Preparation of substituted pyridine N-oxide compounds

US6806371B2 · kind B2 · utility

Assignee

• DSM Fine Chemicals Austria NFG GmbH & Co KG · AT

Inventors

• Thomas Zich · Linz, AT
• Wolfgang Schiek · Passau, DE
• Markus Rossler · Linz, AT
• Christian Seifter · Linz, AT

Key dates

• Filing date: Oct 1, 2003
• Grant date: Oct 19, 2004
• Expiry date: Oct 1, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D213/89
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing substituted pyridine N-oxide compounds of the formula in which R1, R2, R3 and R4 are each H, a carboxyl group or a C1-C12-alkyl radical which may contain atoms from the group of N, O and S, or R1 and R2 and/or R3 and R4 together may each form an optionally substituted C4-C20-alkylene radical which may contain atoms from the group of N, O and S,A is benzyl or a (CH2)m group wherem may be an integer from 1 to 12,Z1 and Z2 are each independently O or S, and Y is H, a C1-C12-alkyl radical which may optionally contain atoms from the group of N, O and S, a C6-C20-aryl radical or a C5-C20-heterocycle, and the radicals may optionally be substituted,or Z2 and Y together form an optionally substituted ring or ring system, in which case the ring or ring system may contain atoms from the group of N, O and S, from the corresponding 4-halopyridine N-oxide of the formula in which X is chlorine, bromine or iodine, by reacting the compound of the formula (II), in the presence of a phase transfer catalyst and of a base, with a compound of the formulaHZ1-A-Z2-Y  (III)in which Z1, Z2, A and Y are each as defined above, at a temperature up to the reflux temperature, …