Synthesis, structure and antimicrobial activity of 6-(propan-2-yl)-3-methyl-morpholine-2,5-dione

► A novel cyclodidepsipeptide, containing an alanine moiety, was synthesized. ► Diastereoisomers, tautomers and anions of the compound were studied by DFT. ► Prototropic tautomerism and anion formation were explored by IR spectroscopy. ► The cyclodidepsipeptide showed antimicrobial activity against four bacterial strains.