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The general structures of nitrilium ions
A nitrilium ion is a nitrile that has been protonated , [RCNH]+ , or alkylated , [RCNR′]+ .[1]
Synthesis [ edit ]
Nitriles are only weakly basic[2] and are poor nucleophiles, but they will attack very reactive electrophiles such as carbocations .[3]
Nitrilium salts can be prepared by reacting nitriles with trialkyloxonium salts . The nitrilium ions thus formed can then be reduced to secondary amines with sodium borohydride in diglyme . This is a convenient route to secondary amines of the form RCH2 —NH—R′.[4]
As intermediates [ edit ]
Nitrilium ions are believed to be intermediates in the hydrolysis of nitriles,[5] the Beckmann rearrangement , the Friedel-Crafts cyclization of amines to isoquinolines ,[6] the Schmidt reaction with ketones,[7] and the Ugi , Ritter , Pinner and Passerini reactions.
References [ edit ]
^ IUPAC Gold Book : nitrilium ions
^ Clayden, Jonathan ; Greeves, Nick; Warren, Stuart ; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. p. 200. ISBN 978-0-19-850346-0 .
^ Clayden, Jonathan ; Greeves, Nick; Warren, Stuart ; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. p. 436. ISBN 978-0-19-850346-0 .
^ March, J. ; Smith, M. (2007). Advanced Organic Chemistry (6th ed.). New York: John Wiley & Sons. p. 1814 . ISBN 978-0-471-72091-1 .
^ Clayden, Jonathan ; Greeves, Nick; Warren, Stuart ; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. p. 294. ISBN 978-0-19-850346-0 .
^ March, J. ; Smith, M. (2007). Advanced Organic Chemistry (6th ed.). New York: John Wiley & Sons. p. 716 . ISBN 978-0-471-72091-1 .
^ March, J. ; Smith, M. (2007). Advanced Organic Chemistry (6th ed.). New York: John Wiley & Sons. p. 1613 . ISBN 978-0-471-72091-1 .