A series of 6-aryl-5-cyano-2-thiouracils was synthesized, the reaction of which with diethyl chloroethynylphosphonate leads to the selective formation of new 3-phosphonylated thiazolo[3,2-a]pyrimidines. For the starting 6-aryl-5-cyano-2-thiouracils and their phosphonylated derivatives, antiviral activity against influenza A (H₁N₁) virus and cytotoxicity were studied.

A series of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines was synthesized for the first time by the reactions of chloroethynylphosphonates with unsubstituted and 5(6)-substituted 2-thiouracils. The reaction of chloroethynylphosphonates with 6-substituted 2-thiouracils bearing electron-donor groups (CH₃, Ph) proceeded with high regioselectivity involving the cyclization through the N³-nitrogen atom to form new 3-phosphonylated thiazolo[3,2-a]-5-oxopyrimidines with good yield. In the case of unsubstituted and 5-methyl-2-thiouracils, cyclization occurred predominantly through the N¹ atom and partially via the N³-nitrogen atom to form a mixture of the corresponding thiazolo[3,2-a]-7- and 5-oxopyrimidines. A dramatic change in the reaction regioselectivity was observed in the case of 6-trifluoromethyl-2-thiouracil that afforded 2- and 3-phosphonylated 5-oxothiazolopyrimidines in a 1:1 ratio.

The reaction of diethyl chloroethynylphosphonate with methyl (ethyl) 6-methyl-4-aryl-2-thio-1,2,3,4-tetrahydropyrimidine-5-carboxylate proceeded through the replacement of the chlorine atom and subsequent intramolecular cyclization to yield methyl (ethyl) 3-(diethoxyphosphoryl)-5-aryl-7-methyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylates.

Phosphorus-substituted heterocycles are an important class of organophosphorus compounds that are widely used in the drug development, agrochemistry, materials science, and organic synthesis as ligands for transition metal complexes. Much attention is paid to the development of methods for the synthesis of such compounds. To date, two main strategies for the synthesis of phosphorus-substituted heterocycles have been developed: (1) direct phosphorylation of the heterocycle and (2) heterocyclization with the participation of organophosphorus synthons, in particular compounds with a C_sp–P bond (P-alkynes). This review analyzes data on the synthetic potential of P-alkynes for the construction of various heterocyclic systems, including pyrazoles, oxazoles, thia(dia)zoles, triazoles, pyridines and pyrimidines, quinolines, as well as (poly)fused systems. Achievements in this field of synthesis of phosphorus-containing heterocyclic compounds, advantages and limitations of the approaches used for 1980–2023 are presented.

An effective approach to the selective synthesis of vinyl phosphonates was developed based on the reaction of 2-chloro-2-phenylethenylphosphonic acid dichloride with some alcohols.

This mini-review summarizes the latest advances in the study of the anticancer activity of azo compounds. The data shows the high potential of this class of compounds, which allows us to determine the existing vectors of development in this area, and evaluate the effectiveness of the modifications of azo compounds. The review covers the period from 2006 to 2022.