Stereoselective total synthesis of ( + )-brefeldin A

A total synthesis of ( + )-brefeldin A, an antibiotic fungal metabolite, has been achieved stereoselectively starting from ( + )-mannitol and ( + )-glutamic acid.     

Synthesis and structure revision of tyroscherin, and bioactivities of its stereoisomers against IGF-1-dependent tumor cells

Synthesis of the proposed structure of tyroscherin, a growth inhibitor of IGF-1-dependent cancer cells, was succeeded by one-pot Julia coupling. However, spectral data of the synthetic compound were not identical with those of natural tyroscherin. The stereochemistry of tyroscherin is revised to be 2S,3R,8R,10R by syntheses of stereoisomers. Synthetic tyroscherin showed more potent activity than its stereoisomers against IGF-1-dependent cancer cells.     

Design and performance of an evolved gas analysis ion attachment mass spectrometer

We designed a simple evolved gas analysis (EGA) system to act as a sampler between solid samples at atmospheric pressure and the high vacuum inside a mass spectrometer. The newly designed stainless steel system is simple, small and rugged and fulfills all the basic requirements for EGA. The temperature is programmable with 60°C/min as the maximum heating rate and the temperature range is up to 600°C. With this system coupled with lithium ion attachment mass spectrometry (IAMS), it is possible to study the temperature‐programmed decomposition of a number of solid materials by detecting any chemical species on a real‐time basis. For illustrative purposes, EGA‐IAMS experiments of polyethylene polymers have been conducted. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous analysis of haloperidol, its three metabolites and two other butyrophenone-type neuroleptics by high performance liquid chromatography with dual ultraviolet detection

We investigated simultaneous determination of haloperidol (HAL), its three metabolites [reduced HAL (R-HAL), 3-(4-fluorobenzoyl)propionic acid (FBPA) and 4-(4-chlorophenyl)-4-hydroxypiperidine (CPHP)] and two related compounds [spiperone (SPI) and droperidol (DRO)] in phosphate-buffered saline using high-performance liquid chromatography (HPLC) coupled with dual ultraviolet detection (220 and 250 nm). Retention times of HAL, R-HAL, FBPA, CPHP, SPI and DRO were 16.8, 11.8, 10.2, 4.1, 12.6 and 8.3 min, respectively. Their lower limits of detection were 7.5, 14, 4.5, 12, 10 and 20 ng/mL in the same order. The coefficients of variation for their intra- and inter-day assays were less than 7.8 and 9.4%, respectively. Of the other centrally acting drugs, only amoxapine interfered with the peak of DRO. Using our procedure, the binding study of tested compounds to synthetic melanin, human serum albumin and alpha1-acid glycoprotein was performed by determining the unbound concentration to total concentration ratio. These results indicated that simultaneous assay of HAL, R-HAL, FBPA, CPHP, SPI and DRO in phosphate-buffered saline by HPLC equipped with dual ultraviolet detection is simple, sensitive and reproducible. Also, our assay system can be applied to the binding study of these compounds to synthetic melanin, human serum albumin and alpha1-acid glycoprotein.     

New heterocyclic compounds derived from diethyl 2,5-dioxo-1,4-cyclohexanedicarboxylate and 2-aminobenzophenone

The synthesis and properties of a new class of heterocyclic compounds 5–8 derived from 2-aminobenzo-phenone and diethyl 2,5-dioxo-1,4-cyclohexanedicarboxylate were investigated.     

Synthesis of both the enantiomers of sclerosporin and sclerosporal,sporogenic substance of sclerotinia fructicola1

Both the enantiomers of sclerosporin $\text{1}$ and sclerosporal $\text{2}$ were synthesized from (-)-carvone. (4R,9R,10S)-(+)-Sclerosporin and (4R,9R,10S)-(-)-sclerosporal were identified as the natural enantiomers by a comparison of their CD-spectra. An intramolecular Diels-Alder route was proved to be an efficient method of preparing sufficient amounts of (+)-$\text{1}$ for the biological study.     

Visualization of the local ionic wind profile in a DC corona discharge field by laser-induced phosphorescence emission

Experimental visualization for ionic wind motion originated from DC corona discharges in a needle-plate electrode system has been investigated. A vapor-phase biacetyl tracer with laser-induced phosphorescence emission is used for optically characterizing the ionic wind profile. The ionic wind blows the excited biacetyl molecules away in continuing the visible phosphorescence emission for a long radiative lifetime. The captured image with elapsing time from the excitation presents the shifting location of radiative tracer along the ionic wind direction. The experimental results show the ionic wind profile enhanced in the electric field direction corresponding to the corona discharge progress. Especially, the ionic wind near an initiating point of corona discharges is focused as an advantage of this optical technique. The ionic wind velocity along the electrode axis can be obtained at the location close enough to the corona discharge initiation point, and the velocity at 0.5 mm from the discharge point is figured out as 9.3 to 19.2 m/s under the condition of the EHD Reynolds number of 0.95×10³ to 2.1×10³.