Synthesis of some new benzimidazol-2-yl-(1,1,4,1'') terphenyl-2,4-dicarbonitrile and related heterocyclic systems of expected biological activities

The synthesized benzimidazoles compounds were prepared from the condensation reaction between o-phenylene diamine and carbonyl compound in 4N HCl to form (1),through nucleophilic substitution and decarboxylation to give (2) which is reacted with malononitrile and morpholine in ethanol to give (3). Their cyclization with formamide, sodium nitrite and triethylorthoformate afforded a series of polycyclic heterocycles containing condensed quinazoline, triazine rings and formimidic acid ethylester derivatives (4-6). Also condensation of compound (3) with acetic anhydride, phthalic anhydride and anisaldehyde to give condensed quinazoline, isoindolo and benzylidene rings (7-9). The compound (9) reacted with mercaptoacetic acid in zncl2 to form thiazolidin ring (10) which reacted with 2-chlorobenzaldehyde to give compound (11), also compound (3) fused with ethylcyanoacetate to form compound (12). (Scheme1) Chloroderivatives (5) reacted with nucleophilic reagents such as hydrazine hydrate to give the hydrazino derivative (13) which, in turn, proved to be a useful intermediate. In fact the triazolo derivatives (14) and (15) were produced from the reaction of (13) with formic acid and carbon disulfide respectively in addition, treatment of (13) in acetic acid and an aqueous solution of sodium nitrite at room temperature, gave the azido derivative (16). (Scheme2)