| The reaction of 1-benzoyl-3-arylthioureas (la-f) with acetone/bromine and acetophenone/bromine in the presence of triethylamine was described. The results showed that the structure of products depended on the triethylamine. In the case of excess triethylamine is present, the reaction of 1-benzoyl-3-arylthioureas (la-f) with acetone/bromine gave the 1 -benzoyl-3 -aryl-4-hydroxy-4-methyl imidazoline-2- thiones (3a-4). On the other hand, if the ratio of compounds la-f and triethylarnine is equal, the product is 1 -benzoyl-3-aryl-4-methylimidazole-2-thiones (4a-f). Interestingly, compounds 3a-f can be transformed to 4a-f when the solution of 3a-f was heated or addition of acid. Therefore, we can conclude that the reaction of 1- benzoyl-3-arylthioureas (la-f) with acetone/bromine afforded the 1 -benzoyl-3 -aryl-4- hydroxy-4-methyl imidazoline-2-thiones (3a-f) firstly, if triethylamine is excess, compounds 3a-f are stable and then can be isolated, if not so, compounds 3a-f transformed to 4a-f automatically under the condition of reaction. Similarly, the reaction of 1-benzoyl-3-arylthioureas (la-f) with acetophenone/bromine was carried out in the presence of excess or equal molar triethylamine, 1-benzoyl-3-aryl-4- hydroxy-4-phenylimidazoline-2-thiones (5a-f) and I -benzoyl-3-aryl-4-phenyli mida- zole-2-thiones (6a-f) were obtained, respectively. The structures of 3a-f, 4a-f, Sa-f and 6a-f were confirmed by hR., NMR, MS spectra and elemental analyses. In addition, the reaction of 1-benzoyl-3-arylthioureas (la-f) with butanone/bromine and acetaldehyde/bromine in the presence of triethylamine were also explored.
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