Synthesis and human leukocyte elastase inhibitory activity of novel 2-spiro(2′,2′-diphenylcyclopropane) cephalosporin sulfones

A new series of 2-spiro(2,2-diphenylcyclopropane) cephalosporin sulfones was synthesizes as potent human leukocyte elastase inhibitors.SynPhar Laboratories Inc., #2 Taiho Alberta Centre, 4290-91A Street, Edmonton, Canada T6R 5V2. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1517–1523, November, 1998.     

Studies on monobactams II. Synthesis and β-lactamase inhibitory activity of 4α-methyl-3-[(thien-2-yl)-methylene]-2-azetidinone-1-sulfonate

Two monobactam derivatives, potassium 4-methyl-(3E)-[(thien-2-yl)methylene]-2-azetidinone-1-sulfonate and its (3Z)-isomer, were prepared and evaluated for their -lactamase inhibitory activities. These compounds were devoid of -lactamase inhibitory activity.SynPhar Laboratories Inc., #2, 4290-91A Street, Edmonton, Alberta T6E 5V2, Canada. Tokushima Research Institute, Taiho Pharmaceutical Co., Ltd., 224-2 Ebisuno Hiraishi, Kawauchi-cho, Tokushima 771-01, Japan. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1548–1552, November, 1998.     

Application of sodium metaperiodate for the determination of ribavirin in pharmaceutical formulations

Three simple and sensitive visible spectrophotometric methods (A-C) have been described for the assay of ribavirin either in pure form or in pharmaceutical formulations. They are based on the oxidation of ribavirin with excess sodium metaperiodate and estimating either the products formed (dialdehyde with MBTH, method A; iodate with metol-sulphanilamide, in the presence of Mo(VI) and iodide, method B) or the amount of periodate consumed (celestine blue in the presence of telurium (IV), method C). All of the variables have been optimized and the reaction mechanisms presented. The concentration measurements are reproducible within a R.S.D. of 1.0%. Recoveries are 99.2-101.2%.     

K α L 1 satellite multiplet structure of photon-excited chlorine atoms

Summary An attempt is made to study theK _α L ¹ satellite multiplet structure of chlorine atoms in different compounds by photon excitation. A comparison of the averageK _α L ¹ group energy shift from the diagram line with those based on Dirac-Fock evaluations with different number ofM-shell electrons shows a reasonable agreement. The intensity ratios are found to be higher than those studied in Mg compounds in general.     

Reductive etherification of carbonyl compounds with alkyl trimethylsilylethers using polymethylhydrosiloxane (PMHS) and catalytic B(C6F5)3

A facile synthesis of symmetrical and unsymmetrical ethers is achieved by reductive coupling of carbonyl compounds with alkoxysilanes. This reaction is performed using inert polymethylhydrosiloxane as the hydride source and B(C₆F₅)₃ as the catalytic activator of the PMHS.     

Synthesis of homoallylic chiral tertiary alcohols via chelation-controlled diastereoselective nucleophilic addition on alpha-alkoxyketones: application for the synthesis of the C(1)-C(11) subunit of 8-epi-fostriecin

[reaction: see text] Chiral beta-syn-alkoxyhomoallylic alcohols derived from alkoxyallylboration of aldehydes upon oxidation provided the corresponding chiral ketones. Chelation-controlled nucleophilic addition to these ketones occurred in a highly stereoselective manner to afford anti-homoallylic tertiary alcohols. This methodology has been applied for the synthesis of the C(1)-C(11) subunit of C(8)-epi-fostriecin.     

Reactivity ratios of ethyl acrylate,n-butyl methacrylate copolymer system by 1H-NMR

Ethyl acrylate (EA) and n-butyl methacrylate (n-BMA) copolymers were prepared in solution and the composition of the copolymer samples was estimated by ¹H-NMR spectroscopic techniques. Because the characteristic signals, which vary with the composition of the copolymer, were absent, the ratio of intensities of down-field protons to that of the total protons was used for the estimation of copolymer composition. Reactivity ratios were calculated from these values by using the Kelen-Tudos differential linear equation.     

A novel conversion of erythro phospholane epoxides to one-carbon atom homologated allylic alcohols

A novel synthetic approach is described to incorporate one more carbon atom at C-2 position of phospholane oxides as homologated allylic alcohol by treatment of erythro-2,3-epoxy-3-methylphospholane 1-oxides with excess of dimethylsulfonium methylide.     

Two new 5-deoxyflavones from Albizia odoratissima

Two new 5-deoxyflavones, 7,8-dimethoxy-3',4'-methylenedioxyflavone (1) and 7,2',4'-trimethoxyflavone (2) together with a known flavone, 7,4'-dimethoxy-3'-hydroxyflavone (3) were isolated from the rootbark of Albizia odoratissima. The structures of these new compounds were elucidated by electrospray ionization mass spectrometry (ESI-MS) and 1D and 2D-NMR spectral studies including (1)H-(1)H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser enhancement spectroscopy (NOESY).     

Copper dipyridine dichloride as a mild and efficient catalyst for a one pot condensation bigenelli reaction

The condensation reaction of aldehydes, β‐ketoesters and urea/thiourea in presence of a catalytic amount of CuPy₂Cl₂ complex proceeded under very mild reaction conditions in high yield (80‐90%).