EFFECTIVE SYNTHESIS OF 5-IODOMETHYL-2-PHENYLIMINOTHIAZOLIDINE

Abstract

Thioamides and thioureas are interesting building blocks for the synthesis of azaheterocycles with valuable biological properties. The electrophilic cyclization of N-alkenylthioamides and N-alkenylthioureas is one of the methods of their synthesis. It is known that halogen-induced cyclization of N-alkenylthioamides and thioureas leads to the annealing of 5- or 6-membered cycles. In particular, the cyclization of allylthioamides in the presence of halogen gives halomomethylthiazolines. N-allyl-N-arylthioureas react with halogens, arylselenyl chloride or aryl tert-trichloride to form thiazolidine rings.
 The three-component reaction between unsaturated amine, isocyanate or isothiocyanate and halogen is the one of the methods for the synthesis of halogenated oxazolines or thiazolines. This reaction considered the using of propargyl amine, isocyanate and halogen, which leads to the formation of halomomethylidenoxazolidine or halomomethylidenethiazolidine. The formed vinyl halides are universal building blocks in organic synthesis due to their ability to modify. The aim of this work is to study the course of the three-component reaction between allylmethylamine, phenylisothiocyanate and iodine. The use of allylamine will allow to introduce a halogenomethyl group into the azaheterocycle, which will greatly facilitate its functionalization.
 The reaction of equimolar amounts of phenylisothiocyanate, allylmethylamine and iodine was performed in acetonitrile. This led to an increase in the yield of the target reaction product. Increasing the reaction temperature from room to 50 ° C also increased the yield. The 5-iodomethyl-3-methyl-2-phenylimino-1,3-thiazolidine was isolated as a light brown oil after treatment of the reaction mixture with potassium carbonate. Obviously, the process of iodocyclization is preceded by the formation of N-allyl thiourea, which effectively enters into the electrophilic heterocyclization reaction with the participation of an additional nucleophilic center - a sulfur atom.
 Thus, the resulting three-component reaction of phenylisothiocyanate, allylmethylamine and iodine is an effective method for the synthesis of bioperspective iodomethylthiazolidine, submitted for further functionalization.
 Keywords: electrophilic cyclization; allylmethylamine, three-component reaction; iodomethylthiazolidine.