The Mg/Fe = 3 hydrotalcite as reusable solid catalyst was found to be an excellent heterogeneous base catalyst for the synthesis of 3,4-dihydropyrimidinones/thiones, a multicomponent reaction using substituted aromatic aldehyde, ethyl acetoacetate and urea/thiourea. The work has been carried out under thermal solvent free conditions. Mg/Fe = 3 hydrotalcite heterogeneous solid catalyst offers simple means of recovery and the isolated catalyst was reused for number of times without significant loss of catalytic activity.

Glacial acetic acid as a protic acid was employed as a catalyst in a solvent free condition for facile preparation of di(indolyl)methanes (DIMs) via one-pot condensation of indole with aryl or heteroaryl aldehydes. Various aryl and heteroaryl aldehydes were efficiently converted to the corresponding di(indolyl)methanes (1a-p) in high yields. The described novel synthetic method proposes several advantages of safety, mild condition, short reaction times, high yields, simplicity and the inexpensively glacial acetic acid compared to other catalysts.