REACTION OF 4,6-DIAMINO-2-MERCAPTOPYRIMIDINE WITH ALKYL HALIDE

319 Volume 5, Issue 10: Special Issue (EJAR) ISSN: 2181-2020 MPHAPP THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE “MODERN PHARMACEUTICS: ACTUAL PROBLEMS AND PROSPECTS” TASHKENT, OCTOBER 17, 2025 in-academy.uz REACTION OF 4,6-DIAMINO-2-MERCAPTOPYRIMIDINE WITH ALKYL HALIDE Salieva G.B.1 Otajonov S.R.2 Karimov A.1 Turlibekov M.2 Kholiqov T.S.2 1 Tashkent Pharmaceutical Institute, Tashkent city, Republic of Uzbekistan 2 National University of Uzbekistan, Tashkent city, Republic of Uzbekistan e-mail: [email protected] https://doi.org/10.5281/zenodo.17336473 Pyrimidine derivatives are among the most important compounds in medicinal chemistry and pharmaceutics [1], possessing a wide range of biological activities, including antidiabetic [2], antiinflammatory [3], anticancer [4], antibacterial [5], antihypertensive, as well as antifungal and antitubercular properties [6]. The aim of this work is to obtain new potential classes of biologically active compounds through the synthesis of an S-alkylated derivative of 4,6-diamino-2-mercaptopyrimidine – 2-{(npentylthio)}pyrimidine-4,6-diamine. According to the literature, such derivatives may exhibit antibacterial, antifungal, antitumor, and insecticidal properties. Therefore, their synthesis and subsequent evaluation of biological activity are the main objectives of this study. Synthesis of 2-{(n-pentylthio)}pyrimidine-4,6-diamine A two-necked round-bottom flask equipped with a reflux condenser was charged with 50 mg (0.351 mmol) of DAMP, which was dissolved in 5.0 mL of MeOH. Then, 0.35 mL of 1.0 N NaOH solution (0.35 mmol) was added, and the reaction mixture was stirred at room temperature for 1 h, resulting in the formation of a yellowish compound. The obtained product was dissolved in 5.0 mL of DMF. To this solution, 0.052 mL (density 1.215 g/mL, 0.421 mmol) of n-pentyl bromide was added dropwise, and the mixture was stirred at 50 °C for 16 h under magnetic stirring. The reaction progress was monitored by TLC. After completion, the mixture was cooled to room temperature, and the solvent was removed under reduced pressure using a rotary evaporator. The crude product was purified by extraction with chloroform and water. Yield: 50.69 mg (68%). Product: 2-{(n-pentylthio)}pyrimidine-4,6-diamine – brown solid. m.p.: 92–93 °C. Rf: 0.62 (system: ethyl acetate:hexane 1:2). HRMS (ESI-TOF): m/z [M+H⁺] calcd. for C₉H₁₇N₄S⁺ = 213.1168; found = 214.1236. Thus, the reaction of DAMP with n-pentyl bromide afforded 2-{(n-pentylthio)}pyrimidine-4,6diamine in 68% yield. The physical and spectral properties of the product were determined.