Methods and approaches for determination and enantioseparation of (RS)‐propranolol

Propranolol, a β‐adrenergic receptor antagonist, is a chiral compound that is marketed as a racemate, but only the (S)‐(?)‐enantiomer is responsible for the β‐adrenoceptor blocking activity. Different chromatographic methods have been applied for separation and determination of enantiomers of (RS)‐propranolol. In this article a review is presented on different liquid chromatographic methods used for enantioseparation of (RS)‐propranolol, using both HPLC and TLC. In addition, some aspects of enantioseparation under achiral phases of liquid chromatography have been briefly mentioned.     

Greener approach toward synthesis of biologically active s-Triazine (TCT) derivatives: A recent update

The greener methodology to synthesize s-triazine derivatives (also known as TCT) is described, including synthesis through microwave, ultrasound, and solvent-free conditions. This review mainly focuses on reactions of TCT (2,4,6-trichloro-1,3,5-triazine) with various substituents having amine and hydroxy functionalities to give corresponding triazine derivatives under a greener approach. The results of reactions indicate that, unlike classical methods, green methods result in better yields of the product, through a rapid reaction, under mild reaction conditions, and by easy workup procedures.     

Organotin (IV) complexes derived from tridentate Schiff base ligands: Synthesis,spectroscopic analysis,antimicrobial and antioxidant activity

Organotin complexes of Schiff bases (derived from the condensation of hydrazides with salicylaldehyde derivatives) were prepared and their characterization was done using several spectroscopic techniques like FTIR, NMR (¹H, ¹³C, and ¹¹⁹Sn) and mass spectrometry. The spectroscopic data of the ligands and their corresponding complexes revealed that the Schiff bases chelated to the tin metal in a tridentate manner through –ONO atoms (oxygen atom of the hydroxyl group of the salicylaldehydic derivatives, the nitrogen atom of azomethine group, and the oxygen atom of enolic group present in the carboxylic acid hydrazides). Around tin atom pentacoordinated geometry was exhibited. The synthesized ligands and their complexes have been assessed for their biological potency (antibacterial, antifungal and antioxidant using Ciprofloxacin, Fluconazole and Ascorbic acid as reference compounds) and few of the compounds showed optimistic activity. The ligands having electron withdrawing group attached showed greater antimicrobial activity as compared to the other ligands. The complexes showed the better activity than the ligands. The general trend followed by the complexes was diphenyl ?> ?dibutyl ?> ?dimethyl substituted complexes. Compound 11 was the most active against microbes. The antioxidant activity increased with electron donating group. The phenyl substituted complexes showed better activity as compared to the dibutyl and dimethyl substituted complexes. Compound 20 was the best antioxidant.     

Cobalt(II) Complex Catalysed Epoxidation with Molecular Oxygen

Cobalt(II) complexes 1 or 2, catalyses the epoxidation of alkenes in the presence of molecular oxygen and 2-methylpropanal in high yields.     

High‐performance liquid chromatographic enantioseparation of (RS)‐bupropion using isothiocyanate‐based chiral derivatizing reagents

A high‐performance liquid chromatographic (HPLC) method for enantioseparation of bupropion was developed using two isothiocyanate‐based chiral derivatizing reagents, (S)‐1‐(1‐naphthyl) ethyl isothiocyanate, (S)‐NEIT, and (R)‐α‐methyl benzyl isothiocyanate, (R)‐MBIT. The diastereomers synthesized with (S)‐NEIT were enantioseparated by reversed‐phase HPLC using gradient elution with mobile phase containing water and acetonitrile, whereas diastereomers synthesized with (R)‐MBIT were enantioseparated using triethyl amine phosphate buffer and methanol. Derivatization conditions were optimized and the method was validated for accuracy, precision and limit of detection. The limit of detection was found to be 0.040–0.043 µg/mL for each of the diastereomers prepared with (S)‐NEIT. Copyright © 2013 John Wiley & Sons, Ltd.     

Novel,Mild, and Highly Efficient Method for the Synthesis of 2-Arylbenzothiazoles by the Oxidation of 2-Arylbenzothiazolines with Silicon Lewis Acids

Oxidation of structurally diverse 2-arylbenzothiazolines to give the corresponding 2-arylbenzothiazoles has been carried out in benzene using dimethyldichlorosilane and trimethylchlorosilane. Short reaction times, mild reaction conditions, easy and quick isolation of the products, and excellent yields are the main advantages of this procedure.     

An Efficient Method for Agrobacterium-Mediated Genetic Transformation and Plant Regeneration in Cumin (Cuminum cyminum L.)

Cumin is an annual herbaceous medicinally important plant having diverse applications. An efficient and reproducible method of Agrobacterium-mediated genetic transformation was herein established for the first time. A direct regeneration method without callus induction was optimised using embryos as explant material in Gamborg’s B5 medium supplemented with 0.5-μM 6-benzyladenine and 2.0-μM α-naphthalene acetic acid. About 1,020 embryos (a mean of 255 embryos per batch) were used for the optimisation of transformation conditions. These conditions were an Agrobacterium cell suspension of 0.6 OD₆₀₀, a co-cultivation time of 72 h, 300-μM acetosyringone and wounding of explants using a razor blade. Pre-cultured elongated embryos were treated using optimised conditions. About 720 embryos (a mean of 180 embryos per batch) were used for transformation and 95 % embryos showed transient β-glucuronidase expression after co-cultivation. Putative transformed embryos were cultured on B5 medium for shoot proliferation and 21 regenerated plants were obtained after selection and allowed to root. T₀ plantlets showed β-glucuronidase expression and gene integration was confirmed via PCR amplification of 0.96 and 1.28 kb fragments of the hygromycin-phosphotransferase II and β-glucuronidase genes, respectively. In this study, a transformation efficiency of 1.5 % was demonstrated and a total of 11 transgenic plants were obtained at the hardening stage, however, only four plants acclimatised during hardening. Gene copy number was analysed by Southern blot analysis of hardened plants and single-copy gene integration was observed. This is the first successful attempt of Agrobacterium-mediated genetic transformation of cumin.     

Bioactive Penta-Coordinated Diorganotin(Iv) Complexes of Pyridoxalimine Schiff Bases

Abstract

Diorganotin(IV) complexes of an extended system derived from the condensation of pyridoxal hydrochloride with 2-amino phenol (H₂L¹), 2-amino-4-methyl phenol (H₂L²), 2-amino-4-chloro phenol (H₂L³), 2-amino-4-nitro phenol (H₂L⁴), 1-amino-2-naphthol hydrochloride (H₂L⁵) have been synthesized by the reaction of dichlorodiorganotin(IV) in a 1:1 molar ratio with these ligands. Spectral studies (IR, ¹H, ¹³C, ¹¹⁹Sn NMR) along with physical data evidenced the formation of penta-coordinated species with the ligands acting as tridentate (ONO) with oxygen occupying the axial positions, and nitrogen at one of the equatorial positions. The ligands and their organotin complexes have been evaluated for antimicrobial activity against phytopathogenic fungi Candida albicans and Aspergillus niger at 25 ± 1 °C and bacteria Bacillus subtilis, Escherichia coli, and Staphylococcus aureus at 37 ± 1 °C. The activities of the ligands have been enhanced on complexation and the results indicate that they exhibit significant antimicrobial properties.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Microproteomic analysis of 10,000 laser captured microdissected breast tumor cells using short-range sodium dodecyl sulfate-polyacrylamide gel electrophoresis and porous layer open tubular liquid chromatography tandem mass spectrometry

Precise proteomic profiling of limited levels of disease tissue represents an extremely challenging task. Here, we present an effective and reproducible microproteomic workflow for sample sizes of only 10,000 cells that integrates selective sample procurement via laser capture microdissection (LCM), sample clean-up and protein level fractionation using short-range SDS-PAGE, followed by ultrasensitive LC-MS/MS analysis using a 10 μm i.d. porous layer open tubular (PLOT) column. With 10,000 LCM captured mouse hepatocytes for method development and performance assessment, only 10% of the in-gel digest, equivalent to ～1000 cells, was needed per LC-MS/MS analysis. The optimized workflow was applied to the differential proteomic analysis of 10,000 LCM collected primary and metastatic breast cancer cells from the same patient. More than 1100 proteins were identified from each injection with >1700 proteins identified from three LCM samples of 10,000 cells from the same patient (1123 with at least two unique peptides). Label free quantitation (spectral counting) was performed to identify differential protein expression between the primary and metastatic cell populations. Informatics analysis of the resulting data indicated that vesicular transport and extracellular remodeling processes were significantly altered between the two cell types. The ability to extract meaningful biological information from limited, but highly informative cell populations demonstrates the significant benefits of the described microproteomic workflow.     

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...