DE2752366A1 - 3,3-Di:methyl-4-pentene thio acid derivs. - are intermediates for cyclopropane carboxylic acid insecticides - Google Patents

Abstract

thio acid amide derivs. of formula (I) are new. (where R1 and R2 are each H, alkyl, aralkyl or aryl, or together with the N atom to which they are attached form a heterocyclic ring). (I) are intermediates for cyclopropane carboxylate insecticides such as 2-(2,2-dichloro-vinyl)-3,3-dimethyl-cyclopropane carboxylic acid-2-phenoxy-benzyl ester.

Description

3, 3-Dimethyl-4-penten-thioamides and methods

for their preparation The present invention relates to new 3,3-dimethyl-4-pententhioamides, and a method for their production.

The new 3,3-dimethyl-4-penten-thioamides serve as intermediates for the production of insecticides such as 2- (2,2-dichlorovinyl) -3,3-dimethyl-cyclopropanecarboxylic acid-2-phenoxy-benzyl ester. The preparation of the 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarboxylic acid on which these insecticides are based by reacting 1,1-dichloro-4-methyl-1,3-pentadiene with diazoacetic ester and the following Hydrolysis is already known (Farkas et al, Collect. Czechosl.

Chem. Commun. 24, 2230 (1959)). However, this method has one Number of disadvantages. So the handling of large amounts of diazoacetic ester is the can decompose explosively, with great risks in technology. The use of diazo compounds is also problematic from a physiological point of view.

It has also been suggested to replace the carboxylic acid 1-cyano-2- (2,2-dichlorovinyl) -3,3-dimethyl-cyclopropane to be used as an intermediate stage for the preparation of the insecticidally active carboxylic acid ester. This nitrile can be removed from the corresponding aldoxime by splitting off water (cf.

German Offenlegungsschrift 2 621 832) or by base-catalyzed Ring closure from 3-bromo-1-cyano-2,2-dimethyl-5,5,5-trichloropentene (cf. Deutsche Offenlegungsschrift 2 621 831). However, these methods suffer from that Deficiency that 1-cyano-2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropane even under drastic Conditions can only be saponified in low yields to the corresponding carboxylic acid can.

There were now the new 3,3-dimethyl-4-penten-thioamides of the formula I. in which R1 and R2 are independently hydrogen, alkyl, aralkyl or aryl or together with the adjacent nitrogen form a heterocyclic radical, found.

A process for the preparation of the new 3,3-dimethyl-4-pentene-thioamides of the formula I has also been found, which is characterized in that thioacetamides of the formula II in which R1 and R2 have the above meaning, with a 3-methyl-2-buten-1-yl derivative of the formula III in which X stands for halogen, sulfonate or phosphate and converts a base.

As already mentioned, the new 3,3-dimethyl-4-pententhioamides are used as intermediates for the production of insecticidal cyclopropanecarboxylic acid derivatives. They are produced by adding tetrahiogenomethane to the double bond of the compounds according to the invention in the presence of suitable catalysts and the resulting compound of the general formula IV dehydrohalogenated by the action of a base to form a compound of the general formula V and these are hydrolyzed under acidic or alkaline conditions in a manner known per se to give the corresponding cyclopropanecarboxylic acids, or it is first hydrolyzed and then the corresponding terrahalomethane is added and then dehydrohalogenated under the action of this base. This method is the subject of an older, unpublished patent application (cf. German patent application P 27 32 213.0).

The new 3,3-dimethyl-4-penten-thioamides according to the invention and the process for their production enable them to be carried out economically the above-mentioned process for the preparation of 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarboxylic acid, in which the disadvantages already mentioned are avoided.

3,3-Dimethyl-4-ententhioamides of the general type are particularly preferred Formula I, in which R1 and R2 represent alkyl radicals with 1 to 4 carbon atoms, aralkyl radicals with 7 to 9 carbon atoms, especially benzyl or aryl, especially phenyl or together with the adjacent nitrogen a heterocycle such as pyrrolidine, Form piperidine or morpholine.

Examples of particularly preferred thioacetamides are in detail named: N, N-dimethyl-thioacetamide, N, N-diethyl-thioacetamide, N, N-di-n-butyl-thioacetamide, N, N-dipropyl-thioacetamide, N, N-diisobutyl-thioacetamide, N-methyl-N-octadecyl-thioacetaramide, N-methyl-N-phenyl-thioacetamide, N-ethyl-N-cyclohexylthioacetamide, N-butyl-N-phenyl-thioacetamide, N-Benzyl-N-methyl-thioacetamide, N, N-dibenzyl-thioacetamide, thioacetylpyrrolidine, Thioacetyl piperidine, Thioacetyl morpholine, thioacetamide, N-methyl-thioacetamide, N-butyl-thioacetamide, N-phenyl thioacetantide.

It is surprising that the process for the preparation of the new 3,3-dimethyl-4-pententhio acids is so selective that a 1,4-elimination on 3-methyl-2-buten-1-yl derivatives of the general formula II takes place very easily in the presence of bases to form isoprene. This elimination occurs in the absence of a thioacetamide of the general formula (II) predominates, is largely suppressed under suitable reaction conditions. The S-alkylation, which is followed by deprotonation, then takes place selectively the base and a rearrangement to the 3,3-dimethyl-4-pententhioamides of the general Formula I follows.

Using N, N-dimethyl-thioacetamide and 3-methyl-2-buten-1-yl chloride (prenyl chloride) as starting materials, the reaction can proceed in the presence of a tert. Amine can be represented by the following equation: The process for preparing the 3,3-dimethyl-4-pententhioamides according to the invention has a number of advantages. Thus, the thioacetamides of the formula (II) are readily and easily accessible starting materials, which are obtained from the heaps by exchange reaction with phosphorus pentasulfide (Liebigs Ann.Chem.

716, 209 (1968)) or from amide chlorides by reaction with hydrogen sulfide (Chem. Ber. 96, 2671 (1963)). Also the 3-methyl-2-buten-1-yl halides of the formula (III) (prenyl halides) are made from isoprene and equimolar in a simple manner Amounts of hydrogen halide obtained. Furthermore, the reaction execution is as One-pot reaction compared to all two-stage processes in which alkylation is used first a salt and then the deprotonation is carried out with base (Houben-Weyl, Methods of Organ Chemistry, VII / 4, p. 435) are advantageous.

Those involved in the production of the new 3,3-dimethyl-4-pententhioamides 3-Methyl-2-buten-1-yl derivatives serving as starting materials are represented by the formula (III) generally defined. X is preferably chlorine, bromine, methanesulfonate, p-toluenesulfonate or dimethyl phosphate. Examples include: prenyl chloride. Prenyl bromide, prenyl mesylate, prenyl toxylate.

For the preparation of the compounds according to the invention, preference is given to tertiary amines such as triethylamine, dimethylbenzylamine, pyridine, ethyl diisopropylamine, Dimethylaniline, 1,8-diazobicyclo (5.4.0) undec-7-en, 1,5-diazabicyclo (4.3.0) -non-5-en, Triethylenediamine, alkali hydroxides such as sodium hydroxide or potassium hydroxide, alkali carbonates such as potassium carbonate, sodium carbonate, alcoholates such as potassium t-butylate or amides used as lithium diisopropylamide.

All inert organic solvents are suitable as diluents. These preferably include hydrocarbons such as gasoline, cyclohexane, toluene and ether such as diethyl ether, tetrahydrofuran, dioxane, dimethoxyethane, halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, alcohols such as methanol, ethanol, butanol and others such as acetonitol, dimethyl sulfoxide, dimethylformamide or hexamethylphosphoric triamide.

The reaction temperatures can vary within a relatively wide range will. In general, between 20 and 1,600 ° C., preferably between 50 and 1 200C. When carrying out the inventive method is used in generally the reaction components and the base in an equimolar ratio. However, deviations from this ratio are possible.

One mole of thioacetamide (II) is preferably 1 to 2 equivalents 3-wethyl-2-buten-1-yl derivatives (III) and 1 to 2 equivalents of base reacted. You can submit both all reactants in a diluent and the Extend the reaction with heating as well as one of the components, in particular that 3-methyl-2-buten-1-yl derivative (III) or the base, slowly to the other reactants to be dosed in the course of the reaction. After the reaction, the resulting salt can both by aqueous work-up and by filtering from suitable diluents be separated. The 3, 3-dimethyl-4-pententhiosäureride (I) is isolated according to the properties either by distillation or by chromatography or by crystallization. However, it can also be used for further implementation directly in Solution can be used as a non-isolated product.

The following examples explain the process according to the invention without specify a restriction with regard to its scope of application.

Example 1 10.3 g (0.1 mol) of N, N-dimethylthioacetamide, 11.5 g (0.11 Mol) prenyl chloride and 14.3 g (0.11 mol) ethyldiisopropylamine are in 100 11 toluene Heated under reflux for 4 hours. After cooling, the solution is shaken with it Water out, dries and fractionates. 14.7 g (0.086 mol, 86%) N, N, 3,3-tetramethyl-4-pentene-thioic acid amide.

NMR (CDCl3): 1.2 (s, 6 H), 3.0 (s, 2 H), 3.3 (s, 3 B) 3.45 (s, 3 H), 4.8-6.2 (m, -CH = CH2), Example 2 10.3 g (0.1 mol) of N, N-dimethylthioacetamide, 14.9 g (0.1 mol) of prenylbroiide and 10 g (0.1 mol) of triethylamine are dissolved in 100 ml of toluene Heated under reflux for 3 hours. After working up, 13.9 g (0.081 Mol, 81%) N, N, 3,3-tetramethyl-4-pen-thioic acid amide, which is identical to the above product was.

Example 3 14.5 g (0.1 mol) thioacetyliorpholine, 11.5 6 (0.11 mol) Prenyl chloride and 11 g (0.11 mol) of triethylamine are dissolved in 100 11 toluene for 4 hours heated to reflux. After working up, 3,3-dimethyl-4-pentene-thioic acid morpholide was isolated.

NMR (CDCl3): # 1.2 (s, 2H); 3.0 (s, 2H); 3.6-3.9 (m, 6H); 4.2-4.5 (m, 2H); 4.8-6.2 (-CH = CH2).

Claims (1)

Claims, I '1i 3,3-dimethyl-4-penten-thioamides of the general formula in which Rt and R2 are independently hydrogen, alkyl, aralkyl or aryl or together with the adjacent nitrogen form a heterocyclic ring Claim 1 in which R1 and R2 have the meaning given in claim 1, characterized in that thioacetamides of the general formula (II) in which R1 and R2 have the meaning given above with 3-methyl-2-buten-1-yl derivatives of the general formula (III) in which X stands for halogen, sulfonate or phosphate and a base is reacted.