Process for the preparation of pyridine-2-3-dicarboxylic acid derivatives, and novel 1-amino-1,4-dihydropyridine-2-3-diarboxylic acid derivatives
US4748244A · kind A · utility
6Cited by
2References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 3, 1985 |
| Grant date | May 31, 1988 |
| Priority date | — |
| Expiry date | May 3, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D491/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the preparation of pyridine-2,3-dicarboxylic acid derivatives of formula ##STR1## which process comprises reacting a hydrazone of formula II ##STR2## with a maleic acid derivative of formula III ##STR3## to give a 1-amino-1,4-dihydropyridine-2,3-dicarboxylic acid derivative of formula IV ##STR4## and subsequently removing R.sub.9 R.sub.10 NH. In the above formulae, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.9, R.sub.10 and X are as defined in claim 1. The pyridine-2,3-dicarboxylic acid derivatives of formula I are intermediates for the preparation of herbicidal compounds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.