3-methylthio-1,2-dithiolylium salts : Reaction with 4-hydroxy-6-methyl-2H-pyran-2-one and 4-hydroxycoumarin

The reaction of 4- and 5-aryl-3-methylthio-1,2-dithiolylium iodides with 4-hydroxy-6-methyl-2$\text{H}$-pyran-2-one and 4-hydroxycoumarin has been studied. 4-Substituted salts yielded 3-aryl-7-methyl-2-thioxo-2$\text{H}$,5$\text{H}$-pyrano 3,2-c]pyran-5-ones and 3-aryl-2-thioxo-2H,5H-pyrano3,2-c]benzoe]pyran-5-ones, respectively, whereas 5-substituted salts gave rise to 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-6-methyl-2$\text{H}$-pyran-2,4-diones and 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-2$\text{H}$-benzo b]-pyran-2,4-diones.