Quantitative analysis of methylguanidine and guanidine in physiologic fluids by high-performance liquid chromatography-fluorescence detection method.

A rapid and sensitive high-performance liquid chromatographic method has been developed for the quantitative analysis of methylguanidine and guanidine in physiological fluids. These quanidino compounds are separated on a 6 x 0.23 cm cation-exchange column with 0.5 M sodium hydroxide solution. The guanidino compounds are detected with a fluorometer, which monitors the fluorescent guanidine derivatives produced by the reaction of the eluted constituents with 9,10-phenanthrenequinone. Sensitivity to sub-nanomole levels of methylguanidine and guanidine is demonstrated. The method was successfully applied to physiological fluids such as serum and cerebrospinal fluid from uremic patients.     

Chemical and biological modification of bleomycin,an antitumor antibiotic

Dedicated to Professor John C. Sheehan on the occasion of his sixty-fifth birthday. Chemical and biological modifications of bleomycin, an antitumor glycopeptide antibiotic, have been achieved by three procedures analogous to the modifications of penicillin.     

Raman spectra of anthracene negative ions in tetrahydrofuran solution

Raman spectra of anthracene mono- and di-negative ions in tetrahydrofuran solution were obtained by HeNe and Ar⁺ laser exciting lines. In addition to some frequency shifts from neutral anthracene, remarkable enhancement of intensities by the resonance Raman effect was observed for many aromatic ring vibrations.     

Elimination of the 4-hydroxyl group of the alkaloids related to morphine—I

Sinomenine, an alkaloid of the Japanese plant Sinomenium acutum, was converted to the 4-phenylether by the Ullmann reaction in a good yield. The Clemmensen reduction of sinomenine-phenylether and of its derivatives gave (+)-3-methoxy-4-phenoxy-N-methyl-Δ^x-morphinan.

Hydrogenation and successive sodium-liquid ammonia reduction of (+)-3-methoxy-4-phenoxy-N-methyl-Δ^x-morphinan gave (+)-3-methoxy-N-methylmorphinan.     

Elimination of the 4-hydroxyl group of the alkaloids related to morphine—II

Dihydrothebaine-φ, dihydrothebainone-Δ⁵-enol methylether and dihydrothebainone were converted to the respective 4-phenylethers by Ullmann reaction in good yields. These phenylether derivatives were reduced to 4-desoxy compounds by sodium-liquid ammonia reduction.

Clemmensen reduction of the phenylether and the desoxy derivatives gave (-)-3-methoxy-4-phenoxy-N-methyl-morphinan and (-)-3-methoxy-N-methylmorphinan respectively.     

Synthetic studies on β-lactam antibiotics. VII. Mild removal of the benzyl ester protecting group with aluminum trichloride

The benzyl ester protecting group in β-lactam derivatives can be cleanly removed by treatment with aluminum trichloride under mild conditions, preferably in the presence of anisole, to give the corresponding free acids in high yields.     

Leaching behavior of metal-containing species in residual oils with different organic solvents

The leaching behavior of two different residual oils is investigated with 24 organic solvents including alkanes, aromatics, esters, ethers ketones, alcohols and nitrogen compounds. A 2-g portion of sample oil is shaken with 20 ml of the organic solvent. The leaching of the organic matrix of the oil is determined by weighing the dissolved organic matrix after removal of solvent. The leaching of vanadium, iron and nickel was determined by flame atomic absorption spectrophotometry after ashing of the dissolved fraction. The leaching of those metals depends strongly on the solvent used; for example, vanadine is almost completely leached into toluene, but only slightly into methanol. The leaching of iron is poor compared with that of vanadium or nickel. In most solvents, leaching of those metal-containing species is poorer than that of organic material. Exceptionally, N,N-dimethylformamide is more efficient in leaching vanadium species than organic material.     

Molecular rotation and lattice dynamical properties for cyclodextrin-ferrocene and some its ring-substituted derivative clathrates

This paper reports the unusual relaxation effect in the⁵⁷Fe Mössbauer spectra of -cyclodextrin(-cyclopentadienyl)(-ethylcyclopentadienyl)iron(II) clathrate. At low temperatures it consists of a simple quadrupole doublet. However, the Mössbauer spectrum collapses to a broad peak at 320 K. This behavior is interpreted in terms of a model that a ferrocene molecule in the cavity of clathrate lattices rotates as temperature is raised. The relaxation reaches a critical rate, a lifetime of the excited nuclear state. The relaxation time for the reorientation of (-cyclopentadienyl)(-ethylcyclopentadienyl)iron(II) in a cavity was 1.2×10^–7 s at 320 K and a barrier to rotation of about 8.8 KJ/mol was estimated.