DD296685A5 - PROCESS FOR THE PREPARATION OF THIOCYCLAM - Google Patents

Abstract

In the process for producing thiocyclam, * (Nereistoxin) is reacted with the alkali metal salt of a polythionate in a 2-phase system. It works at p H 7-9 and temperatures between 0 and 60C. The thiocyclam is extracted from the organic phase with oxalic acid in an aprotic solvent as hydrogenoxalate. {Insecticide; thiocyclam; nereistoxin; Natriumtrithionat; sodium tetrathionate; * 1,2-dithiolane}

Description

Field of application of the invention The invention relates to a process for the preparation of thiocyclam, which is of importance as an insecticidal active ingredient. Characteristic of the known state of the art There are various synthetic routes known that are used for Thiocyclamherstellung.

1. Known from JP-PS 76136689, the reaction of 1- (N, N-dimethylamino) -2,3-dichloropropane with sodium bisulfide and sulfur to thiocyclam. A disadvantage is the low yield of thiocyclam, the cause of which is to be sought in the formation of polysulfides of different composition in competing reactions.

2. According to JP-PS 80127387 2- (N, N-dimethylamino) -1,3-dimercaptan is reacted with sulfur. The same starting material gives according to DE-OS 2039666 in the reaction with sulfur dichloride the desired product. Furthermore, according to DE-OS 2039666, O-sodium 2- (N, N-dimethylamino) -1,3-dithiosulfatopropane is reacted with sodium sulfide to give thiocyclam. A disadvantage of all these methods is that nereostoxin formed as a by-product is not converted to thiocyclam and thus lost in yield. The reason lies in the fact that no method is known with the Nereistoxin is converted directly into the thiocyclam.

3. Japanese Patent 83203146 teaches to react 4- (N, N-dimethylamino) -1,2-dithiolane-1-oxide with H2S to obtain thiocyclam.

The disadvantage here is the high preparative effort which is due to the fact that only the 1-oxide is produced from nereistoxin and then has to be treated with gaseous H ₂ S.

Object of the invention

The invention has the goal, in particular, of converting the nereostoxin, which is by-produced in the various processes, directly into thiocyclam with little preparative effort.

Explanation of the essence of the invention

The invention has for its object to produce from Nereistoxin Thiocyclam, wherein the reaction is designed so that by-products are formed only in very small quantities and in particular Nereistoxin is no longer present in the product.

The object is achieved in that 4- (N, N-dimethylamino) -1,2-dithiolane (Nereistoxin) is reacted with the alkali salt of a polythionate in a 2-phase system. The pH is maintained between 7 and 9, preferably between 7.5 and 8, with the aid of a phosphate buffer. At a temperature between 0 and 60 ° C, preferably at room temperature, the mixture is stirred vigorously for 5-20 hours. The product is precipitated with oxalic acid dissolved in an aprotic solvent from the organic phase.

Exemplary embodiments The invention will be explained in more detail below on some embodiments. example 1

2.39 g (0.01 mol) of 4- (N, N-dimethylamino) -1,2-dithiolane hydrogen oxalate (nereistoxin hydrogen oxalate) and 6.1 g (0.02 mol) of sodium tetrationate (Na ₂ S ₁ O ₆ .2H ₂ O) are stirred in a 2-phase system of Imolaren phosphate buffer (pH7) and 75 ml of diethyl ether at 5 ° C for 20 hours. Subsequently, the ether is separated in a separating funnel and the aqueous phase extracted with 50 ml of ether. The combined ether phases are dried over sodium sulphate and precipitated with oxalic acid in dioxane the hydrogen oxalate of the thiocyclam. 1.4 g (50% of theory) of colorless powder are obtained.

Example 2

2.39 g (0.01 mol) of 4- (N, N-dimethylamino) -1,2-dithiolane-diethoxalate (Nereistoxinhydoxoxalat) and 5.7 g (0.02 mol) of sodium irithionate (Na ₂ S ₃ Os. 3H ₂ O) are in 2-phase system of 75 ml of 1 molar phosphate buffer (pH = 8.5) and 75 ml of chloroform stirred at 55 ° C for 5 hours. Subsequently, the chloroform is separated in a separating funnel and the aqueous phase extracted with 50 ml of chloroform. The combined organic phases are dried over sodium sulfate and precipitated with oxalic acid in tetrahydrofuran, the hydrogen oxalate of thiocyclam. 1.25 g (45% of theory) are obtained.

Example 3

2.39 g (0.01 mol) of 4- (N, N-dimethylamino) -1,2-dithiolane hydrogen oxalate (nereistoxin hydrogen oxalate) and 6.1 g (0.02 mol) of sodium tetrathionate (Na ₂ S ₄ O ₆ - 3H ₂ O) are stirred in a 2-phase system of 1 molar phosphate buffer (pH 7.5) and 75 ml of methylene chloride at 20 ° C for 15 hours. Anschießend the methylene chloride is separated in a separating funnel and extracted the aqueous phase with 50 ml of methylene chloride. The combined organic phases are dried over sodium sulfate and precipitated with oxalic acid in diethyl ether, the hydrogen oxalate of thiocyclam. 1.8 g (65% of theory) of colorless powder are obtained. F. 125-30T (dec., Dioxane) C ₇ H ₁₃ NO ₄ S ₃ (271.4)

Ber. C31.01 H4.82 N5.16 S35.40 C31.21 H4.91 N5.07 S35.21 mol. Wt. of thiocyclam 181 (mass spectroscopy)

Claims (5)

1. A process for preparing thiocyclam from 4- (N, N-dimethylamino) -1,2-dithiolane (Nereistoxin) and the alkali metal salt of a polythionate, characterized in that the reaction at a pH of 7-9 in a 2 Phase system is carried out at temperatures between 0 and 6O ⁰ C and a reaction time of 5-20 hours with vigorous stirring and the resulting thiocyclam is precipitated with oxalic acid in an aprotic solvent from the organic phase of the 2-phase system as hydrogen oxalate. 2. The method according to claim 1, characterized in that is used as alkali salts of polythionates sodium trithionate or sodium tetrathionate. 3. The method according to claim 1 and 2, characterized in that the reaction is carried out at pH 7.5-8 and to maintain the pH constant, a phosphate buffer is used. 4. The method according to claim 1 to 3, characterized in that the reaction is carried out at room temperature. 5. The method according to claim 1 to 4, characterized in that methylene chloride is used as the organic phase.