Synthesis and Antimicrobial Activity of Phthalide Derivatives of Cytisine, Anabasine, and Salsoline

Aminophthalide derivatives of cytisine, anabasine, and salsoline were obtained in high yields via condensation of the alkaloids with o-formylbenzoic acid. Their structures were proven using 1 H and 13 C NMR spectroscopy and data from 2D COSY 1 H– 1 H and HMQC 1 H– 13 C spectra. Studies of their antimicrobial activity showed moderate antimicrobial activity of 3-( N -cytisin-1-yl)isobenzofuran-1(3 H )-one and 3-( N -salsolin-1-yl)isobenzofuran-1(3 H )-one against Gram-positive test strain Staphylococcus aureus ATCC 6538 and Gram-negative test strain Escherichia coli ATCC 25922.