DE1420969B - Process for the preparation of 4,5-dihalopyridazone- (6) - Google Patents

Description

Subject of the patent application P 14 20 011.4-44 is a process for the preparation of 4,5-dihalopyridazones- (6) the general formula

O X

in which R _{1 is} an optionally substituted aliphatic or aromatic radical and X and Y are halogen atoms, by reacting mucohalogenic acids in mineral acidic aqueous solution at room temperature with - optionally in the alkyl or aryl radical by sulfonic acid, sulfonic acid amide, alkyl. Alkoxy, halogen, acylamino and / or nitro groups substituted - alkyl or aryl hydrazines and treatment of the reaction products with concentrated sulfuric acid or by heating mucohalic acids together with - optionally substituted in the alkyl or aryl radical by the groups mentioned - alkyl or aryl hydrazines in mineral acid aqueous solution.

It has been found that in the preparation of 4,5-dihalopyridazones- (6) the general formula

R ₁ -N

O X

in which R _{1 is} an optionally substituted aliphatic or aromatic radical and X and Y are halogen atoms, by reacting mucohalogenic acids in mineral acidic aqueous solution at room temperature with - optionally in the alkyl or aryl radical by sulfonic acid. Sulfonic acid amide, alkyl, alkoxy, halogen, acylamino and / or nitro groups substituted - alkyl or aryl hydrazines and treatment of the reaction products with concentrated sulfuric acid or by directly heating mucohalic acids together with - optionally in the alkyl or aryl radical by the mentioned Groups substituted - alkyl or aryl hydrazines in mineral acidic aqueous solution can also use alkyl and aryl hydrazines, which by carboxyl, carbalkoxy, carbonamide, cyano, amino groups or by - carrying alkyl or aryl groups - sulfonylamino, carbonylamino, carbonyl - and sulfonyl groups are substituted.

Otherwise, the measures and information in the main patent apply.

The parts and percentages given in the examples are weight units.

example 1

69 parts of l-aminobenzene-4-carboxylic acid are added Diazotized in the usual way and reduced with 230 parts of tin dichloride. 85 parts are added to the mixture Mucochloric acid, stir the whole thing for 20 hours at room temperature and filter the reaction product away. After drying, it is introduced into 500 parts of concentrated sulfuric acid with stirring. Man stirs for a further 12 to 15 hours and then pours the mixture into ice water, whereby the 1- (4-carboxyphenyl) -4,5-dichloropyridazon- (6) obtained as a pale yellow powder with a melting point of 303 to 304 ° C. in a yield of 136 parts.

B e i s ρ i e 1 2

85 parts of 2-hydrazinopropionitrile, which is obtained by reacting hydrazine hydrate with acrylonitrile, are allowed to flow into 500 parts of 8% strength hydrochloric acid with stirring. To this mixture is added 170 parts ίο mucochloric acid are added and the whole was heated for 1 hour at 90 ⁰ C. After cooling, 210 parts of l- (2-cyanoethyl) -4,5-dichlorpyridazon- (6) as a colorless compound of melting point 99 to 100 ° C.

B e i s ρ i e 1 3

20 parts of 3-aminophenylhydrazine dihydrochloride prepared by diazotization of 3-aminoacetanilide, reduction of the diazo compound to the hydrazine and hydrolysis of the Acetaminophenylhydrazins with 8% hydrochloric acid are heated with 17 parts Mucochloric acid in 200 parts of 8% hydrochloric acid for 1 hour at 9O ⁰ C . Cooling gives 32 parts of 1- (3-aminophenyl) -4,5-dichloropyridazone (6) hydrochloride. The same compound is obtained in a yield of 15 parts when the above mixture is stirred at 40 ° C. for 48 hours.

The free 1 - (3 - aminophenyl) - 4,5 - dichloropyridazon- (6) is obtained in the form of pale yellow crystals from melting point 145 ° C by neutralizing 'the aqueous solution of the hydrochloride with Sodium bicarbonate solution.

B e i s ρ i e 1 4

20 parts p'-Aminoäthylhydrazin and 45 parts of mucochloric acid is heated in 300 parts of 8% hydrochloric acid for 2 hours at 9O ⁰ C. By cooling is obtained 32 parts of 1 - β - aminoethyl - 4,5 - dichlorpyridazon- (6) hydrochloride in In the form of a colorless crystalline product that melts at 240 ° C.

C ₆ H ₇ ON ₃ Cl ₂ · HCl (244.5):

Calculated:

<C 29.46, H 3.30, O 6.54, N 17.16, Cl 43.5; found:

C 29.6, H 3.4, O 7.0, 'N 17.3, Cl 43.0.

Claims (1)

Claim: Development of the method according to patent application P 14 20 011.4-44 for the production of 4,5-Dihalopyridazonen- (6) of the general formula N = R ₁ - N in which R _{1 is} an optionally substituted aliphatic or aromatic radical and X and Y are halogen atoms, by reaction of mucohalogenic acids in mineral acidic aqueous solution at room temperature with - optionally in the alkyl or aryl radical by sulfonic acid, sulfonic acid amide, alkyl, alkoxy, Halogen, acylamino and / or nitro groups substituting ten - alkyl or aryl hydrazines and treatment the reaction products with concentrated sulfuric acid or by direct heating of mucohalogenic acids together with - optionally in the alkyl or aryl radical the groups mentioned substituted - alkyl or aryl hydrazines in mineral acidic aqueous Solution, characterized in that one uses alkyl or aryl hydrazines which by carboxyl, carbalkoxy, carbonamide, cyano, amino groups or by - alkyl or Substituted sulfonylamino, carbonylamino, carbonyl and sulfonyl groups carrying aryl radicals are.