Do deprotonated amidoximes undergo the Tiemann rearrangement in the gas phase?

Abstract

The Tiemann rearrangement in the condensed phase involves base-catalysed transformation of suitably substituted amidoximes to ureas, e.g. R¹(NH₂)CNOR² [graphic omitted] NHCNR¹ [graphic omitted] R¹NHCONH₂

In contrast, deprotonated amidoximes, in the gas phase, undergo only minor reaction through Tiemann intermediates. Instead, they decompose by loss of hydroxylamine, e.g.^–NHC(Me)NOH ↔ NHC(Me)– [graphic omitted]OH →[(MeCN)^–NHOH]→^–CH₂CN + NH₂OH a process substantiated by ¹⁵N and ²H labelling and product-ion studies.