General methods for synthesizing 2,4-diacylpyrroles and their precursors containing one or two masked acyl groups
General methods for synthesizing 2,4-diacylpyrroles and their precursors containing one or two masked acyl groups
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合成2,4-二酰基吡咯及其含有一个或两个掩蔽酰基的前体的一般方法
DOI：
10.1039/p19930000273
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
L. Piscopo
中科院分区：
文献类型：
--
作者：
Silvano Cadamuro;I. Degani;Stefano Dughera;R. Fochi;A. Gatti;L. Piscopo
本文报道了由吡咯、2-酰基吡咯和3-酰基吡咯直接酰化合成2，4-二酰基吡咯的方法。其中，3-酰基吡咯的Friedel-Crafts酰化是最通用和有利的方法，因为它利用容易获得的起始原料。此外，它总是区域特异性的，并且容易在温和条件下以非常高的产率（81-100%）提供含有相同或不同酰基的2，4-二酰基吡咯。另一种方法是合成含有一个或两个被1，3-苯并二硫杂环戊烯基或1，3-苯并氧硫杂环戊烯基掩蔽的酰基的2，4-二酰基吡咯的前体，然后用HgO-35%水溶液水解。HBF4Me2SO。总产量总是很好（52-60%）。当需要在受保护的酰基存在下进行操作时，间接酰化是对直接酰化的安全补充。
A thorough study of the synthesis of 2,4-diacylpyrroles by direct acylation of pyrrole and 2- and 3-acylpyrroles is reported. Among these, Friedel–Crafts acylation of 3-acylpyrroles is the most general and advantageous method because it utilises easily accessible starting materials. In addition it is always regiospecific and readily provides 2,4-diacylpyrroles containing identical or different acyl groups in very high yields (81–100%) under mild conditions. Alternative procedures concern the synthesis of precursors of 2,4-diacylpyrroles containing one or two acyl groups masked by a 1,3-benzodithiolyl or 1,3-benzoxathiolyl group and subsequent hydrolysis with HgO–35% aq. HBF4Me2SO. Overall yields are always good (52–60%). Indirect acylation constitutes a secure complement to direct acylation when it is necessary to operate in the presence of protected acyl groups.