Z. Önal, Neslihan Atli, I. Ilhan
2009
Citations
0
Influential Citations
0
Citations
Journal
Heterocyclic Communications
Abstract
l-Amino-5-(4-methylbenzoyl)-4-(4-methylphenyl)pyrimidine-2(l/f)-thione (1) react with the various isothiocyanates (2a-g) under different conditions to yield the new W,AT-disubstituted thioureas (3a-g). The structures of these compounds (3a-g) were determined by elemental analysis, IR, Ή and C NMR spectroscopic measurements. Introduction It is obvious that pyrimidine derivatives are an important class of organic compounds. They show various interesting pharmacological properties including antiviral, antibacterial·, antitumor and antiflammatory effects. Some of them are frequently encountered in many drugs used for the treatment of hypothyroidy, hypertension, cancer chemotherapy or HIV infection". I-Amino-5-(4-methyIbenzoyI)-4-(4-methyIphenyl)pyrimidine-2(l//)-thione is synthesized in two steps from 4-(4methylbenzoyO-S-^-methylphenytyfuran^.S-dione·. 1-Aminopyrimidine derivatives exhibiting a free N-NHrmoiety, which should apply to several subsequent reactions. The reactions of aminopyrimidine derivatives with several anhydrides, 1,3-dicarbonyl compounds, isocyanates and isothiocyanates have been reported in different conditions ~. In this paper, the reactions of 1 with the various isothiocyanates 2a-g under different conditions were presented. We have synthesized the new JV,W-disubstituted thioureas 3a-g from the reactions between l-amino-5-(4-methylbenzoyl)4-(4-methylphenyl)pyrimidine-2(l//)-thione and the various alkyl-/arylisothiocyanates 2a-g (Scheme 1). Results and Discussion Several Ν,Ν'-disubstituted thioureas 3a-g (Scheme-1) were easily obtained in good yields (55-65%) from nucleophilic addition of 1 to the coresponding alkyl-/arylisothiocyanates 2a-g. The moderate yield of the reactions can be explained by the chemical behavior of 4,5-substituted pyrimidine-2-thione towards the compounds 2a-g. The carbon atoms represent the electrophilic site in the molecules of the isothiocyanates so they can be interacted with nucleophilic reactions'. The reactions were heating without solvent up to (120-135°C) (see Experimental). The structures of the obtained tyAT-disubstituted thioureas 3a-g were confirmed by interpreting their IR, Ή NMR and C NMR spectroscopic techniques, besides the elemental analysis (3a as examples). The compound 3a was obtained from the reaction of l-amino-5-(4-methylbenzoyl)-4-(4-methyIphenyl)pyrimidine2(l//)-thione 1 with phenylisothiocyanate 2a in 64% yield. In the FT IR spectra of compound 3a, the -NH absorbtion band was found to be at 3400-3300 cm' and the C=S absorbtion bands were at 1240 cm'. The C=O absorbtion band was observed at 1660 cm'. The Ή-nmr signals were found to be at 9.60 (s, 2H, -NH) and 7.61-7.33 ppm (m, 14H, ArH). The Ή NMR spectrum 3a, contains two singlet peaks at 2.35, 2.26 ppm representing the methyl groups. Finally, the elemental analysis data along with spectroscopic data (see Experimental) confirm the structure of 3a. The results of measurements of 3b-g were given in the experimental part.