Synthesis of Tetra-substituted Phenanthroimidazole Derivatives Using SBA-Pr-SO3H

Sba-15 (santa barbara amorphous), as a hexagonal mesoporous silica with 6 nm pore diameter, was synthesized and then its internal surface was modified with (3-mercaptopropyl)trimethoxysilane following an oxidation process to gain sba-pr-so3h. the latter was then characterized; sem image showed uniform particles about 700-900 nm and tem image demonstrated the presence of parallel channels, which resemble the pores configuration of sba-15. additionally, the weight reduction in tga curve in the temperature range of 200-600 °c (about 20% mass loss) established that the anchored propyl sulfonic acid groups onto the sba-15 pores is about 1.2 mmol/g. this data was also confirmed by back-titration of sba-pr-so3h with standardized naoh and hcl solutions. afterwards, a one pot four-component reaction of 9,10-phenanthraquinone, aromatic aldehyde, aniline, and ammonium acetate was designed for the preparation of tetrasubstituted imidazoles (phenanthro[9,10-d]imidazole) derivatives in the presence of sba-pr-so3h as a mesoporous solid acid catalyst. phenanthro[9,10-d]imidazole derivatives were produced by the use of this technique in short reaction times and good to high yields.