DE1420969C - Process for the preparation of 4,5 dihalopyridazones (6) - Google Patents

Description

The subject of patent 1 420 011 is a process for the preparation of 4,5-dihalogenpyridazonen- (6) der general formula

O X

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 substituted - alkyl or aryl hydrazines and treatment of the reaction products with concentrated sulfuric acid or by heating mucohalo 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

oxyphenyl) -4,5-dichloropyridazon- (6) as a pale yellow powder with a melting point of 303 to 304 ° C in one Yield of 136 parts is obtained.

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 of mucochloric acid are added and the whole was heated for 1 hour at 9O ⁰ C. After cooling, 210 parts of l- (2-cyanoethyl) -4,5-dichlorpyridazon- (6) as a colorless compound of melting point 99 up to 100 ⁰ C.

B e i s ρ i e 1 3

20 parts of 3-aminophenylhydrazine dihydrochloride, prepared by diazotizing 3-aminoacetanilide, reducing the diazo compound to hydrazine and hydrolyzing acetaminophenylhydrazine with 8% hydrochloric acid, are heated to 90 ° C. with 17 parts of mucochloric acid in 200 parts of 8% hydrochloric acid for 1 hour . Cooling gives 32 parts of 1- (3-aminophenyl) 4,5-dichloropyridazone (6) hydrochloride. The same compound is obtained in a yield of 15 parts if the abovementioned mixture is stirred at 40 ^° C. for 48 hours.

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

O X

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 substituted - alkyl or aryl hydrazines and treatment of the reaction products with concentrated sulfuric acid or by direct heating of mucohalogenic acids together with - optionally substituted in the alkyl or aryl radical by the groups mentioned - alkyl or aryl hydrazines in mineral acid aqueous solution can also use alkyl and aryl hydrazines which are substituted by carboxyl, carbalkoxy, carbonamide, cyano, amino groups or by - sulfonylajnino, carbonylamino, carbonyl and sulfonyl groups - carrying alkyl or aryl groups.

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 (II) chloride. 85 parts are added to the mixture Mucochloric acid, stir the whole thing for 20 hours at room temperature and nitrate the reaction product away. After drying, it is introduced into 500 parts of concentrated sulfuric acid with stirring. Man stir for 12 to 15 hours and then pour the mixture into ice water, the l- (4-carb-

Example 4

20 parts / i-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 a colorless crystalline product which melts at 24O ⁰ 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: Further development of the process according to patent 1420 011 for the production of 4,5 - dihalogenpyridazonen- (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 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 th - alkyl or aryl hydrazines and treatment of the reaction products with concentrated sulfuric acid or by direct heating of mucohalogenic acids together with - optionally substituted in the alkyl or aryl radical by the groups mentioned - alkyl or aryl hydrazines in aqueous mineral acid solution, characterized in that alkyl - Or arylhydrazines are used which are substituted by carboxyl, carbalkoxy, carbonamide, cyano, amino groups or by - sulfonylamino, carbonylamino, carbonyl and sulfonyl groups carrying alkyl or aryl radicals.