Synthesis of Methyl Derivatives of 8-Desmethylxanthyletine and 8-Desmethylseseline, Potential Antiproliferative Agents.

A number of new methyl derivatives of pyranocoumarins, related to 8-desmethylxanthyletine and to 8-desmethylseseline, were synthesized. The syntheses were performed by cyclization in boiling N,N-diethyl aniline of the propargyl or methylpropargyl ethers of the appropriate methyl derivatives of 7-hydroxycou-marin. Methyl groups have been introduced into positions which look most promising for enhancement of the photoreactivity of the compounds towards DNA.