Polyhedral Monocarbaborane Chemistry. A Review of Recent Developments Among C-Aryl Monocarbaborane Systems

2002 ◽  
Vol 67 (7) ◽  
pp. 869-912 ◽  
Author(s):  
Andreas Franken ◽  
Colin A. Kilner ◽  
Mark Thornton-Pett ◽  
John D. Kennedy
Keyword(s):  
Aromatic Aldehydes ◽  
High Yield ◽  
Second Step ◽  
Coupling Reactions ◽  
Recent Developments ◽  
One Step ◽  
Alternative Routes ◽  
Interesting Species

The Brellochs Reactions, of nido-B10H14 with aromatic aldehydes to give [6-Ar-nido-6-CB9H11]- anions in high yield, now permits excellent entries into C-aryl monocarbaborane chemistry, which is reviewed. From [6-Ar-nido-6-CB9H11]-, one-step cluster-closure, cluster-Aufbau, or cluster-dismantling reactions yield [1-Ph-closo-1-CB11H11]-, [7-Ph-nido-7-CB10H12]-, [1-Ph-closo-1-CB9H9]-, [2-Ph-closo-2-CB9H9]-, [4-closo-4-PhCB8H8]- and [6-Ph-arachno-6-CB8H13]. Second-step reactions involving these products yield [2-Ph-closo-2-CB10H10]-, [6-Ph-nido-6-CB8H11], [1-Ph-closo-1-CB7H7]- and [4-Ph-closo-4-CB8H8]-, as well as alternative routes to [1-Ph-closo-1-CB11H11]- and [1-Ph-closo-1-CB9H9]-. This readier access to this extensive suite of C-aryl monocarbaboranes permits a readier examination of their derivative chemistry. Monohalogenated and poly-halogenated species [1-Ph-closo-1-CB9H9-nXn]- and [1-Ph-closo-1-CB11H11-nXn]- have been formed as well as (SMe2)-substituted {CB11} and {CB10} systems. Coupling reactions with para-substituted [XC6H4CB11H10X]- systems give rod-like anions, and with poly-iodinated [PhCB11H5I6]- and [PhCB9H4I5]- give the globular [PhCB11H5Ar5I]- and [PhCB9H4Ar4I]- anions. Additional interesting species include [PhCB11H10CH=CHCH3]-, [PhCB11H10SMe(CH2)4OH]- and [PhCB9H8-6-OH]-. A review with 49 references.

scholarly journals CYCLIZATION AND HYDROGENATION OF (+)-CITRONELLAL TO MENTHOLS OVER ZnBr2 AND Ni CATALYSTS SUPPORTED ON γ-Al2O3

2010 ◽  
Vol 10 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Elvina Dhiaul Iftitah ◽  
M. Muchalal ◽  
Wega Trisunaryanti ◽  
Ria Armunanto
Keyword(s):  
Mild Condition ◽  
Hydrogen Atmosphere ◽  
Nitrogen Atmosphere ◽  
High Yield ◽  
Second Step ◽  
Ni Catalysts ◽  
One Step ◽  
The One ◽  
Al2o3 Catalyst ◽  
Very High

Two steps transformation of (+)-citronellal, cyclization and hydrogenation, on ZnBr2/γ-Al2O3 and Ni/γ-Al2O3 catalyst have been realized with the selectivity to cyclization products (isopulegols) was very high (yield up to ~92.58%) over ZnBr2/γ-Al2O3 under mild condition (90 °C and 1 atm nitrogen atmosphere) with high Brønsted acid concentration, while at the same time very low cyclization rates were achieved over Ni/γ-Al2O3 with low or no Brønsted acidity, respectively. The highest cyclization rates were observed over Ni/ZnBr2/γ-Al2O3 under mild condition (90 °C and 1 atm hydrogen atmosphere). The second step transformation towards cyclization products, hydrogenation to menthols, was performed with Ni/γ-Al2O3 under hydrogen atmosphere. Surprisingly the one-step transformation of (+)-citronellal into menthols was investigated over Ni/γ-Al2O3 with yield ~84% under hydrogen atmosphere (90 °C, 1 atm) by exploiting the presence of acidic and hydrogenation sites on the catalyst surface. On the Ni/γ-Al2O3 catalyst it was found that the cyclization of (+)-citronellal to isopulegols occurs on the surface of the support. In the presence of the noble metal, the isopulegols are further hydrogenated to the menthols.   Keywords: cyclization, hydrogenation, citronellal, isopulegol, menthol

Dual Nickel/Palladium-Catalyzed Reductive Cross-Coupling Reactions Between Two Phenol Derivatives

2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian
Keyword(s):  
Functional Group ◽  
Low Cost ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivatives ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
One Step ◽  
Aryl Tosylates ◽  
Low Sensitivity

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.

Visible Light Assisted Hantzsch Reaction: Synthesis of Polycyclic Dihydropyridines

2019 ◽  
Vol 16 (8) ◽  
pp. 676-682
Author(s):  
Ankusab Noorahmadsab Nadaf ◽  
Kalegowda Shivashankar
Keyword(s):  
Reaction Time ◽  
Light Intensity ◽  
Ammonium Acetate ◽  
Low Cost ◽  
Aromatic Aldehydes ◽  
Light Irradiation ◽  
High Yield ◽  
Short Reaction Time ◽  
Green Protocol ◽  
Dihydropyridine Derivatives

The polycyclic dihydropyridine nucleus represents the heterocyclic system of invaluable core motifs with wide applications in chemical, biological and physical properties. Although this kind of compounds have been extensively synthesized by other groups, the synthesis of these compounds under CFL light intensity were not explored. The synthesis of polycyclic dihydropyridine derivatives were achieved through the reaction of 4-hydroxycoumarin, aromatic aldehydes and ammonium acetate under CFL light irradiation conditions. A series of polycyclic dihydropyridine derivatives were prepared under CFL light irradiation conditions with high yield, short reaction time, ambient condition and without the use of catalyst. The results displayed an efficient method for the synthesis of polycyclic dihydropyridine derivatives. Clean profile, short reaction time, low cost and use of CFL light intensity instead of catalyst making it a genuinely green protocol.

A Simple Synthesis of the Anticancer Drug Altretamine

2020 ◽  
Vol 17 (8) ◽  
pp. 628-630
Author(s):  
Vu Binh Duong ◽  
Pham Van Hien ◽  
Tran Thai Ngoc ◽  
Phan Dinh Chau ◽  
Tran Khac Vu
Keyword(s):  
Aqueous Solution ◽  
Anticancer Drug ◽  
Potassium Hydroxide ◽  
Large Scale ◽  
Synthesis Method ◽  
Practical Method ◽  
Cyanuric Chloride ◽  
Simple Synthesis ◽  
High Yield ◽  
One Step

A simple and practical method for the synthesis on a large scale of altretamine (1), a wellknown antitumor drug, has been successfully developed. The synthesis method involves the conversion of cyanuric chloride (2) into altretamine (1) by dimethylamination of 2 with an aqueous solution of 40% dimethylamine and potassium hydroxide in 1, -dioxan 4in one step to give altretamine (1) in high yield.

scholarly journals Mechanisms of Primary Membranous Nephropathy

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 513
Author(s):  
Yan Gu ◽  
Hui Xu ◽  
Damu Tang
Keyword(s):  
Membranous Nephropathy ◽  
Full Spectrum ◽  
The Past ◽  
Phospholipase A2 Receptor ◽  
Kidney Glomerulus ◽  
Recent Developments ◽  
One Step ◽  
Stage Renal Disease ◽  
End Stage ◽  
Antibody Levels

Membranous nephropathy (MN) is an autoimmune disease of the kidney glomerulus and one of the leading causes of nephrotic syndrome. The disease exhibits heterogenous outcomes with approximately 30% of cases progressing to end-stage renal disease. The clinical management of MN has steadily advanced owing to the identification of autoantibodies to the phospholipase A2 receptor (PLA2R) in 2009 and thrombospondin domain-containing 7A (THSD7A) in 2014 on the podocyte surface. Approximately 50–80% and 3–5% of primary MN (PMN) cases are associated with either anti-PLA2R or anti-THSD7A antibodies, respectively. The presence of these autoantibodies is used for MN diagnosis; antibody levels correlate with disease severity and possess significant biomarker values in monitoring disease progression and treatment response. Importantly, both autoantibodies are causative to MN. Additionally, evidence is emerging that NELL-1 is associated with 5–10% of PMN cases that are PLA2R- and THSD7A-negative, which moves us one step closer to mapping out the full spectrum of PMN antigens. Recent developments suggest exostosin 1 (EXT1), EXT2, NELL-1, and contactin 1 (CNTN1) are associated with MN. Genetic factors and other mechanisms are in place to regulate these factors and may contribute to MN pathogenesis. This review will discuss recent developments over the past 5 years.

scholarly journals Constructing Large 2D Lattices Out of DNA-Tiles

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1502
Author(s):  
Johannes M. Parikka ◽  
Karolina Sokołowska ◽  
Nemanja Markešević ◽  
J. Jussi Toppari
Keyword(s):  
Self Assembly ◽  
Dna Nanotechnology ◽  
Building Blocks ◽  
High Yield ◽  
Dna Nanostructures ◽  
Liquid Interfaces ◽  
Basic Principles ◽  
Dna Tiles ◽  
One Step ◽  
Solid Liquid

The predictable nature of deoxyribonucleic acid (DNA) interactions enables assembly of DNA into almost any arbitrary shape with programmable features of nanometer precision. The recent progress of DNA nanotechnology has allowed production of an even wider gamut of possible shapes with high-yield and error-free assembly processes. Most of these structures are, however, limited in size to a nanometer scale. To overcome this limitation, a plethora of studies has been carried out to form larger structures using DNA assemblies as building blocks or tiles. Therefore, DNA tiles have become one of the most widely used building blocks for engineering large, intricate structures with nanometer precision. To create even larger assemblies with highly organized patterns, scientists have developed a variety of structural design principles and assembly methods. This review first summarizes currently available DNA tile toolboxes and the basic principles of lattice formation and hierarchical self-assembly using DNA tiles. Special emphasis is given to the forces involved in the assembly process in liquid-liquid and at solid-liquid interfaces, and how to master them to reach the optimum balance between the involved interactions for successful self-assembly. In addition, we focus on the recent approaches that have shown great potential for the controlled immobilization and positioning of DNA nanostructures on different surfaces. The ability to position DNA objects in a controllable manner on technologically relevant surfaces is one step forward towards the integration of DNA-based materials into nanoelectronic and sensor devices.

Fast one-step synthesis of N-doped carbon dots by pyrolyzing ethanolamine

2014 ◽  
Vol 2 (36) ◽  
pp. 7477-7481 ◽  
Author(s):  
Xinwei Dong ◽  
Yanjie Su ◽  
Huijuan Geng ◽  
Zhongli Li ◽  
Chao Yang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Dots ◽  
High Yield ◽  
One Step ◽  
Doped Carbon Dots

N-doped CDs can be obtained directly with high yield by pyrolyzing ethanolamine in air within just 7 minutes with the assistance of hydrogen peroxide.

New chiral tridentate ligands for asymmetric catalysis

2006 ◽  
Vol 78 (2) ◽  
pp. 311-320 ◽  
Author(s):  
Kevin Murtagh ◽  
Brian A. Sweetman ◽  
Patrick J. Guiry
Keyword(s):  
Asymmetric Catalysis ◽  
High Performance ◽  
Aromatic Aldehydes ◽  
Asymmetric Induction ◽  
Tridentate Ligand ◽  
Coupling Reactions ◽  
Tridentate Ligands ◽  
Molecular Complexation ◽  
Cross Coupling Reactions ◽  
Moderate Yield

The synthesis of new tridentate, isoquinoline-derived ligands, involving successive Suzuki cross-coupling reactions, is described. We were able to resolve 1-[3-(2-hydroxy-phenyl)-isoquinolin-1-yl]-naphthalen-2-ol via molecular complexation with N-benzylcinchonidinium chloride, whereas 1,3-bis(2-hydroxy-naphthalen-1-yl)-isoquinoline was resolved by chromatographic separation of its epimeric camphorsulfonates. Their barrier to rotation about the central biaryl axis was evaluated via racemization studies. Application of enantiopure 1,3-bis(2-hydroxynaphthalen-1-yl)-isoquinoline in the addition of diethylzinc to aldehydes proceeded in moderate yield but without asymmetric induction. A new tridentate ligand, 4-tert-butyl-2-chloro-6-[1-(2-hydroxymethyl-naphthalen-1-yl)-isoquinolin-3-yl]-phenol, was prepared in good yield and resolved by semipreparative high-performance liquid chromatography (HPLC). Its application in the addition of diethylzinc to a range of aromatic aldehydes proceeded in near perfect enantioselectivities at low ligand loadings of 1 mol %.

Sign in / Sign up

Export Citation Format

Share Document