Synthesis of some substituted 4-hydroxymethyl benzofuryl-5-propenoic acid lactone

Xanthotoxin [8-methoxy psoralene] [1], a drug currently used for the treatment of leukodermia, has been the subject of several workers for more than 9decades due to its pharmacological and chemical interest [1-5] It has been previously shown that when 4-hydroxymethylxanthotoxin was subjected to methylation by dimethyl sulphate in alkaline medium gave the cyclized product 6 7-dimethoxy-4-hydroxymethyl-5-benzofurylpropenoic acid lactone [4][6]. Similar structure analogue in which the lactone oxygen [1'], is substituted by sulfer, was obtained by cleavage methylation of the corresponding 4-thioguanidinyl methyl derivative [7]. Structure elucidation of both cyclized products was based on their 1H NMR spectra