180208-01-9Relevant academic research and scientific papers
ZIF-67 Derived Co/NC Nanoparticles Enable Catalytic Leuckart-type Reductive Amination of Bio-based Carbonyls to N-Formyl Compounds
Li, Chuanhui,Meng, Ye,Yang, Song,Li, Hu
, p. 5166 - 5177 (2021/10/25)
It is of great significance to develop non-precious metal catalysts with excellent catalytic activity, stability, and acid resistance for biomass valorization. Herein, catalytic amination of biomass carbonyl compounds was achieved via a Leuckart-type reaction over Co nanoparticles (NPs) embedded N-doped carbon catalyst, which was prepared by thermolysis of ZIF-67 precursor at different temperatures in the N2 atmosphere. The Co/NC-800 catalyst exhibited excellent catalytic activity and recyclability in furfural reductive amination to mono-substituted formamide, which was attributed to the synergistic catalytic action of Co NPs and nitrogen base sites of the catalyst. The reductive amination mechanisms were elucidated by theoretical calculations, and showed that the initial formation of C?N bond was derived from the condensation of furfural and formamide, followed by dehydration to form C=N double bond, which was then reduced by hydrogen species Co?H? and NH+. The developed catalytic system was applicable to different carbonyls for the synthesis of corresponding N-formyl compounds with up to 99 % yield.
Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
supporting information, p. 2107 - 2116 (2019/03/26)
An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
Leuckart-Wallach Route Toward Isocyanides and Some Applications
Neochoritis, Constantinos G.,Zarganes-Tzitzikas, Tryfon,Stotani, Silvia,D?mling, Adrian,Herdtweck, Eberhardt,Khoury, Kareem,D?mling, Alexander
supporting information, p. 493 - 499 (2015/09/22)
Isocyanide-based multicomponent reactions (IMCR) are among the most important chemical reactions to efficiently generate molecular diversity and have found widespread use in industry and academia. Generally, isocyanides are synthesized in 1-2 steps starting from primary amines. Here, we provide experimental detail on an alternative approach toward formamides and, thus, isocyanides via the Leuckart-Wallach reaction in an improved variation. The resulting >50 synthesized and characterized formamides are useful starting materials for IMCR, as well as other chemistries. The advantage of using the Leuckart-Wallach pathway to formamides and isocyanides is the lower price, on average, of the starting materials, as well as their differential and complementary structural diversity, as compared to the primary amine pathway.
3-Phenyl-substituted imidazo[1,5-a]quinoxalin-4-ones and imidazo[1,5- a]quinoxaline ureas that have high affinity at the GABA(A)/benzodiazepine receptor complex
Jacobsen, E. Jon,Stelzer, Lindsay S.,Belonga, Kenneth L.,Carter, Donald B.,Im, Wha Bin,Sethy, Vimala H.,Tang, Andrew H.,Von Voigtlander, Philip F.,Petke, James D.
, p. 3820 - 3836 (2007/10/03)
A series of imidazo[1,5-a]quinoxalin-4-ones and imidazo[1,5- a]quinoxaline ureas containing substituted phenyl groups at the 3-position was developed. Compounds within the imidazo-[1,5-a]quinoxaline urea series had high affinity for the GABA(A)/benzodiaze
