Chemical Science International Journal

Aims: To carry out reactions between hydrochlorides of 2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones and N-bromosuccinimide (and/or bromine), to determine way of reactions.

Study Design: Official design.

Place and Duration of Study: Department of Organic Chemistry, Institute of the Chemistry of Plant Substances (ICPS) between January 2012 and September 2013.

Methodology: We have synthesized 6-methyl-2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones from ethyl b-aminocrotonate and g-butyro- or d-valerolactames in the presence of different agents, such as РСl₅, POCl₃ and SOCl₂. For convenient operations the oily bases of 6-methyl-2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones have been transmuted into the appropriate hydrochlorides. Bromination by equimolar amount of hydrochlorides with N-bromosuccinimide at room temperature in water gives 5-bromo-6-methyl-2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones. Treatment of them by bromine resulted in the formation of perbromides. The reactions were monitored  and controlled by TLC. Bromine-products were characterized by IR, ¹H NMR, mass-spectra determinations and chemical transformation.

Results: Electrophilic substitution at C5 atom was successfully carried out when we have used N-bromosuccinimide. Perbromides of 6-methyl-2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones were produced when we have used bromine. Perbromides performed to hydrobromides and bromine complexes when we have treatment of them by acetone and NaHCO₃ solution respectively.

Conclusion: Bromination of hydrochlorides of 6-methyl-2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones by N-bromosuccinimide gives 5-bromine-derivatives. Bromination of them by bromine followed to the formation of perbromides of 6-methyl-2, 3-tri(tetra)methylene-3, 4-dihydropyrimidine-4-ones which are performed to hydrobromides and bromine complexes when we have used corresponding treatments.