Process for producing cyclic ureas
US4918186A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1989 |
| Grant date | Apr 17, 1990 |
| Priority date | — |
| Expiry date | Mar 7, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D263/22
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for producing a cyclic urea is provided. The process comprises reacting a diamine expressed by the formula (II) EQU R-HN-R'-NH-R (II) wherein R represents hydrogen atom or a lower alkyl group and R' represent dimethylene group, a lower alkyl group-substituted dimethylene group, trimethylene group, a lower alkyl group-substituted trimethylene group, tetramethylene group, a lower alkyl group-substituted tetramethylene group, but a case where R represents hydrogen atom and R' represent dimethylene group, a case where R represents hydrogen atom and R' represents a lower alkyl group-substituted dimethylene group and a case where R represent methyl group and R' represents dimethylene group are excluded, with phosgene in the presence of a dehydrochlorinating agent. In the process, the diamine is first converted to its hydrochloride, followed by reacting the hydrochloride with phosgene in water solvent while maintaining a pH of the reaction liquid in the range of 5.0 to 8.0 by said dehydrochlorinating agent to obtain a cyclic urea expressed by the formula (I) ##STR1## wherein R and R' are each as defined above.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.