JPH06782B2 - 6-piperazino-3-oxo-2,3-dihydro-1H-pyrazolo [3,4-d] pyrimidines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a novel 6-piperazino-3-useful herbicide.
Oxo-2,3-dihydro-1H-pyrazolo [3,4-
d] Pyrimidines.

[Conventional technology]

A compound in which a ring containing nitrogen or carbonyl is condensed with a pyrimidine ring, for example, as a compound having a pyridopyrimidine structure, Chemical Abstracts (Chem. Abstr.) 90 Vol 54
893 (1979), Vol. 97, 182350 (198).
Those described in 2) are known. However, there is a great difference in structure from the compound of the present invention, and the usefulness of these known compounds for agricultural use has not been clarified at all.

[Outline of Invention]

The present invention has the general formula [I] [In the formula, R ¹ is hydrogen or an aralkyl group, and R ² is a lower alkyl group. ] 6-piperazino-3 represented by
-Oxo-2,3-dihydro-1H-pyrazolo [3,4-
d] It relates to pyrimidines.

[Substance of the present application]

The substance of the present application is represented by the general formula [I], and examples of the aralkyl group of R ^{1 in} the formula include a benzyl group, a diphenylmethyl group, a triphenylmethyl group, and the like, and particularly a benzyl group. It is preferable.

The alkyl group for R ² includes a methyl group, an ethyl group,
A propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a Sec-butyl group, a tert-butyl group, and the like, among which a methyl group is preferable.

Further, the substance of the present application may be in a free state or in a salt form, for example, an acid addition salt form. Such salts can also be used as herbicides. Examples of the acid addition salt include mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid, and organic acids such as acetic acid, maleic acid and citric acid.

Hereinafter, the substances of the present application will be exemplified.

[Production Method] The substance of the present invention represented by the general formula [I] can be produced according to the following reaction formula. The case where R ¹ is a benzyl group will be described as an example.

The method for producing the compound is specifically shown in the reference example described later.
As a reaction solvent when producing a compound from a compound, alcohols such as methanol, ethanol and pu-propanol, ketones such as acetone and methyl isobutyl ketone, halogenated hydrocarbons such as chloroform and dichloromethane, aromatic compounds such as toluene and benzene. Group hydrocarbons can be used, and alcohols are preferably used. The molar ratio of compound to compound is 1
The reaction is carried out at a temperature of 0 to 70 ° C., preferably 10 to 30 ° C. for 10 minutes to 8 hours, preferably 1 to 5 hours.

The specific operation is as described in the examples below.

Further, the compound in which R ¹ is hydrogen can be obtained by hydrogenolysis of a compound corresponding to the compound. As the hydrocracking catalyst, Pd-C, Raney Ni, Pt-
C, PdO, or the like is used. The reaction solvent is an alcohol such as methanol, ethanol or isopropanol, a carboxylic acid such as formic acid, acetic acid or propionic acid, a mixed solvent such as ethanol-formic acid or ethanol-acetic acid, and hydrogen is supplied at atmospheric pressure to 10 mg / cm ^2. 10 to 100
React at 0.1 ° C. for 0.1 to 10 hours. After the reaction, the target compound can be obtained by a conventional method.

〔Usefulness〕

The substance of the present invention has excellent activity as a herbicide. That is, the substance of the present application can be used as a paddy field and upland herbicide. The weeds to be used as herbicides are particularly effective against paddy field weeds such as Taenia japonicus, Pleurotus cornucopia, Kokonagi, Firefly, Hera modada, etc., and field weeds such as Hie, Mehibushiba, Oinutade, Aoyu, Kogomekaya and Shiraza.

In order to use the substance of the present invention as a herbicide, the substance of the present invention alone or in combination with a carrier, a surfactant, a dispersant, an auxiliary agent or the like is formulated into a wettable powder, an emulsion, a fine granule or a granule, and the like. Dilute to different concentration and spray or apply directly.

Hereinafter, the present invention will be specifically described with reference to Examples and the like.

[Examples, etc.]

Reference Example 1 2- (4-benzylpiperazino) -4-hydroxypyrimidine-5-carboxylic acid ethyl ester To an ethanol solution of 25.2 g of sodium hydroxide, 160 g of 1-amidino-4-benzylpiperazine sulfate (0.60 mo
l) was added, and diethyl ethoxymethylenemalonate 1 was added.
29.4 g (0.60 mol) was added dropwise over 20 minutes. After refluxing for 5.5 hours, the mixture was cooled, and the precipitated crystals were separated by filtration. The crystals thus obtained were washed with water and then dried to obtain 131.4 g of the title compound. (Yield 64%) Melting point 151-153 ° C. ¹ H-NMR spectrum (CDCl ₃ solution, δ ppm) 1.36
(3H, t, J = 7Hz), 2.49 (4H, m), 3.54 (2H, s), 3.93 (4H, m), 4.35
(2H, q, J = 7Hz), 7.31 (5H, s), 8.63 (1H, s) Reference Example 2 2- (4-benzylpiperazino) -4-chloropyrimidine-5-carboxylic acid ethyl ester 2- (4-benzylpiperazino) -4-hydroxypyrimidine-5-carboxylic acid ethyl ester (compound synthesized in Reference Example 1) 130.0 g (0.38 mol) and thionyl chloride 390 m
The mixture was refluxed for 10 hours. Toluene 600m
Was added and then distilled to remove excess thionyl chloride. The mixture was ice-cooled, sodium hydroxide aqueous solution was added to make the mixture alkaline, and the mixture was extracted with chloroform. Chloroform layer is MgS
After drying with O ₄ , chloroform was distilled off under reduced pressure to obtain 120.2 g of the title compound as an oily product.
(Yield 88%) ¹ H-NMR spectrum (CDCl ₃ solution, δppm) 1.36
(3H, t, J = 7Hz), 2.50 (4H, m), 3.56 (2H, br.s), 3.92 (4H, m),
4.32 (2H, q, J = 7Hz), 7.35 (5H, s), 8.79 (1H, s) Example 1 6- (4-benzylpiperazino) -2-methyl-3-oxo-2,3- Dihydro-1H-pyrazolo [3,4-d] pyrimidine 2- (4-) synthesized in Reference Example 2 in a solution of 2.0 g of 2-methylhydrazine in EtOH (20 m) at room temperature (about 20 ° C).
Benzylpiperazino) -4-chloropyrimidine-5-carboxylic acid ethyl ester 5.3 g chloroform (12
m) The solution was added and stirred for 3 hours. Ethyl acetate was added to the solid obtained by distilling off the solvent, and the mixture was well stirred, and 3 g of crystals was collected by filtration. (Yield 63%) Melting point 210-212 ° C. ¹ H-NMR spectrum (CDCl ₃ solution, δppm) 2.55
(4H, m), 3.60 (5H, s), 3.96 (4H, m), 6.98 (1H, brs), 7.36 (5H,
m), 8.72 (1H, s). Example 2 6-piperazino-2-methyl-3-oxo-
2,3-dihydro-1H-pyrazolo [3,4-d] pyrimidine 6-benzylpiperazino-2-methyl-3-oxo-
A solution of 3.0 g of 2,3-dihydro-1H-pyrazole [3,4-d] pyrimidine in EtOH (30 m) was added with a catalytic amount of 1
Add 0% palladium-carbon, and add 3 at 60 ° C under hydrogen atmosphere.
I stirred it for a while. After cooling, the catalyst was filtered off and the filtrate was concentrated to give 1.8 g (yield 88%) of the title compound as yellow crystals.

Melting point 272 to 276 ° C. (decomposition) ¹ H-NMR spectrum (DMSO-d ₆ solution, δ ppm)
3.20 (4H, m), 3.64 (3H, s), 4.24 (2H, m), 8.70 (1H, s), IR spectrum (KBr tablet, cm ⁻¹ ) 3600 to 3300, 1700, 1621, 1565,
1443,

Claims (1)

[Claims] 1. A general formula [I] [In the formula, R ¹ is hydrogen or an aralkyl group, and R ² is a lower alkyl group. ] 6-piperazino-3 represented by
-Oxo-2,3-dihydro-1H-pyrazolo [3,4
-D] pyrimidines.