Facile Yb(OTf)3 promoted one-pot synthesis of polyhydroquinoline derivatives through Hantzsch reaction

Recent advances in ionic liquids: green unconventional solvents of this century: part II

“…Some green production processes/procedures in this reaction, such as microwave (26,27) or ultrasound irradiation (28) and the use of Lewis acids (29Á 31) have been reported. Also, Lewis bases (32), Brønsted acids (33Á35), rare metal salts (36,37), or organo catalysts (38Á40) etc., do act as promoters to catalyze Mannich-type reactions. The present authors also did contributed to a greener procedure development by using microwave irradiation (41).…”

A simple and efficient approach for synthesis of 1,4-dihydro-pyridines using nano-crystalline solid acid catalyst

“…However, the yield of 1,4-DHP obtained by Hantzsch method is generally low [13][14][15]. Various methods for the synthesis of dihydropyridine derivatives are described in the literature including condensation of aromatic aldehydes, β-dicarbonyl compounds and ammonium acetate using of microwave [16], ionic liquids [17], tetrabutylammonium hydrogen sulfate [18], silica gel/NaHSO 4 [19], AlCl 3 .6H 2 O [20], TMSI [21], triphenylphosphine [22], InCl 3 [23], I 2 [24], cellulose sulfuric acid [25], alumina sulfuric acid [26], SiO 2 /HClO 4 [27], metal triflate [28], Fe(CF 3 CO 2 ) 3 [29], nano CuO [30], nano MgO [31], ultrasound irradiation [32], solvent free [33], and aqueous media [34].…”

A One-pot Multi-component Synthesis of Dihydropyrimidinone/Thione and Dihydropyridine Derivatives via Biginelli and Hantzsch Condensations using t-BuOK as a Catalyst Under Solvent-free Conditions

“…Classical Hantzsch synthesis of these compounds is carried out in acetic acid or by refluxing in alcohol for a long time [8]. Several other methods are reported including use of microwaves [9], molecular iodine [10], cyanuric chloride [11], ionic liquids [12], silica gel/NaHSO 4 [13], TMSCl-NaI [14], metal triflates [15] and ultrasound irradiations [16].…”