Geiparvarin Analogs. 4.1. Synthesis and Cytostatic Activity of Geiparvarin Analogs Bearing a Carbamate Moiety or a Furocoumarin Fragment on the Alkenyl Side Chain

As a continuation of previous studies on the synthesis and antitumor activity of geiparvarin analogues bearing a carbamate moiety in the alkyl side chain, a series of N-substituted [(E)-3-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)-2- butenyl]carbamates (15a-f) were synthesized and tested with the objective to investigate the reason for the marked difference of cytostatic activity found between alkyl and phenyl derivatives. A series of compounds, characterized by different physicochemical properties, were designed in order to study this hypothesis. Moreover, to further investigate the modification of the alkenyl side chain, (E)- and (Z)-[2-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)propenyl]-7H-furo[3,2- g][1]benzopyran-7-one (11a,b) were synthesized, the latter compounds being the combination of two units, namely, the 3(2H)-furanone ring system endowed with potent alkylating properties and the furocoumarin portion which binds to DNA resulting in potential DNA-targeted alkylating agents. The compounds were tested for their cytostatic activity against proliferation of murine (L1210) and human (Molt/4, CEM, or MT-4) tumor cells. The highest cytostatic activity found within both series of carbamic derivatives (15a-d,k and 15e,g-j) was associated with the highest global lipophilicity. With regard to compounds 11a,b, the cytostatic activity of (Z)-furocoumarin 11b might be related to a specific interaction with DNA (i.e., intercalation).