scholarly journals Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts

2020 ◽  
Vol 16 ◽  
pp. 1579-1587
Author(s):  
Soundararajan Karthikeyan ◽  
Radha Krishnan Shobana ◽  
Kamarajapurathu Raju Subimol ◽  
J Helen Ratna Monica ◽  
Ayyanoth Karthik Krishna Kumar
Keyword(s):  
The Novel ◽  
Reaction Conditions ◽  
Efficient Catalyst ◽  
Direct Transformation ◽  
Chemoselective Synthesis

The direct transformation of Morita–Baylis–Hillman (MBH) adducts into molecules of interest is a crucial process wherein allylic hydroxy-protected or halogenated MBH adducts are commonly preferred. Herein, we report an azidophosphonium salt (AzPS)-catalysed straight forward protocol for synthesising structurally demanding (E)/(Z)-cinnamyl-1H-1,2,3-triazoles and halomethylcoumarins from MBH adducts. The novel methodology, efficient catalyst, and direct utilization of MBH adducts under mild reaction conditions qualify the reported procedures as powerful synthetic tools.

scholarly journals Azidophosphonium salt directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromo-methyl coumarins from Baylis-Hillman adducts

2020 ◽  
Author(s):  
S Karthikeyan ◽  
R Shobana ◽  
K R Subimol ◽  
J Helen Ratna Monica ◽  
Ayyanoth Karthik Krishna Kumar
Keyword(s):  
Reaction Conditions ◽  
Efficient Catalyst ◽  
Direct Transformation ◽  
Chemoselective Synthesis

Direct transformation of Baylis Hillman adducts into molecules of interest is a crucial process, thereby allylic hydroxy protected or halogenated BH adducts are commonly preferred.  Herein, we report a azidophosphonium salt catalysed (QPS) straight forward protcol for synthesising structurally demanding (E) / (Z) cinnamyl-1H-1,2,3-triazoles and halomethyl coumarins from unaltered BH adducts.  Novel methodology, efficient catalyst and direct utilization of BH adducts in presence mild reaction conditions identifies the reported procedures as a powerful synthetic tool.

scholarly journals One-Pot Synthesis of Novel Multisubstituted 1-Alkoxyindoles

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1466
Author(s):  
Ye Eun Kim ◽  
Hyunsung Cho ◽  
Yoo Jin Lim ◽  
Chorong Kim ◽  
Sang Hyup Lee
Keyword(s):  
Alkyl Halide ◽  
The Novel ◽  
Reaction Conditions ◽  
One Pot ◽  
One Pot Synthesis ◽  
Consecutive Reactions ◽  
Intramolecular Condensation ◽  
Synthetic Sequence ◽  
Novel Target

Studies on a one-pot synthesis of novel multisubstituted 1-alkoxyindoles 1 and their mechanistic investigations are presented. The synthesis of 1 was successfully achieved through consecutive four step reactions from substrates 2. The substrates 2, prepared through a two-step synthetic sequence, underwent three consecutive reactions of nitro reduction, intramolecular condensation, and nucleophilic 1,5-addition to provide the intermediates, 1-hydroxyindoles 8, which then were alkylated in situ with alkyl halide to afford the novel target products 1. We optimized the reaction conditions for 1 focusing on the alkylation step, along with the consideration of formation of intermediates 8. The optimized condition was SnCl2·2H2O (3.3 eq) and alcohols (R1OH, 2.0 eq) for 1–2 h at 40 °C and then, base (10 eq) and alkyl halides (R2Y, 2.0 eq) for 1–4 h at 25–50 °C. Notably, all four step reactions were performed in one-pot to give 1 in good to modest yields. Furthermore, the mechanistic aspects were also discussed regarding the reaction pathways and the formation of side products. The significance lies in development of efficient one-pot reactions and in generation of new 1-alkoxyindoles.

Palladium-catalyzed highly regioselective hydroaminocarbonylation of aromatic alkenes to branched amides

2017 ◽  
Vol 15 (14) ◽  
pp. 2910-2913 ◽  
Author(s):  
Jinping Zhu ◽  
Bao Gao ◽  
Hanmin Huang
Keyword(s):  
Reaction Conditions ◽  
Efficient Catalyst ◽  
Palladium Catalyzed

Pd(t-Bu3P)2 has been successfully identified as an efficient catalyst for the hydroaminocarbonylation of aromatic alkenes to branched amides under relatively mild reaction conditions.

Synthesis of the Novel Thienopyrimidine-Based S-Glycoside Analogues via Nucleophilic Addition/Cyclization/Glycosylation Reactions

2013 ◽  
Vol 781-784 ◽  
pp. 999-1002
Author(s):  
Qiu Hong Dai ◽  
Kun Zou ◽  
Ming Guo Liu ◽  
Lin Luo ◽  
Nian Yu Huang
Keyword(s):  
Elemental Analysis ◽  
Nucleophilic Addition ◽  
The Novel ◽  
Reaction Conditions ◽  
Biological Screening ◽  
Structural Motifs ◽  
Efficient Approach

The title compounds thienopyrimidine-basedS-glycoside analogues were synthesized through the nucleophilic addition/cyclization/glycosylation reactions in good yields from easily accessible starting materials under mild reaction conditions. All of compounds were characterized by NMR, MS, IR and elemental analysis. The efficient approach allowed the facial synthesis of small libraries of thienopyrimidine-basedS-glycoside analogues with different structural motifs for biological screening.

scholarly journals Übergangsmetall-Carben-Komplexe, CXXXIV [1]. Synthese neuer Mono- und Biscarben-Komplexe der VI. Nebengruppe; Röntgenstruktur des ersten Bis[amino(alkoxy)carben]-Komplexes / Transition Metal Carbene Complexes, CXXXIV [1]. Synthesis of New Mono- and Bis-Carbene Complexes of Group VIb Elements; Structure of the First Bis[amino(alkoxy)carbene]-Complex

1984 ◽  
Vol 39 (5) ◽  
pp. 668-674 ◽  
Author(s):  
Ernst Otto Fischer ◽  
Rudolf Reitmeier ◽  
Klaus Ackermann
Keyword(s):  
Molecular Structure ◽  
Transition Metal ◽  
Spectroscopic Data ◽  
The Novel ◽  
Nucleophilic Agent ◽  
Reaction Conditions ◽  
Carbene Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Compounds

The hexacarbonyl compounds of chromium, molybdenum and tungsten react with the highly nucleophilic agent Li NiPr2 and in a subsequent alkylation with (Et3O)BF4 to give the carbene complexes (CO)5M[C(N′Pr2)OEt] (1, 3, 4). In case of W(CO)6 and Mo(CO)6 the novel biscarbene complexes cis(CO)4M[C(NiPr2)OEt]2 (2, 5) are additionally obtained. Reaction conditions, properties and spectroscopic data of the new compounds are reported. The molecular structure of cis(CO)4W[C(NiPr2)OEt]2 (4) was determined by X-ray crystallography

scholarly journals Coordination polymers of benzenediseleninate, the seleno analog of terephthalate

2014 ◽  
Vol 70 (a1) ◽  
pp. C1235-C1235
Author(s):  
Robert Burrow ◽  
Giancarlo Belmonte
Keyword(s):  
Coordination Polymers ◽  
Water Molecules ◽  
Gravimetric Analysis ◽  
The Novel ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Subsequent Formation ◽  
Metal Centers ◽  
Infrared Spectral

The proligand para-benzenediseleninic acid, (HO2SeC6H4SeO2H) (Figure), is the seleno analog to the commonly used MOF spacer proligand, terephthalic acid. Novel coordination polymers based on this proligand, and Mn(II), Fe(II), Co(II), Ni(II), Cu(II) or Zn(II) metal centers containing auxiliary water molecules, [M(O2SeC6H4SeO2)2(H2O)n], were synthesized. Depending on the reaction conditions, different pure or mixed phases can be produced. Crystal to crystal transformations of the novel coordination polymers were studied with powder X ray diffraction, infrared spectral analysis and thermal gravimetric analysis. These coordination polymers can be dehydrated with subsequent formation of new anhydrous coordination polymer phases. Some of these phases can be rehydrated to lead back to the crystalline starting materials or to new crystalline hydrated phases. We are working on the complete structural characterization of the phases.

Silica Gel Supported Dual Acidic Ionic Liquid as a Recyclable and Efficient Catalyst for Esterification and Acetalization Reactions

2011 ◽  
Vol 233-235 ◽  
pp. 1336-1339 ◽  
Author(s):  
Qiang Zhang ◽  
Hong Su ◽  
Jun Luo
Keyword(s):  
Ionic Liquid ◽  
Catalytic Activity ◽  
Silica Gel ◽  
Covalent Bond ◽  
High Catalytic Activity ◽  
The Novel ◽  
Hydrogen Sulfate ◽  
Efficient Catalyst ◽  
Acidic Ionic Liquid

A supported dual acidic ionic liquid was prepared via anchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto common silica gel by covalent bond. The novel immobilized acidic ionic liquid illustrated high catalytic activity in esterification and acetalization reactions. The products could be separated by simple decantation and the recovered catalyst could be recycled without remarkable loss of catalytic activity even after eight runs for esterification and six runs for acetalization.

Carbocation-Mediated Rearrangements Within [n.m.1]Propellane Frameworks

1991 ◽  
Vol 44 (4) ◽  
pp. 593 ◽  
Author(s):  
MG Banwell ◽  
JH Ryan ◽  
DA Winkler
Keyword(s):  
Prolonged Exposure ◽  
Methanesulfonic Acid ◽  
Mineral Acid ◽  
Allylic Alcohol ◽  
The Novel ◽  
Reaction Conditions

Mild thermolysis of the tetracyclic mesylate (6) in the presence of traces of mineral acid afforded a mixture of the rearrangement products (21) and (22) as well the σ-anti- bishomotetralin (20). On treatment with methanesulfonic acid in dichloromethane, compound (20) gives rise to the [5.4.1] propellene (21) which, on prolonged exposure to these reaction conditions, isomerizes to the mesyloxymethyl compound (22). Under the same conditions, the σ-anti- bishomoindan (4) is converted into the [5.3.1] propellene (3) which, in turn, slowly rearranges to the [4.3.1] propellene (23). A mechanistic rationalization of these observations is advanced which also accounts for the formation of the novel by-product (16) observed during Simmons-Smith cyclopropanation of allylic alcohol (15a).

scholarly journals Graphene encapsulated low-load nitrogen-doped bimetallic magnetic Pd/Fe@N/C catalyst for the reductive amination of nitroarene under mild conditions

2021 ◽  
Author(s):  
Jianguo liu ◽  
Shanshan Lin ◽  
Longlong Ma
Keyword(s):  
Noble Metals ◽  
Reductive Amination ◽  
Bimetallic Catalyst ◽  
Environmentally Friendly ◽  
Pharmaceutical Products ◽  
The Novel ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Doped Graphene ◽  
Catalytic Reactivity

Aniline is a group of important platform molecules and is widely used in the synthesis of other high-value chemicals and pharmaceutical products. How to produce high-value anilines as the high-value chemical intermediates more efficiently and more environmentally has always been a research topic in the industry. Catalytic hydrogenation is an environmentally friendly method for preparing halogenated anilines. Traditional noble metals catalysis face cost and noble metals residue problems. To improve the purity of the product and the activity and recyclability of the catalyst, we prepared a Pd/Fe magnetic bimetallic catalyst supported on N-doped carbon materials to reduce nitrobenzene to aniline under mild conditions. The loading of Pd was very low, which was 1/10 of the content of common commercial precious metal Pd/C and Pt/C catalysts, which was only 0.5%. And the prepared bimetallic Pd/Fe@N/C catalyst showed excellent catalytic reactivity with the conversion rate of nitrobenzene > 99%, and the selectivity of aniline 99% under mild reaction conditions of 0.8 MPa H2 and 40 °C. A variety of halogenated and aliphatic nitro compounds were well tolerated and had been transformed to the corresponding target amine products with excellent selectivity. In addition, the novel N-doped graphene-encapsulated bimetallic magnetic Pd/Fe@N/C catalyst not only had magnetic physical properties, which was easy to separate, recover, and used for the recycling of the catalyst without metal leaching but also catalyzed highly selective reductive amination of aromatics was a green, economical and environmentally friendly reaction with the only H2O as a by-product.

scholarly journals In situ Generated Ru(0)-HRO@Na-β From Hydrous Ruthenium Oxide (HRO)/Na-β: An Energy-Efficient Catalyst for Selective Hydrogenation of Sugars

2020 ◽  
Vol 8 ◽  
Author(s):  
Sreedhar Gundekari ◽  
Heena Desai ◽  
Krishnan Ravi ◽  
Joyee Mitra ◽  
Kannan Srinivasan
Keyword(s):  
Aqueous Medium ◽  
Reaction Temperature ◽  
Energy Efficient ◽  
Ruthenium Oxide ◽  
Green Process ◽  
Sugar Alcohols ◽  
Reaction Conditions ◽  
Efficient Catalyst ◽  
Hydrogenation Reactions

A green process for the hydrogenation of sugars to sugar alcohols was designed in aqueous medium using hydrous ruthenium oxide (HRO) as a pre-catalyst supported on Na-β zeolite. Under optimized reaction conditions, sugars such as xylose, glucose, and mannose converted completely to the corresponding sugar alcohols xylitol, sorbitol, and mannitol with 100% selectivity. The pre-catalyst (HRO) is converted in situ to active Ru(0) species during the reaction under H2, which is responsible for the hydrogenation. The catalyst was recyclable up to five cycles with no loss in activity. The reduction of HRO to the active Ru(0) species is dependent on the reaction temperature and H2 pressure. Ru(0) formation increased and consequently an increased hydrogenation of sugars was observed with an increase in reaction temperature and hydrogen pressure. Further, in situ generation of Ru(0) from HRO was assessed in different solvents such as water, methanol, and tetrahydrofuran; aqueous medium was found to be the most efficient in reducing HRO. This work further demonstrates the use of supported HRO as an efficient pre-catalyst for biomass-based hydrogenation reactions.

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