Abstract: The invention relates to medicine, and more specifically to pharmacology, and in particular to synthetic biologically active derivatives of pyrimidine, and it is designated mainly for use as antiviral, immune-stimulating, antichlamydial, antituberculous, psychodepressant, analgesic, and hepatoprotective remedies. Besides that, these compounds may be used for treating malignant neoplasms, and also in veterinary. The objective of the invention is obtaining new chemical substances possessing pronounced biological activity of wide range. The proposed objective is achieved by synthesis of 2,4-dioxo-5-arylidenimino-1,3-pyrimidines of the general formula where R is chosen out of group H, OH, alkoxyl, dialkylamino, benzo, dibenzo, or 3,4-dioxolano General method of producing the claimed compounds and example of synthesis, a list of 25 compounds synthesized and tested, results of identification, and data on wide comparative testing their biological properties and toxicity are presented.