Process for manufacturing 5-formyl-pyridine-2,3-dicarboxylic acid esters

US8629279B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Michael Rack · Eppelheim, DE
• Joachim Gebhardt · Monsheim, DE
• Frederik Menges · Schriesheim, DE
• Michael Keil · Freinsheim, DE
• Rodney F. Klima · Morrow, US
• David A. Cortes · Fairless Hills, US
• Robert Leicht · Hannibal, US
• Helmut Zech · Bad Dürkheim, DE
• Jochen Schröder · Lambsheim, DE

Key dates

• Filing date: Dec 7, 2009
• Grant date: Jan 14, 2014
• Expiry date: Jul 16, 2030

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D213/80
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for manufacturing a 5-formyl-pyridine-2,3-dicarboxylic acid ester (I) wherein Z is hydrogen or halogen; Z1 is hydrogen, halogen, cyano or nitro and R1, R2 are independently C1-C10-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) R3—O—N═O (III) wherein R3 is C1-C8-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, Z1, R1 and R2 are as in formula (I), and (ii) reacting oxime compound (IV) with an aliphatic C1-C10-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.