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 a 15N-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 using 1H NMR spectroscopy.