New substituted isocoumarins and Dihydroisocoumarins and their cytotoxic activities.

New isocoumarins were prepared in an efficient way from 2-iodobenzoic acid derivatives and hept-1-yne in a Sonogashira reaction, followed by spontaneous cyclization. Catalytic hydrogenation gave the corresponding dihydroisocoumarins. A 4-chloroisocoumarin was prepared on an alternative pathway. Some of the new compounds showed moderate cytotoxic activities against a human leukemia cell line (HL 60).