4-diamino-5-p-chlorophenyl-6-methylthio-pyrimidine (11) was prepared from 9c as a typical example using identifical conditions described for 7. The synthesis of 5,6-fused pyrimidines (14a–f), (19) and (23a–e) was also accomplished using the cyclic ketene-S,S-acetals (13a–c) and (22a–b). The present method is found to be more convenient and efficient than reported methods for alkoxy and methylthiopyrimidines
酮醇-S,S-乙缩醛(5a–c)在醇性钠的醇盐存在下与胍和硫脲反应,得到2-氨基和2-巯基-4-烷氧基-5-芳基-6-甲基-吡啶二酰亚胺(6a–k)分别以良好的收成。α-氰基碳烯-S,S-乙缩醛(9a–d)同样产生了带有胍的5-取代的2,4-二氨基-6-烷氧基-吡啶亚胺(10a-e),总收率为50-60%。未交换的2,4-二氨基-5- p -氯苯基-6-甲硫基嘧啶(11)制备图9c为使用用于描述identifical条件的典型例子7。5,6-稠合嘧啶的合成(14a–f),(19)和(23a–e)也使用环状乙烯酮-S,S-缩醛(13a–c)和(22a–b)完成。发现本方法比报道的烷氧基和甲硫基嘧啶的方法更方便和有效。
Vilsmeier–Haack reactions of carbonyl compounds: synthesis of substituted pyrones and pyridines
作者:Ajith Dain Thomas、Josemin、C.V Asokan
DOI:10.1016/j.tet.2004.04.017
日期:2004.5
Vilsmeier–Haack reaction of substituted phenylacetones leads to the formation of conjugated iminium salts which on aqueous basic work up afford 3-formyl-4-pyrones and on ammonium acetate-induced cyclization afford 5-aryl-4-chloronicotinaldehydes in good yields.
Photoredox-Catalyzed C–H Arylation of Internal Alkenes to Tetrasubstituted Alkenes: Synthesis of Tamoxifen
作者:Quannan Wang、Xiaoge Yang、Ping Wu、Zhengkun Yu
DOI:10.1021/acs.orglett.7b03223
日期:2017.11.17
Visible-light-induced direct C–H arylation of S,S-functionalized internal alkenes, that is, α-oxo ketene dithioacetals and analogues, has been efficiently realized with aryldiazonium salts (ArN2BF4) as coupling partners and Ru(bpy)3Cl2·6H2O as photosensitizer at ambient temperature. The strategy to activate the internal olefinic C–H bond by both the alkylthio and electron-withdrawing functional groups