Formation of pyridazino[6,1-c][1,4]oxazin-8(7H)-ones by intramolecular cycloaddition of azoalkenes
作者:Thomas L. Gilchrist、Robert C. Wasson、Frank D. King、Gordon Wootton
DOI:10.1039/p19870002517
日期:——
of 2-allyloxyalkanoic acids (1) and of prop-2-ynyloxyacetic acid have been prepared. These hydrazides have then been converted into the hydrazones (6) and (7), respectively, by reaction with phenacyl chloride. The azoalkenes have been generated from the hydrazones by reaction with sodium carbonate. The products isolated were the pyridazino-oxazinones (8)[from (6)] and (9)[from (7)], formed by spontaneous
已经制备了2-烯丙氧基链烷酸(1)和丙-2-炔氧基乙酸的酰肼(3)和(4)。然后,通过与苯甲酰氯反应,将这些酰肼分别转化为the(6)和(7)。通过与碳酸钠反应,由生成了偶氮烯烃。分离的产物是由偶氮烯烃的自发分子内环加成反应形成的哒嗪-恶嗪酮(8)[来自(6)]和(9)[来自(7)]。(6b)和(6c)具有不相邻于羰基的不对称碳中心的化合物各自产生非对映异构的恶嗪的混合物,但是在每种情况下具有相当大的选择性(6:1)。这归因于过渡态中的空间效应。用衍生自酰肼(3)和(4)的和溴代丙酮酸乙酯进行了一系列类似的转化。还已经制备了N-乙酰基-N-烯丙基甘氨酸酰肼(11)。通过与碳酸钠反应,将由该酰肼和苯甲酰氯形成的hydr (13)转化为偶氮烯,将其环化,得到吡嗪并[1,2 - b ]哒嗪-8-一(14a)。)。
Electrophotocatalytic Decarboxylative C−H Functionalization of Heteroarenes
formation with proton reduction remain an unsolved challenge. Herein, we report an electrophotocatalytic approach that merges organic electrochemistry with photocatalysis to achieve the efficient direct decarboxylative C−H alkylation and carbamoylation of heteroaromatic compounds through hydrogen evolution. This electrophotocatalytic method, which combines the high efficiency and selectivity of photocatalysis
An efficient method for the synthesis of multiply functionalized oligonucleotides (ONs) utilizing a novel H-phosphonate alkyne-based linker for multiple functionalization (LMF) is developed. The strategy allows for the conjugation of various active entities to oligonucleotide through the postsynthetic attachment of LMF at the 5′-terminus of ONs using H-phosphonate chemistry followed by conjugation of
The large‐scale synthesis of englerin A (see scheme) and subsequent structure‐activity relationship studies have led to the discovery of highly potent analogues. TBS=tert‐butyldimethylsilyl.
Silver-catalyzed intramolecular hydroamination of alkynes in aqueous media: efficient and regioselective synthesis for fused benzimidazoles
作者:Xu Zhang、Yu Zhou、Hengshuai Wang、Diliang Guo、Deju Ye、Yungen Xu、Hualiang Jiang、Hong Liu
DOI:10.1039/c0gc00668h
日期:——
A simple, convenient and green synthetic approach to diverse fused tricyclic benzimidazoles has been developed by Ag(I) complex catalyzed intramolecular hydroamination under the classic method or by microwave irradiation in water. This strategy presents an operationally simple and environmentally friendly transformation, in which various substituted benzimidazoles facilitated efficient cyclization