Regioselective Synthesis of
Functionalized 3-(Methylthio)phenols by the First Formal [3+3] Cyclocondensations
of 1,3-Bis(trimethylsilyloxy)-1,3-butadienes with 1,1-Bis(methylthio)-1-en-3-ones
The [3+3] cyclocondensation of 1,3-bis(silyl enol ethers) with 1,1-bis(methylthio)-1-en-3-ones results in the regioselective formation of 3-(methylthio)phenols. The products represent useful synthetic building blocks, which are not readily available by other methods.
A new general synthesis of 3- and 3,4-substituted 4a–q, 3,4-annelated 7a–d and condensed tricyclic 9a–e thiophenes has been developed through Simmons-Smith reaction on the respective α-oxoketene dithioacetals. Extension of the reaction to α-cinnamoylketene dithioacetals 10a–e and its higher enyl analogs 13a–d, 15a–c gave the corresponding 3-styryl 11a–e and 3-di- and trienyl 14a–d, 16a–c thiophenes
A facile ring cleavage of cyclic ketones. Synthesis of 9-(alkoxycarbonylalkyl)pyrido[1,2-a]pyrimidines
作者:Zhi-tang Huang、Xiao-jun Wang
DOI:10.1016/s0040-4039(01)81033-9
日期:1987.1
2-(Hexahydro-2-pyrimidinylidene)cycloalkanones react with ethyl propiolate in alcoholic solution to give 9-(alkoxycarbonylalkyl)-pyrido[1,2-a]pyrimidinesring cleavage of cyclic ketones.
α-Oxoketene dithioacetals mediated heteroaromatic annulation protocol for benzoheterocycles: an efficient regiocontrolled synthesis of highly substituted and annulated indazoles
作者:S Peruncheralathan、T.A Khan、H Ila、H Junjappa
DOI:10.1016/j.tet.2004.02.029
日期:2004.4
An efficient regiocontrolled synthesis of highly substituted and annulated indazoles involving base induced addition–elimination of 1,3-diphenyl-5-cyanomethylpyrazole to a variety of acyclic and cyclic α-oxoketene, followed by acid assisted cycloaromatization of the resulting conjugate adducts has been reported.
Preparation of lithium 5-lithiomethy-3-methylpyrazole-1-carboxylate and its reaction with α-oxoketene dithioacetals: A new general method for substituted and annelated pyrazolo[1,5-a]pyridines
metallated at the C-5 methyl carbon atom to form lithium 5-lithiomethyl-3-methylpyrazole-1-carboxylate 3 which on reaction with α-oxoketene dithioacetals 4a-d, 12a-c and 15a-b yields substituted and annelated pyrazolo[1,5-a]pyridines 7a-d, 13a-c and 16a-b.
5-甲基吡唑衍生物1在C-5甲基碳原子上金属化形成5-锂硫基甲基-3-甲基吡唑-1-羧酸锂3,与α-氧杂环丁烯二硫缩醛4a-d,12a-c和15a-b反应生成取代并退火的吡唑并[1,5 - a ]吡啶7a-d,13a-c和16a-b。