Enzyme-catalysed one-pot synthesis of 4H-pyrimido[2,1-b] benzothiazoles and their application in subcellular imaging.

Enzymes, which provide more efficient and eco-friendly strategies for various functional molecules' construction than traditional chemo-catalysts, were utilized for the synthesis of 4H-pyrimido[2,1-b] benzothiazole derivatives. Reported herein is a trypsin-catalysed three- component Biginelli reaction of aldehyde, β-ketoester and 2-amino benzothiazole in one pot, affording a streamlined pathway to diverse ring-fused pyrimidines. In addition to using commercially available aromatic aldehydes as substrates, acetaldehyde, the chemical liquid with rather low boiling point and difficult to handle above room temperature, is utilized to further extend the range of substrates. It was verified that most of the tested substrates exhibited satisfactory reactivity. In addition, several substrates indicated AIE (Aggregation-Induced Emission) property and have been investigated as potential biomarkers.