Process for preparation of 4-aryl-1,2,4-triazol-3-ones
US5728834A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1996 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Nov 14, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D249/12
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for preparing 4-aryl-1,2,4-triazol-3-ones and 4-aryl-5-alkoxy-1,2,4-triazol-3-ones. A reaction mixture includes a primary aromatic amine, an alkyl carbazate and a trialkyl orthoformate. The reactants are heated in a reaction vessel in the presence of an acid catalyst and a polar solvent. After the reaction is complete, the solvent is removed, water is added, and the slurry is filtered to isolate 4-aryl-5-alkoxy-1,2,4-triazol-3-one. Alternatively, after the reaction is complete, an alkali metal alkoxide is added to the reaction mixture in the vessel, and the new mixture is again heated until the reaction is complete. The solvent is distilled from the mixture, and the remaining mixture is diluted with water. The slurry is separated from mixture, washed and dried to obtain 4-aryl-1,2,4-triazol-3-one in near 100% yield.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.