Ultrasound-Assisted Expeditious Synthesis of Thioxoimidazolidinone-Chromone Conjugates, followed by Investigation of Dual Role of TBN as a Radical Nitrating Agent and Desulfurizing Agent toward the Preparation of β-Nitro Imidazolidine-Chromone Conjugates in Ecofriendly Solvent

A novel and efficient "on water" mediated, catalyst-free ultrasound-assisted synthesis of thioxoimidazolidinone-chromone conjugates, followed by the synthesis of β-nitro imidazolidine-chromone conjugates, has been reported in our study. The key aspect of this protocol includes the dual role of TBN. Mechanistic studies suggested that TBN first acts as a desulfurizing agent and then as a radical nitrating agent. In addition, we also carried out an extension of our work, i.e., derivatization of the nitro functionality of β-nitro imidazolidine-chromone conjugates using tosylhydrazine. The use of readily available starting materials, catalyst-free greener solvent, and simple reaction conditions are the major advantages of this strategy.