One-Pot Synthesis of Thiochromone and It’s Derivatives

Thiochromones are known to possess useful optical properties and rich bioactivities, including antioxidant, antimicrobial, and anticancer properties. They are known to inhibit tumor cell growth, induce apoptosis, and have antiplatelet aggregation effects. Thiochromones are also used as synthons and precursors in organic synthesis for bioactive agents. Although many synthetic approaches to oxygen containing counterparts, chromones, have been reported, research on the synthesis of thiochromones are scarce. The synthesis of thiochromones can be challenging due to the inherent nature of sulfur, including its multiple oxidation states and tendency to form diverse bonding patterns. Here we report the one-pot synthesis of thiochromone, where two transformations of the starting material, 3-(arylthiol)propanoic acid, are performed within a single reaction vessel, eliminating the need for intermediate purification step. This one-pot reaction worked well with a variety of substrates with both electron withdrawing and donating groups on the aromatic ring of 3-(arylthiol)propanoic acids to give thiochromone with good yields (up to 81%). This approach offers advantages like time and cost savings, increased efficiency, and reduced waste. This synthetic approach will allow access to a broader scope of thiochromones due to the readily available thiophenols. The thiochromones can be utilized for additional synthetic applications for the synthesis of thioflavanones and 2-alkylthiochroman-4-ones, an important class of sulfur-heterocycles with rich biological activities.