DD267043A1 - PROCESS FOR PREPARING PYRAZOL CARBON ACID AMIDES - Google Patents

Abstract

The invention relates to a process for the preparation of Pyrazolcarbonsaeureamiden. The aim of the invention is to develop a process for the preparation of N-furfuryl-5-alkylthio or aralkylthio-3-amino-1-aroyl-4-carbonsaeureamiden. These pyrazolecarboxylic acid amides can be used as organic intermediates for further syntheses. They are particularly suitable for the preparation of potentially biologically active compounds. According to the invention, the pyrazolecarboxylic acid amides of general formula III in which R is an alkyl or aralkyl radical and R 1 is an optionally substituted phenyl or heterocyclic radical can be prepared by reacting the substituted N-furfuryl-acrylamides of general formula I in which R is as above is defined with Carbonsaeurehydraziden of the general formula II, in which R1 has the above meaning, are prepared.

Description

Field of application of the invention

The invention relates to a process for the preparation of N-furfuryl-5-alkylthio or aralkylthio-3-amino-1-aroyl-4-carboxylic acid amides. These pyrazolecarboxamides can be used as organic intermediates for further syntheses. They are particularly suitable for the preparation of potentially biologically active compounds.

Characteristic of the known state of the art

N-Furfuryl-5-alkylthio or aralkylthio-3-amino-1-aroyl-4-carboxylic acid amides 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 * Vvkstoffo.

Explanation of the essence of the invention

The object of the invention is to develop an ancestor ^for the preparation of N-furfuryl-5-alkylthio or aralkylthio-3-amir> i: -1-aroyl-4-carboxylic acid amides,

According to the invention, the pyrazolecarboxamides of the general formula III in which R is an alkyl or aralkyl radical and R ^{1 is} an unsubstituted or substituted phenyl or heterocyclic radical can be prepared by reacting the substituted N-furfuryl-acrylamido of the general formula I where R is as defined is defined above, with Carbonsäurohydraziden of the general formula II, in which R ^{1 has} the above meaning, are prepared.

The reactions are carried out in organic solvents, preferably in alcohols, at a molar ratio of the substituted N-furfuryl acrylate / amide I and carboxylic acid hydrazide II of 1: 1. The reaction temperatures are at the boiling temperatures of the solvents used. Depending on these boiling temperatures, the reaction times are 2 to 10 hours. After cooling the reaction mixtures to B ⁰ C and filtering off the Pyrazolcarbonsäureamide III are obtained in crystalline form. Concentration of the filtrates allows further product to be isolated in crystalline form. The crude products are further purified by recrystallization from organic solvents.

Ausführungsbeisplole

Embodiment 1

N-Furfuryl-S-amino-i-benzoyl-B-methylthio-pyrazole -carboxylic acid amide A mixture of 0.01 mol of N-furfuryl-2-cyano-3,3-bis (methylthio) acrylamide, 0.01 mol of bonhydrazide and 15 ml of ethanol is refluxed for 5 hours. The reaction mixture is then allowed to crystallize at 5 ° C, the precipitate is filtered off, washed with ethanol and obtained by concentration of the filtrate in vacuo more product. The crude products are recrystallized from ethanol, Ausb.:50%d.Th. M .: 100-101 ⁰ C

C ₁₇ H ₁₆ N ₄ O ₃ S (356.4) Ber. C57.31 H4.49 N 15.73 S8.98

Gef. C57.04 H5.52 N 15.63 S9.40

IR (KBr): NH ₂ 3460.3390, NH 3320, CO 1675, 1620crrr '; ¹ H-NMR (CDCl ₃ ): CH ₃ S 2.45 (s, 3H), CH ₂ 4.60 (d, 2H), furan protons: H-3.4C 6.30 (m, 2H), H-5C 7.40 (m, 1H), aromatic protons:

7.55,8,15 (m, 5H), NH ₂ 7,60 (broad signal), 6,70 (broad signal) ppm.

Exemplary embodiment Z

N-Furfuryl-3-amino-1- (fur-2-oyl) -5-methylthio-pyrazole-4-carboxylic acid amide 0.01 mole N-furfuryl-2-cyano-3,3-bis-methylthio) -acrylamide and 0, 01 mol of furancarboxylic acid hydrazide are reacted as described in Example 1

Ausb.:95%d. Th. Mp .: 157-159 ⁰ C

C ₁₆ H ₁₄ N ₄ O ₄ S (346.4) Bcr. C52.62 H4.04 N 16.16 S9.24

Gef. C 61.99 H 4.01 N 16.03 S 9.12

[ί I) -CH ₂ NHGOG (GN) = G (SR) ₂ 0

II

U ILoH ₀ NHGO-O = O-SR

H _o N-0 _v N-GOR

III

Claims (1)

A process for the preparation of pyrazolecarboxamides of the general formula III in which R is an alkyl or aralkyl radical and R ^{1 is} an optionally substituted phenyl or heterocyclic radical, characterized in that substituted N-furfuryl-acry'amides of the general formula I in which R is as above dined, with carboxamides of the general formula II, in which R ^{1 has} the above meaning, are reacted. To this 1 page Formoln