CS232324B1 - 2-substituted-4-alkoxy-5-mercapto-3-oxo-2H-pyridazines and their preparation - Google Patents

Abstract

The invention relates to 2-substituted-4-alkoxy-5-mercapto-3-oxo-2H-pyridazines of the general formula I HS. R1O N—R2 (1/ O) in which H1 represents alkyl with 1 to 4 carbon atoms, R2 represents alkyl with 1 to 4 carbon atoms, cyclohexyl, benzyl, phenyl optionally substituted with 1 to 2 substituents from the group of chlorine, methyl, trifluoromethyl. The above compounds are prepared by reacting 2-substituted-4-alkoxy-5-chloro-3-oxo-2H-pyridazines of the general formula II Cl rIq' ^N-R2 /11/ O - 1 2 in which R and R have the meanings already given, ■ with sodium or potassium hydrogen sulfide in a medium of alcohol at a temperature of -10 to Compounds of the general formula I can be used as intermediates in the synthesis of pesticidally active substances.

Description

The invention relates to 2-substituted-4-alkoxy-5-amino-3-oxo-2H-pyridazines and to a method for their preparation. The compounds are used as intermediates in the synthesis of pesticidally active substances.

Physically known 2,4-disubstituted-3-oxo-2H-pyridazin-5-ols of the general formula ^xøN— A ¹ in which A ¹ represents alkyl with 1 to 4 carbon atoms, phenyl, aralkyl, cyclohexyl, A ² represents halogen, alkoxy, alkylthio, etc., used as intermediates in the synthesis of carbonic, phosphoric and thiophosphoric acid esters (Os. pat. Nos. 140 062 and 146 172). Also known are 2-substituted-4-alkylthio-3-oxo-2H-pyridazin-5-thiols of the general formula

HS.

X ^Z S

-χ1 in which X represents alkyl with 1 to 6 carbon atoms, cyclohexyl, phenyl, X represents alkyl with 1 to 4 carbon atoms as intermediates for the synthesis of organic substances, mainly phosphoric acid esters /Čs. AO No. 188 517/.

We have now found 2-substituted-4-alkoxy-5-mercapto-3-oxo-2H-pyridazines of the general formula I HS /1/, ,1 in which R ¹ represents alkyl with 1 to 4 carbon atoms, R*' represents alkyl with 1 to 4 carbon atoms, cyclohexyl, benzyl, phenyl optionally substituted with 1 to 2 substituents from the group consisting of chlorine, methyl, trifluoromethyl.

At the same time, a method for preparing compounds of general formula 1 by reacting 2-substituted-4-alkoxy-5-chloro-3-oxo-2H-pyridazines of general formula II has been found.

Cl.

R ¹ O ^NA ¹ /11/,

2

In which R and R have the meanings already given with sodium or potassium hydrogen sulfide in an alcohol environment from the group consisting of methyl alcohol, ethyl alcohol or propyl alcohol at a temperature of -10 to +60 °C.

The following examples illustrate, but do not limit, the subject matter of the invention.

Example

Preparation method of 2-methyl-4-methoxy-5-mercapto-3-oxo-2H-pyridazine

To 0.86 mol of ethanolic potassium hydrosulfide (11.73%) was added 0.43 mol of 2-methyl-4-methoxy-5-chloro-3-oxo-2H-pyridazine in portions at 15 °C with stirring. The reaction mixture was stirred for 6 h at 20 °C and 15 min at reflux. After cooling, the solid was separated by filtration and dried. After mixing with water, the insoluble part was filtered off, the filtrate was acidified to pH 1. The precipitated solid was separated by filtration. Ethyl alcohol was distilled off from the ethanolic filtrate under reduced pressure. The residue was extracted with water, after washing twice with toluene, the aqueous solution was acidified with hydrochloric acid to pH 1. The precipitated solid was combined with the solid already obtained from the aqueous solution. After drying and crystallization from cyclohexane, a white solid with a melting point of 88-90 °C was obtained in 81% yield, which had the following composition:

Analysis for CgHgNjOjS /®« ^h · 172.13/

Calculated: Found: 16.27% N 18.63% S 16.11% N 18.30% S IR spectra in ^CC1 4 ^: */SH/ ^{: 2,573 cm l} /c=o/ ^{: 1,661 oa_ l} /C=N/ ^{: 1,580 ohms}

UV spectra in CH-jOH: λ/nm/, /log £ / 215 /4.07/; 262 /4.22/ 342 /3.97/

The following compounds were prepared using the same procedure:

and

2-phenyl-4-Bethoxy-5-mercapto-3-oxo-2H-pyridazine mp 140-142 °C, yield 87 %

Analysis for C^H^N^OjS /m.h. 234.26/

Calculated: 11.96% N 13.69% S Found: 12.11% N 13.81% S

2-(3'-trifluoromethyl-4- ^chlorophenyl )-4-methoxy-5-mercapto-3-oxo-2H-pyridazine mp 97-100 °C, yield 80.6%

Analysis for CjgHg^ClNgOgS /m.w. 336.70/

Calculated: 8.32% N 9.52% S

Found: 8.50% N 9.68% S

2-phenyl-4-ethoxy-5-mercapto-3-oxo-2H-pyridazine mp 104-106 °C, yield 84.6 %

Analysis for ^C ;2 ^H 12 ^N 2°2 ^S / ^m,h · 248.28/

Calculated: 11.28 %N 12.91 %S Found: 11.42 %N 13.04 %S

2-phenyl-4-isopropoxy-5-mercapto-3-oxo-2H-pyridazine mp 78-80 °C, yield 91.4 %

Analysis for Cj^H^NgOgS /m.h. 262.30/

Calculated: 10.69 % N 12.22 % S Found: 10.81 % N 12.37 % ^S 2-(4'-chlorophenyl)-4-methoxy-5-mercapto-3-oxo-2H-pyridazine

mp 147-149 °C, yield 78.5 %

Analysis for CjjHgClNgC^S /m.h. 268.44/

Calculated: 10.43 % N 11.94 % S 13.21% Cl Found: 10.30 % N 12.19 % S 13.22% Cl

2-[4 ^, -tolyl]~4-methoxy-5-mercapto-3-oxo-2H-pyridazine mp 116-119 °C, yield 87.9%

Analysis for ^C 2 ^H 2 ^N 2°2 ^S bn.h. 248.28/

Calculated: 11.28 %N 12.91 %S Found: 11.29 %N 12.74 %S

2-cyclohexyl-4-methoxy-5-mercapto-3-oxo-2H-pyridazine mp 28-31 °C, yield 73.2 %

Analysis for C^H^gNgOgS /m.h. 240.31/ Calculated: 11.66 «Ν 13.34 % S

Found: 11.73% N 13.38% S

2-methyl-4-propoxy-5-mercapto-3-oxo-2H-pyridazine m.p., 52-54 °C, yield 90.1%

Analysis by CgH^gNgOgS /m.h. 200.24/

Calculated: 13.99% N 16.01% S

Found: 14.11% N 16.22% S

2-benzyl-4-methoxy-5-mercapto-3-oxo-2H-pyridazine mp 77-79 °C, yield 74.2 %

Analysis for CjgHggNgOgS /m.h. 248.28/ Calculated: 11.28 %N 12.91 %S

Found: 11.47%N 13.16%S

Claims (2)

232324 4 Analysis for C ^ HH g gNgOjS / m.h. N, 13.34%. Found: 11.73% N, 13.38%. S 2-Methyl-4-propoxy-5-mercapto-3-oxo-2H-pyridazine. 52-54 ° C, yield 90.1% Analysis for C 9 H 13 N 8 O 2 S / mh N, 16.01%. Found: 14.11% N, 16.22%. S, 2-Benzyl-4-methoxy-5-mercapto-3-oxo-2H-pyridazine, m.p. 77-79 ° C, 74.2% yield Analysis for GI HggNgOgS / m.h. N, 12.91% S Found: 11.47% N 13.16% S BEFORE THE INVENTION METHOD 1. 2-Substituted-4-alkoxy-5-mercapto-3-oxo-2H -pyridazines of formula I HS. wherein R is alkyl of 1 to 4 carbon atoms, R is alkyl of 1 to 4 carbon atoms, cyclohexyl, benzyl, phenyl optionally substituted with 1 to 2 substituents from the chloro group; methyl, trifluoromethyl. 2. A process for preparing compounds according to claim 1, wherein the 2-substituted-4-alkoxy-5-chloro-3-oxo-2H-pyridazine of formula (II) is reacted with Cl, wherein R and R are as defined above, with sodium or potassium hydrogen sulfide in the alcohol group of the group consisting of ethyl alcohol, ethyl alcohol or propanol at -10 to +60 ° C. Severografia, n. P., MOST Price 2,40 Kcs