Abstract The synthesis of alicyclic 2-methylenethiazolo[2,3-b]quinazo­l­inones is performed via base-promoted cascade reactions, starting from either β-amino propargylamides using carbon disulfide, or ethyl 2-isothiocyanatocarboxylates by addition propargylamine. In both cases the reaction proceeds way a favoured 5-exo-dig process during second ring closure, as confirmed full NMR spectroscopic ...