Ring openings of γ- and δ-lactones to form γ- and δ-hydroxyamides. Cyclodehydration. Mass spectra of δ-hydroxyamides

Abstract

Ring openings of γ- and δ-lactones were effected with potassium amide or hydrazine to form γ- and δ-hydroxyamides, which were cyclodehydrated with sulfuric acid to give γ- and δ-lactams, respectively. These products are, respectively, phthalimidines and 3,4-dihydroisocarbostyrils having no substituent on nitrogen or having the N—NH 2 group. The possible linear dehydration of the δ-hydroxyamides was not observed. The δ-hydroxyamides exhibited, on mass spectrometry, a type of carbon–carbon cleavage that has apparently not been reported for ordinary alcohols. An example of the "ortho effect" in mass spectra of o-disubstituted benzene derivatives is also discussed.