Practical Synthesis of New Chiral Cis-Phthalazinones with Potential for High Phosphodiesterase(PDE4) Inhibitory Activity

New chiral cis-tetrahydrophthalazinones were synthesized directly from the corresponding chiral (4R)- and (4S)-isopropyl-l,3-thiazolidine-2-thione amides in one-pot reaction involving mild aminolysis with hydrazine monohydrate followed by intramolecular condensation.