DD256693A1 - PROCESS FOR PREPARING CYANIMIDODITHIOCHOKENOEENESTERS - Google Patents

Abstract

The invention relates to a process for the preparation of Cyanimidodithiokohlensaeureestern of the general formula III, in which R 1 is alkyl, alkenyl or aralkyl, R 2 aryl or hetaryl, which may optionally be substituted andX oxygen or sulfur. According to the invention, monoester potassium salts of the general formula I are first of all chloromethylated with a 20-30-fold molar excess of bromochloromethane in the presence of 0.5 to 2 mol% of a phase transfer catalyst such as triethylbenzylammonium bromide at temperatures between 30C and 60C, and the resulting chloromethyl cyanimidodithiocarbonate the general formula II then reacted with alkali metal thiolates or phenolates. Formulas (I), (II) and (III)

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a process for the preparation of certain unsymmetrically substituted esters of Cyanimidodithiokohlensäure u. a. as intermediates of interest.

Characteristic of the known technical solutions

Unsymmetrically substituted esters of cyanimidodithiocarbonic acid have long been known (J. Org. Chemistry 32,1566

Aryl or Hetarylthiomethyl- and aryl or Hetaryloxymethylcyanimidodithiocarbonate have not been previously described in the literature. However, they are in principle accessible by alkylation of the monoester potassium salts of cyanimidodithiocarbonic acid with aryl and hetaryl chloromethyl ethers or thioethers.

As is known, aryl chloromethyl ethers are not very stable, are very susceptible to hydrolysis and can be prepared only with great preparative effort (J. Appl. Chem. 3,266 [1953]).

The processes for the preparation of aryl-chloromethylthioethers, for example from the corresponding thiols and formaldehyde / hydrochloric acid (J.Amer.Chem. Soc. 67,655 [1945]) or with bromochloromethane (J. Org. Chemistry 42,3094 [1977]) are not generally applicable, so that certain, especially hetaryl chloromethylthioethers can not be prepared in this way and are hitherto unknown from the literature.

Object of the invention

The aim of the invention is to develop a simple process for the preparation of certain unsymmetrically substituted esters of cyanimidodithiocarbonic acid.

Explanation of the essence of the invention

This problem, Cyanimidodithiokohlensäureester of the general formula III, in the

R ₁ = alkyl, alkenyl or aralkyl,

R ₂ = aryl or hetaryl, which may optionally be substituted and X = oxygen or sulfur

to produce, according to the invention is achieved by reacting monoester potassium salts of general formula I with a 20-30fachen molar excess of bromochloromethane in the presence of 0.5 to 2 mol% of a phase transfer catalyst such as triethyl-benzyl-ammonium bromide at temperatures between 30 First chloromethylated ° C and 60 ° C and the resulting chloromethyl cyanimidodithiocarbonate of the general formula II then reacted with alkali metal thiolates or phenolates.

The monoester potassium salts of the cyanimidodithiocarbonic acid esters (formula I) which are used as starting materials can be obtained by known methods (J. Org. Chemistry 32, 1566 [1967]).

embodiment

The examples are intended to explain the process of the invention in more detail.

Example 1:

Preparation of chloromethyl cyanimidodithiocarbonates (Formula II)

a) Chloromethyl methyl cyanimidodithiocarbonate: 68 g (0.4 mol) of potassium methyl cyanimidodithiocarbonat are suspended in 800 ml bromochloromethane and stirred for 15 hours at 35-45 ° C after addition of 1,5gTriethylbenzyl ammonium bromide. Then separated from the precipitated potassium bromide, the solution is washed with water and distilled off the excess bromochloromethane. The residue obtained is recrystallized from ethanol.

Yield: 40-52 g (55-72%) Melting point: 58-6O ⁰ C In an analogous manner can be obtained from 0.1 mol of the corresponding monoester potassium salts of cyanimidodithiocarbonic acid:

b) Chloromethyl ethyl cyanimidodithiocarbonate Yield: 11.2 g (58%)

c) Chloromethyl-n-propyl cyanimidodithiocarbonate Yield: 13.6 g (65%)

d) Chloromethyl-isopropyl-cyanimidodithiocarbonate Yield: 16.7 g (80%)

e) Allyl chloromethyl cyanimidodithiocarbonate Yield: 18.5 g (90%)

f) Benzyl chloromethyl cyanimidodithiocarbonate Yield: 18.7 g (73%) Melting point: 96-99 ° C

Example 2:

Aryl or hetarylthiomethyl cyanimidodithiocarbonates (formula III, X = S)

a) (Benzothiazole) -yl-thiomethyl-methyl-cyanimidodithiocarbonate: 8.4 g (0.05 mol) of 2-mercaptobenzothiazole, 9 g (0.05 mol) of the chloromethyl-methyl-cyanimidodithiocarbonate obtained according to Example 1a, 3.5 g of anhydrous Potassium carbonate and 50 ml of acetone are stirred under reflux for four hours After filtration and removal of the acetone, the remaining residue is triturated with ethanol, filtered off with suction and recrystallized.

Yield: 10.2 g (65.5%) Melting point: 96-99 ° In an analogous manner, for example, 0.05 mol of the chloromethylmethylcyanimidodithiocarbonate obtained according to Example 1a and 0.05 mol of the corresponding thiol can be prepared:

b) (S-Allylthio-1H-thiadiazol-S-yl-thiomethyl-methyl-cyanimidodithiocarbonate Yield: 7.5 g (45%) Melting point: 86-88 ° C

c) (4,6-Dimethyl-pyrimidin-2-yl-thiomethyl) -methyl-cyanimidodithiocarbonate Yield: 9.4 g (66%)

Melting point: 116-118 ° C

d) (Benzimidazol-2-yl-thiomethyl) -methyl-cyanimidodithiocarbonate Yield: 3.5 g (24%) Melting point: 194-196 ° C (dec.)

e) Methyl (4-nitrophenylthiomethyl) cyanimidodithiocarbonate Yield: 15g (50%)

Melting point: 110-113 ⁰ C

f) (benzothiazole) -yl-thiomethyl-benzyl cyanirnidodithiocarbonate

From 8.4 g (0.05 mol) of 2-mercaptobenzothiazole and 12.8 g (0.05 mol) of the benzyl chloromethylcyanimidodithiocarbonate obtained according to Example 1f. Yield: 7.7 g (40%)

Example 3:

Aryloxymethyl cyanimidodithiocarbonates (Formula III, X = O)

a) Methyl (4-nitro-phenoxy-methyl) cyanimidodithiocarbonate: 8 g (0.05 mol) of sodium 4-nitro-phenolate, 9 g (0.05 mol) of chloromethyl-methyl-cyanimidodithiocarbonate and 1 g of potassium iodide are dissolved in 75 ml of dry acetone heated under reflux for six hours. After separating the precipitated sodium chloride, the solution is distilled and the remaining residue is recrystallized.

Yield: 7.4 g (52.5%) Melting point: 118.5 to 120.5 ⁰ C In an analogous manner can mol obtain the corresponding sodium or potassium phenate of 0.05 mol chloromethyl-methyl-cyanimidodithiocarbonat and 0.05 become:

b) (4-Chloro-3-methyl-phenoxy-methyl) -methyl-cyanimidodithiocarbonate Yield: 8.1 g (56.5%) Melting point: 111-113 ° C

c) Methyl fS-nitro-phenoxy-methyll-cyanimidodithiocarbonate Yield: 8.4 g (59.5%) Melting point: 103-104 ° C

Portnelblatt

Ott

KS

R-S

C = Ij - C = S

ClCH ₂ S

CH ₂ BrCl

C = IT - C = II (D (H)

R ₂ XH

C = IT - C ξ Ν

R ₁ S

(III)

Claims (1)

Process for the preparation of cyanimidodithiocarbonic acid esters of general formula III in which R ₁ = alkyl, alkenyl or aralkyl, R ₂ = aryl or hetaryl, which may optionally be substituted and X = oxygen or sulfur mean, characterized in that monoester potassium salts of the general formula I with a 20-30fachen molar excess of bromochloromethane in the presence of 0.5 to 2 mol% of a phase transfer catalyst such as triethyl-benzyl-ammonium bromide at temperatures between 30 ° C and 60 ⁰ Initially chloromethylated and then reacting the resulting chloromethyl cyanimidodithiocarbonate of the general formula II with alkali metal thiolates or phenolates.