Palladium Supported on Mesoporous Silica/Graphene Nanohybrid as a Highly Efficient and Reusable Heterogeneous Catalyst for C−H Functionalization

Abstract

Mesoporous silica/graphene (KIT‐6/G) with pendent 3‐mercaptopropyl groups has been prepared by condensation of surface silanols and (3‐mercaptopropyl)trimethoxysilane (MPTMS). Treatment of the mercaptopropylated with Pd(CH3CN)2Cl2 gave a heterogeneous Pd‐catalyst (Pd@KIT‐6/G‐SH). The catalytic activity of the catalyst was investigated in two types of C−H functionalized for the synthesis of 2‐cyanoacetanilide and 2‐arylpyridine 1‐oxide derivatives via C−H activation. Additionally, for the study of the effect of thiol ligand, the Pd@KIT‐6/G was prepared from the treatment of Pd(CH3CN)2Cl2 with KIT‐6/G. The catalyst has been successfully recovered and reused without loss of activity over seven cycles of reactions.

Palladium Catalyzed Cross‐Dehydrogenative Coupling/Annulation Reaction: A Practical and Efficient Approach to Hydroxyisoindolo[1,2‐b]quinazolinone

“…[24] Other oxidants such as K 2 S 2 O 8 , H 2 O 2 , AgOAc and Cu(OAc) 2 did not promote the desired reaction (Table 1, entries 7- 10). Other catalysts including Cu(OAc) 2 , PdCl 2 , Ru(p-cymene)Cl 2 , Ru(COD)Cl 2 , and Co(OAc) 2 were also ineffective under the present conditions (Table 1, entries [15][16][17][18][19]. Additionally, the increase in the mount of TBHP to four equivalents has resulted in a yield increase of up to 52 % (Table 1, entry 12).…”

“…Based on above introduction and also as part of our ongoing research studies on the C-H activation reactions and organic synthesis, [18][19][20][21][22][23] herein we present the tandem palladium-catalyzed CDC reaction followed by an intramolecular cyclization between arylquinazolinones and aldehydes under tert-butyl hydroperoxide (TBHP) as a convenient oxidant to afford hydroxyisoindolo [1,2-b]quinazolinone. To the best of our knowledge, this is the first report of CDC/annulation reaction for the formation of hydroxyisoindolo[1,2-b]quinazolinone polyheterocyclic frameworks (Scheme 1d).…”

Palladium nanoparticle‐decorated magnetic pomegranate peel‐derived porous carbon nanocomposite as an excellent catalyst for Suzuki–Miyaura and Sonogashira cross‐coupling reactions

“…The temperature stability of Pd/Fe 3 O 4 @PC 900 was decreased compared to Fe 3 O 4 @PC 900 . This may be attributed to the catalytic activity of Pd species in the oxidative degradation of PC 900 …”

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

“…3‐mercaptopropyltrimethoxysilane (MPTMS) is the mostly used mercaptosilane for the preparation of sulfur FSs . T. T. V. Tran et al.…”

“…have reacted (3‐chloromethyl)pyridinehydrochloride with thiol FS in the presence of triethylamine . On the other hand, in few cases, thiol FSs have been utilized without undergoing the aforementioned chemical modifications . In spite of the procedure dealing the condensation of MPTMS and silica under refluxing conditions in the solvents like toluene, thiol FSs can be prepared by hydrothermal saline promoted grafting (HSPG) method …”