CS245065B1 - Process for preparing 2-alkylthio-4,6-diamino-s-triazines - Google Patents

Abstract

The solution concerns the method of preparing 2-alkylthio-4,6-diamino-s-triazines by reacting 2-amino-4,6-dichloro-s-triazines with an equivalent amount of alkanethiol in the presence of a hydrogen chloride-binding agent, or an alkaline salt of alkanethiol in a non-polar water-immiscible or only limitedly miscible solvent at a temperature of 0 to 70 °C under the presence of surfactants or interphase transfer catalysts. The invention can be used primarily in the chemical industry and in pharmacy

Description

2

The present invention relates to a process for preparing 2-alkylthio-4,6-diamino-s-triazines by reacting 2-amino-4,6-dichloro-s-triazines with an equivalent amount of alkanethiol in the presence of a hydrogen chloride-binding agent or alkali metal alkanethiol in non-polar water with an unmixed or only a limited stirring solvent at a temperature of 0 to 70 ° C in the presence of surfactants or interfacial transfer catalysts.

The invention can be used in particular in the chemical industry and in pharmacy.

The present invention relates to a process for the preparation of 2-alkylthio-4,6-diamino-s-triazines of the formula I

S-R

^Λ Ν -ΑΑ Ν \ _Ο (I) wherein R ^1, R ^2, R ^3, R ⁴ is hydrogen or a lower alkyl radical having 1 to 5 carbon atoms and R ⁵ represents a lower alkyl radical having 1 to 5 carbon atoms.

In Formula I, the alkyl radicals are mainly methyl, ethyl, η-propyl, i-propyl, tert-butyl, n-butyl and the like.

It is particularly preferred that R ⁵ is methyl, R ¹ and R ³ are hydrogen and R ² and R ⁴ are t-butylamine, ethylamine or i-propylamine.

It is known that some 2-alkylthio-4,6-diamino-s-triazines and mixtures thereof have wide application in the preparation of herbicidal compositions. mainly:

2-ethylamino-4-methylmercapto-6-tert-butylamino-s-triazine as terbutyrene,

2,4-bis-i-propylamino-6-methylmercapto-s-triazine as promethrin,

2,4-diethylamino-6-methylmercapto-s-triazine as simetrin,

2-ethylamino-4-i-propylamino-6-methylmercapto-s-triazine such as ametrin,

2-i-propylamino-4-methylamino-6-methylmercapto-s-triazine such as desmethylene and a mixture of terbutyrene and terbutylazine (2-ethylamino-4-chloro-6-tert-butylamino-s-triazine) as topogard.

The latter mixture is most often prepared by mixing and special treatment of the individual specially formulated active ingredients.

Various methods for the preparation of the compounds of the formula I are known and technoligically used, but on a technical scale neither of them gives complete satisfactory results without various disadvantages. The starting material in all technically used preparation methods is C3N3Cl3 cyanuric chloride. The principle of the synthesis of the compounds of the formula I is that two chlorine atoms in the cyanuric chloride molecule are replaced by the same or different amino groups and the third chlorine atom is replaced by an alkylthio group.

The known and technically used methods of preparation can be divided into three groups.

In the first group there are preparation processes in which the chlorine atom is replaced by the alkylthio group (most often methylthio) first in the cyanuric chloride molecule and only then the remaining two chlorine atoms are replaced with amines to give the desired product. Apart from various difficulties in the preparation of technical 2-alkylthio-4,6-dichloro-s-triazines, the disadvantage of this process is the need to purify the prepared 2-alkylthio-4,6-dichloro-s-triazine prior to subsequent reactions with amines.

The second group of known methods for the preparation of the compounds of formula (I) may include processes in which the chlorine atoms are first substituted in the cyanuric chloride molecule by amines and the alkylthio group is introduced last in the cananic chloride molecule. However, it is known that the third nucleophilic exchange of chlorine in a cyanuric chloride molecule is feasible only at high temperatures and at elevated pressure when working directly with the alkanethiol and the hydrogen chloride binding agent or alkali alkali metal salt.

Other possibilities for replacing the third chlorine atom in the cyanuric chloride molecule with an alkylthio group are also known, but these processes require an increased number of process steps and often subsequent purification of the product.

In the case of the last group of methods for the preparation of the compounds of the formula I, the following sequence of the individual steps of the substitution of the chlorine atoms in the amino-cyanuric chloride-alkylthio-amine group cyanuric chloride molecule must be maintained in the synthesis. If a solvent which is miscible with water is used as the reaction medium, its aqueous mixture (preferably acetone-water) may need to be operated in the temperature range of -10 to 0 ° C in order to prepare the 2-amino-4,6-dichloro-s-triazine. was selective. Likewise, in the subsequent reaction with alkanethiol in the presence of hydrogen chloride-binding agents (optionally with alkali alkanethiol salt), it is necessary to work in the temperature range of 0 to 5 ° C in order to make the reaction selective (U.S. Pat. No. 145,197). The introduction of the second amino group into the cyanuric chloride molecule can then be carried out already at normal pressure and at a temperature of 60 to 70 ° C in good yield.

However, if a nonpolar, immiscible or limited miscible solvent (preferably toluene, xylene, etc.) is used, the first chlorine atom in the cyanuric chloride molecule is selectively and quantitatively substitutable with an amino group under adiabatic conditions up to 70 ° C (US Pat. No. 156,446).

It has now been found that a process for the preparation of the 2-alkylthio-4,6-diamine-s-triazines of formula I is readily practicable

(I) wherein R ¹ , R ² , R ³ and R ⁴ represent! hydrogen atoms or a lower alkyl radical of 1 to 5 carbon atoms and R ⁵ represents a lower alkyl radical of 1 to 5 carbon atoms by reacting 2-amino-4,6-dichloro-s-triazines with an equivalent amount of alkanethiol in the presence of a hydrogen chloride-binding agent, or an alkali alkali metal salt of the invention.

The principle of the invention is that the reaction is carried out in a biphasic environment of water and a non-polar water-immiscible or only a limited-stirring solvent at a temperature of 0-70 ° C, preferably at 30-40 ° C, in the presence of surfactants or phase catalysts. or mixtures thereof.

Solubilizers from the group of polyoxyethylated, polyoxypropylated alkylphenols or their sulphates or mixtures thereof can be used as surfactants or interfacial transfer catalysts.

Further, alkali metal alkylbenzenesulfonic acid salts and compounds of formula II may be used

⁷ R6R + R8R9 _and b- (If), wherein R ^e, R ^7, R ⁸ and R ⁹ is an aliphatic and / / or cyclic groups of 1 to 45 carbon atoms, optionally substituted with hydroxyl or methyl, A ⁺ is N ⁺ , P ^{@ +} and B @ - are halogen, nitrate, hydrosulfate, carbonate, and the nature of the anion does not significantly affect the properties of the compounds.

It is also possible to use macro-heterocyclic compounds of formula II (-Z-CH 2 -CH 2 -) n (III), wherein Z is an oxygen or nitrogen atom and n is an integer of 4 to 8.

The macro-heterocyclic compounds can be used as chemical indi- viduals or adsorbed on carriers.

The main advantage of this process is that the reaction proceeds selectively and the last reaction step - replacing the third chlorine in the cyanuric chloride molecule with a second amine - also in this reaction system provides quantitative yields at normal pressure and at elevated temperature.

A further advantage of the process according to the invention for the preparation of the 2-alkylthio-4,6-diamino-s-triazines is that in the industrial production, all the reaction steps from cyanuric chloride as starting material to the final products of the general formula I are carried out selectively and almost quantitative yields under mild and technically undemanding conditions, with no intermediate needing to be isolated or purified. In this way, the final products of formula I and good high yields with high purity can be obtained directly from cyanuric chloride in a single reaction vessel.

The process of the invention also makes it possible to prepare mixtures of 2-alkylthio-4,6-diamino-s-triazines (preferably with the same amines) in one step.

The cyanuric chloride starting material is reacted with an equivalent amount of amine and hydrogen chloride-binding agent, the necessary equivalent of alkanethiol is added in the presence of hydrogen chloride-binding or alkali alkaliethane directly, and then the equimolar amounts of alkylamine and hydrogen chloride are added to the neutral reaction mixture.

These examples illustrate but do not limit the scope of the invention.

Claims (1)

A method for the preparation of 2-alkylthio-4,6-diamino-s-triazines of the general formula I SR '' ... X ^ Rlt (H in which R1, R2, R3, R4 represent hydrogen atoms or a lower alkyl radical having 1 to 5 carbon atoms, R 5 represents a lower alkyl radical having 1 to 5 carbon atoms, reacting 4,8-dichloro-2-amino-s-triazines with an equivalent amount of alkanethiol in the presence of a binder hydrogen chloride, or alkali solialcanol, characterized in that the reaction is carried out in a biphasic water and non-polar water-immiscible or merely mixing solvent at a temperature of 0 to 70 ° C, preferably at 30 to 40 ° C, in the presence of surfactants or intermediate phase catalysts or mixtures thereof of a group of polyoxyethylated, polyoxypropylated alkylphenols, optionally their sulfates, alkali metal alkylbenzene sulfonic acid salts, wherein the alkyl moiety is wherein RB, R7, R8 and R9 are aliphatic and / or cyclic groups having 1 to 45 carbon atoms, optionally substituted with hydroxyl or methyl groups, wherein RB, R7, R8 and R9 are aliphatic and / or cyclic groups having from 1 to 45 carbon atoms. , A + denotes a nitrogen or phosphorus cation and B "denotes an halogen, nitrate, hydrosulfate, carbonate, and macrolide heterocyclic compounds of general formula (III) (- Z-CH 2 -CH 2 -L, (III) wherein Z is oxygen or nitrogen and n is an integer of 4 to 8.