“…The chemistry of 4-hydroxycoumarin was explored extensively for new compounds, including warfarin, dicoumarol, and flocoumafen, which have significant pharmacological importance and are used as anticoagulants in medicine. [15][16][17][18][19] In contrast, the chemistry of 4-hydroxy-2Hchromene-2-thione (VI), a sulphur-containing analogue of 4-hydroxycoumarin, is far less explored than that of 4-hydroxycoumarin (IV). 20,21 However, 4-hydroxydithiocoumarin (V) and 4-hydroxy-2H-thiochromen-2-one (VII) are two well-studied molecules (Fig.…”