Two‐Step Synthesis of 1,3‐Disubstituted 3,4‐Dihydro‐4‐thioxoquinazolin‐2(1 H )‐ones from 1‐Bromo‐2‐fluorobenzenes

An efficient synthesis of 3‐alkyl‐3,4‐dihydro‐4‐thioxobenzoquinazolin‐2(1 H )‐ones 3 has been accomplished in two steps and in satisfactory yields from 1‐bromo‐2‐fluorobenzenes 1 . Thus, the reaction of 1‐fluoro‐2‐lithiobenzenes, generated by the Br/Li exchange between 1 and BuLi, with alkyl isothiocyanates, gives N ‐alkyl‐2‐fluorobenzothioamides 2 , which, in turn, react with a series of isocyanates in the presence of NaH to give the desired products 3 .