Synthesis of new derivatives of imidazo- [2,1-B] [1,3,4] -thiadiazoles based on 2-bromine-6-P-X-phenyl imidazo [2,1-B] - [1,3,4] thiadiazoles

The synthesis of new derivatives of 2-bromo-5 R-6-P-iodine/p-bromophenyl imidazo [2,1-B] [1,3,4] thiadiazoles has been studied by means of electrophilic substitution. It has been revealed that by this method the reaction of bromination of thio cyanation and nitration by electrophilic mechanism was carried out at low temperature and with good yield. So, as such a highly reactive ability of the imidazole fragment in 5-unsubstituted derivatives of imidazo [2,1-B] [1,3,4] thiadiazoles is due to the fact that the diene system is preserved to a greater extent in it compared to the thiadiazole fragment, i.e. the imidazole part has the highest dipole moment. The structure of obtained compounds has been defined by means of infrared spectrometry. It has been revealed that the effect of new introduced functional groups on the 5 position of these heterocycles is the cause of the change in the intensity of some peaks of these compounds. Since, in comparison with the initial product, when the hydrogen of the 5^th position of the imidazole fragment is replaced by electrophilic agents, the absorption bands of stretching and bending vibrations have been observed in a strong intense field. The reaction of nitration of 2-bromo-6-p-iodophenyl imidazo [2,1-b] [1,3,4] thiadiazole has been investigated. The results of the study showed that the nitration of this hetero cycle only replaces the hydrogen atoms of the 5^th position of imidazole fragment by the nitro group, but the hydrogens of the 6-p-iodophenyl groups remain unchanged, i.e. do not undergo a substitution reaction. Since the data of IR spectrometry showed that the presence of plane bending vibrations in the areas of 1134, 1171, 954 and 989 cm^-1 indicates the presence of four hydrogen atoms in the p-iodophenyl group. (author)