Various 4-methylthiosydnones were prepared by the reaction of 3-substituted sydnones with DmSO and acetyl chloride, while the reaction with methyl phenyl sulfoxide and acetyl chloride gave 4-chlorosydnones. Treatment of 3-substituted sydnones with DmSO and methyl phenyl sulfoxide together with acetyl perchlorate, followed by refluxing with aqueous potassium chloride gave 4-methylthio- and 4-phenylthiosydnones
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
Direct Arylation of Sydnones with Aryl Chlorides toward Highly Substituted Pyrazoles
作者:Andrew W. Brown、Joseph P. A. Harrity
DOI:10.1021/acs.joc.5b00143
日期:2015.2.20
The direct arylation of the C4 position of both N-alkyl- and N-arylsydnones with aryl/heteroaryl chlorides has been realized. The reaction is quite general and allows access to a wide range of 4-substituted sydnones. Yields of more challenging substrates can be improved through the use of aryl bromides.