Molybdate and silica sulfuric acids as heterogeneous alternatives for synthesis of gem-bisamides and bisurides from aldehydes and amides, carbamates, nitriles or urea

Molybdate sulfuric acid (MSA) and silica sulfuric acid (SSA) has been prepared and used as efficient solid catalysts for the synthesis of gem-bisamides and bisurides via the one-pot three-component reaction of two moles of amides, nitriles, carbamates or urea with aldehydes. The catalytic efficiency of SSA, MSA, or H2SO4 98% per H+ sites as turnover number (TON), turnover frequency (TOF), and atomic economy (AE) was calculated and compared for quantitative evaluation of catalysts. The AE, TON, and TOF factors show the superiority of the SSA versus MSA and H2SO4. Short reaction times, simple work-up, chemoselectivity, low loading, and reusability of solid acid catalysts are extra advantages than current methods reported in the literature with corrosive acidic catalysts.

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► MSA and silica sulfuric acid (SSA) are efficient catalysts for the synthesis of gem-bisamides and bisurides.
► The catalytic performances as TON and TOF was higher for SSA than MSA.
► The catalytic performance as AE was much higher for MSA than SSA.
► SSA and MSA are solid, water-insoluble and stable alternatives of H2SO4.