Process for preparing substituted pyridines
AssigneeBayer Aktiengesellschaft
InventorsNorbert Lui, Hans Panskus, Albert Schnatterer
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Abstract
The invention relates to a process for preparing substituted pyridines in a simple and cost-effective manner in good yields by reacting substituted 1,4-dihydropyridines with methyl nitrite in the presence of an acid that contains less than 20% by weight of oxidizing components.
Claims10
A process for preparing a substituted pyridine of formula (i)
- 3
- wherein
- R1 and R5 are identical or different and each represents C1-C10-alkyl or C6-C10-aryl,
- R2 and R4 are identical or different and each represents hydrogen, C1C10-alkyl, CN, or COOR6 wherein R6 is C1-C10-alkyl, and
- R3 represents hydrogen, C1-C10-alkyl or represents C6-C10-aryl that is optionally substituted by halogen, nitro, COOR6 (wherein R6 is C1-C10-alkyl), CN, or C1-C10-alkyl,
- comprising reacting a substituted 1,4-dihydropyridine of formula (II)
- 4
- wherein R1 to R5 are as defined for formula (I), with methyl nitrite in the presence of an acid containing less than 20% by weight of oxidizing components.
A process according to claim I wherein the substituted 1,4-dihydropyridine starting material is 4-(4-fluorophenyl)-2,6-diisopropyl-3,5-di(methoxycarbonyl)-1,4-dihydropyridine and the substituted pyridine product is 4-(4-fluorophenyl)-2,6-diisopropyl-3,5-di(methoxycarbonyl)-pyridine.
Dependencies are inferred from the claim text.