61235-16-3Relevant academic research and scientific papers
Insights into the role of zirconium in proline functionalized metal-organic frameworks attaining high enantio- and diastereoselectivity
Nguyen, Khoa D.,Kutzscher, Christel,Ehrling, Sebastian,Senkovska,Bon, Volodymyr,de Oliveira, Marcos,Gutmann, Torsten,Buntkowsky, Gerd,Kaskel, Stefan
, p. 41 - 50 (2019)
A chiral zirconium-based catalyst, DUT-67-Pro containing 8-connected Zr6-clusters is obtained by post synthetic functionalization of Zr6O6(OH)2(TDC)4(HCOO)2 (DUT-67, TDC = 2,5-thiophenedicarboxylate) with the chiral monocarboxylic acid, L-proline. 13C and 15N solid state MAS and DNP NMR studies of DUT-67-Pro confirm the integration of L-proline into the porous framework. The chiral MOF catalyst exhibits an excellent catalytic activity at low temperature (298 K) with an unprecedented syn-(S,S)-product selectivity in an asymmetric aldol addition reaction of cyclohexanone to 4-nitrobenzaldehyde (yield = 95%, ee = 96%). Comparative catalytic studies using a molecular Zr6-cluster model compound indicate the Zr6-moiety to be responsible for this inverse diastereoselectivity compared to well-established L-proline organocatalysis and a mechanism is proposed to explain the Zr6-cluster-mediated syn-selectivity. Masking residual acidic active sites in the cluster of the framework was found to be a key prerequisite to achieve the high enantioselectivity. The purely heterogeneous catalytic system based on DUT-67-Pro is highly stable and can be recycled several times.
Reversible regulation of a benzamidine-catalyzed aldol reaction by CO 2
Ilgen, Florian,Konig, Burkhard
, p. 1053 - 1056 (2009)
The catalytic activity of benzamidine during an aldol reaction was reversibly switched on and off with CO2 as an orthogonal signal without affecting the converted substrate or products.
Study of the effect of polymorphism on the self-assembly and catalytic performance of an l-proline based molecular hydrogelator
Díaz-Oltra, Santiago,Berdugo, Cristina,Miravet, Juan F.,Escuder, Beatriu
, p. 3785 - 3791 (2015)
An exhaustive study of the polymorphism found for aggregates and hydrogels of an l-proline based hydrogelator under different preparation conditions is undertaken. The effect of heating temperature, aging time, ultrasound and pH switching on the self-assembly in water has been studied. WAXD analysis of the freeze-dried materials revealed the presence of four polymorphs, three of which could be isolated under specific conditions. Polymorphic differences have been studied by DSC, FTIR, circular dichroism and electron microscopy. Furthermore, the catalytic activity of each polymorph has been tested for the direct aldol reaction between cyclohexanone and 4-nitrobenzaldehyde revealing differences in the reaction rates that could be attributed to differences in molecular packing and aggregate morphology among them. The current study highlights the role that polymorphism plays in the application of functional supramolecular soft materials.
One-pot synthesis of spirooxazino derivatives via enzyme- Initiated multicomponent reactions
Wang, Jun-Liang,Chen, Xiao-Yang,Wu, Qi,Lin, Xian-Fu
, p. 999 - 1005 (2014)
A novel enzyme-initiated multicomponent reaction from readily available aldehyde, nitrostyrene, cyclohexanone and acetamide substrates was discovered, enabling the facile construction of six new C-C/-N bonds and two rings in single step, one-pot operation, for the synthesis of spirooxazino derivatives in moderate to high yields. Several methods such as isotope labelling and enzyme mutation were used to probe the possible mechanism of this complex synthesis.
Asymmetric aldol reaction catalyzed by the self-Assembled nanostructures of L-Proline containing amphiphilic dipeptide: A morphological dependence
Shao, Mingzhe,Jin, Qingxian,Zhang, Li,Liu, Minghua
, p. 1349 - 1350,2 (2012)
An L-proline containing amphiphilic dipeptide was found to self-assemble into nanosphere and nanofiber structures. These nanostructures could catalyze an asymmetric aldol reaction in water. Good reactivity and enantiomeric selectivity was observed for the
Natural eutectogels: Sustainable catalytic systems for C-C bond formation reactions
D'Anna, Francesca,Meli, Alessandro,Ramón, Diego J.,Rizzo, Carla,Saavedra, Beatriz
supporting information, p. 6555 - 6565 (2021/09/10)
Natural eutectogels were prepared by combining the properties of amino acids with the ones of deep eutectic solvents. The soft materials obtained were fully characterised by determining the gel-sol transition temperatures and analysing the mechanical and
Structure optimization of lipopeptide assemblies for aldol reactions in an aqueous medium
Soares, Bruna M.,Sodré, Pedro T.,Aguilar, Andrea M.,Gerbelli, Barbara B.,Pelin, Juliane N. B. D.,Argüello, Karina B.,Silva, Emerson R.,De Farias, Marcelo A.,Portugal, Rodrigo V.,Schmuck, Carsten,Coutinho-Neto, Maurício D.,Alves, Wendel A.
, p. 10953 - 10963 (2021/05/26)
Four amphiphilic peptides were synthesized, characterized, and evaluated regarding their efficiency in the catalysis of direct aldol reactions in water. The lipopeptides differ by having a double lipid chain and a guanidinium pyrrole group functionalizing one Lys side chain. All the samples are composed of the amino acids l-proline (P), l-arginine (R), or l-lysine (K) functionalized with the cationic guanidiniocarbonyl pyrrole unit (GCP), l-tryptophan (W), and l-glycine (G), covalently linked to one or two long aliphatic chains, leading to surfactant-like designs with controlled proline protonation state and different stereoselectivity. Critical aggregation concentrations (cac) were higher in the presence of the GCP group, suggesting that self-assembly depends on charge distribution along the peptide backbone. Cryogenic Transmission Electron Microscopy (Cryo-TEM) and Small Angle X-ray Scattering (SAXS) showed a rich polymorphism including spherical, cylindrical, and bilayer structures. Molecular dynamics simulations performed to assess the lipopeptide polymorphs revealed an excellent agreement with core-shell arrangements derived from SAXS data and provided an atomistic view of the changes incurred by modifying head groups and lipid chains. The resulting nanostructures behaved as excellent catalysts for aldol condensation reactions, in which superior conversions (>99%), high diastereoselectivities (ds = 94?:?6), and enantioselectivities (ee = 92%) were obtained. Our findings contribute to elucidate the effect of nanoscale organization of lipopeptide assemblies in the catalysis of aldol reactions in an aqueous environment.
“Ship-in-a-Bottle” Strategy for Immobilization of 9-Amino(9-deoxy)epi-Cinchona Alkaloid into Molecularly Imprinted Solid Acid: Acetal Hydrolysis/Asymmetric Aldol Tandem Reaction
Wei, Shuai,Zhang, Jianing,Li, Shan,Ma, Xuebing
, p. 627 - 636 (2020/12/09)
Direct immobilization of versatile 9-amino(9-deoxy)epi-cinchona alkaloids without molecule modification to achieve heterogeneous organocatalysis is of interest in the low-cost production of optically active compounds. In this paper, an exquisite “ship-in-a-bottle” strategy for direct and simple immobilization of 9-amino-(9-deoxy)epi-quinine (QNNH2) into hollow polystyrene nano-bowl with imprinted free space around ?SO3H was developed via acid-base reaction and radical polymerization. The heterogeneous organocatalyst with 0.44 mmol g?1 of QNNH2 and 0.48 mmol g?1 of residual ?SO3H possessed fast mass transfer due to the characteristic architectural features, such as thin shell thickness, free space around catalytic site, and hollow interior. In heterogeneous acetal hydrolysis/asymmetric aldol tandem reaction, good to excellent catalytic performances (90–95 % yields, anti/syn=88/12–96/4, and 97–99 % ee anti) for acetals bearing electron-withdrawing substituents (R=o, m, p-NO2, Cl) were achieved. The “ship-in-a-bottle” QNNH2 displayed good stability and reusability with excellent catalytic performances in the reuses.
Development of fructose-1,6-bisphosphate aldolase enzyme peptide mimics as biocatalysts in direct asymmetric aldol reactions
Brady, Dean,Juma, Wanyama,Makatini, Maya,Peme, Thabo
, p. 36670 - 36681 (2021/12/02)
This study describes the design and synthesis of mimetic peptides modelled on the catalytic active site of the fructose-1,6-bisphosphate aldolase (FBPA) enzyme. The synthesized peptides consisting of the turn motifs and catalytic site amino acids of FBPA
Homochiral bifunctional L-prolinamide- and L-bis-prolinamide-catalyzed asymmetric aldol reactions performed in wet solvent-free conditions
Anaya de Parrodi, Cecilia,Domínguez-Huerta, Alejandra,Hernández Pérez, Julio M.,Huelgas, Gabriela,Rojas Cabrera, Haydee,Sabala, Rocío,Somanathan, Ratnasamy,de la Higuera Macías, Maximiliano
supporting information, p. 22 - 36 (2020/12/04)
In this study, the novel bifunctional homochiral thiourea-L-prolinamides 1–4, tertiary amino-L-prolinamide 5, and bis-L-prolinamides 6 and 7 were prepared from enantiomerically pure (11R,12R)-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene 8 and (11S,12S
