Non-porous interpenetrating Co-bpe MOF for colorimetric iodide sensing

2021 ◽  
Vol 50 (38) ◽  
pp. 13430-13437
Author(s):  
Deepika Rani ◽  
Kuldeep Kumar Bhasin ◽  
Monika Singh
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Mechanism

An interpenetrating non-porous ladder shaped MOF, Co-bpe, display remarkable solvatochromic iodide sensing through a double nucleophilic substitution mechanism.

Experimental and quantum-chemical study of nucleophilic substitution mechanism in berberine

2015 ◽  
Vol 51 (11-12) ◽  
pp. 997-1007 ◽  
Author(s):  
Oleg N. Burov ◽  
Mikhail E. Kletskii ◽  
Nikita S. Fedik ◽  
Sergey V. Kurbatov ◽  
Anton V. Lisovin
Keyword(s):  
Nucleophilic Substitution ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Substitution Mechanism

Synthesis of 7-Acyl-2,4-disubstituted Pteridines by Radical Nucleophilic Substitution and Displacement Reactions

Pteridines ◽  
2004 ◽  
Vol 15 (4) ◽  
pp. 129-148 ◽  
Author(s):  
Thomas Döring ◽  
Romesh C. Boruah ◽  
Wolfgang Pfleiderer
Keyword(s):  
Nucleophilic Substitution ◽  
Uv Spectra ◽  
Structural Modifications ◽  
Cyclic Amines ◽  
H Nmr ◽  
Substitution Mechanism ◽  
Acyl Radicals ◽  
Elemental Analyses ◽  
Displacement Reactions ◽  
Pteridine Derivatives

Abstract 2,4-Disubstituted pteridine derivatives (1-3) react with acyl radicals very selectively in position 7 by a nucleophilic Substitution mechanism (4-10). Oxidation of the 2-methylthio group proceeds with m-chloroperbenzoic acid in good yields to the corresponding 7-acyl-2-methylsulfonyl-4-aminopteridines (11-16). The methylsulfonyl group can easily been displaced by nucleophiles such as aliphatic amines (27, 29, 32-42, 45), cyclic amines (56-61), aromatic amines (30, 31) and amino acids (43-54). Oxygen nucleophiles lead to 7-acyl-isopterin derivatives (62-66). The acyl side-chain is also prone to structural modifications leading to the corresponding secondary alcohols on NaBH4 reduction (74-77) or to imino derivatives on reactions with amines (67-73) which can analogously been reduced to 2,4-disubstituted 7-( l-aminoalkyl)pteridines (80-85). An interesting H-shift was observed during heating of 32, 78 and 79 with benzylamine leading not to the benzylimines but the isomeric benzylideneamino derivatives 86-88. Various acetylations by acetic anhydride (AC2O) gave 89-93 and reduction of the pyrazine moiety to the 5,6,7,8-tetrahydro-pteridine derivatives 94-96 proceeded in the expected manner. The characterization of ther newly synthesized pteridine derivatives was performed by 1H-NMR spectra, UV-spectra and elemental analyses. Measurements of the basic pKa values of a selection of 2,4,7-trisubstituted pteridines were pteridines to characterize the dication, monocation and the neutral species by their UV-spectra.

The Syntheses, Characterization and Crystal Structures of a Series of Heterocyclic β-Diketones and Their Isoxazole Compounds

2020 ◽  
Vol 16 (8) ◽  
pp. 1174-1184
Author(s):  
Biyun Su ◽  
Yifan Hou ◽  
Li Wang ◽  
Xiaoteng Li ◽  
Dandan Pan ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Crystal Structures ◽  
1H Nmr ◽  
Single Molecule ◽  
Room Temperature ◽  
Hydroxylamine Hydrochloride ◽  
Phase System ◽  
X Ray ◽  
Coordination Sites ◽  
Substitution Mechanism

Background: In the field of coordination chemistry, the introduction of heterocyclic substituents into the structure of β-diketone enables ligand to produce multiple coordination sites. The adoption of small steric oxime group into the structure of heterocyclic β-diketone by Schiff-base condensation will further increase coordination sites and facilitate the generation of polynuclear structures. Objective: A series of β-diketones (2a-2c) containing different heterocycles such as pyridine, thiophene and furan and their corresponding isoxazole compounds (3a-3c) were synthesized. Materials and Methods: The Claisen condensations were investigated in a solvent-free rheological phase system at room temperature to obtain heterocyclic β-diketones 2a-2c, which further reacted with hydroxylamine hydrochloride to obtain heterocyclic isoxazoles 3a-3c. All these compounds were well characterized by EA, IR, 1H NMR and X-ray crystal diffraction to confirm the structures. Synthetic mechanisms of compounds and the effects of different heterocycles on reactivity were discussed deeply. Result: 1H NMR indicated that these β-diketones do not exist as a total diketonic form but an equilibration between diketone and enol forms in CDCl3 solvent, in which the enol form accounts for 98.0% in 2a, 94.3% in 2b, 95.5% in 2c. While the crystal structures of 2a-2c showed that the reaction allows to isolate diketones in solid state. Crystal structures of 3a-3c showed that the neutral β-ketone oximes resonate and cyclize to form the target heterocyclic isoxazoles. Conclusion: SN1 nucleophilic substitution mechanism of Claisen ketoester condensation was proposed for the syntheses of 2a-2c, and SN1 single molecule nucleophilic substitution reaction mechanism was put forward for 3a-3c.

ChemInform Abstract: Nucleophilic Substitution Mechanism in 1,3,5-Triazine Derivatives

ChemInform ◽  
2010 ◽  
Vol 23 (30) ◽  
pp. no-no
Author(s):  
V. A. SAVELOVA ◽  
ZH. P. PISKUNOVA ◽  
L. P. DRIZHD ◽  
N. A. TARAN
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Mechanism ◽  
Triazine Derivatives
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