Synthesis and antibacterial activity of certain quinoline and quinazoline derivatives containing sulfide and sulfone moieties

Some aryl and/or heterocyclic mercaptans were allowed to react with 8‐quinolyl chloroacetate (II), 8‐quinolinoxyacetyl chloride (IV) and 3‐(2′‐chloroethyl)‐2‐methyl‐3,4‐dihydroquinazolin‐4‐one (X) in dry benzene and/or sodium hydroxide in absolute ethanol to give corresponding 8‐quinolyl‐α‐mercaptoacetate (V), 8‐quinolinoxythioacetate (VI) and 3‐(2′‐arylmercaptoethyl)‐2‐methyl‐4‐(3H)quinazolin‐4‐ones or 3‐(2′‐heterocyclicmercaptoethyl)‐2‐methyl‐4(3H)‐quinazolin‐4‐ones (XIa‐h). The mercaptans V and XI were subjected to oxidation with hydrogen peroxide/acetic acid mixture (1:2) to afford the corresponding sulfones VII and XII. The structures of the synthesized compounds were elucidated by spectroscopic (IR and 1 H‐NMR) and elemental analyses. Some of these compounds were tested for their antimicrobial activities in comparison with tetracycline as a reference compound.