Process for the preparation of pure N,N'-asymmetrically substituted phenylureas
US5283362A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1992 |
| Grant date | Feb 1, 1994 |
| Priority date | — |
| Expiry date | Jul 31, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D295/215
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Process for the preparation of very pure ureas of the formula phenyl--(NH--CO--NR.sub.1 R.sub.2).sub.n in which phenyl represents an unsubstituted or substituted phenyl or phenylene group and R.sub.1 and R.sub.2 are either identical and each represent an alkyl group, or are different, in which case R.sub.1 represents a hydrogen atom and R.sub.2 represents an alkyl or phenyl group, or R.sub.1 and R.sub.2, together with the nitrogen atom, represent an aliphatic heterocyclic ring and n is the number 1 or 2, by reacting a phenylurea of the formula phenyl--(NH--CO--NH.sub.2).sub.n with an amine of the formula NR.sub.1 R.sub.2 H at temperatures from 100 to 200.degree. C. in a diluent which is inert under the reaction conditions, the reaction being interrupted before by-products are formed, and the urea which is formed being removed from the starting compounds, and the unreacted starting compounds being returned to the process if appropriate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.