Acid-promoted rapid solvent-free access to substituted 1,4-dihydropyridines from β-ketothioamides

beta-Ketothioamides (KTAs) have been used as building blocks with aldehydes and beta-enaminonitriles for synthesis of 1,4-dihydropyridines in the presence of AcOH under solvent-free conditions within 5 min. This new strategy exhibits remarkable features such as high chemoselectivity, mild reaction conditions, easily available substrates, and good yields.