I2-DMSO Promoted Deaminative Coupling Reactions of Glycine Esters: Access to 5-(Methylthio)pyridazin-3(2H)-ones.

An unprecedented, one-step strategy for the synthesis of 5-(methylthio)pyridazin-3(2H)-one derivatives has been developed through iodine triggered deaminative coupling of glycine esters with methyl ketones and hydrazine hydrate in DMSO. These transformations in the absence of hydrazine helped to generate different 3-methylthio-4-oxo-enoates in good yields. Notably, DMSO played multiple roles such as oxidant, methylthiolating reagent, and solvent.