Marine solids/NaNO3: As Natural and Efficient Catalysts for Aldol condensation

Abstract

A new and efficient method have been developed for the synthesis of α,β-unsaturated carbonyl compounds from various aldehydes and ketones, using marine calcinated coral/NaNO₃ and cuttlebone/NaNO₃, as natural and efficient catalysts for cross aldol condensation. The aim of present study was to study the marine solids/NaNO₃: as natural and efficient catalyst for Aldol condensation. The materials were purchased from Merck and Aldrich Companies. The IR spectra were recorded on a Perkin-Elmer RXI infrared spectrometer. H NMR spectra were recorded on a 400 MHz Brucker FT-NMR spectrometer. The SEM image was recorded on 1455 VP LEO-Germany. TLC accomplished the purity of substrates and reactions monitored on silica gel (Merck, Germany) Polygram SIGL/UV254 plates. The melting points are uncorrected. Results showed that, the marine solid are efficient catalysts for aldol condensation, but cuttlebone/NaNO₃ catalyze this reaction in shorter time (1 hr) than calcinated coral/NaNO₃ (6 hr). However, these marine solids have several advantages such as small amount of the catalyst, good absorbent natural solid, easy to handle, and products in good-to-high yields. In conclusion we found marine catalysts, Calcinated Cuttlebone/NaNO₃ or Coral/NaNO₃ to be an effective catalyst for aldol condensation from ketones having α-hydrogens and aldehydes in 50 % ethanol at reflux conditions. The α,β-unsaturated carbonyl products were obtained in good to high yields. This method offered marked improvement compared to previously reported ones.