CS252340B1 - 4-chloro-6-methoxy-3-methyl-1H-pyrazolo (3,4-b) quinoline and its Np-methyl derivative - Google Patents

Abstract

The solution relates to 4-chloro-6methoxy-3-methyl-1H-pyrazolo[3,4-b]quinoline and its N-methyl derivative of the general formula I Cl R where R is a hydrogen atom or a methyl group. These new, previously undescribed substances are useful as intermediates for the preparation of substances exhibiting significant biological effects, in particular antiviral and antitumor effects.

Description

The invention relates to 4-chloro-6-methoxy-3-methyl-1H-pyrazolo [3,4-b] quinoline and its N-methyl derivative of the general formula I

Cl

Wherein R is hydrogen or methyl. These novel substances, which have not been described yet, are useful as intermediates for the preparation of substances having significant biological effects, in particular antiviral and antitumor activity.

The invention relates to 4-chloro-6-methoxy-3-methyl-1H-pyrazolo [3,4-b] quinoline and its N'-methyl derivative of the formula I

wherein H is hydrogen or methyl.

These novel substances, which have not been described yet, are useful as intermediates for the preparation of substances having significant biological effects, in particular antiviral and antitumor activity.

The compound of formula I wherein R is hydrogen may be prepared according to the invention by cyclizing 3- (4-methoxyanilino) -5-methyl-1H-pyrazole-4-carboxylic acid with phosphorous oxychloride. According to the invention, a compound of formula I wherein H is methyl may be prepared by methylating a compound of formula I wherein R is hydrogen with dimethyl sulfate in the presence of powdered potassium hydroxide in an aprotic solvent environment, preferably dimethylsulfoxide, at room temperature.

The process for preparing the substances is simple and provides the desired substances in satisfactory yields. Further details can be found in the following examples. These examples are merely illustrative and not limiting.

He did

4-chloro-6-methoxy-3-methyl-1H-pyrazolo [3,4-b] quinoline

A mixture of 3- (4-methoxyenilino) -5-methyl-1 H -pyrazole-4-carboxylic acid (4.5 g, 18 mmol) and phosphorus pentoxide (40 mL) was refluxed for 1 hour. The syrupy residue obtained by distilling the excess phosphorus pentoxide was poured onto ice and basified with 4M sodium hydroxide solution. After cooling, the insoluble matter was aspirated and washed with water. Crystallization from chloroform gave 4.25 g (94%) of yellow crystals of m.p. Mp 232-236 ° C.

Example 2

4-chloro-6-methoxy-1,3-dimethyl-1H-pyrazolo [3,4-b] quinoline

To a suspension of 4-chloro-6-methoxy-3-methyl-1H-pyrazolo [3,4-b] quinoline (9.9 g, 40 nuaol) in dimethylsulfoxide (100 mL) was added powdered potassium hydroxide (2.5 g). 45 mmol) and the mixture was stirred at room temperature for 4 hours. Dimethyl sulfate (5.6 g, 45 mmol) was then added and the mixture was stirred at room temperature for 8 hours. The mixture was poured into water, the precipitate was filtered off with suction and washed with water. The crude product was clarified by vacuum sublimation. 8.0 g (76%) of m.p. Mp 128-133 ° C.

Claims (1)

SUBJECT OF THE INVENTION 4-chloro-6-methoxy-3-methyl-1H-pyrazolo [3,4-b] quinoline and its N-methyl derivative of the formula I CH ₃ O Cl l \ T'N ' -CH, (I) wherein R is hydrogen or methyl,