Green synthesis of pyrimido [2,1-b] benzothiazoles using graphene oxide substituted tris(hydroxymethyl)aminomethane sulfonic acid as environmentally friendly carbon catalyst

In this study, graphene oxide was modified with tris(hydroxymethyl)aminomethane using an amide formation reaction and treated with chlorosulfonic acid to produce a sulfonated catalyst. The catalyst was characterized using reliable analytical methods including Fourier Transform Spectroscopy (FTIR), X-ray diffraction analysis (XRD), Field Effect Scanning Electron Microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDAX), and Thermogravimetric Analysis (TGA). The production process of Pyrimido [2,1-b] benzothiazoles was efficiently conducted using the new catalyst, resulting in high product yields without the use of a solvent. The synthesis proceeded effectively using 2-aminobenzothiazole, aldehydes, and ethyl or methyl acetoacetate with the catalyst. Various products were synthesized using different aldehydes with diverse functional groups. The reported procedure and catalyst offer several advantages, including being carbon-based, operating under solvent-free conditions, having short reaction times, being a recoverable catalyst, featuring simple purification, and being environmentally friendly. With these excellent properties, the synthesized functionalized graphene oxide can be utilized in various research areas, and its properties can be further expanded.