Abstract:The synthesis was performed using 5-methyluracil mono-and bis-derivatives with the halogencontaining pharmacophore groups in the composition of molecules; their physiochemical and biological properties were studied. These reactions are a typical example of substitution reactions on heteroatom N (1) of uracil molecule using as the second component the reaction of halothane-the known inhaled anesthetic. The reactions were carried out in a solvent system: benzene-dimethyl formamide and diethyl ether, under conditions of phase transfer catalysis DB-18-crown-6-complex (alkaline medium), by heating from 2 to 11 hours, followed by purification, and drying of the resulting products.The structure of the synthesized compounds was confirmed by elemental analysis, IR and 1 HNMR spectra. The purity was controlled by the methods of thin-layer and gas-liquid chromatography. Chromatography, IR and 1 HNMR spectra of the final products were identified in comparison with the chromatograms, IR and 1 HNMR spectra of the initial compounds. Variation of the reaction conditions and changes in methods of synthesis enabled to receive the synthesized compounds of high purity and to increase their practical output up to 43-80%. Molecular complex of Bacterial lectin and 5-methyluracil bis-derivative was obtained.The toxicity and anti-tumor activity of some of the synthesized compounds were investigated. We have found that the new molecular complex of Bacterial lectin and 5-methyluracil bis-derivative has high antitumor activity in Limphosarcoma Plissa-62.8% (activity criterion > 50%), which allows us to consider the synthesized compound as a physiologically active compound with the prospect for further study as a potential vehicle for anti-tumoral treatment in patients.