| 摘要 |
PROBLEM TO BE SOLVED: To easily obtain a hydroxy-2-halogenopyridine derivative in high yield on an industrial scale at a low cost by reacting a halogenosulfonylpyridine derivative with a carboxylic acid salt and subjecting the reaction product to acylation, reaction with a halogenation agent and solvolysis. SOLUTION: The objective derivative of formula V (when Zn is OR2, B1 to B4 are each hydroxyl group and when Zn is H or an alkyl, B1 to B4 are each same as Zn is produced by reacting a halogeno-2-sulfonylpyridine derivative of formula I (R1 is an alkyl or the like; at least one of X1 to X4 is a halogen and the others are each H or an alkyl) with a carboxylic acid salt to obtain a derivative of formula II [when Xn ((n) is 1-4) is a halogen, Y1 to Y4 are each hydroxyl group and when Xn is H or an alkyl, Y1 to Y4 are each same as Xn], acylating the product to obtain a derivative of formula III [when Yn is hydroxy, Z1 to Z4 are each OR2 (R2 is an acyl) and when Yn is H or an alkyl, Z1 to Z4 are each same as Yn], reacting the product with a halogenation agent and finally solvolyzing the obtained derivative of formula IV (A is a halogen).
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