CO2 coupling with epoxides catalysed by using one-pot synthesised, in situ activated zinc ascorbate under ambient conditions

2020 ◽  
Vol 49 (23) ◽  
pp. 7673-7679
Author(s):  
Feda'a M. Al-Qaisi ◽  
Abdussalam K. Qaroush ◽  
Amneh H. Smadi ◽  
Fatima Alsoubani ◽  
Khaleel I. Assaf ◽  
...  
Keyword(s):  
Mechanistic Study ◽  
Ambient Conditions ◽  
One Pot

A mechanistic study for efficient CO2 coupling with epoxides to yield the corresponding carbonates catalyzed by zinc ascorbate under ambient conditions under external additive-free conditions.

scholarly journals Straightforward Regio- and Diastereoselective Synthesis, Molecular Structure, Intermolecular Interactions and Mechanistic Study of Spirooxindole-Engrafted Rhodanine Analogs

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7276
Author(s):  
Assem Barakat ◽  
Matti Haukka ◽  
Saied M. Soliman ◽  
Mohammad Ali ◽  
Abdullah Mohammed Al-Majid ◽  
...  
Keyword(s):  
Chemical Yield ◽  
Azomethine Ylide ◽  
Nucleophilic Attack ◽  
Mechanistic Study ◽  
Diastereoselective Synthesis ◽  
One Pot ◽  
Crystal Stability ◽  
Intermolecular Contacts ◽  
One Step

Straightforward regio- and diastereoselective synthesis of bi-spirooxindole-engrafted rhodanine analogs 5a–d were achieved by one-pot multicomponent [3 + 2] cycloaddition (32CA) reaction of stabilized azomethine ylide (AYs 3a–d) generated in situ by condensation of L-thioproline and 6-chloro-isatin with (E)-2-(5-(4-chlorobenzylidene)-2,4-dioxothiazolidin-3-yl)-N-(2-morpholinoethyl)acetamide. The bi-spirooxindole-engrafted rhodanine analogs were constructed with excellent diastereo- and regioselectivity along with high chemical yield. X-ray crystallographic investigations for hybrid 5a revealed the presence of four contiguous stereocenters related to C11, C12, C19 and C22 of the spiro structure. Hirshfeld calculations indicated the presence of many short intermolecular contacts such as Cl...C, S...S, S...H, O...H, N...H, H...C, C...C and H...H interactions. These contacts played a very important role in the crystal stability. The polar nature of the 32CA reaction was studied by analysis of the conceptual DFT reactivity indices. Theoretical study of this 32CA reaction indicated that it takes place through a non-concerted two-stage one-step mechanism associated with the nucleophilic attack of AY 3a to the electrophilic ethylene derivative.

Low pH Chemical Etch Route for Smooth H-Terminated Si(100) And Study Of Subsequent Chemical Stability

1997 ◽  
Vol 477 ◽  
Author(s):  
B. J. Hinds ◽  
D. E. Aspnes ◽  
G. Lucovsky
Keyword(s):  
Optimal Solution ◽  
Native Oxide ◽  
Mechanistic Study ◽  
Ambient Conditions ◽  
Auger Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chemical Etch ◽  
Atomically Flat

ABSTRACTTo form atomically flat H-passivated Si(100) surfaces, wet chemical etching of sacrificial SiO2 layer has been examined. Roughness and chemical overlayer thickness, as monitored by ellipsometry shows a minima at an optimal solution of 1:0.5:30 HF(49wt\%):H2SO4 (98wt\%):H2O. A mechanistic study offers no evidence for a chemical smoothing from preferential non-Si(100) facet etching. Silicon planarization can be induced by rapid thermal annealing RTA of chemical oxides. The H-terminated Si(100) surfaces are found to be moderately reactive to ambient conditions as monitored by in-situ ellipsometry and Auger analysis. Atomic force microscopy (AFM) measurements show Si(100) surfaces to have a rms ∼1.0Å and Rmax values of 1.6–0.9Å. With measured roughness incorporate into ellipsometric model, a 5Å native oxide overlayer is rapidly incorporated into the Si(100) surface.

scholarly journals A binuclear CuII/CaII thiocyanate complex with a Schiff base ligand derived from o-vanillin and ammonia

2020 ◽  
Vol 76 (3) ◽  
pp. 423-426
Author(s):  
Nataliya Plyuta ◽  
Olga Yu. Vassilyeva ◽  
Vladimir N. Kokozay ◽  
Iryna Omelchenko ◽  
Svitlana Petrusenko
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Ammonium Thiocyanate ◽  
Ambient Conditions ◽  
Calcium Atom ◽  
One Pot ◽  
Thiocyanate Complex ◽  
Binuclear Molecule ◽  
Square Planar

The new heterometallic complex, aqua-1κO-bis(μ2-2-iminomethyl-6-methoxyphenolato-1κ2 O 1,O 6:2κ2 O 1,N)bis(thiocyanato-1κN)calcium(II)copper(II), [CaCu(C8H8NO2)2(NCS)2(H2O)], has been synthesized using a one-pot reaction of copper powder, calcium oxide, o-vanillin and ammonium thiocyanate in methanol under ambient conditions. The Schiff base ligand (C8H9NO2) is generated in situ from the condensation of o-vanillin and ammonia, which is released from the initial NH4SCN. The title compound consists of a discrete binuclear molecule with a {Cu(μ-O)2Ca} core, in which the Cu...Ca distance is 3.4275 (6) Å. The coordination geometries of the four-coordinate copper atom in the [CuN2O2] chromophore and the seven-coordinate calcium atom in the [CaO5N2] chromophore can be described as distorted square planar and pentagonal bipyramidal, respectively. In the crystal, O—H...S hydrogen bonds between the coordinating water molecules and thiocyanate groups form a supramolecular chain with a zigzag-shaped calcium skeleton.

Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik
Keyword(s):  
Asymmetric Synthesis ◽  
Chiral Auxiliary ◽  
Bioactive Molecules ◽  
One Pot ◽  
Enantiomerically Pure ◽  
Stereoselective Glycosylation ◽  
One Pot Synthesis ◽  
Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

scholarly journals NIR responsive tumor vaccine in situ for photothermal ablation and chemotherapy to trigger robust antitumor immune responses

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lirong Zhang ◽  
Jingjing Zhang ◽  
Lixia Xu ◽  
Zijian Zhuang ◽  
Jingjin Liu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Tumor Vaccine ◽  
Oxidative Polymerization ◽  
Delivery Mode ◽  
Tumor Treatment ◽  
One Pot ◽  
Photothermal Ablation ◽  
Prolonged Retention ◽  
The One

Abstract Background Therapeutic tumor vaccine (TTV) that induces tumor-specific immunity has enormous potentials in tumor treatment, but high heterogeneity and poor immunogenicity of tumor seriously impair its clinical efficacy. Herein, a novel NIR responsive tumor vaccine in situ (HA-PDA@IQ/DOX HG) was prepared by integrating hyaluronic acid functionalized polydopamine nanoparticles (HA-PDA NPs) with immune adjuvants (Imiquimod, IQ) and doxorubicin (DOX) into thermal-sensitive hydrogel. Results HA-PDA@IQ NPs with high photothermal conversion efficiency (41.2%) and T1-relaxation efficiency were using HA as stabilizer by the one-pot oxidative polymerization. Then, HA-PDA@IQ loaded DOX via π-π stacking and mixed with thermal-sensitive hydrogel to form the HA-PDA@IQ/DOX HG. The hydrogel-confined delivery mode endowed HA-PDA@IQ/DOX NPs with multiple photothermal ablation performance once injection upon NIR irradiation due to the prolonged retention in tumor site. More importantly, this mode enabled HA-PDA@IQ/DOX NPs to promote the DC maturation, memory T cells in lymphatic node as well as cytotoxic T lymphocytes in spleen. Conclusion Taken together, the HA-PDA@IQ/DOX HG could be served as a theranostic tumor vaccine for complete photothermal ablation to trigger robust antitumor immune responses.

scholarly journals PCl3-mediated transesterification and aminolysis of tert-butyl esters via acid chloride formation

2021 ◽  
pp. 174751982098753
Author(s):  
Xiaofang Wu ◽  
Lei Zhou ◽  
Fangshao Li ◽  
Jing Xiao
Keyword(s):  
Acid Chloride ◽  
Bioactive Molecules ◽  
Mechanistic Studies ◽  
One Pot ◽  
Tert Butyl ◽  
Butyl Esters

A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.

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