DD267044A1 - PROCESS FOR PREPARING PYRAZOL DERIVATIVES - Google Patents

Abstract

The invention relates to a process for the preparation of pyrazole derivatives. The aim of the invention is to develop a process for the preparation of 3,3-thio-bis (N-furfuryl-5-amino-1-aryl-pyrazole-4-carboxylic acid amides). These pyrazole derivatives 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 pyrazole derivatives of the general formula III where R is an optionally nitro-, alkyl- or halogen-substituted phenyl radical can be prepared by reacting the N, N-difurfuryl-1,3-dithietane-2,4-diylidene-bis ( cyanoacetamides) I with hydrazine derivatives of the general formula II in which R has the above meaning.

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a process for the preparation of S ^ '- thio-bis-N-Furfuryl-S-amino-i-aryl-pyrazoM-carboxamides). These pyrazole derivatives can be used as organic intermediates for further syntheses. They are particularly suitable for the preparation of potentially biologically active compounds.

Characteristic of the Prior Art 3,3'-THO-bis (N-furfuryl-5-amlno-1 - & ^! - pyrazole-4-carbonylamides) 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 de.x essence of the invention The object of the invention is to provide a process for the preparation of 3,3'-thio-bis (N-furfuiy-5-amino-1-aryl-pyrazole-4-

carboxamides).

According to the invention, the pyrazole derivatives of general formula III in which R is an optionally nitro, alkyl or

halogen-substituted phenyl radical is prepared by reacting the N, N'-difurfuryl-1,3-dithietane-2,4-diylidene-bis (cyanoacetamides) I with hydrazine derivatives of the general formula II in which R has the above meaning. The reactions are carried out in organic solvents, preferably in chloroform. The N, N'-difurfuryl-1,3-dithietane-2,4-diylidene-bis (cyanoacetamide) I and the hydrazine derivatives II are reacted in a molar ratio of 1: 4. The reaction temperatures are at the boiling temperatures of the solvents used. The reaction times range depending on these

Boiling temperatures from 30 minutes to 3 hours. After completion of the reaction, the solvent is distilled off in vacuo and the residues from organic Recrystallized solvents. AusfOhrungsbelsplele Execution badge 1

3,3'-thio-BI8 (N-fi.-furyl-5-amino-1-phenyl-pyrazol-4-carbonsäuroamid)

A mixture of 0.01 mol of N, N'-difurfuryl-1,3-dithietane-2,4-diylldenebis (cyanoacetamide), 0.04 mol of phenylhydrazine and 20 ml of chloroform is refluxed for one hour. The solvent is distilled off in vacuo and i recrystallized the residue from organic solvents

Au8b.:70%d.Th. M.p .: 239-240 ^e C

CnH ₂ (N ₈ O ₄ S (SH?) Calc. C 60.60 H 4.37 N 18.86 S 5.38

C 60.03 H 4.36 N 18.29 S 5.10

IR (KBr): NH 3430.3300m, C0164Oc (TT ¹ ;

¹ H-NMR (DMSO-d _e ): CH ₂ 4.50 (d, 4H), furan protons: H-3.4 C 6.35 (m, 4 H). H-5C 7.25 (m, 2H), aromatic protons: 7.35 (m, 10H),

NH ₂ 9.65 (broad signal), NH 8.50 (t, 1 H) ppm. Car Guide Beltplet 2 S ^ '- thio bisfN-furfurvl-S-amino-Hp mtro-phenyDpyrazol ^ -carbonsaureamid]

0.01 moles of N, N'-di-furfuryl-S-cithietane, adiylidene-bis-cyanoacetamide, and 0.04 moles of p-nitrophenylhydrazine are reacted as described in Example 1

 Ausb.:70%d.Th. Schmp.:221-223°C

C ₃₀ H ₂₄ N ₁₀ OeS (684.7) Ber. C 52.63 H 3.50 N 20.46 S 4.67

Gef. C 52.59 H 3.37 N 20.09 S 4.38

"C = C (CN) COr ^- IHCH ₂ -U YY

+ 2 RNHNH,

II

O-

H ₂ N-

• σ

G-CONHOH ₀ -D ί]

² ^^

C-NH ₂

III

Claims (2)

1. A process for the preparation of pyrazole derivatives of the general formula III in which R is an optionally nitro, alkyl or halogen-substituted phenyl radical, characterized in that the N.N'-DifurfuryM.S-dithietane ^ adiylidene bis-cyanacotamide) I with hydrazine derivatives of the general formula II, in which R has the above meaning, is reacted. 2. The method according to claim 1, characterized in that the N, N'-difurfuryl-1,3-dithietane-2,4-diylidene-bis (cyar.acetamid) is reacted with an excess of the hydrazine derivative II.