Patent ID: 6054583
Filing Date: 2000-04-25
Classification: C07D

Abstract:
A process for preparing a 2-substituted pyridine of formula (I) ##STR4## comprising the steps of (i) reacting a 2-substituted pyridine of formula (II) during a period of from 5 minutes to 12 hours ##STR5## with sec-butyllithium to form a 2-lithiopyridine intermediate of formula (III) ##STR6## (ii) reacting during a period of from 1 minute to 12 hours a 2-lithiopyridine intermediate of formula (III) with an electrophile, selected from the group consisting of an alkyl iodide, a bromoalkyl alkyl ether, an iodoalkyl tlkyl ether, an aldehyde, a ketone, a N,N-dialkylamide, an alkyl sulfate, a boron ester, an alkyl disulfide, an aryl disulfide, a nitrile, an alkyl chloroformate, carbon dioxide, a trialkylsilyl chloride, a trialkyltin chloride, sulfur dioxide, sulfonyl chloride and a source of positive halogen, to form a 2-substituted pyridine of formula (I) whereinX is bromo or iodo,each Y is a group that is not reactive with the lithium compound under the reaction conditions of an anhydrous, aprotic solvent in an oxygen-free atmosphere at a temperature of from -100.degree. C. to 25.degree. C., and is indetendently selected from the group consisting of a hydrogen atom, fluoro, chloro, alkyl, fluoroalkyl, trichloromethyl, alkoxy, fluoroalkoxy, alkylthio, fluoroalkylthio, N,N-dialkylcarboxamide, phenyl, and phenyl substituted with one or more groups independently selected from fluoro, chloro, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, alkylthio, fluoroalkylthio, and N,N-dialkylcarboxamide, andZ is the residue of the electrophile and is selected from the group consisting of alkyl, alkoxyalkyl, alkylthio, phenylthio, formyl, acetyl, benzoyl, carboxyl or carboxylate, chlorosulfonyl, sulfo or sulfonate, alkoxycarbonyl, trialkylsilyl, trialkyltin, and halo.