ChemInform Abstract: The First Example of Ring Expansion of N-Tosylaziridines to 2-Aroyl-N-tosylazetidines with Nitrogen Ylides in an Aqueous Medium.

<div>The isolation and reactivities of two pentacoordinated phosphorus–tetracoordinated boron bonded compounds were</div><div>explored. A strong Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the</div><div>pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF</div><div>stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a</div><div>unique rearrangement reaction, that involved a two-fold ring expansion, to give an unusual fused bicyclic compound or it</div><div>could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive</div><div>towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound,</div><div>a phosphoranyl-triarylborate, was found to have a vastly different reactivity to the trihydroborate as it was highly stable</div><div>towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure</div>

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Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

10.26434/chemrxiv.8263415.v1 ◽

2019 ◽

Cited By ~ 3

Author(s):

Hannah E. Burdge ◽

Takuya Oguma ◽

Takahiro Kawajiri ◽

Ryan Shenvi

Keyword(s):

Intramolecular Cyclization ◽

Cross Coupling ◽

Building Blocks ◽

Ring Expansion ◽

Dual Catalysis ◽

Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

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Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

10.26434/chemrxiv.8263415 ◽

2019 ◽

Author(s):

Hannah E. Burdge ◽

Takuya Oguma ◽

Takahiro Kawajiri ◽

Ryan Shenvi

Keyword(s):

Intramolecular Cyclization ◽

Cross Coupling ◽

Building Blocks ◽

Ring Expansion ◽

Dual Catalysis ◽

Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

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Biomimic Oxidation Kinetics of Folic Acid by Amine μ-peroxo Complex in Aqueous medium

Journal of Chemistry and Chemical Sciences ◽

10.29055/jccs/530 ◽

2017 ◽

Vol 7 (12) ◽

pp. 1196-1201

Author(s):

S. Ignatius Arockiam

Keyword(s):

Folic Acid ◽

Aqueous Medium ◽

Oxidation Kinetics ◽

Peroxo Complex ◽

Kinetics Of

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Surface interaction of sweet potato peels (Ipomoea batata) with Cd(II) and Pb(II) ions in aqueous medium

10.31221/osf.io/gfdht ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Aqueous Medium ◽

Sweet Potato ◽

Adsorption Process ◽

Low Cost ◽

Correlation Coefficients ◽

Order Kinetic ◽

Thermodynamic Evaluation ◽

Dissociative Mechanism ◽

Pseudo Second Order ◽

Potato Peels

The removal of Cd(II) and Pb(II) ions from aqueous medium was studied using potato peels biomass. The adsorption process was evaluated using Atomic Absorption Spectrophotometer (AAS). The Vibrational band of the potato peels was studied using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption process was carried out with respect to concentration, time, pH, particle size and the thermodynamic evaluation of the process was carried at temperatures of 30, 40, 50 and 60(0C), respectively. The FTIR studies revealed that the potato peels was composed of –OH, -NH, –C=N, –C=C and –C-O-C functional groups. The optimum removal was obtained at pH 8 and contact time of 20 min. The adsorption process followed Freundlich adsorption and pseudo second-order kinetic models with correlation coefficients (R2) greater than 0.900. The equilibrium adsorption capacity showed that Pb(II) ion was more adsorbed on the surface of the potato peels biomass versus Cd (II) ion (200.91 mg/g > 125.00 mg/g). The thermodynamic studies indicated endothermic, dissociative mechanism and spontaneous adsorption process. This study shows that sweet potato peels is useful as a low-cost adsorbent for the removal of Cd(II) and Pb(II) ions from aqueous medium.

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