Catalyse hétérogène de l'hydratation des nitriles en amides par le phosphate naturel dopé par KF et le phosphate trisodique

Efficient Hydration of Nitriles to Amides in Water, Catalyzed by Ruthenium Hydroxide Supported on Alumina

“…A larger scale experiment (tenfold scale-up, 0.4 mol % Ru) for benzonitrile at 423 K showed a turnover frequency (TOF) of 13 h À1 , and the turnover number (TON) reached 234. These values are the highest of those reported for the heterogeneous hydration of benzonitrile so far: KF/Al 2 O 3 (TOF 0.2 h À1 , TON 0.5 based on KF), [17] KF/phosphate (0.2 h À1 , 0.9 based on KF), [18] MnO 2 /SiO 2 (0.2 h À1 , 0.7 based on MnO 2 ), [19] (RuCl) 2 Ca 8 (PO 4 ) 6 (OH) 2 (0.2 h À1 , 6 based on Ru), [21] and NaNO 3 on fluoroapatite (NaNO 3 / FAP; 2 h À1 , 6 based on NaNO 3 ). [22] Hydration of the a,b-unsaturated nitrile cinnamonitrile proceeded only at the cyano group to afford the corresponding a,b-unsaturated amide (entry 9).…”

“…Despite the advantages of heterogeneous hydration, for example, easy catalyst/ product separation and recycling, only a few examples have been reported. Unactivated neutral alumina (stoichiometric hydration without water), [16] Raney copper, [4] KF/Al 2 O 3 , [17] KF/phosphate, [18] MnO 2 /SiO 2 , [19,20] Ru-substituted hydroxyapatite ((RuCl) 2 Ca 8 (PO 4 ) 6 (OH) 2 ), [21] and NaNO 3 on fluoroapatite (NaNO 3 /FAP) [22] are examples. However, turnover numbers are still very low ( 6) or stoichiometric, catalysts can not be reused, and/or the type of nitrile is limited.…”

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

“…More difficult, but equally important, is the synthesis of amides by controlled hydration of nitriles (Scheme 40); here the presence of a high amount of carboxylic acids as by-products is commonly observed. KF/NP and TSP have been tested in this reaction leading to good yields with high selectivity [107], using high amount of catalyst (3-4 g for 5 mmol of nitriles), 0.2-0.4 mL of water and 10 mL of alcohol as solvent. For example, benzamide (11a) was obtained with 98% yield after 2 h of reaction time in refluxing of pentan-1-ol using KF/NP.…”

Catalysis by phosphates: A simple and efficient procedure for transesterification reaction

“…Thus ZnCl 2 /NP has been used as excellent acidic catalyst for Friedel-Crafts alkylation [6], 1,3-dipolar cycloaddition [7], acyclonucleoside synthesis [8] and 3,4-dihydropyrimdin-2(1H)-one synthesis [9]. KF/NP catalyzed efficiently nitrile hydration [10], Michael addition [4,[11][12][13], Knoevenagel condensation [5,14], flavanone synthesis [15], nucleobase alkylation [16] and nucleoside synthesis [17]. On the other hand, we have demonstrated that Na/NP, as strongly basic catalyst, can promote Knoevenagel condensation [14], alkene epoxidation [18], Claisen-Schmidt condensation [19,20] and Michael addition [21].…”