Application of diethyl 1-diazo-2-oxopropylphosphonate (Bestmann−Ohira reagent) as a cycloaddition partner with nitroalkenes has been extensively investigated. Base-mediated reaction of the Bestmann...

Phosphonylpyrazoles from Bestmann-Ohira reagent and nitroalkenes: synthesis and dynamic NMR studies.

The current review is a surgey of the analytical methodology for pharmaceuticals and related drugs reported in either Analytical Abstracts or Chemical Abstracts between November 1990 and November 1992. Areas that are included are lised in the Review Contents. The citations selected represent only a sampling of the published work and not include articles of a biochemical or clinical nature. The review is organized into major sections related to type of compound. In most instances a cited work will appear in only one of these

Pharmaceuticals and related drugs.

1,3-Dipolar cycloaddition of diazo compounds with olefinic substrates is a promising atom-economic strategy for the construction of functionalized pyrazoles. Over the last few years, our group has been engaged in the synthesis of phosphonyl/sulfonylpyrazoles and pyrazole esters by employing Bestmann-Ohira Reagent (BOR) and its sulfur and ester analogs as 1,3-dipole precursors with various dipolarophiles. This account describes the novel synthetic methods developed in our laboratory, in the perspective of closely related work by others, for the synthesis of phosphonyl/sulfonylpyrazoles, pyrazole esters and the total synthesis of Withasomnine, a natural product, by using 1,3-dipolar cycloaddition as the key step.

Synthesis of Functionalized Pyrazoles via 1,3-Dipolar Cycloaddition of α-Diazo-β-ketophosphonates, Sufones and Esters with Electron-Deficient Alkenes.

UV-visible and atomic spectrophotometry and HPLC techniques were applied for the determination of tetracycline (TC) in pharmaceutical preparations via complexation of the drug with Au(III) and Hg(II) ions in solutions. The mole ratio of TC to metal ions was 1 : 1. Maximum peak absorption at λ 425 and 320 nm for the two ions, respectively, was optimized at heating temperature 75°C for 15 minutes at pH = 4 followed by the extraction with ethyl acetate. The percentage of extraction and stability constants for the two complexes was 95.247, 95.335% and ,  M−1, respectively. HPLC method was applied without extraction process. The analytical data obtained from direct calibration curves of UV-visible absorption, FAAS, and HPLC for Au(III) complexes were recovery (100.78, 104.85, and 101.777%, resp.); detection limits (0.7403, 0.0997, and 2.647 μg/ml, resp.); linearity (5–70, 5–30, and 10–150 μg/ml, resp.), and correlation coefficient (0.9991, 0.9967, and 0.9986, resp.). The analytical data obtained from direct calibration curves for Hg(II) complexes by UV-visible spectrophotometry and HPLC were recovery (100.95 and 102.000%, resp.); detection limits (0.5867 and 2.532 μg/ml, resp.); linearity (5–70 and 10–150 μg/ml, resp.); and correlation coefficients (0.9989 and 0.9997, resp.).

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Determination of Tetracycline in Pharmaceutical Preparation by Molecular and Atomic Absorption Spectrophotometry and High Performance Liquid Chromatography via Complex Formation with Au(III) and Hg(II) Ions in Solutions

Spectrophotometric determination of oxytetracycline in pharmaceutical preparations using sodium molybdate as analytical reagent.

Complex Formation of Uranyl Acetate with Tetracycline and its Utilization for their Microdetermination

The structure and tautomerism of 5-amino-4-arylazopyrazoles (2a-f) are investigated in aqueous media. In solutions of pH>5 these compounds exist as ring N—1 protonated species. At pH>10 they afford anions which are stabilized by delocalization of the negative charge in the ring as well as on the arylazo moiety. Controlled potential electrolysis and polarographic analysis indicate that 2a-f are reduced via a four electron reduction process to triaminopyrazole and the corresponding substituted aniline derivative. A mechanism is suggested and discussed.

A. Kasem

Papers

Complex Formation of Uranyl Acetate with Tetracycline and its Utilization for their Microdetermination

Structure of 5-Amino-4-Arylazopyrazoles in Ethanolic Aqueous Media