Tracking an ultrafast C-S bond breaking in the UV-induced sulfur-substituted 2-aminoazole

2-aminothiazole is a common sulfur-bearing molecular scaffold in prebiotically plausible and biologically active compounds. UV-irradiation experiments and quantum-chemical calculations reveal that the substitution of a ring sulfur in the 2-aminoazoles family allows absorption in the UV-B range and opens an ultrafast (~100 fs) ring-opening photochemical channel through the C-S bond breaking. As a result, the formed reactive intermediate can undergo either electrocyclic reactions or the addition of water molecules to its structure, potentially altering therapeutic agents. Consequently, modified pharmaceutics might not perform their intended functions and trigger harmful effects on cells.