CS261416B1 - 2-Phenyl-4-acetamino-S-dialkylamino-3-oxo-2H-pyridazines and processes for their preparation - Google Patents

Abstract

The solution concerns 2-phenyl-4-amino-5-dialkylamino-3-oxo-2H-pyridazines of general formula I, in which R1 and R2 are the same or different alkyl with 1 to 4 carbon atoms, or together with nitrogen atoms form a 6-membered heterocyclic ring, or with oxygen as another heteroatom. The mentioned new substances are prepared by reacting 2-phenyl-4-amino-5-dialkylamino-3-oxo-2H-pyridazine hydrochloride of the general formula II, in which R1 and R2 have the previously mentioned meaning, or by reacting 2-phenyl-4-acetylamino-5-dialkylamino-3-oxo-2H-pyridazine of the general formula III, in which R1 and R2 have the already mentioned meaning, with with an alkali metal hydroxide, an alkali carbonate, an alkaline alkoxide with 1 to 3 carbon atoms in the alkyl, triethylamine or pyridine in water or an organic solvent at a temperature of 60 to 100 °C. The compounds serve as intermediates in the production of pesticides.

Description

The present invention relates to 2-phenyl-4-amino-5-dial- ₍ cylamino-3-oxo-2H-pyridazines) and to their preparation, which compounds can be used as intermediates in the preparation of pesticides.

The literature discloses 2-phenyl-4-dialkylamino-5-amino-3-oxo-2H-pyridazines of the general formula IV wherein R < ¹ > R ² 'is a "alkyl". Prepare 2-phenyl-4,5-dichloro-3-oxo-2H-pyridazine with sodium nitrite in dimethylformamide, followed by reaction of the resulting product with an alkylamine and reduction to the final product according to the scheme [Angew.

Chem. 77, 282 (1965)].

We have now found 2-phenyl-4-amino-5-dialkylamino-3-oxo-2H-pyridazines of the formula I or 2-phenyl-4-acetylamino-5-dialkylamino-3-oxo-2H-pyridazine of the formula III

wherein R ¹ and R ² are the same or different C 1 -C 4 alkyl, or together with the nitrogen atom form a 6-membered heterocyclic ring, optionally with oxygen as another heteroatom.

The process for the preparation of compounds of formula I by reaction of 2-phenyl-4-amino-5-dialkylamino-3-oxo-2H-pyridazine hydrochloride II

wherein R ¹ and R ² are as defined above,

R ^ ‘• N

her

(III) wherein R ¹ and R ² are as previously defined, with an alkali metal hydroxide or an alkali carbonate or alkali alkoxide of 1 to 3 carbon atoms in the alkyl or triethylamine or pyridine in a water or organic solvent at a temperature of 60 to 100 C.

The following examples illustrate but do not limit the invention.

Example 1

2-phenyl-4-amino-5-morpholino-3-oxo-2H-pyridazin

A mixture of 3.1 g of 2-phenyl-4-amino-5-morpholino-3-oxo-2H-pyridazine hydrochloride (0.01 mol), 5 cm ^{3 of} triethylamine and 100 cm ^{3 of} ethanol was stirred at reflux for 2 h. Upon completion, ethanol was distilled off from the reaction mixture, the residue was triturated with water, separated by filtration. This gave 2.5 g of a white solid, mp: 214.3 ° C.

Analysis for C 14 H 16 N 4 O 2 (MW: 272.30).

Calcd / found:

61.75 / 61.61% C, 5.92 / 5.87% H,

20.58 / 20.41% N.

IR (CHCl 3), v / cm -1;

652, 3,394, 3,454.

UV (CH 2 OH), λ / nm, (loge):

251 (3.32), 317 (2.91).

Example 2

2-phenyl-4-amino-5-dipropylamino-3-oxo-2H-pyridazin

A mixture of 6.4 2-phenyl-4-acetylamino-5-dipropylamino-3-oxo-2H-pyridazine (0.02 mol), 2.3 g of potassium hydroxide (0.04 mol) and 100 cm ^{3 of} 1-propanol The mixture was stirred at boiling point for 2 hours, distilled off after cooling

1-propanol, the residue triturated with water gave 5.8 g of a white solid with m.p. t. 89.4 ° Celsius.

Analysis for C16H22N4O (m / h: 286.36).

Calcd / found:

67.10 / 67.31% C, 7.74 / 7.82% H,

19.59 / 19.53% N.

Example 3

2-Phenyl-4-amino-5- (N-ethyl-N-butylamino) -3-oxo-2H-pyridazine

A mixture of 9.3 g of 2-phenyl-4-acetylamino-5- (N-ethyl-N-butylamino) -3-oxo-2H-pyridazine, 0.1 g of Na in 100 cm ^{3 of} ethanol was stirred at reflux for 8 hours. The further procedure is identical to Example 1.

6.1 g of a white crystalline substance were obtained from cyclohexane, m.p. t. 92.6 ° C.

Analysis for C16H22N4O.

Calcd / found:

67.10 / 66.86% C, 7.74 / 7.90% N,

19.59 / 20.01% N.

Example 4

2-phenyl-4-amino-5-piperidino-3-oxo-2H-pyridazin

A mixture of 8.6 g of 2-phenyl-4-acetylamino-5-piperidino-3-oxo-2H-pyridazine, 5.6 g of potassium hydroxide and 80 ml of 99.6% ethanol was stirred at reflux for 4 hours. The precipitated crystalline material was collected by filtration. Yield: 7.6 g of white crystalline solid, mp 172.4 ^o C.

Analysis for C 15 H 20 N 4 O (MW: 272.34).

Calcd / found:

66.37 / 66.72% C, 7.40 / 7.29% H,

20.57 / 20.79% N.

IR (CHCl3), m / z ¹ :

652, 3,382, 3,472.

Claims (3)

2 G 1 4 1 6 5. This gave 2.5 g of a white solid, mp: 214.3 ° C. Analysis for C 14 H 16 N 4 O 2 (m / h: 272.30). Calcd / Found: 61.75 / 61.61% C, 5.92 / 5.87% H, 20.58 / 20.41% N. IR (CHCl 3), n / cm -1; 1,652, 3,394, 3,454. UV (CH 3 OH), λ / nm, (loge): 251 (3.32), 317 (2.91). Example 2 2-Phenyl-4-amino-5-dipropylamino-3-oxo-2H-pyridazine Mixture of 6,4 2-phenyl-4-acetylamino-5-dipropyl-amino-3-oxo-2H-pyridazine (0, 2 moles of potassium hydroxide (0.04 moles) and 100 cm 3 of 1-propanol were stirred at the temperature for 2 hours, after cooling, 1-propanol was distilled off, the residue after crushing gave 5.8 g of a white solid with tt. 89.4 ° Celsius. Analysis for C 16 H 22 N 4 O (m. Li .: 286.36). Calculated: 67.10 / 67.31% C, 7.74 / 7.82% H, 19.59 / 19.53% N. Example 3 2-Phenyl-4-amino-5- (N-ethyl -N-Butylamino-3-oxo-2H-pyridazine A mixture of 9.3 g of 2-phenyl-4-acetylamino-5- (N-ethyl-N-butylamino) -3-oxo-2H-pyridazine, 0.1 of Na2O in 100 cm @ 3 of ethanol was stirred for 8 hours. The next procedure was as described in Example 1. 6.1 g of white crystalline solid from cyclohexane was obtained, mp 92.6 DEG C. Analysis for C16 H22 N4 O. Calculated: 67, 10 / 66.86% C, 7.74 / 7.90% N, 19.59 / 20.01% N. Example 4 2-Phenyl-4-amino-5-piperidino-3-oxo-2H-pyridazine A mixture of 8.6 g of 2-phenyl-4-acetylamino-5-piperidino-3-oxo-2H-pyridazine, 5.6 g of potassium hydroxide and 80 ml of ethyl alcohol 99.6% was stirred at reflux for a period of time. The precipitated crystalline material was collected by filtration to give 7.6 g of a white crystalline solid, mp 172.4 DEG C. Analysis for C15 H20 N4 O (mh: 272.34) Calculated: 66.37 / 66.72 % C, 7.40 / 7.29% H, 20.57 / 20.79% N. IR (CHCl3), .delta. : 1 652, 3 382, 3 472. PREDMET 1. 2-phenyl-4-amino-5-dialkylamino-3-oxo-2H-pyridazines of general formula I pf-? O? I) in which R1 and R2 are! the same 1 to 4 carbon or non-boron alkyls, together with the nitrogen atom, form a 6-membered ring, with oxygen as the next one. 2. A process for preparing the compounds of formula (I), wherein the 2-phenyl-4-amino-5-dialkylamino-3-oxo-2H-pyridazine hydrochloride of formula (II) is Rt N —z — x ρλχ wherein R1 and R2 are as defined above, are treated with an alkali metal hydroxide or alkali metal carbonate or alkali metal alkoxide in the alkyl or triethylamine or pyridine at water or organic solvent at a temperature of Θ0 to 100 ° C. 3. A process for the preparation of compounds of the general formula (I), characterized in that 7, p is 2-phenyl-4-acetylamino-5-dinkylamino-3-oxo-2H-pyridazine of the general formula III. wherein R1 and R2 are as defined above, are treated with an alkali metal hydroxide or alkali carbonate or alkali alkoxide having 1 to 3 carbon atoms or triethylamine or a pyridine in a water or organic solvent medium The correct name of the invention is: (54) 2-phenyl-4-amino-5-diakylamino-3-oxo -2H-pyridazines and to prepare them for the inventions and discoveries