TiO2 as a new and reusable catalyst for one-pot three-component syntheses of α-aminophosphonates in solvent-free conditions

ZnO nanoparticle by solar energy and their catalytic application for α-amino phosphonates synthesis

“…In the literature, Agawane and Nagarkar reported synthesis of a-amino phosphates by CeO 2 nanoparticle [23], whereas Hosseini-Sarvari reported it by using TiO 2 [24]. The same reaction was reported by kassaee and co-workers using nanocrystalline ZnO [25], where nanoparticles were synthesized by 'solid state reaction method' reported by Zhu and co-workers [26].…”

Silica gel and polystyrene supported aluminum chloride as heterogeneous catalysts for the preparation of α‐aminophosphonates

“…Aliphatic aldehydes need slightly more time to produce corresponding α-aminophosphonates (entries 19,20). It was pleasing to observe that even acid-sensitive substrates such as cinnamaldehyde and furan-2-carbaldehyde gave the corresponding α-aminophosphonates without any decomposition, conjugate addition to the α,β-unsaturated carbonyl group or generation of polymeric by-products under the present reaction conditions (entries [21][22][23][24]. Ketones also afforded the corresponding phosphates in relatively good yields (entries 25, 27).…”

“…Three-component condensation of an aldehyde, an amine, and a phosphite is the most convenient method for the preparation of these compounds. Several types of catalysts were introduced previously for this purpose, such as ZrCl 4 [11], AlCl 3 [12], LiClO 4 [13], SiO 2 -NH 4 HCO 3 [14], Al(OTf) 3 [15], ionic liquid [bmim]Cl-AlCl 3 [16], Mg(ClO 4 ) 2 [17], TiCl 4 [18], Al 2 O 3 -SbCl 3 [19], ZrOCl 2 ·8H 2 O [20], TiO 2 [21], amberlyst-15 [22], [Cu(3,4-tmtppa)](MeSO 4 ) 4 [23], sulfamic acid [24], FeCl 3 [25], sodium dodecyl sulfate [26], mesoporous aluminosilicate nanocage [27], and H 3 BO 3 [28]. Most of the above-mentioned methods suffer from the drawbacks such as generation of environmentally perilous waste material, tedious workup, long reaction times, the use of malodorous trialkyl phosphite as the phosphorus nucleophile, unsatisfactory yields, complicated operations, and the use of moisture-sensitive, expensive, hazardous, difficult to handle, or unreusable catalysts.…”

TiO2nanoparticles catalysed synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles using hydrogen peroxide under ambient light

“…[40,41] In addition, there are several reactions which are catalysed by TiO 2 NPs as catalyst due to its unique surface properties. [42,43] High activity, reusability, strong oxidising power, easy availability, nontoxicity, and long-term stability are other advantages of TiO 2 NPs as a recyclable catalyst. [44À46] Diluted solution of hydrogen peroxide is a universal, ecologically clean and convenient way to handle reagents for different oxidations in the liquid phase.…”