Method A. Cyclization of Phenylthioureas. A solution of 0.05 mol of the phenylthiourea in 120 ml of CHC13 was treated dropwise at ambient temperature with 10 mi of Br2. The resultant mixture was stirred and refluxed for 1 hr, solvent was removed in L'UCUO, and crude HBr salt was converted to the free base using aqueous NaOH solution. The free base was converted to the HCI salt using Etz0. HCI and recrystallized from the appropriate wl. ...
