A practical ‘one-pot’ synthesis of ethyl isoquinoline-3-carboxylate by domino reactions: a potential entry to constrained nonproteogenic amino acid derivatives

Two simple and efficient ‘one-pot’ preparations of isoquinoline-3-carboxylates by domino reactions using phthalaldehydes and imidate (route A) or diethyl aminomalonate (route B) are described. The third route involves the use of ethyl glycinate, aminoacetonitrile and phthalaldehyde which yields the respective ethyl isoquinoline-3-carboxylate and isoquinoline-3-carbonitrile.