Stereoelectronic Effects in the Nucleophilic Addition to the sp-Hybridized Carbon of a Ketene and Vinyl Cation:  When Is a Mesityl Effectively Smaller than a Phenyl Ring?1

Vinyl fluorides play an important role in drug development as they serve as bioisosteres for peptide bonds and are found in a range of biologically active molecules. The discovery of safe, general and practical procedures to prepare vinyl fluorides remains an important goal and challenge for synthetic chemistry. Here we introduce an inexpensive and easily-handled reagent and report simple, scalable, and metal-free protocols for the regioselective and stereodivergent hydrofluorination of alkynes to access both the E and Z isomers of vinyl fluorides. These conditions were suitable for a diverse collection of alkynes, including several highly-functionalized pharmaceutical derivatives. Mechanistic and DFT studies support C–F bond formation through a vinyl cation intermediate, with the (E)- and (Z)-hydrofluorination products forming under kinetic and thermodynamic control, respectively.<br>

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Recent Progress in Chemosensors Using Aldehyde-bearing Fluorophores for the Detection of Specific Analytes and their Bioimaging

Current Medicinal Chemistry ◽

10.2174/0929867325666180117095528 ◽

2019 ◽

Vol 26 (21) ◽

pp. 4003-4028 ◽

Cited By ~ 1

Author(s):

Fangjun Huo ◽

Yaqiong Zhang ◽

Caixia Yin

Keyword(s):

Biomedical Research ◽

Nucleophilic Addition ◽

Recent Progress ◽

Biological Imaging ◽

Tissue Imaging ◽

Fluorescence Probes ◽

Biological Applications ◽

Convenient Procedure ◽

Nucleophilic Mechanism

In recent years, aldehyde-appended fluorescence probes have attracted increasing attention. Fluorescent biological imaging includes many modern applications for cell and tissue imaging in biomedical research. Meanwhile, the nucleophilic mechanism is a very simple and convenient procedure for the preparation of aldehyde-sensing probes. This tutorial review focuses on aldehyde-bearing chemosensors based on nucleophilic addition mechanism with biological applications.

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New Amine and Aromatic Substituted Analogues of Phencyclidine: Synthesis and Determination of Acute and Chronic Pain Activities

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207322666191016152157 ◽

2019 ◽

Vol 22 (8) ◽

pp. 570-576

Author(s):

Maryam Shokrollahi ◽

Marjaneh Samadizadeh ◽

Mohsen Khalili ◽

Seyed A. Sobhanian ◽

Abbas Ahmadi

Keyword(s):

Nmda Receptors ◽

Phenyl Ring ◽

Piperidine Ring ◽

Methyl Group ◽

Physiological Properties ◽

Antinociceptive Effects ◽

The Central Nervous System ◽

Analgesic Activities ◽

Compound Ii ◽

New Compounds

Background: Phencyclidine (PCP, I) is a synthetic drug with remarkable physiological properties. PCP and its analogues exert many pharmacological activities and interact with some neurotransmitter systems in the central nervous system like particular affinity for PCP sites in NMDA receptors or dopamine uptake blocking or even both. Aim and Objective: The following research, methyl group with electron-donating and dipole moment characters was added in different positions of phenyl ring along with the substitution of benzylamine (with many pharmacological effects) instead of piperidine ring of I to produce new compounds (II-V) of this family with more analgesic activities. Materials and Methods: Analgesic activities of these new compounds were measured by tail immersion and formalin tests for acute and chronic pains, respectively. Also, the outcomes were compared with control and PCP (10 mg/kg) groups. Results: The results indicate that compounds III, IV, and V have more acute and chronic antinociceptive effects than PCP and compound II which may be concerned with more antagonizing activities of these new painkillers for the blockage of dopamine reuptake as well as high affinity for NMDA receptors PCP binding site. Conclusion: It can be concluded that the benzylamine derivative of phencyclidine with a methyl group on the benzyl position on phenyl ring (V) is a more appropriate candidate to reduce acute and chronic (thermal and chemical) pains compared to other substituted phenyl analogs (II-IV) and PCP.

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Oxidation of (1-hydroxybenzyl)ferrocene and its derivatives substituted in phenyl ring with bis(triphenylsilyl) chromate

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19823375 ◽

1982 ◽

Vol 47 (12) ◽

pp. 3375-3380 ◽

Cited By ~ 1

Author(s):

Jaroslav Holeček ◽

Karel Handlíř ◽

Milan Nádvorník ◽

Milan Vlček

Keyword(s):

Linear Dependence ◽

Rate Constants ◽

Oxidation Rate ◽

Phenyl Ring ◽

Equilibrium Constants ◽

Aprotic Solvents ◽

Protonation Equilibrium ◽

Oxidation Of Alcohols ◽

Hammett Σ Constants ◽

Sulphuric Acid Medium

Kinetics have been studied of oxidation of (1-hydroxybenzyl)ferrocenes substituted in phenyl ring with bis(triphenylsilyl) chromate in benzene solutions as well as protonation of these alcohols in sulphuric acid medium. Logarithms of the oxidation rate constants (kobs, 20-40 °C) and those of the protonation equilibrium constants (KR+, 25 °C) show linear dependence on the Hammett σ constants, the ρ constant values being -0.86 to -0.40 and -2.50, respectively. These negative values suggest that the both processes are influenced by the same effects and confirm the mechanism proposed earlier for oxidation of alcohols with ferrocenyl substituent by action of bis(triphenylsilyl) chromate in aprotic solvents.

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Formation of spiro adduct from N-methyl-N-(2,4,6-trinitrophenyl)glycine anion

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890440 ◽

1989 ◽

Vol 54 (2) ◽

pp. 440-445 ◽

Cited By ~ 1

Author(s):

Vladimír Macháček ◽

Alexandr Čegan ◽

Miloš Sedlák ◽

Vojeslav Štěrba

Keyword(s):

Nmr Spectroscopy ◽

Dimethyl Sulfoxide ◽

Equilibrium Constant ◽

Mole Fraction ◽

Nucleophilic Addition ◽

Adduct Formation ◽

First Case ◽

C Nmr

The intramolecular nucleophilic addition of N-methyl-N-(2,4,6-trinitrophenyl)glycine anion in methanol-dimethyl sulfoxide mixtures produces spiro[(3-methyl-5-oxazolidinone)-2,1'-(2',4',6'-trinitrobenzenide)]. The spiro adduct has been identified by means of 1H and 13C NMR spectroscopy. This is the first case when the formation of a Meisenheimer adduct with carboxylate ion is observed. Logarithm of the equilibrium constant of adduct formation increases linearly with the mole fraction of dimethyl sulfoxide in its mixture with methanol.

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