Erythrosine B Loaded Sulfone Conjugated Pyrene-Based Covalent Organic Framework as a Photocatalytic Tool for Oxidative Thioamide Cyclization

Organic transformations play a vital role in enhancing the scope of pharmaceuticals through the design and development of small bioactive molecules. The facile synthesis of these molecules is more feasible in the presence of catalysts. Nowadays, photocatalysts are quickly replacing the earlier ones due to their eco-friendlier nature and by following the rules of green chemistry. Herein, we are proposing the design and development of a covalent organic framework TBP-SE through the loading of erythrosine B on sulfone-conjugated 2-D pyrene assembly (TBP-S). TBP-SE is a highly crystalline (65.9%) COF with good photostability and fast charge separation (band gap, 2.1 eV). In the photocatalytic study, the TBP-SE is observed as a promising heterogeneous catalyst for efficient cyclization of thioamide to 1,2,4-thiadiazole in high yield (96.5%) along with promising recyclability (5 times).