Amidoxim‐Nachbargruppen in Cyclodehydrierungsreaktionen

Abstract

Amide Oxime Functions as Neighbouring Groups in Cyclodehydrogenation Reactions Dehydrogenation of the o‐(tertiary amino)benzamide oximes 4, which are monosubstituted at the amide N atom of the neighbouring group, by the mercury edta complex yields tricyclic amino nitrones 9 with a quinazoline 3‐oxide moiety or lactams 8. Product formation depends on the nature of the N substituent, the size of the amine ring, and the reaction conditions. The configuration of the amide oximes and the conformation of the tricyclic systems is determined by NMR‐spectroscopic methods.

Bridgehead nitrogen heterocycles which contain the quinazoline moiety – synthesis and cycloaddition of 1,2-dihydroquinazoline 3-oxides

“…9 Corresponding aminonitrones have been formed from oaminobenzamidoximes by cyclocondensation either to imines formed in situ upon reaction with an aldehyde 10 or to transient iminium ions generated by dehydrogenation [Hg(II), EDTA] of a tertiary amine. 11, 12 The same laboratory have also reported formation of the tricyclic N-oxides 3 with a perhydro-pyrido or -pyrrolo ring fused to the 1,2-a edge of the quinazoline nucleus. The cyclic nitrones were generated, in the presence of Hg(II)-EDTA complex, from appropriately substituted benzaldoximes in a type of intramolecular Mannich reaction, [13][14][15] for some substrates, e.g.…”