A general and efficient approach to 2H-indazoles and 1H-pyrazoles through copper-catalyzed intramolecular N–N bond formation under mild conditions
作者:Jiantao Hu、Yongfeng Cheng、Yiqing Yang、Yu Rao
DOI:10.1039/c1cc13908h
日期:——
A new efficient copper-catalyzed intramolecular amination reaction has been developed to readily synthesise a wide variety of multi-substituted 2H-indazole and 1H-pyrazole derivatives from easily accessible starting materials under mild conditions. A highly selective ligand for estrogen receptor β was prepared in three steps by employing this method.
Two-Step Synthesis of 3,4-Dihydropyrrolopyrazinones from Ketones and Piperazin-2-ones
作者:Cosme Sandoval、Ngiap-Kie Lim、Haiming Zhang
DOI:10.1021/acs.orglett.8b00197
日期:2018.2.16
An expedient two-stepsynthesis of 3,4-dihydropyrrolopyrazinones has been achieved via a Vilsmeier–Haack reaction of ketones, followed by an annulation of the corresponding chloroaldehydes with commercially available piperazin-2-ones. A variety of cyclic and acyclic ketones and piperazin-2-ones participated in this two-step chemistry, affording the desired 3,4-dihydropyrrolopyrazinones in up to 78%
Efficient Synthesis of 4- and 5-Substituted 2-Aminopyrimidines by Coupling of β-Chlorovinyl Aldehydes and Guanidines
作者:Anna S. Komendantova、Alexander V. Komkov、Yulia A. Volkova、Igor V. Zavarzin
DOI:10.1002/ejoc.201700737
日期:2017.8.10
A general, practical and simple synthesis of functionalized 2-aminopyrimidines starting from β-chlorovinyl aldehydes and amidines is reported. In the presence of potassium carbonate, various ketones have been efficiently incorporated into the pyrimidine derivatives by two-step sequence involving the Vilsmeier-Haack reaction followed by the condensation with guanidines. The protocol is distinguished
Synthesis of New Thieno[b]azepinediones from α-Methylene Ketones
作者:Evelyne Migianu、Gilbert Kirsch
DOI:10.1055/s-2002-31963
日期:——
New substituted 6,7-dihydro-4H-thieno[3,2-b]azepine-5,8-diones were synthesized in seven steps, starting from substituted u-methylene ketones, via 3-aminothiophene-2-carboxylic acid alkyl esters.
Titanacyclobutenes or Titanium Vinyl Carbene Complexes? Reactivity of Organotitanium Species Generated by the Reaction of γ-Chloroallyl Sulfides with a Titanocene(II) Reagent
conjugated dienes and vinyl cyclopropanes as major products, thus suggesting the formation of vinyl carbene complexes as intermediates. On the contrary, the organotitanium species generated from acyclic beta,gamma-disubstituted gamma-chloroallyl sulfides revealed titanacyclobutene-like reactivity, and their reaction with 1,5-diphenylpentan-3-one produced homoallyl alcohols. These organotitanium species