A simple synthesis of Δ2-oxazines, Δ2-oxazines, Δ2-thiazolines and 2-substituted benzoxazoles
作者:Helmut Vorbrüggen、Konrad Krolikiewicz
DOI:10.1016/0040-4020(93)80021-k
日期:1993.1
Carboxylic acids react readily at O°→+24°C with amino alcohols, amino mercaptans and o-aminophenols in the presence of triphenylphosphine- or tributylphosphine dichloride (generated from the reaction of the phosphines with hexachloroethane or CCl4) and triethylamine in acetonitrile to form the corresponding Δ2-oxazolines, Δ2-oxazines, Δ2-thiazolines and 2-substituted benzoxazoles in reaction step in
Thiazolinium salts and their reactions with nucleophiles
作者:A. D. Clark、P. Sykes
DOI:10.1039/j39710000103
日期:——
2,3-Dialkyl- and 3-alkyl-2-aryl-2-thiazolinium salts were prepared by quaternisation of the corresponding 2-thiazolines. Some 3-alkyl-2-alkylthio-2-thiazolinium salts were obtained by quaternisation of 2-alkylthio-2-thiazolines; the products included bicyclic salts obtained from αω-dibromides and 2-thiazoline-2-thiol. In some cases attempted quaternisation yielded only the 3-alkylthiazolidine-2-thiones
Primary thioamides have been utilised directly in water, without any derivatisation, to selectively thioacylate primary amines. By employing 2-hydroxyethylamines, the reaction can be extended to the preparation of 2-thiazolines via formation of β-hydroxythioamides.
Visible‐Light‐Induced Cycloaddition of α‐Ketoacylsilanes with Imines: Facile Access to β‐Lactams
作者:Jian‐Heng Ye、Peter Bellotti、Tiffany O. Paulisch、Constantin G. Daniliuc、Frank Glorius
DOI:10.1002/anie.202102451
日期:2021.6.7
report the synthesis of β-lactams from α-ketoacylsilanes and imines, which proceeds via a formal [2+2] photochemical cycloaddition with in situ generation of siloxyketene. This mild and operationally simple reaction proceeds in an atom-economic fashion with broad substrate scope, including aldimines, ketimines, hydrazones, and fused nitrogen heterocycles, affording a variety of important β-lactams with satisfactory
19-Nor-Vitamin D Analogs With 1,2- or 3,2-Cyclopentene Ring
申请人:DeLuca Hector F.
公开号:US20110082122A1
公开(公告)日:2011-04-07
19-nor-vitamin D analogs having an additional cyclopentene ring connecting carbon 1 and carbon 2, or connecting carbon 3 and carbon-2 of the A-ring of the analog, and pharmaceutical uses therefore, are described. These compounds exhibit selective in vitro activities, making them therapeutic agents for the treatment or prophylaxis of some types of cancers, particularly leukemia, colon cancer, breast cancer, skin cancer or prostate cancer.