Polymethylene derivatives of nucleic bases bearing ω-functional groups: IX—An unusual reaction of methyl 2-thiocyano-5-chloropentanoate with uracyl and thymine

Although the search of inhibitors of the key enzymes of HIV replication has remained a topical and intensively studied topic over the last several decades, potential inhibitors of the enzymes bearing thiocyano groups have been little studied. In this work, we tried to synthesize polymethylene derivatives of nucleic bases bearing thiocyano groups at the ω-position of the polymethylene chain. The reaction of new alkylating reagents, methyl α-thiocyano-ω-chloroalkanoates, with nucleic bases led to a complicated and barely separated product mixture. The only exceptions were the reactions of uracil or thymine with methyl 2-thiocyano- 2-chloropentanoate, in which 2-( N 1 -uracilyl or -thyminyl)tetrahydrothiophene-2-carboxylates were isolated in 45–50% yields. The potential mechanism of the reaction is discussed.