Clay (KSF and K10)-supported heteropoly acids: Friendly, efficient, reusable and heterogeneous catalysts for high yield synthesis of 1,5-benzodiazepine derivatives both in solution and under solvent-free conditions

Production of biodiesel through esterification of palmitic acid using 12-tungestoposphoric acid supported on nanocavity of aluminium incorporated mesoporous SBA-15

“…In continuation of our work on the catalytic properties of heteropoly acids (HPAs) [14,15], we focus our attention on the infl uence of PW 12 /Al-SBA-15 as a catalyst in the esterifi cation reaction of palmitic acid, where the parameters of temperature, time and reagent: catalyst molar ratios were examined.…”

Multisite Solid Catalyst for Cascade Reactions: The Direct Synthesis of Benzodiazepines from Nitro Compounds

“…As suggested by one of the referees the first intermediate in Scheme could also be formed by a monoenamine from diaminobenzene with the ketone and a second molecule of this ketone. In an alternative mechanism it has been proposed16 that the carbonyl group of the ketone is protonated and reacts with the amine group to give the corresponding imine (see intermediate imine I in Scheme ). Then, the intermediate imine attacks the carbonyl group of a second activated ketone giving diimine II and water.…”

“…Besides these inconveniencies, the use of the catalysts described above requires the neutralization of the acid while producing undesired waste. To avoid that, different heterogeneous acid catalysts such as sulfated zirconia,14 AlPW 12 O 40, 15 clay‐supported heteropoly acids,16 clinoptylolite‐type zeolite adsorbents,17 and zeolites18 (Heulandite, HY, ZSM‐5) have been used for preparing 1,5‐benzodiazepines starting from o ‐phenylenediamines, and, in most cases, the cyclocondensation between o ‐phenylenediamine and the ketone requires catalyst‐to‐phenylenediamine mass ratios of between 2.5 and 5.…”

Porous Catalytic Systems in the Synthesis of Bioactive Heterocycles and Related Compounds

“…Fazaeli et al reported the synthesis of 1,5-benzodiazepine derivatives using Keggin-type polyoxometalates, H 3 PW 12 O 40 (HTP), and H 3 PMo 12 O 40 supported on clays (montmorillonite KSF and K-10) as heterogeneous catalysts (Scheme 42) [161]. The material with the best catalytic activity was HTP/KSF in the optimal conditions of reaction.…”