A new In–SiO2 composite catalyst in the solvent-free multicomponent synthesis of Ca2+ channel blockers nifedipine and nemadipine B

An In–SiO2 composite was prepared by the sol–gel method and was applied as a heterogeneous Lewis acid catalyst in the multicomponent Hantzsch synthesis of symmetrical and non-symmetrical 1,4-DHPs. The Ca2+ channel blockers nifedipine and nemadipine B were synthesized in a single step through a solvent-free protocol.