Synthesis and characterization of novel Schiff bases containing pyrimidine unit

The work involves synthesis of novel Schiff base derivatives containing a pyrimidine unit starting with chalcones. 4-Aminoacetophenone was reacted with 4-nitrobenzaldehyde or 4-chlorobenzaldehyde in basic medium giving chalcones, [I](a) and [I](b), respectively, by Claisen-Schemidt reaction. The chalcones [I](a) and [I](b) were reacted with urea in HCl medium giving oxopyrimidines, [II](a) and [II](b). They were also reacted with thiourea in basic medium to give thioxopyrimidines, [III](a) and [III](b). The novel mono and bis Schiff bases, [VIII](na), [VIII](nb), [IX](na), [IX](nb), [X](na), [X](nb), [XI](na), and [XI](nb) were synthesized by the reaction of pyrimidine derivatives; oxopyrimdines, [II](a) and [II](b) and thioxopyrimidines, [III](a) and [III](b) with 4-(4'-n-alkoxybenzoloxy) benzaldehyde [VI]and polymethylene-a, x-bis-4-oxybenzaldehydes [VII](m), respectively, in dry benzene using drops of glacial acetic acid as a catalyst. The synthesized compounds were characterized by melting points, elemental analysis, FTIR, and H-1 NMR spectroscopy. (C) 2013 Production and hosting by Elsevier B. V. on behalf of King Saud University.