Direct determination of benzamides in serum by column-switching high-performance liquid chromatography.

A column-switching high-performance liquid chromatographic method with fluorescence detection was developed for the simultaneous determination of four benzamide-type anti-psychotic drugs: sulpiride, tiapride, sultopride and metoclopramide in human serum. In this method, a TSKgel Super-ODS column was used as an analytical column, and a TSKgel G 2000SW was prepared as a pretreatment column. Under the optimized analytical conditions, four benzamide-type anti-psychotic drugs were eluted within 18 min. The detection limits (S/N = 3) for sulpiride, tiapride, sultopride and metoclopramide are 1 ng/ml, 4 ng/ml, 2 ng/ml and 0.5 ng/ml, respectively. Finally, the method was applied to the determination of sulpiride in human serum samples obtained after a single oral dose of sulpiride.     

Semi-local units modulo Gauss sums

For thep-th cyclotomic fieldk, Iwasawa proved thatp does not divide the class number of its maximal real subfield if and only if the odd part of the group of local units coincides with its subgroup generated by Jacobi sums related tok. We refine and give a quantitative version of this result for more general imaginary abelian fields. Our result is an analogy of the famous result on “semi-local units modulo cyclotomic units”. Partially supported by Grant-in-Aid for Scientific Research (C), Grant 09640054.     

Synthesis of 3-hydroxyindolin-2-one alkaloids, (±)-donaxaridine and (±)-convolutamydines A and E, through enolization-Claisen rearrangement of 2-allyloxyindolin-3-ones

Claisen rearrangement triggered by enolization of 2-allyloxyindolin-3-ones with DBU was performed in order to prepare 3-allyl-3-hydroxyindolin-2-ones. Total synthesis of 3-hydroxyindolin-2-one alkaloids, (±)-donaxaridine, as well as (±)-convolutamydines A and E, was achieved by transformation of the allyl moiety of 3-allyl-3-hydroxyindolin-2-ones.     

Rapid ruthenium-catalyzed synthesis of pyranopyrandiones by reconstructive carbonylation of cyclopropenones involving C[bond]C bond cleavage

Pyranopyrandiones were prepared by a novel ruthenium-catalyzed carbonylative dimerization of cyclopropenones via C-C bond cleavage. For example, treatment of dipropylcyclopropenone with a catalytic amount of Ru3(CO)12 and NEt3 in THF under 15 atm of carbon monoxide at 140 degrees C for 20 h gave a novel functional monomer, 3,4,7,8-tetrapropylpyrano[6,5-e]pyran-2,6-dione, in an isolated yield of 81%. Unsymmetrically substituted pyranopyrandiones were also obtained by ruthenium-catalyzed carbonylative coupling of cyclopropenones with alkynes under similar reaction conditions.     

New class of potent catalysts of O2.-dismutation. Mn(III) ortho-methoxyethylpyridyl- and di-ortho-methoxyethylimidazolylporphyrins

Three new Mn(III) porphyrin catalysts of O2.-dismutation (superoxide dismutase mimics), bearing ether oxygen atoms within their side chains, were synthesized and characterized: Mn(III) 5,10,15,20-tetrakis[N-(2-methoxyethyl)pyridinium-2-yl]porphyrin (MnTMOE-2-PyP(5+)), Mn(III)5,10,15,20-tetrakis[N-methyl-N'-(2-methoxyethyl)imidazolium-2-yl]porphyrin (MnTM,MOE-2-ImP(5+)) and Mn(III) 5,10,15,20-tetrakis[N,N'-di(2-methoxyethyl)imidazolium-2-yl]porphyrin (MnTDMOE-2-ImP(5+)). Their catalytic rate constants for O2.-dismutation (disproportionation) and the related metal-centered redox potentials vs. NHE are: log k(cat)= 8.04 (E(1/2)=+251 mV) for MnTMOE-2-PyP(5+), log k(cat)= 7.98 (E(1/2)=+356 mV) for MnTM,MOE-2-ImP(5+) and log k(cat)= 7.59 (E(1/2)=+365 mV) for MnTDMOE-2-ImP(5+). The new porphyrins were compared to the previously described SOD mimics Mn(III) 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)), Mn(III) 5,10,15,20-tetrakis(N-n-butylpyridinium-2-yl)porphyrin (MnTnBu-2-PyP(5+)) and Mn(III) 5,10,15,20-tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin (MnTDE-2-ImP(5+)). MnTMOE-2-PyP(5+) has side chains of the same length and the same E(1/2), as MnTnBu-2-PyP(5+)(k(cat)= 7.25, E(1/2)=+ 254 mV), yet it is 6-fold more potent a catalyst of O2.-dismutation , presumably due to the presence of the ether oxygen. The log k(cat)vs. E(1/2) relationship for all Mn porphyrin-based SOD mimics thus far studied is discussed. None of the new compounds were toxic to Escherichia coli in the concentration range studied (up to 30 microM), and protected SOD-deficient E. coli in a concentration-dependent manner. At 3 microM levels, the MnTDMOE-2-ImP(5+), bearing an oxygen atom within each of the eight side chains, was the most effective and offered much higher protection than MnTE-2-PyP(5+), while MnTDE-2-ImP(5+) was of very low efficacy.     

Toward inorganic electrides

Electrides are materials in which alkali metals (Li through Cs) ionize to form bound alkali cations and "excess" electrons. The electrons reside in large cavities or channels or both in the host lattice. We report here the first synthesis of thermally stable inorganic electrides with cation-to-electron ratios of 1:1 as in organic electrides. Although alkali metal adducts to alumino-silicate zeolites are well known, the cation-to-electron ratio is generally 3:1 or greater because these zeolites contain alkali cations prior to incorporation of the alkali metal. In this work, two pure silica zeolites, ITQ-4and ITQ-7, with pore diameters of approximately 7 A, absorb up to 40 wt % cesium from the vapor phase (even at room temperature). The other alkali metals (except Li) can also be introduced at elevated temperatures. The optical and magnetic properties of the cesium-loaded samples suggest ionization to form Cs+ and e- with substantial electron-spin pairing. The metal-loaded samples are stable to at least 100 degrees C and are able to reduce small aromatic molecules such as benzene and naphthalene to the radical anions within the pores of the zeolite.     

Simultaneous quantitative measurement of fourteen adrenal steroids by capillary column gas chromatography-mass spectrometry, and its clinical application

Until now, there has been little work covering all of the main native adrenal-cortical steroids in blood. We therefore established a method for the simultaneous quantitative measurement of 14 native adrenal-cortical steroids, which involves capillary column gas chromatography-mass spectrometry (GC--MS). Serum steroids were purified from serum with the Extrelut mini-column and then converted into stable derivatives for GC-MS by a combination of boronic cyclization and trimethylsilyl and methyloxime derivatization. The sensitivities (with a signal-to-noise ratio greater than or equal to 7) of our GC-MS method ranged from 0.1 to 1.0 ng/ml of serum, and the coefficients of variation of intra- and inter-assays were less than 19% for each steroid. Our newly devised method involving a capillary column GC-MS system has been proven to be a simple and suitable method for a diagnosis requiring simultaneous detection of many native adrenal steroids in clinical practice. The analysis time is only 4 h.     

Wavelength effect on the photoinduced reaction of polymethylmethacrylate

Polymethylmethacrylate (PMMA) containing benzophenone (BP) was photo-irradiated with monochromatic radiation of wavelength 260–360 nm using the Okazaki Large Spec-trograph (OLS). On irradiation of PMMA films containing BP in air, the sensitized main-chain scission and photocrosslinking of PMMA took place simultaneously. These reactions are dependent on irradiation wavelength. The threshold wavelength for both reactions is found to be ca. 380 nm. The number of main-chain scission and amount of gel increased with the increase of BP concentration in PMMA. Photosensitized main-chain scission favors the irradiation of radiation at ca. 280 nm and photocrosslinking takes place efficiently with the exposure of 340 nm radiation. A possible mechanism for photosensitized reaction is proposed. © 1995 John Wiley & Sons, Inc.