CS232323B1 - Process for preparing 2-substituted-4-alkylthio-5-chloro-3-oxo-2H-pyridazines - Google Patents

Abstract

The invention relates to the preparation of 2-substituted-4-alkylthio-5-chloro-3-oxo-2H-pyridazines of the general formula I in which r' means alkyl with 1 to 4 carbon atoms, R means alkyl with 1 to 4 carbon atoms, benzyl, cyclohexyl, phenyl, hydrogen or substituted by chlorine, methyl or trifluoromethyl of 2-substituted-4,5-dichloro-3-oxo-2H-pyridazines with sodium or potassium alkyl mercaptide, in which the alkyl contains 1 to 4 carbon atoms, in an aprotic solvent environment at a temperature of 60 to 140°C. The mentioned compounds can be used as intermediates in the production of pesticides.

Description

The invention relates to a method for the preparation of 2-substituted-4-alkylthio-5-chloro-3-oxo-2H-pyridazines. The compounds can be used for the preparation of pesticidally active substances.

2-aryl-4-alkylthio-5-chloro-3-oxo-2H-pyridazines are known from the literature as herbicides. These are prepared by reacting arylhydrazine with alpha-alkylthio-beta-chloro-beta-formylacrylic acid (Czech Republic patent 146 412/ according to the scheme

+ nH ₂

NH-aryl

The disadvantage of this spfisob is the difficult preparation of alpha-alkylthio-beta-chloro-beta-formylacrylic acid, as well as the difficult preparation of substituted aryls, resp. alkylhydrazines.

Now the preparation of 2-/substituted/-4-alkylthio-5-chloro-3-oxo-2H-pyridazines of the general formula I /1/, t 2 s in which R means alkyl with 1 to 4 carbon atoms, R means alkyl with 1 to 4 carbon atoms, benzyl, cyclohexyl, phenyl free or substituted with a methyl group, a trifluoroethyl group or a chlorine spfisobium according to the invention has been found.

The essence of the invention consists in the reaction of sodium or potassium alkyl mercaptide, in which the alkyl contains 1 to 4 carbon atoms, with 2-substituted-4,5-dichloro-3-oxo-2H-pyridazine of general formula 11

Cl.

Cl /11/, in which R has the already mentioned meaning in the environment of an aprotic solvent such as benzene, toluene, xylene, heptane, cyclohexane at a temperature of 60 to 140 °C.

_The following examples shed more light on, but do not limit, the method of production according to the invention.

Example

Preparation of 2-methyl-4-methylthio-5-chloro-3-oxo-2H-pyridazine

To 0.1 mol of 2-methyl-4,5-dichloro-3-oxo-2H-pyridazine in 150 ml of cyclohexane, 0.105 mol of sodium methylmercaptide suspended in 50 ml of cyclohexane was added with stirring. After the addition, the reaction mixture was heated to the reflux temperature, at which it was stirred for 5 h. After cooling, the sodium chloride was separated by filtration, half of the cyclohexane was distilled from the filtrate, and after cooling, the excluded product was separated by filtration. A white crystalline substance was obtained with m.p. 46 to 48 °C in 81.4%-nom yield.

Analysis for CgH^ClNgOS /m.h. 190.6/

Calculated: 14.69% N 18.60% Cl 16.82% S

Found: 14.88% N 18.71% Cl 16.99% S

IR spectra in CC1 ₄ : UV spectra in CH^OH:

i'/C=0/, 1,661 cm ^-1 v/C=O/, 1,554 cm ^{1 λ} »»τ.^ ^ΏΛ ^ ^> ^ ^{log R} /

212 /4.14/ 244 /3.57/ 332 /3.86/

Example 2

Method for preparing 2-methyl-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

To 0.1 mol of 2-methyl-4,5-dichloro-3-oxo-2H-pyridazine in 150 ml of toluene was added with stirring 0.105 mol of sodium ethyl mercaptide suspended in 50 ml of toluene. The next procedure was the same as in Example 1. After crystallization from hexane, a white crystalline substance with m.p. 32-34°C in 84.0 «-nom yield.

Analysis over C^H^ClNgOS /mh 204.6/ calculated: 13.69% N 17.32% Cl 15.67% S found: . 13.61% N 17.61% Cl 15.77% S IR spectra in CC1 ₄ : v/C^O/, 1,659 ca ¹ v/C=N/, 1,553 ca"'

UV spectra in CH^OH: ^max' ^/nm ' ^?1 /^oge/

215 /4.10/ 333 /3.81/

Example 3

Method for preparing 2-methyl-4-propylthio-5-chloro-3-oxo-2H-pyridazine

To 0.1 mol of 2-ethyl-4,5-dichloro-3-oxo-2H-pyridazine in 100 ml of heptane, 0.105 mol of sodium propyl mercaptide suspended in 100 ml of heptane was added with stirring. The next procedure was the same as in Example 1. Distillation under reduced pressure gave a colorless liquid with mp 96 °C / 26.6 Pa, n ²⁰ = 1.5845 in an 80% yield.

Analysis for C ₈ ^h ,,01N ₂ calculated: 12.81% found: 13.00% and spectra in CC1 ₄ :

UV spectra in CH.jOH:

/m.h. 2' 18, ,6/ 16.22 « Cl 14.67 « 16.41 « Cl 14.88 « >’/C=O/, 1 660 cm’ in/C=N/, 1 553 cm’ Λ /nm/, max ¹ , /log e/

214 /4.13/ 333 /3.89/

Example 4

Method for the preparation of 2-methyl-4-isopropylthio-5-chloro-3-oxo-2H-pyridazine

To 0.15 mol of 2-methyl-4,5-dichloro-3-oxo-2H-pyridazine in 150 ml of toluene was added with stirring 0.155 mol of sodium isopropyl mercaptide suspended in 80 ml of toluene. The next procedure was the same as in Example 1. Distillation under reduced pressure gave a yellowish liquid with a mp of 105 to 109 °C/30 Pa, n ²⁰ = 1.5981 in a 78% yield.

Analysis for CgH^ClNgOS /mh 218.6/ calculated: 42.81 « N 16.22 « Cl 14.67 « S found: 12.98 « N 16.44 « Cl 14.70 « S ich spectra in CC1 ₄ : v/0=0/, 1660 cm v/C=N/, 1553 cm'

UV spectra in CH^OH: A _max /nm/, /logr /

213 /4.16/ 330 /3.86/

Example 5

Method for preparing 2-ethyl-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

To 0.1 mol of 2-ethyl-4,5-dichloro-3-oxo-2H-pyridazine in 150 ml of toluene, 0.105 mol of sodium ethyl mercaptide suspended in 80 ml of toluene was added with stirring. the purple procedure is the same as in example 1.

Distillation under reduced pressure gave a pale liquid with a b.v. 86 °C/.3 Ba, n^® 1.573 6, in 74%-nom yield.

Analysis for CgH^ClNjOS calculated: 12.81% N found: 13.11% N IR spectra in CC1 ₄ :

UV spectra in CH-jOH:

/m.h. 218, ,6/ 16.22% Cl 14.67 %S 16.50% Cl 14.60 %S in/C=O/, 1 657 „ -1 cm >’/C=N/, , 552 cm ^- ' /„„/nm/, max ¹ /log ε /

215 /4.16/ 333 /3.84/

Example 6

Method for preparing 2-propyl-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

To 0.15 mol of 2-propyl-4,5-dichloro-3-oxo-2H-pyridazine in 150 ml of toluene was added with stirring 0.155 mol of sodium ethyl mercaptide suspended in 100 ml of toluene. The next procedure was the same as in example 1.

Distillation under reduced pressure gave a yellowish liquid with a b.p. 88 °C/13 Pa, n^® = 1.5726 in 76%-nom yield.

Analysis for CgH^ClNjOS /m.h. 232.6/ calculated:

found:

IR spectra in

UV spectra in

12.04% N 15.24% Cl 13.78% S 11.96% N 15.36% Cl 14.01% S

CC1 ₄ : v/C=O/, 1,657 cm ^- ' v/C=N/, 1,552 cm ^-1

CH ₃ OS: ^A mex/nm/, /log£ /

215 /4.10/ 333 /3.8.1/

Example 7

Method for preparing 2-cyclohexyl-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

To 0.1 mol of 2-cyclohexyl-4,5-dichloro-3-oxo-2H-pyridazine in .50 ml of toluene, 0.105 mol of sodium ethyl mercaptide in 80 ml of toluene was added with stirring. The next procedure was the same as in Example 1. Distillation under reduced pressure gave a colorless liquid with a m.p. 135 °C/ /20 Pa, np° = 1.5864 in 82%-nom yield.

Analysis for C^H-gClN-OS /m.h. 274.8/ calculated: 10.19% N 12.90% Cl 11 found: 10.26% N 13.11% Cl 11 what spectra in CC1 ₄ : in/C=O/, 1,666 cm ^- in/C=N/, 1,554 cm" UV spectra in CH^OH: ^max ⁷ “ ⁷ ' ⁷¹ °β ^ε/

217 /4.13/ 328 /3.73/

Example 8

Preparation of 2-benzyl-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

To 0.1 mol of 2-benzyl-4,5-dichloro-3-oxo-2H-pyridazine in 150 ml of xylene, 0.105 mol of sodium ethyl mercaptide suspended in 80 ml of xylene was added with stirring. The next procedure was the same as in example 1.

Distillation under reduced pressure gave a yellowish liquid with a b.p. 154 °C/40 Pa, np = 1.5916 in 79%-nom yield.

Analysis for C,,H.,C1N ₂ OS /mh calculated: 9.97 %N 12.62 found: 10.06 %N 12.88 what spectra in CC1 ₄ : э/C=O/, in/C=N/, UV spectra in _CH3OH A /nm, max

280.8/ «Cl 11.42%S%Cl 11.60%S

656 cm~

553 cm ^-1 ', /loge / 214 /4.25/

333 /3.84/

Example 9

Preparation of 2-phenyl-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

To 0.2 mol of 2-phenyl-4,5-dichloro-3-oxo-2H-pyridazine in 200 ml of toluene was added with stirring 0.21 mol of sodium ethyl mercaptide suspended in 50 ml of toluene. The further procedure was the same as in example 1. Crystallization from methyl alcohol gave a white crystalline solid with m.p. 53 to 54 °C in 86% yield.

Analysis for C^ ₂ ^íi 1 jClNgOS /mh 266.7/

calculated: 10.50 % N 13.29% Cl 12.02 %S found: 10.66 % N 12.41% Cl 12.22 %S LC spectra in CCl^: in/C=O/, 1 666 cm ^- ' v'/C=N/, 1 554 cm ^- ' UV spectra in CH-jOH: A /nm/, max ’ /log e/

339 /4.08/

Example 10

Preparation of 2-(4-chlorophenyl)-4-ethylthio-5-chloro-3-oxo-2H-pyridazine

The procedure is the same as in example 9.

A white crystalline solid with m.p. was obtained. 115-118 °C in 74%-nom yield.

Analysis for C ₁₂ H ₁₀ C1 ₂ N ₂ OS /mh 300.2/ calculated: 10.68%S 11.82% Cl found: 11.00% S 12j11% Cl

Example 11

Method for the preparation of 2-(4'-tolyl-C-4-ethylthio-5-chloro-3-oxo-2H-pyridazine. The procedure is the same as in Example 9.

A white crystalline substance with m.p. was obtained. 119-121 °C in 69%-nom yield.

Analysis for C^H^ClNgSO Calcd: 12.62% Cl 11.42% S Found: 12.68% 01 11.77%S

Example 12

Method for the preparation of 2-(3-trifluoromethylphenyl)-4-ethylthio-5-chloro-3-oxo-2H-pyridazine.

The procedure is the same as in example 9.

A white crystalline substance was obtained with m.p. 89-91 °C in 84%-nom yield.

Analysis for C^H^F^ClNgOS /m.h. 334.7/ calculated: 9.57% S 19.60% Cl 17.04% F found: 9.80% S 10.81% Cl 17.12% F

Claims (1)

SUBJECT MATTER A process for the preparation of 2-substituted-4-alkylthio-5-chloro-3-oxo-2H-pyridazines of the formula I, benzyl, cyclohexyl, phenyl, free or substituted by chlorine, methyl or trifluoromethyl, characterized in that 2- substituted-4,5-dichloro-3-oxo-2H-pyridazine of formula II Cl C1 alkyl contains 1 to 4 carbon atoms, in an aprotic solvent environment at a temperature of 60 to 140 ° C. / 11 /,