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 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.

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 Effect of the Novel Antifungal Drug F901318 (Olorofim) on Growth and Viability ofAspergillus fumigatus

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Saskia du Pré ◽  
Nicola Beckmann ◽  
Mariana Cruz Almeida ◽  
Graham E. M. Sibley ◽  
Derek Law ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
De Novo ◽  
Hyphal Growth ◽  
Cell Lysis ◽  
Antifungal Drug ◽  
The Novel ◽  
Content Type ◽  
New Class ◽  
Highly Active ◽  
Germination And Growth

ABSTRACTF901318 (olorofim) is a novel antifungal drug that is highly active againstAspergillusspecies. Belonging to a new class of antifungals called the orotomides, F901318 targets dihydroorotate dehydrogenase (DHODH) in thede novopyrimidine biosynthesis pathway. In this study, the antifungal effects of F901318 againstAspergillus fumigatuswere investigated. Live cell imaging revealed that, at a concentration of 0.1 μg/ml, F901318 completely inhibited germination, but conidia continued to expand by isotropic growth for >120 h. When this low F901318 concentration was applied to germlings or vegetative hyphae, their elongation was completely inhibited within 10 h. Staining with the fluorescent viability dye bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC) showed that prolonged exposure to F901318 (>24 h) led to vegetative hyphal swelling and a decrease in hyphal viability through cell lysis. The time-dependent killing of F901318 was further confirmed by measuring the fungal biomass and growth rate in liquid culture. The ability of hyphal growth to recover in drug-free medium after 24 h of exposure to F901318 was strongly impaired compared to that of the untreated control. A longer treatment of 48 h further improved the antifungal effect of F901318. Together, the results of this study indicate that F901318 initially has a fungistatic effect onAspergillusisolates by inhibiting germination and growth, but prolonged exposure is fungicidal through hyphal swelling followed by cell lysis.

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 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 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.

Thermodynamics of methanesulfonic acid revisited

2000 ◽  
Vol 78 (10) ◽  
pp. 1295-1298 ◽  
Author(s):  
J Peter Guthrie ◽  
Roger T Gallant
Keyword(s):  
Methanesulfonic Acid ◽  
Heat Of Formation ◽  
Methyl Methanesulfonate ◽  
Thermodynamic Quantities ◽  
Heat Of Reaction ◽  
Reaction Conditions ◽  
Free Energy Of Formation ◽  
Sulfite Ion ◽  
Energy Of Formation

Recently we reported a study of the thermodynamics of methanesulfonic acid and some of its derivatives. The foundation of these results was a measurement of the heat of reaction of S-methyl thioacetate with aq sodium hypochlorite, leading to methanesulfonic acid. We have reinvestigated this reaction and discovered that contrary to the initial stoichiometry experiments, the stoichiometry under the reaction conditions is not as was believed and that the heat of reaction observed was spuriously high. We have found a new reaction, that of sulfite ion with methyl methanesulfonate, which does allow a clean determination of the heat of formation of methanesulfonic acid. Revised thermodynamic quantities for methanesulfonic acid, methanesulfonyl chloride, and methyl methanesulfonate are reported here.Key words: sulfonic acid, heat of reaction, free energy of formation, SN2 reaction.

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 Methanation of CO2 Using MIL-53-Based Catalysts: Ni/MIL-53–Al2O3 versus Ni/MIL-53

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1412
Author(s):  
Oana Grad ◽  
Gabriela Blanita ◽  
Mihaela D. Lazar ◽  
Maria Mihet
Keyword(s):  
Prolonged Exposure ◽  
Reaction Medium ◽  
Catalytic Performance ◽  
The Novel ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
Nanoparticle Deposition ◽  
Metallic Particles ◽  
Al2o3 Composite ◽  
Methane Selectivity

MIL-53 and the MIL-53–Al2O3 composite synthesized by a solvothermal procedure, with water as the only solvent besides CrCl3 and benzene-1,4-dicarboxylic acid (BDC), were used as catalytic supports to obtain the novel MIL-53-based catalysts Ni(10 wt.%)/MIL-53 and Ni(10 wt.%)/MIL-53–Al2O3. Ni nanoparticle deposition by an adapted double-solvent method leads to the uniform distribution of metallic particles, both smaller (≤10 nm) and larger ones (10–30 nm). MIL-53–Al2O3 and Ni/MIL-53–Al2O3 show superior thermal stability to MIL-53 and Ni/MIL-53, while MIL-53–Al2O3 samples combine the features of both MIL-53 and alumina in terms of porosity. The investigation of temperature’s effect on the catalytic performance in the methanation process (CO2:H2 = 1:5.2, GHSV = 4650 h−1) revealed that Ni/MIL-53 is more active at temperatures below 300 °C, and Ni/MIL-53–Al2O3 above 300 °C. Both catalysts show maximum CO2 conversion at 350 °C: 75.5% for Ni/MIL-53 (methane selectivity of 93%) and 88.8% for Ni/MIL-53–Al2O3 (methane selectivity of 98%). Stability tests performed at 280 °C prove that Ni/MIL-53–Al2O3 is a possible candidate for the CO2 methanation process due to its high CO2 conversion and CH4 selectivity, corroborated by the preservation of the structure and crystallinity of MIL-53 after prolonged exposure in the reaction medium.

One-Pot Synthesis of 2-Substituted Benzoxazoles Directly from Carboxylic Acids

2008 ◽  
Vol 61 (11) ◽  
pp. 881 ◽  
Author(s):  
Dinesh Kumar ◽  
Santosh Rudrawar ◽  
Asit K. Chakraborti
Keyword(s):  
Carboxylic Acids ◽  
Methanesulfonic Acid ◽  
Acid Chlorides ◽  
Double Bonds ◽  
Reaction Conditions ◽  
One Pot ◽  
Effective Catalyst ◽  
One Pot Synthesis ◽  
Highly Effective

Methanesulfonic acid has been found to be a highly effective catalyst for a convenient and one-pot synthesis of 2-substituted benzoxazoles by the reaction of 2-aminophenol with acid chlorides, generated in situ from carboxylic acids. Aryl, heteroaryl, and arylalkyl carboxylic acids provided excellent yields of the corresponding benzoxazoles. The reaction conditions were compatible with various substituents such as chloro, bromo, nitro, methoxy, cyclopentyloxy, phenoxy, thiophenoxy, and conjugated double bonds. Benzoxazole formation was found to be general with respect to substituted 2-aminophenols.

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