The reaction of sydnones with bromine in acetic anhydride revisited: a new route to 5-substituted-3-aryl-1,3,4-oxadiazol-2(3H)-ones from N-aryl-N-bromocarbonylhydrazines
作者:Jonathan Michael Tumey、Thijs Gerritsen、Jimmy Klaasen、Karunakar Reddy Madaram、Kenneth Turnbull
DOI:10.24820/ark.5550190.p010.488
日期:——
The reaction of 3-phenylsydnone with bromine in aceticanhydride to form 5-methyl-3-phenyl-1,3,4-oxadiazol2(3H)-one has been reexamined and improved. A new mechanism involving a bromocarbonylhydrazine species is proposed and its intermediacy is supported by the observation that it reacts with aceticanhydride to yield the corresponding 1,3,4-oxadiazol-2(3H)-one. The process has been expanded to the
Syntheses of heterocyclic compounds. Part XII. Halogen-substituted 3-arylsydnones
作者:M. Bellas、H. Suschitzky
DOI:10.1039/j39660000189
日期:——
The reactivity of halogen in the benzene ring and also in the 4-position of the sydnone ring of various arylsydnones towards nucleophiles has been investigated. The course of ring-fission in 4-halogenosydnones induced by primary amines differs from that of secondary amines. The reaction in the latter case provides a preparative route to diamino-acid amides. Several new halogenosydnones are described
Catalytic Activity of 1,3-Dibromo-5,5-dimethylhydantoin (DBH) in the One-Pot Transformation of<i>N</i>-Arylglycines to<i>N</i>-Arylsydnones in the Presence of NaNO<sub>2</sub>/Ac<sub>2</sub>O under Neutral Conditions: Subsequent Bromination of these Sydnones to their 4-Bromo Derivatives
作者:Davood Azarifar、Hassan Ghasemnejad-Bosra
DOI:10.1055/s-2006-926380
日期:——
1,3-Dibromo-5,5-dimethylhydantoin (DBH) has been found to efficiently catalyze the one-pot conversion of various N-arylglycines through N-nitrosation and cyclization to sydnones in combination with NaNO2 and Ac2O in high yields (80-94%) under mild and neutral conditions. Also, it was shown that DBH can conveniently promote the bromination of these sydnones to their 4-bromo substituted congeners in excellent yields in DMF at room temperature.