3,4-disubstituted-4,5-dihydro-1H-pyrazoles and a method of preparation
US5324837A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 1992 |
| Grant date | Jun 28, 1994 |
| Priority date | — |
| Expiry date | Aug 17, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D403/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
3,4-Diaryl-4,5-dihydro-1H-pyrazole compounds having a selected 5- or 6-membered aromatic heterocyclic moiety in the 4-position and an optionally substituted phenyl moiety in the 3-position, such as 4,5-dihydro-3-(4-fluorophenyl)-4-(5-trifluoromethyl-2-pyridinyl)-1H-pyrazo le were prepared as intermediates in the preparation of insecticidal 3,4,N-triaryl-4,5-dihydro-1H-pyrazole-1-carboxamide compounds. The 3,4-diaryl-4,5-dihydro-1H-pyrazole compounds can be prepared from appropriate 1,2-diarylethanone compounds by successive treatments with N,N,N',N'-tetramethyldiaminomethane in dichloromethane in the presence of acetic anhydride (to form a Mannich adduct) and hydrazine in the presence of a catalytic amount of trifluoroacetic acid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.