Cobalt (III)–porphyrin Complex as an Efficient and Recyclable Homogeneous Catalyst for the Synthesis of Tetrahydro-2-oxa-4-thia-diazapentalen-5-one Derivatives in Aqueous Medium

: In this study, we successfully synthesized the CoPHrn complex as an efficient and recyclable catalyst for the one-pot, three-component reaction of aromatic aldehydes, 2,4-thiazolidenedione, and hydroxylamine hydrochloride, leading to the synthesis of tetrahydro-2-oxa-4-thia-diazapentalen-5-one derivatives under environmentally friendly conditions. The structures of the newly formed compounds were determined through elemental and spectral analyses. This methodology offers significant advantages, including its eco-friendliness, cost-effectiveness, operational simplicity, extensive reusability, and applicability, as well as the easy recovery of the catalyst using straightforward methods. Additionally, a series of tetrahydro-2-oxa-4-thia-diazapentalen-5- one derivatives were successfully synthesized. Notably, this novel procedure demonstrates remarkable benefits in terms of safety, simplicity, stability, mild reaction conditions, short reaction times, excellent yields, and high purity, all achieved without the use of hazardous solvents.