrazolone. In another example, 4-aminoazozenzene -41-sulphonic acid is diazotised and coupled with 1-(41-phenoxy-31-sulphophenyl) -3-heptadecyl-4-methyl-5-pyrazolone to form a diazo compound which is treated with a 40% sodium hydroxide solution so as to open the pyrazolone ring and form an ozazone of the formula <FORM:0916658/IV (b)/2> Other examples are given.  Specification 916,657 is referred to.