Abstract:
A process for manufacturing a 5-formyl-pyridine-2,3-dicarboxylic acid ester (I) wherein Z is hydrogen or halogen; Z 1 is hydrogen, halogen, cyano or nitro and R 1 , R 2 are independently C 1 -C 10 -alkyl, comprising the steps of (i) reacting a compound of formula (II), wherein the symbols are as in formula (I), with a nitrosation agent (III) R 3 -O-N=O (III) wherein R 3 is C 1 -C 8 -alkyl, in the presence of an alkali metal or alkaline earth metal alcoholates or carbonates in a polar aprotic solvent at a temperature of from -45 to 40°C, to obtain an oxime compound (IV) where Z, Z 1 , R 1 and R 2 are as in formula (I), and (ii) reacting oxime compound (IV) with an aliphatic C 1 -C 10 -aldehyde in the presence of a Lewis acid at a temperature in the range of from 0 to 100°C. The compounds of formula (I) are useful intermediates in the synthesis of herbicidal imidazolinones, like imazamox.
Abstract:
2-[(1-cyanopropyl)carbamoyl]-5-chloromethyl nicotinic acids of formula (I) where Z is hydrogen or halogen; Z 1 is hydrogen, halogen, cyano or nitro; R 1 is C 1 -C 4 alkyl; R 2 is C 1 -C 4 alkyl, C 3 -C 6 cycloalkyl or R 1 and R 2 , when taken together with the atom to which they are attached, represent a C 3 -C 6 cycloalkyl group optionally substituted with methyl, and R 3 is hydrogen or a cation preferably selected from the group consisting of alkali metals, alkaline earth metals, manganese, copper, iron, zinc, cobalt, lead, silver, nickel, ammonium and organic ammonium; are useful intermediates for the synthesis of herbicidal imidazolinones.