DD294938A5 - PROCESS FOR PREPARING PYRAZOL CARBON ACID HYDROCIDES - Google Patents

Abstract

The invention relates to a process for the preparation of pyrazolecarboxylic acid hydrazides. The aim of the invention is to develop a process for the preparation of * and their 1-acylated derivatives. These pyrazolecarboxylic acid derivatives can be used as organic intermediates for further syntheses. They are particularly suitable for the production of potentially biologically active compounds. According to the invention, the pyrazolecarboxylic acid derivatives of the general formula III in which R and R 1 are an alkyl radical and R 2 is a hydrogen atom or an aroyl or hetaroyl radical can be prepared by reacting the acrylic acid hydrazides of the general formula I in which R and R 1 have the above meaning, with hydrazine or hydrazine derivatives of the general formula II in which R 2 is as defined above. Formula {Pyrazolcarbonsaeurehydrazide; aminopyrazole; Alkylthiopyrazole; Hydrazones}

Description

Field of application of the invention

The invention relates to a process for the preparation of N '- [bis (aikylthio) methylene] -5-amino-3-alkylthio-pyrazole-4-carboxylic acid hydrazides and their 1-acylated derivatives.

These pyrazolecarboxylic acid derivatives can be used as organic intermediates for further syntheses. They are particularly suitable for the production of potentially biologically active compounds.

Characteristic of the known state of the art

N'-lBislalkyl'hiolmethylenl-B-amino-a-alkylthio-pyrazoM-carboxylic acid hydrazides and their 1-acylated derivatives are not yet known.

Object of the invention The aim of the invention is the development of a process for the preparation of new pharmaceutical active ingredients. Explanation of the essence of the invention The object of the invention is based on cyanacetic hydrazide, carbon disulfide and hydrazine or Carboxylic acid hydrazides a synthesis of N'-lBislalkylthiolmethylenl-B-amino-S-alkylthio-pyrazoM-carboxylic hydrazides

and their 1-acyHorten derivatives to allow.

According to the invention, the pyrazolecarboxylic acid derivatives of general formula III in which R and R ^{1 are} eioen alkyl radical and R ²

represent a hydrogen atom or an aroyl or Hetaroylrest, by reaction of the acrylic acid hydrazides of the general

Formula I, in which R and R ^{1 have} the above meaning, with hydrazine or hydrazine derivatives of the general formula II, in which R ²

as defined above.

The reactions are carried out in organic solvents, preferably in alcohols. The Reaction temperatures are at the boiling points of the solvents used. In dependence of these Reaction temperatures are the reaction times 30 minutes to 4 hours. When the reaction mixtures are cooled to S ⁰ C, the reaction products crystallize out. They can be filtered off after

and washed with ethanol for further purification from ethanol.

embodiments Exemplary embodiment 1 N'-tBisfmethylthlolmethylenl-B-amino-S-methylthio-pyrazole ^ -carbonsaurehydra / id A mixture of 0.01 mole of N, N-methylmethylthiolmethylene-1-cyano-bis-methylthiolacrylic acid hydrazide, 0.01 mol Hydrazine hydrate and 10 ml of ethanol are refluxed for two hours. The reaction mixture is allowed to cool to 5 ° C,

The precipitate formed is filtered off, washed with ethanol and recrystallized from ethanol.

Aueb.:35%d.Th. M .: 135-137 ⁰ C Implementation Bills 2 N'-IBisCmethylthiolmethylenl-S-amino-i ^ tfur -oyD-S-methylthio-pyrazoM-carboxylic acid

0.01 mol of N'-IBistmethylthioJmethyleni ^ cyano-S.S-bistmethylthiolacrylsäurehydrazid and 0.01 mol of furan-2-carboxylic acid hydrazide are reacted as described in Example 1. The reaction time is 90 minutes.

Yield: 57% of the tenth M .: 158-16O ⁰ C

-J-

(RS) ₂ C = NNH-C (= O) C (CN) = C (SR ¹ ) ₂

R ² NHNH ₂ T

(RS) ₂ C = NNH-C (= O) -

H ₂ N-

C-SR ¹

R ²

• 51.'Ji ¹ -O 6 / "/ - / υ 6"

Claims (1)

A process for the preparation of pyrazolecarboxylic acid hydrazides of the general formula III in which R and R ^{1 are} an alkyl radical and R ^{2 is} a hydrogen atom or an aroyl or hetaroyl radical, characterized in that acrylic acid derivatives of the general formula I where R and R ^{1 are} have the above meaning, with hydrazine or hydrazine derivatives of the general formula II, in which R ^{2 is} as defined above, are reacted. For this 1 page formulas