The Dimroth rearrangement as a probable cause for structural misassignments in imidazo[1,2-a]pyrimidines: A<sup>15</sup>N-labelling study and an easy method for the determination of regiochemistry
Chatzopoulou M., Martínez RF., Willis NJ., Claridge TDW., Wilson FX., Wynne GM., Davies SG., Russell AJ.
© 2018 The Authors Structural misassignments are often seen for complex natural products, but this can also be an issue with seemingly simpler structures. In this paper, we describe how, using a15N-labelled analogue, we established that the Dimroth rearrangement can occur in imidazo[1,2-a]pyrimidines and result in an incorrect regiochemical assignment of such compounds. These studies supported a rearrangement mechanism involving addition of hydroxide ion followed by ring opening. It was also observed that C(2) and C(3) substituted regioisomers could be readily distinguished using1H NMR spectroscopy.