| 摘要 |
PURPOSE:To prepare the titled compound useful as an intermediate of pharmaceuticals, economically, by treating a compound corresponding to the objective compound and having acyl group at the 5-N atom with ammonia, hydrazine or primary or secondary amine, thereby selectively removing said acyl group. CONSTITUTION:The objective compound useful as an intermediate of e.g. diltiazem hydrochloride (a coronary vasodilator) is prepared easily and quantitatively, at normal temperature, by treating the compound of formula I (R is lower alkyl; Ar is phenyl substituted with lower alkoxy) with ammonia, hydrazine or primary or secondary amine thereby selectively removing the acyl group of the 5-N site. The starting compound of formula I is obtained either by carrying out the acylation and cyclization of the compound of formula III with an acid anhydride in one step, or by reacting the compound of formula III with an acid anhydride or an acid halide to acylate the 2'-amino group or further 2-hydroxyl group,and cyclizing the product with an acid anhydride.
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