Patent · US Expired

Process for the preparation of 1-alkyl-pyrazole-5-carboxylic acid esters

US5977378A · kind A · utility

4Cited by

1References

14Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Nikolaus Muller · Monheim, DE
Lutz Heuer · Blomberg, DE
Johannes Kanellakopoulos · Dormagen, DE
Andreas Sattler · Trostberg, DE
Klaus-Peter Heise · Bensberg, DE

Key dates

Filing date	Jan 8, 1998
Grant date	Nov 2, 1999
Priority date	—
Expiry date	Jan 8, 2018

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07D231/14
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

1-alkyl-pyrazole-5-carboxylic acid esters are prepared by reacting the enolate of a 2,4-diketocarboxylic acid ester with an N-alkylhydrazinium salt in the presence of a solvent. This process allows a particularly economic preparation of 1-alkyl-pyrazole-5-carboxylic acid esters in a simple manner and with only little formation of undesirable isomers.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.