A new facile approach to the synthesis of 3-methylthio-substituted furans, pyrroles, thiophenes, and related derivatives.
A new facile approach to the synthesis of 3-methylthio-substituted furans, pyrroles, thiophenes, and related derivatives.
复制标题
DOI：
10.1021/jo702585s
复制
发表时间：
2008-03
期刊：
影响因子：
--
通讯作者：
Guodong Yin;Zihua Wang;Ai‐Hua Chen;M. Gao;A. Wu;Yuanjiang Pan
中科院分区：
文献类型：
--
作者：
Guodong Yin;Zihua Wang;Ai‐Hua Chen;M. Gao;A. Wu;Yuanjiang Pan
2-(甲硫基)-1，4-二芳基-2-丁烯-1，4-二酮(3)是在氧化铜、碘和二甲基亚砜存在下，由容易获得的芳基甲基酮合成的。4-氯苯乙酮与2-乙酰基噻吩交叉偶联反应的成功证实了提出的自排序串联反应机理。化合物3的Z-和E-异构体都很容易通过多米诺骨牌过程转化为相应的3-甲硫基2，5-二芳基呋喃7，该过程涉及双键的还原，然后是Paal-Knorr呋喃合成。同时，4-溴-3-甲硫基-2，5-二芳基呋喃10可以用分子溴处理呋喃7或在一锅中用30%的溴化氢处理二酮3得到4-溴-3-甲硫基2，5-二芳呋喃10。甲硫基的去除是通过在乙醇中用Raney Ni处理7来完成的，这使得二芳基取代的呋喃11具有很好的分离产率。化合物3的双键选择性还原生成饱和的1，4-二酮13，通过Paal-Knorr环化反应很容易转化为相应的3-甲硫基-2，5-二芳基取代的吡咯14和噻吩15。
2-(methylthio)-1,4-diaryl-2-butene-1,4-dione (3) are prepared from readily available aryl methyl ketones in the presence of copper(II) oxide, iodine, and dimethyl sulfoxide. The success of the cross-coupling reaction of 4-chloroacetophenone with 2-acetylthiophene confirms a proposed self-sorting tandem reaction mechanism. Both Z- and E-isomers of compound 3 are readily converted into the corresponding 3-methylthio 2,5-diaryl furan 7 in good yield through a domino process involving the reduction of the double bond followed by the Paal-Knorr furan synthesis. Meanwhile, 4-bromo-3-methylthio 2,5-diaryl furan 10 is obtained either by the treatment of furan 7 with molecular bromine or by the treatment of diketone 3 with 30% hydrogen bromide in acetic acid solution in one pot. Removal of the methylthio group is accomplished by the treatment of 7 with Raney Ni in ethanol, which affords the diaryl-substituted furan 11 in excellent isolated yield. Selective reduction of the double bond of compound 3 leads to the formation of the saturated 1,4-diketone 13, which is easily converted to the corresponding 3-methylthio-2,5-diaryl-substituted pyrrole 14 and thiophene 15 via the Paal-Knorr cyclization reaction.