Open-Chain Nitrogen Compounds. 7. Synthesis and High-Resolution Nuclear Magnetic Resonance Spectroscopy of 3-(Arylazo)-1,3-oxazolidines and 3-(Arylazo)tetrahydro-1,3-oxazines

Article abstract of DOI:10.1021/jo00213a006

The reaction of arenediazonium ions with a mixture of formaldehyde and ethanolamine affords spontaneously a new series of (arylazo)oxazolidines.Extension of the method to diazonium coupling with formaldehyde/propanolamine mixtures leads to the 4-methyl- and 5-methyloxazolidines or to the arylazoxazines.Diazonium coupling with the acetaldehyde/ethanolamine mixture affords the 2-methyloxazolidine analogues.The method has been extended to the synthesis of some tricyclic heterocycles, oxazolidinobenzotriazines and oxazinobenzotriazines, by incorporating the carbonyl moiety in the ortho position of the arenediazonium ion and coupling with the carbinolamine.The products have been subjected to extensive 1H and 13C high-resolution NMR analysis.Some complex proton spectra have been fully resolved, and coupling constants have been determined for the spin-spin interactions in the oxazolidine and oxazine heterocycles.The spectra show evidence for rotational isomerism about the triazene N2-N3 bond in some of these heterocycles.