Novel regioselectivity under conformational control in the methylation of 2,3-dihydroxy-1-naphthaldehyde

Methylation of 2,3-dihydroxy-1-naphthaldehyde with iodomethane and potassium carbonate in acetone selectively etherifies the chelated 2-hydroxy group because ionisation of this destroys the stabilising hydrogen bond and allows the formyl group to take up a preferred conformation away from the reaction centre.