| 摘要 |
A process for preparing 2,3,5-trimethyl-4-methoxy-N-oxide of formula (I) comprises (a) reacting 2,3,5-trimethylpyridine-N-oxide of formula (II) with a chlorinating agent such as POCl3 to obtain 2,3,5- trimethyl-4-chloropyridine of formula (III), (b) oxidizing (III) by use of H2O2 or MCPBA to obtain 2,3,5trimethyl-4- chloropyridine-N-oxide (IV), and (C) reacting (IV) with NaOH or KOH in methanol. (I) is useful as an intermediate in the synthesis of benzimidazole derivs. esp. omeprazole having an antiulcer activity.
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