Process for the production of pyrazoles
US8124787B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 13, 2008 |
| Grant date | Feb 28, 2012 |
| Priority date | — |
| Expiry date | Oct 22, 2028 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D231/14
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the production of a compound of formula (I), which comprises a) reacting a compound of formula (II), wherein R1 and R2 are both independently C1-C6 alkyl, with methylhydrazine in the presence of water and a water-immiscible organic solvent being inert in saponification reactions, to form a compound of formula (III) wherein R1 is as defined for formula (II) and b) saponifying that compound in situ leading to the formation of the compound of formula (I) by b1) adding a base to form the anion of the compound of formula (I) and then adding an; acid to form the compound of formula (I); or b2) adding an acid to form the compound of formula (I).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.