Structure-based design of new KSP-Eg5 inhibitors assisted by a targeted multicomponent reaction

An integrated multidisciplinary approach that combined structure-based drug design, multicomponent reaction synthetic approaches and functional characterization in enzymatic and cell assays led to the discovery of new kinesin spindle protein (KSP) inhibitors with antiproliferative activity. A focused library of new benzimidazoles obtained by a Ugi+Boc removal/cyclization reaction sequence generated low-micromolar-range KSP inhibitors as promising anticancer prototypes. The design and functional studies of the new chemotypes were assessed by computational modeling and molecular biology techniques. The most active compounds-20 (IC50 =1.49 μM, EC50 =3.63 μM) and 22 (IC50 =1.37 μM, EC50 =6.90 μM)-were synthesized with high efficiency by taking advantage of the multicomponent reactions.