Announcement about the defense of the Doctor of Philosophy (PhD) thesis of Toshmurodov Turdibek Tursunmuratovich

I. General information.

The topic of the dissertation, specialty code (the name of the branch where the academic degree is awarded): «Synthesis and chemical transformations of derivatives of 5-amino-1,3,4-thiadiazole-2-thione», 02.00.03 - Organic chemistry (chemical sciences).

Dissertation topic registered number: B2019.2.PhD/K209.

Scientific supervisor: Ziyaev Abdukhakim ,Candidate of Chemical Sciences.

Name of the institution where the dissertation was completed: Institute of the Chemistry of Plant Substances.

Name of the institution where the scientific council works, Number of the scientific council: Institute of the Chemistry of Plant Substances, DSc.02/30.01.2020.K/T.104.01.

Official opponents: Khodjaniyazov Khamid Doctor of Chemical Sciences, Kholikov Tursunali  Doctor of Chemical Sciences.

Leading organization: Tashkent Pharmaceutical Institut                                             

Dissertation direction: theoretical and practical.

II. The aim of the study is the synthesis and conduct of chemical transformations of new derivatives of 5-amino-1,3,4-thiadiazol-2-thione, as well as the determination of their physicochemical properties and biological activity.

III. The scientific novelty of the dissertation research is as follows:

- for the first time systematically studied the interaction of 5-amino-1,3,4-thiadiazol-2-thione with various electrophilic agents and identified the main factors affecting the course of reactions;

- selective alkylation of 5-amino-1,3,4-thiadiazol-2-thione with alkyl halides was carried out and the formation of only S-alkyl derivatives was established;

- for the first time new promising bicyclic derivatives of 1,3,4-thiadiazol-2-thione having in their molecule thiazolidin-4-one, 3-phenyl-thiazolidin-4-one and 3,4-diphenylthiazol-2(3Н)- imine fragments were synthesized;

- for the first time the formation of a new annealed 1,3,4-thiadiazolopyrimidine was established during the interaction of 2-butylthio-1,3,4-thiadiazol-5-phenylthiourea with malonic acid and a reaction mechanism was proposed.

IV. Implementation of research results. Based on the obtained scientific results on the synthesis of 5-amino-1,3,4-thiadiazol-2-thione derivatives and the study of effective methods for their subsequent modifications:

the results of X-ray diffraction analysis of 2-ethylthio-5-amino-1,3,4-thiadiazole, 2-propylthio-5-amino-1,3,4-thiadiazole, 2-butylthio-5-amino-1,3,4-thiadiazole, 2-amylthio-5-amino-1,3,4-thiadiazole, 2-hexylthio-5-amino-1,3,4-thiadiazole, 2-heptylthio-5-amino-1,3,4-thiadiazole, 2-octylthio-5-amino-1,3,4-thiadiazole, 2-butylthio-5-(N-acetylamido)-1,3,4-thiadiazole, 2-benzylthio-5-amino-1,3,4-thiadiazole, 2-(2-chloro-6-fluorobenzylthio)-5-amino-1,3,4-thiadiazole, propyl-(5-(benzylthio)-1,3,4-thiadiazol-2-yl)carbamate and isobutyl-(5-(benzylthio)-1,3,4-thiadiazol-2-yl)carbamate entered into the Cambridge Structural Database (CCDC 1476419, 1476420, 1515377, 1515378, 1984013, 1984018, 1984019, 1984021, 2118098, 2118099, 2206065, 2206066). As a result, these data made it possible to establish the structures of analogous heterocyclic compounds;

a number of new derivatives of 5-amino-1,3,4-thiadiazol-2-thione were used in the scientific project FA-F-6-009: "Study of the cytotoxic, antibacterial, antifungal and antioxidant activity of natural compounds and their synthetic derivatives" to determine their antimicrobial activity (Reference No. 4/1255-2975 of the Academy of Sciences of the Republic of Uzbekistan dated October 28, 2021). As a result, among the studied substances the 1,3,4-thiadiazoles were identified, which have an inhibitory effect on gram-positive bacteria - Staphylococcus aureus and Bacillus subtilis.