Thionation of N-methyl- and N-unsubstituted thiazolidine enaminones

• Published in: Journal of the Serbian Chemical Society Vol. 69; no. 11; pp. 909 - 918
• Main Authors: Markovic, Rade, Rasovic, Aleksandar, Baranac, Marija, Stojanovic, Milovan, Steel, Peter, Jovetic, Stanka
• Format: Journal Article
• Language: English
• Published: Serbian Chemical Society 2004
• Subjects: 1,2-dithiole; 3aλ4,4-trithia; enaminone; lawesson’s reagent; thiazolidine
• ISSN: 0352-5139; 1820-7421
• DOI: 10.2298/JSC0411909M

The potential of directional non-bonded 1,5-type S???O interactions to initiate the incipient stage of an in situ rearrangement of N-unsubstituted thiazolidine enaminones to functionalized 1,2-dithioles has been demonstrated. The spectral characteristics, as well as X-ray structural analysis of a selected rearranged product, indicate that a dynamic interconversion occurs in solution between the 1,2-dithiole and the 3,3a?4,4-trithia-1-azapentalene bicylic form. The lack of the rearrangement in the case of a N-methyl substituted enaminone precursor is attributed to an unfavorable methyl migration in the last reaction step. Pokazan je potencijal usmerenih nevezivnih interakcija 1,5-tipa S???O da iniciraju pocetnu fazu in situ premestanja N-nesupstituisanih tiazolidinonskih enaminona u funkcionalizovane 1,2-ditiole. Spektralne karakteristike, kao i kristalografska strukturna analiza izabranog premestenog proizvoda, ukazuju na brzu interkonverziju izmedju 1,2-ditiola i 3, 3a?4,4-tritija-1-azapentalenskog biciklicnog oblika. Odsustvo premestanja u slucaju N-metil-supstituisanog enaminomskog prekursora pripisano je nefavorizovanom premestanju metil-grupe u zavrsnoj fazi reakcije.