One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Using ZnCl2, CuCl2, NiCl2 and CoCl2 Doped Hydroxyapatite

Calcium, Barium and Strontium apatites: A new generation of catalysts in the Biginelli reaction

“…The yields obtained in this paper were lower than those described by Sebti et al [29]. However, there was a substantial difference in the process of modifying the apatite catalyst.…”

“…Sebti et al have shown that the use of metal halide modified hydroxyapatites or fluoroapatites [29,30] as catalysts for the Biginelli reaction in toluene increases the yield of the product up to 90%.…”

“…The use of a Bi-and Na-modified HAp in neat conditions results in high isolated yields of the product (70%) in half an hour [28]. It has also been shown that non-modified hydroxy-and fluorapatites are less active than modified apatites for the Biginelli reaction in refluxing toluene [29,30]. ) sites [31].…”

Phosphates: New Generation of Liquid-Phase Heterogeneous Catalysts in Organic Chemistry

“…The most simple and straightforward procedure involves the one-pot condensation of a -ketoester with an aldehyde and urea (Scheme 56) under strongly acidic conditions. In heterogeneous media, HAP [131], FAP [132] and NP [133] give very low yields. However, good results are obtained using these phosphates impregnated with Lewis acids, such as ZnCl 2 , CuCl 2 , NiCl 2 or CoCl 2 .…”

Fe(HSO4)3 as an efficient catalyst for the preparation of 3,4-dihydropyrimidin-2(1H)-ones in solution and under solvent-free conditions

“…E-mail: shirini@guilan.ac.ir N-butyl-N,N-dimethyl--phenyl ethyl ammonium bromide [14], samarium iodide [15], ZnCl 2 , CuCl 2 , NiCl 2 and CoCl 2 doped hydroxyapatite [16], H 2 SO 4 [17], silica triflate [18], trichloroisocyanuric acid [19], 12-molybdophosphoric acid [20], covalently anchored sulfonic acid onto silica [21] and propane phosphonic acid anhydride [22]. Most reported methods have shortcomings due to expensive reagents, long reaction times, unsatisfactory yields, and so forth.…”