Synthesis of intermediate multi-functional imidoyl chlorides for preparation of PCN ligands

The reaction of amides with variety of halogenating agents such as PCl5, SOCl2 produces imidoyl halides. Imidoyl halides contain active carbon - halogen bond provide appropriate situation to form C- P bond from trivalent phosphine reagents. It is worth noting that C - P bond is used extensively for synthesis of organophosphorous ligands with P, N and C donor groups. The nature of PCN donor ligands plays fundamental role in determination the performance of chromium catalyst that strongly affected in activity and selectivity of tri/tetramerization of ethylene in selective oligomerization [1 -3]. In the present work amide is prepared by Schiff base condensation of amine and carbonyl group. Chlorination of amide with PCl5 provides new imidoyl chlorides (I1 and I2) as intermediate for PCN ligands preparation. First the appropriate amide was obtained by the reaction of aniline drive and terephthaloyl chloride in basic condition to produce N- aryl benzenediamide. Then the imidoyl chloride synthesized by the reaction of N- aryl benzenediamide and PCl5. The procedure for synthesis of I1 and I2 are shown in Scheme 1.