Synthesis,Characterization, Electrochemical and Antimicrobial Studies of Iron(II) and Nickel(II) Macrocyclic Complexes

Russian Journal of Electrochemistry - Herein, we synthesized [12] membered pyridine based transition metal macrocyclic complexes [MIILCl2] (M = Fe(II) and Ni(II), L = 6,12,5,11-tetraphenyl...     

β-Cyclodextrin-based chiral nanocomposite for thin-layer chromatographic detection of enantiomers of fluoxetine

Enantioselective analysis or separation is very essential for improved therapeutic effects of drugs as the pure enantiomeric drug formulations display potential benefits over racemates. In this work, we carried out (i) the synthesis of a nanocomposite of β-cyclodextrin and 3D graphene (G/β-CD NC), and (ii) its application for the detection of fluoxetine enantiomers [(RS)-FLX)] using a thin-layer chromatographic method. The synthesized nanocomposite was introduced into silica gel slurry while preparation of thin-layer plates. The separation conditions were optimized by altering pH, temperature, and mobile phase composition. The method is simple and easy to be optimized, and it can therefore be exploited to assess and monitor routine work of enantiomeric purity of drug enantiomers. The average precision (as measured by RSD) was in the region of 1.35‒1.65% for the enantiomers of (RS)-FLX. The measured limit of detection and limit of quantification for (RS)-FLX enantiomers were 1.8 and 5.4 mg mL^‒1, respectively.

     

A note on the paper of Kohli and Vashistha

In [1] Kohli and Vashistha gave an analogue of probabilistic version of Pant‘s Theorem ([2], Theorem 1). We note that mappings defined in Examples 3.6 to 3.8 of [1] are not self maps as claimed in the Definitions 3.1 and 3.2. In this context, we provide some relevant examples to complete the interesting results.     

Synthesis,Electrochemical and Antimicrobial Studies of Me6-Dibenzotetraazamacrocyclic Complexes of Ni(II) and Cu(II) Metal Ions

Russian Journal of Electrochemistry - Me6-dibenzotetraaza[14] annulene type macrocyclic complexes of Ni(II) and Cu(II) have been synthesized by template method and characterized by employing...     

Different approaches in thin-layer chromatography for enantioresolution of acebutolol using colistin sulfate as chiral selector

JPC – Journal of Planar Chromatography – Modern TLC - This work reports the enantioresolution of (RS)-acebutolol (ACB) by a thin-layer chromatographic method involving colistin sulfate...     

Sensitive enantioseparation and determination of isoprenaline in human plasma and pharmaceutical formulations

A simple, sensitive and fast RPHPLC method was developed and validated for the enantioselective determination of (RS)‐isoprenaline (Ipn) in human plasma. The enantiomers were converted to diastereomeric derivatives using s‐triazine (cyanuric chloride) based chiral derivatizing reagents. l ‐isoleucine and l ‐methionine were introduced as chiral auxiliary in s‐triazine and two new monochloro‐s‐triazine reagents were synthesized. These reagents were characterized and used for synthesis of diastereomeric derivatives of (RS)‐Ipn spiked in human plasma. (RS)‐Ipn was isolated (purified and characterized) from a commercial pharmaceutical formulation and was used as the standard racemic sample. Structures of the two diastereomeric derivatives were optimized for lowest energy using the Gaussian 09 Rev A. 02 program and hybrid density functional B3LYP with 6‐31G* basis set which showed the spatial orientation of hydrophobic groups on stereogenic centers in the diastereomeric derivatives. The results were correlated with the mechanism of separation and elution order. Limit of detection values were found to be 24.6 and 26.8 ng mL^?1 for the first and second eluting diastereomeric derivatives, respectively.     

Covalent Organic Frameworks-based Nanocomposites for Oxygen reduction reaction

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Due to the sluggish nature of the oxygen reduction reaction (ORR), it requires electro-catalysts to speed up the kinetics of ORR at a...     

Sensitive RP-HPLC Enantioseparation of (<Emphasis Type="Italic">RS</Emphasis>)-Ketamine via Chiral Derivatization Based on (<Emphasis Type="Italic">S</Emphasis>)-Levofloxacin

Enantioseparation of (RS)-ketamine has been achieved in the form of its diastereomeric hydrazones. A new chiral reagent was synthesized from enantiomerically pure (S)-levofloxacin by converting its carboxyl group into a hydrazide derivative: the reagent provided a reaction site for the ketonic group present in (RS)-ketamine. Because of the structural feature of the chiral reagent formation of diastereomeric hydrazones of (RS)-ketamine was successful without protection of its amino group. The diastereomeric hydrazones were separated on a reversed-phase C₁₈ column with a mobile phase consisting of MeCN and 0.1% TFA under gradient elution from 35 to 65% of MeCN. The limit of detection was found to be 3.2 and 3.4 nmol for first and second eluting diastereomeric hydrazones, respectively. The separation mechanism and elution order of the diastereomeric hydrazones were proposed and supported by developing the geometry optimized ‘lowest energy’ structures of the two diastereomeric hydrazones using DFT-based Gaussian software.     

Development of a thin-layer chromatographic method for the enantioresolution of sotalol using levofloxacin as chiral selector

JPC – Journal of Planar Chromatography – Modern TLC - In this work, a commercially available, chirally pure pharmaceutical containing carboxylic group, namely, levofloxacin was utilized...     

Inter-relationship between optical dielectric constant and interatomic separation of mixed crystals in ionic and covalent binary compound families

An ion dependent dielectric model is developed for mixed binary crystals. The interatomic separation (R) and optical dielectric constant (ε_∞) of the mixed crystals are computed from the measured values of R and ε_∞ of pure crystals. An empirical relation between ε_∞ and R is therefore found for mixed crystals by using the computed values. It is found that the dielectric behaviour of ionic mixed crystals is cation dependent while that of covalent mixed crystals is anion dependent. The prescribed theory can therefore be used to form different mixed crystals with particular values of ε_∞ required in any specific opto-electronic devices.