Desaminierungsreaktionen, 54. Zerfall von 1‐Cyan‐1‐propandiazonium‐Ionen

Deamination Reaction, 54 [1] . – Decomposition of 1‐Cyano‐1‐propanediazonium Ions The nitrous acid deamination of 2‐aminobutanenitrile ( 9 ) was studied with regard to product distribution and stereochemistry. The formation of 2‐(hydroxyimino)butanenitriles ( 21, 22 ; 8 – 28%) indicates the intervention of 1‐cyanopropyl radicals ( 24 ) that are captured by NO. The polar reactions lead mainly to elimination ( 10 – 13 ) and nucleophilic substitution ( 14 – 16 ), rearrangement playing a minor role. ( R )‐ 9 was prepared from ( R )1‐2‐aminobutanoic acid. The nitrous acid deamination of ( R )‐ 9 afforded the cyanohydrin 16 with 81% net inversion. Owing to destabilization of the carbocation 26 by CN, the S N 2 route of nucleophilic displacement is preferred over S N 1. The influence of CN is shown to be smaller than that of CF 3 .