Process for the preparation of substituted quinazoline-2,4-diones
US5710319A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 16, 1995 |
| Grant date | Jan 20, 1998 |
| Priority date | — |
| Expiry date | Nov 16, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D239/96
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the preparation of quinazoline-2,4-diones of the formula (I) ##STR1## in which R.sup.1 is (C.sub.1 -C.sub.12)alkyl, (C.sub.3 -C.sub.8)cycloalkyl or (C.sub.7 -C.sub.10)aralkyl, it being possible for the aryl group to be substituted by one or more halogen atoms, and R.sup.2, R.sup.3, R.sup.4 and R.sup.5, independently of one another, are halogen, alkyl, alkoxy or hydrogen, which comprises reacting anthranilic acid esters of the formula (II) ##STR2## in which R is (C.sub.1 -C.sub.10)alkyl and R.sup.2 to R.sup.5 are as defined above, with isocyanates R.sup.1 -.dbd.C.dbd.O in an aprotic reaction medium to give carbamoylanthranilic acid esters of the formula (III) ##STR3## in which R, R.sup.1 to R.sup.5 are as defined above, and cyclizing these products in the presence of alkali metal alcoholates, alkali metal amides, alkali metal hydrides, alkaline earth metal alcoholates, alkaline earth metal amides, alkaline earth metal hydrides or tetraalkylammonium hydroxides.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.