DE2100685C2 - Process for the preparation of pure 4-amino-5-halogen-pyridazonen- (6) - Google Patents

Description

wherein R ¹ , R ² and X have the aforementioned meaning, from mixtures of the two substances with the aid of extraction with organic solvents, in an amount of 100 to 1500 wt .-% solvent, based on the weight of the two isomers in the isomer mixture Temperatures between 15 and 100 ° C. characterized in that the organic solvents used are chloroform, methylene chloride. Diethylether, Dloxan or isopropanol used.

The F.rfindung relates to a process for the preparation of pure 4-Amtno-5-haIogen-pyrldazonen- (6) Ungen by separation of the ^{4-Amlno-Verbinc)} from mixtures with the isomeric 5-amino-4-halogenpyridazonen- (6) by extraction of the isomers with chloroform, methylene chloride. Diethyl ether. Dloxan or isopropanol.

It is known from German Patent 11 05 232 that by reacting 4.5-Dlhalogenpyrldazonen- (6) with ammonia or amines, mixtures of 4.5- and 5.4-AmInohaIogenpyrldazoiien- (6) are obtained Separation from each other necessary. The substances are also pesticides, whereby mostly only one isomer has a herbicidal effect or one isomer far exceeds the other in terms of effectiveness. l-PhenyM-amino-S-chloir-pyrldazon-io) Is, for example, a selective beet herbal. The amination of the l-phenyl-4,5-dlchloropyridazone gives a mixture of approx. % 1-phenyl-amir.oS-chloropyrldazone and about 20% of the isomeric l-phenyM-chlorine -S-amlnoconnection; The latter compound has only half the selectivity of 4-aminopyrldazone. A separation by, for example, fractional crystallization does not give a satisfactory result

NH

R ²

Π.

where R ', R ² and X have the aforementioned meaning, from mixtures of the two substances with the aid of extraction with organic solvents, in an amount of 100 to 1500% by weight of solvent, based on the weight of the two isomers in the isomer mixture, at temperatures between 15 and 100 ⁰ C is advantageous. if the organic solvent used is chloroform. Methylene chloride Diethyl ether. Dioxane or isopropanol used

Compared to the known processes in which the isomeric end products are separated from one another without extraction, the process according to the invention gives the two isomers 4,5- and 5.4-Amlno-halogenpyrldazone- (6) each in better yield and purity. With regard to the above-mentioned disclosure requirements, the two isomers described there can also be used in better purity. z. B. above 91% of theory can be obtained. In addition, the process according to the invention permits the production of further isomers pyridazone- (6) "from corresponding mixtures in a simpler way. In comparison to the information given in the examples of the disclosure, lower extraction temperatures and smaller amounts of solvent can be used. These advantageous results surprisingly with polar or Im

Purity of the isomer end products. In addition to the isomers, by-products can also be formed, e.g. B. 4-Hydroxy-5-halo-pyridazons- (6) in the case of using water in the reaction.

The German Offenlegungsschrift 16 20 186 describes a process for the separation of the isomeric 4,5- and 5,4-amino-chloro-I-phenyI-pyridazone- (6) by extraction of the 5-amino compound and other by-products with non-polar solvents from the group of aromatic or hydroaromatic hydrocarbons. The 4-amino compound is so according to the information from Offenlegungsschrift obtained in yields of approximately 95%.

It has now been found that pure 4-amino-5-ha! Ogen-pyridazone- (6) the general formula

R ₂ -NH

where R ¹ denotes the methyl, cyclohexyl, benzyl or phenyl, tolyl or trifluoromethylphenyl ^{radical, R 2} denotes a hydrogen atom or the methyl radical and X stands for a chlorine or bromine atom, by separating off their isomers S-Amino ^ - halogen-pyridazonen- (6) of the general formula

Compared to the teaching of the patent application essential more polarizable solvents achieved.

The starting mixtures are mixtures of the two pyridazones (6) I and II in any proportions, advantageously in a weight ratio of 1 to 80% by weight of pyridazone (δ) II. based on pyrldazone I, in Consideration.

Isomer mixtures are preferably used, which from corresponding reactions, for. B. the reaction of 4,5-dihalogen-pyridazonen- (6) with ammonia or methylamine originate. Such reaction mixtures can be worked up to give the mixture of isomers produced as desired, for example according to the procedure described in DP 11 05 232. The isomer mixture can contain further by-products formed by the reaction or work-up of the reaction mixture, e.g. B. corresponding 4-hydroxy-5-halogen compounds, and optionally residual solvents, ζ. B. up to 10% by weight of water. Suitably removed vo ^r extraction inorganic Verbindüngen by washing of the isomeric mixture with water.

For example, there are mixtures of the following 4,5-amino-halogen-pyrldazones and their 5,4-isomers into consideration: 4-amino-, 4-methylamino-5-chloro-1-phenylpyridazone- (6), corresponding 5-bromine compounds and analogous 1-methyl, 1-cyclohexyl, 1-benzyl, 1-m-trifluoromethylphenyl, 1-p-toluyl compounds.

The solvent is used in the extraction in an amount of from 100 to 1500, preferably from 200 to 1500, by weight based on the weight of the two isomers in the isomer mixture. The extraction is' 5 and O0 ^c, C, preferably between 15 and 35 C. Drucki> s or under pressure, continuously or '.'! Skontlnulerlich dun at a temperature between.! ; e leads.

The extraction can be carried out as follows: The isomer mixture, optionally washed with water is mixed with the solvent and during 5 to 60 minutes with thorough mixing at the Extraction temperature extracted The extraction can can be designed in any way in terms of equipment, ζ. Β by shaking. Suspending, repeated passage of the solvent through the extraction material. In rotating extractors, in standing extractors in battery circuit. Extraction presses. In this context it is referred to Ullmann's encyclopedia of technical chemistry. 3 ed., Volume I. (1951) pages 678-686. After the extraction, the undissolved pyrlda / on- (6) I is separated off by filtration.

The pyridazonyl II in known catfish can be separated from the extract. / B. by cooling the extract and fractional crystallization, by partitioning between the solvent used and another solvent or by precipitation from the extract with the aid of a solvent which is miscible with the extract mixture. / B not more than 15% by weight, contaminated by by-products, it is usually sufficient to remove the solvent from the extract and remove the remaining pyramid from a suitable solvent, e.g. the above-mentioned ones, iUrnzukrlställlsieren. | ':. ·. ·. g I ■

The one after the trial? of the invention producible Compounds are pesticides and valuable starting materials for numerous syntheses, e.g. B. the production of dyes and pesticides. Regarding the use, please refer to the publications mentioned referenced.

The parts and percentages given in the following examples are parts by weight and percentages by weight. The percentages of the pyridazones are determined by UR spectroscopy.

example 1

100 parts of crude I-phenyl ^ amino-S-chloro-pyridazon- (6) (87% 4-amino-5-chlorine compound; 13% 4-chloro-5-amino compound), made by reacting the corresponding 4,5-dichloro compound with ammonia is mixed with 300 parts of chloroform for 15 minutes at 25 to 30 ° C. After filtering off 82 parts of l-PhenyM-amino-S-chloropyridazon- (6) are obtained as residue (99.5? Ig) with a m.p. 199 to 231 ° C.

By distilling off the chloroform from the filtrate 11.5 parts of l-PhenyM-chloro-S-amino-pyridazon- (6) are obtained with a melting point of 139 to 140 ° C (recrystallized from ethanol).

Example 2

If the separation is carried out as in Example 1 with crude 1-phenyl-4-amino-5-bromo-pyridazon- (6) (85% 4-amino-5-bromo compound; 9% 4-bromo-5-amino compound) one receives 84.5 parts of l-phenyl-4-amino-5-bromo-pyridazon- (o) from m.p. 213 to 215 ° C (97.5%) and from the Ftltra »8 parts of l-phenyl-4-bromo-S-aminopyridazon- (6) of melting point 126 ° to 127 ° C. (recrystallized from methanol).

Example 3

When carrying out the separation as in Example I with 50 parts of crude l-phenyl-4-amino-5-bromo-pyridazon- (6) (83% 4-amino-5-bromo compound; 4% 4-bromo-5-amino compound) and 120 parts of diethyl ether as the extractant 42.3 parts of l-PhenyM-amino-S-bromo-pyridazon- (6) are obtained of m.p. 215 to 217 ° C (97.5% Ig).

Example 4

If the separation is carried out as in Example 3 with 130 parts of dioxane as the extractant, one obtains 42 parts of I-phenyl-4-amino-5-bromo-pyridazon- (6) with a melting point of 216 ° to 218 ° C. (98.5%).

Example 5

If the separation is carried out as in Example 3 with 130 parts of isopmpanol as the extractant, one obtains 42 parts of 1-phenyl-4-amine-5-bromo-pyrldazon- (6) with a melting point of 216 to 218 ° C. (98.5% Ig).

Example 6

If the separation is carried out as in Example 1 with crude 1-methyl-4-amino-5-chloro-pyridazone- (6) (9 (K 4-amino-5-chloro compound; 10% 4-chloro-5-amino- compound) yields 84.8 parts of l-methyl-4-chloro-amlno -'- pyrldazon- (6), mp. 203-204 ¹ C (98.5v.ig) distillation of the obtained FMtrats 1 8 parts · methyl -4-chloro-5-amlno-pyridazon- (6) of melting point 111 to 113 ° C (recrystallized from ethanol)

^ ₁ example 7

If the separation is carried out analogously to Example 1 with crude 1-BenzyM-amino-S-chloro-pyrldazon-CO) (75% 4-amino-5-chloro compound; 23 & 4-chloro-5-arhino compound) one obtains 72.8 parts of l-benzyl-S ^ -arnlno-chloro-pyridazone (6), mp. 220-221 ⁰ C (98, SiVlIg) concentration of Flltrats is obtained 18 parts of 1-

BenzyM-chloro-S-amino-pyrldazon-io) of melting point 107 to 108 ° C (recrystallized from ethanol).

Example 8

When performing the separation analogous to the example! 1 with crude l-cyclohexyM-amlno-S-chloro-pyridazon-io) (75% 4-amino-5-chloro compound; 19% 4-chloro-5-amino compound) one receives 63.5 parts of l-CyclohexyM-amino-S-chloropyridazon- (6) from m.p. 219 to 221 ° C (98%). Concentrating the filtrate gives 15 parts of 1-cyclohexyl-4-chloro-5-aminopyr! Dazone- (6) of melting point 96 to 98 ° C (recrystallized from cyclohexane).

Example 9

When performing the separation as in Example 1 with crude 1- (m-trifluoromethyl-phenyl) -4-amino-5-bromopyridazone- (6) (79% 4-amino-5-bromo compound; 9% 4-bromo-5 -amino compound), 73.2 parts of 1- (m-trifluoromethylphenyl) -4-amino-5-bromypyridazon- (6) of melting point 174 ° to 176 ° C. (99%) are obtained. By concentrating the filirate you get 7 parts! - (rn-Trif! Uor-methy! -Nh _e ny!) -

4-bromo-5-am! No-pyridazon- (6) of melting point 146 ° to 147 ° C. (recrystallized from ethanol).

Example 10

If the separation is carried out as in Example 1 with crude 1- (p-methylphenyl) -4-methy Iamino-5-chloro-pyridazon- (6) (89% 4-methylamino-5-chloro compound; 11% 4-chloro 5-methylamino compound) one receives 79.2 parts of l-tp-methyl-phenvU ^ -methylamino-S-chloropyridazon- (6) of melting point 208 to 210 ^° C. (99%). By concentrating the filtrate, 8.5 parts of 1-ip-methylphenyl) -4-chloro-5-methylamino-pyridazon- (6) of melting point 175 to 176 ^° C. (recrystallized from ethanol) are obtained.

Example 11

100 parts of crude l-PhenyM-amino-S-chloro-pyridazon- (6) (87% 4-amino-S-chloro compound. 13% 4-chloro-5-amino compound) are mixed with 200 parts of methylene chloride at 20 to 25 ° C for 30 minutes. To suctioning off gives 84 parts of 1-PbenyM-amino-S-chloropyridazon-fft * as residue (98.5% Ig) with a m.p. 199-200 ° C

Claims (1)

21 OO 685 Claim: Process for the preparation of pure 4-amino-5-halo-pyridazone- (6) the general formula R ² -NH where R ¹ denotes the methyl, cyclohexyl, benzyl or phenyl, tolyl or trifluoromethylphenyl ^{radical, R 2} denotes a hydrogen atom or the methyl radical and X denotes a chlorine or bromine atom, by separating 5-amino-4 from its isomers -halogenpyridazonen- (6) of the general formula