Pyrolysis of 3-hydroxy-2-arylhydrazonoalkanoic acid derivatives
作者:Nouria A. Al-Awadi、Yehia A. Ibrahim、Elizabeth John、Aneesha Parveen
DOI:10.1016/j.tet.2010.11.074
日期:2011.2
conditions including pyrolysis, dehydration under Mitsunobu conditions or with aceticanhydride or aceticacid. According to their method of synthesis these 1,2-diaza-1,3-butadienes underwent subsequent reactions to give interesting products, and in the presence of proper dienophiles gave the corresponding cycloaddition products. Also, a new approach to pyrazole-3-carboxylic acid derivatives was discovered
Cu‐Promoted Sydnone Cycloadditions of Alkynes: Scope and Mechanism Studies
作者:Júlia Comas‐Barceló、Robert S. Foster、Béla Fiser、Enrique Gomez‐Bengoa、Joseph P. A. Harrity
DOI:10.1002/chem.201406118
日期:2015.2.16
reaction of sydnones and terminal alkynes, providing significant reduction in reaction times. Specifically, the use of Cu(OTf)2 is found to provide 1,3‐disubstituted pyrazoles, whereas simply switching the promoter system to Cu(OAc)2 allows the corresponding 1,4‐isomers to be produced. The mechanism of the Cu‐effect in each case has been investigated by experimental and theoretical studies, and they
Inhibitors of factor Xa with a neutral P1 specificity group
申请人:——
公开号:US20030092740A1
公开(公告)日:2003-05-15
The present application describes inhibitors of factor Xa with a neutral P1 specificity group of formula I:
1
or pharmaceutically acceptable salt forms thereof, wherein R and E may be groups such as methoxy and halo.
A synthetically useful approach for one-pot preparation of 1-aryl-3-trifluoromethylpyrazoles using in situ generated nitrile imines and mercaptoacetaldehyde applied as 1 equiv of acetylene is presented. This protocol comprises (3 + 3)-annulation of the mentioned reagents to form 5,6-dihydro-5-hydroxy-4H-1,3,4-thiadiazine, followed by cascade dehydration/ring contraction reactions with p-TsCl. In addition