Process for preparing pyridine-2,3-dicarboxylic acid compounds
AssigneeSugai Chemical Ind. Co., Ltd.
InventorsTakaharu Yamashita, Mitsuhiro Kodama
Life of this patent
Estimating the term…
Abstract
A process for preparing pyridine-2,3-dicarboxylic acid compounds of the following formula, which comprises preparing .alpha.-halo-oxalacetic acid diesters by reacting oxalacetic acid diester alkali metallic salts with an acid and a halogenating agent or by reacting oxalic acid diesters with halo-acetic acid esters, and then reacting the obtained .alpha.-halo-oxalacetic acid diesters with 2-propenal compounds and ammonia. ##STR1## wherein R.sup.1 and R.sup.2 are, identical or different, a lower alkyl group, and R.sup.3 is a hydrogen atom or a lower alkyl group. The pyridine-2,3-dicarboxylic acid componds obtained by the process of the ivention are useful as an intermediate for manufacturing agricultural chemicals and pharmaceuticals.
Claims8
A process for preparing pyridine-2,3-dicarboxylic acid compounds of the formula (1);
- ##STR12## wherein R.sup.1 and R.sup.2 are, identical or different, each a lower alkyl group, and R.sup.3 is a hydrogen atom or a lower alkyl group, which comprises,
- reacting a compound of the formula (2):
- ##STR13## wherein R.sup.1 and R.sup.2 are the same as defined above and M is an alkali metal, with an acid and a halogenating agent to give a compound of the formula (3):
- ##STR14## wherein R.sup.1 and R.sup.2 are the same as defined above and X is a halogen atom, and then, reacting the compound of formula (3) with a compound of the formula (4):
- ##STR15## wherein R.sup.3 is the same as defined above, and ammonia.
Dependencies are inferred from the claim text.