EPR and optical absorption studies of vanadyl impurity in zinc potassium phosphate hexahydrate single crystal

Electron paramagnetic resonance (EPR) study of VO²⁺ doped zinc potassium phosphate hexahydrate single crystal is carried out. The angular variation of the spectra is studied in the three crystallographic planes. The principal value of spin Hamiltonian parameters g and A and the direction cosines which principal axes make with the crystallographic axes are determined. The observed values are site I: g_∥=1.9664±0.0002, g_⊥=1.9973±0.0002, A_∥=150±2×10⁻⁴, A_⊥=60±2×10⁻⁴ cm⁻¹; site II: g_∥=1.9276±0.0002, g_⊥=1.9921±0.0002, A_∥=155±2×10⁻⁴ and A_⊥=62±2×10⁻⁴ cm⁻¹. By comparison of direction cosines of g from EPR with the direction cosines of different bonds obtained from crystal structure data it is ascertained that the VO²⁺ ion occupies Zn²⁺ substitutional sites. The optical absorption study of the crystal at room temperature is also carried out. The bands observed in the optical absorption spectrum are attributed to d-d transitions. The EPR results together with the optical data are employed to estimate the molecular orbital (MO) coefficients. These MO coefficients (also called bonding coefficients) are further used to discuss the nature of bonding of VO²⁺ ion with different ligands in the crystal.     

Study of ion transport and materials properties of K+-ion conducting solid polymer electrolyte (SPE): [(1-x) PEO: xCH3COOK]

Study of ion transport behavior in K⁺-ion conducting solid polymer electrolyte (SPE) films: [(1-x) PEO: xCH₃COOK] has been reported. Poly (ethylene oxide) PEO has been used as polymeric host and potassium acetate: CH₃COOK as complexing salt. SPE films in varying salt concentrations have been prepared by hot-press cast method. SPE film: [95PEO: 5CH₃COOK] has been identified as Optimum Conducting Composition (OCC) with room temperature conductivity (σ _rt) ~ 2.74 × 10⁻⁷ S/cm. As a consequence of salt complexation in polymeric host, σ _rt-enhancement of approximately two orders of magnitude was achieved in SPE OCC film. Ion transport property has been characterized in terms of ionic conductivity (σ), total ionic (t _ion)/cation (t ₊) transference numbers using different ac/dc techniques. Temperature-dependent conductivity measurement was done to explain mechanism of ion transport and to evaluate activation energy (E _a). XRD, FTIR, and DSC techniques were used to study materials property in SPE OCC film which also confirmed the complexation of salt in the polymeric host as well as increase in degree of amorphousity.

     

Spectrophotometric determination of ritodrine and isoxsuprine hydrochlorides using 4-aminoantipyrine

A simple, accurate, and rapid method for the quantitative determination of ritodrine hydrochloride (RTH) and isoxsuprine hydrochloride (ISH) in both pure and dosage forms, is described. The method is based on the development of pink colored product as a result of the condensation of 4-aminoantipyrine with phenols in the presence of an alkaline oxidizing agent. The resulting products are measured at 510 nm for both drugs, with molar absorptivities of 0.98 x 10(4) and 1.20 x 10(4) L/mol x cm for RTH and ISH, respectively. A study of the effect of commonly associated excipients revealed that they did not cause interference.     

Chromium(II) chloride reduction of α,β-unsaturated nitroalkenes. a facile route to carbonyl compounds.

α,β-Unsaturated nitroalkenes are readily reduced by chromium(II) chloride to the corresponding carbonyl compounds in good yields.     

In vitro multiplication in Kaempferia galanga linn

Kaempferia galanga is an important medicinal plant that is facing threat of extinction owing to indiscriminate and unsustainable harvesting in the wild. Conventional breeding is difficult in this plant, and in vitro multiplication is important to conservation and propagation. Leaf and rhizome explants of Kaempferia were aseptically cultured on MS medium with various combinations of indole-3-acetic acid (IAA), benzyl amino purine (BAP), napthalene acetic acid (NAA), 2-4-dichlorophenoxy acetic acid (2,4-D) and kinetin at concentrations ranging from 0.5 to 2.5 mg/L. High-frequency organogenesis and multiple shoot regeneration was induced from rhizome explants on MS medium supplemented with 0.5 mg/L of IAA and 2.5 mg/L of BAP. Rooting was induced in MS medium with 0.5 mg/L of IAA and 2 mg/L of BAP.     

Lithiation of 1-chloromethylbenzotriazole: generation and elaboration of benzotriazolyloxiranes

1-Benzotriazolylchloromethyllithium generated from 1-chloromethylbenzotriazole (1) and LDA reacts with enolizable and nonenolizable ketones to give benzotriazolyloxiranes 2a-g in good yields. The oxiranyllithiums 4a-d generated from 2a-d and n-BuLi at -78 degrees C were trapped by a variety of electrophiles to give oxiranyl derivatives 5a-j in good to excellent yields. Lewis-acid-promoted nucleophilic ring opening of benzotriazolyloxiranes 2a,f,g with allyltrimethylsilane gave the corresponding 1,7-octadien-4-ols 6a-c in 68-75% yield. Hydrolysis of alpha-acylbenzotriazolyloxiranes 5g,h provided 3-hydroxy-1,2-diones 7a and 7b in 73 and 86% yield, respectively.     

HPLC Determination of Ritodrine Hydrochloride in Pharmaceutical Formulations

A simple, rapid, and accurate HPLC method is described for the determination of ritodrine hydrochloride (RTH) in both pure form and pharmaceutical formulations. A Hypersil Shendon ODS column with a mobile phase of dibasic phosphate buffer and acetonitrile (75 : 25) and isoxsuprine hydrochloride were used as an internal standard. The flow rate was 1 mL min^–1 and the effluent was monitored at 270 nm pH 4.0. The calibration graph is linear in the range 2–30 g mL^–1. The proposed HPLC method has been successfully employed for the determination of RTH in Yutopar tablets and injection solutions.