[en] Estramustine phosphate (EMP), a nor-nitrogen mustard carbamate derivative of estradiol-17β-phosphate, causes G₂/M phase arrest in treated cells through its specific binding to microtubule associated proteins. Since cells in the G₂/M phase are the most radiosensitize, cell culture experiments were performed to determine whether EMP would enhance the radiosensitivity of related human tumor cells. A Phase II prospective study of concomitant radiotherapy (RT) and EMP plus Velban for locally advanced carcinoma of the prostate was carried out. Three established human tumor cells, DU-145 cells (prostate), MCF-7 cells (breast), and U-251 cells (malignant glioma), were used to determine cell survival curves with and without the drug. Flow cytometry was used to obtain the cell cycle distribution of cells that were exposed to the drug for periods of 1 day to 1 week. Patients with locally advanced prostate cancer were entered into the Phase II study. All patients received a total tumor dose of 65-70 Gy over 7 weeks. Oral EMP was administered daily and Velban was administered weekly, concomitantly during the course of RT. Radiosensitization was dependent on the exposure time and the drug concentration prior to radiation. No radiosensitization was obtained when cells were exposed to the drug after irradiation. The enhancement ratios varied from 1.3-1.6 at the 10% survival level. All patients who received the combined RT and EMP plus Velban achieved complete response. The rate of PSA (prostate specific antigen) reduction was very prompt compared to that of the RT alone group. There were no disproportionately enhanced side effects for the combined regimen. EMP enhances radiation induced cytotoxicity in several human tumor cells in culture. The effect is most significant after prolonged exposure to the drug before irradiation. Documented G₂/M phase cell cycle block by EMP is the likely mechanism of radiosensitization. 9 refs., 2 figs., 1 tab

[en] Let $X$ be an affine algebraic variety endowed with an action of complexity one of an algebraic torus $\mathbb{T}$. It is well known that homogeneous locally nilpotent derivations on the algebra of regular functions $\mathbb{K}[X]$ can be described in terms of proper polyhedral divisors corresponding to the $\mathbb{T}$-variety $X$. We prove that homogeneous locally nilpotent derivations commute if and only if a certain combinatorial criterion holds. These results are used to describe actions of unipotent groups of dimension two on affine $\mathbb{T}$-varieties.

Bibliography: 10 titles. (paper)

[en] The stereoselectivity of the intramolecular Diels-Alder reactions of 1 and its derivatives were investigated by ab initio calculations. The stereoselectivity mainly originates from the steric repulsion and the orbital interactions. The additional s-cis and s-trans conformations by introducing the carbonyl group at the neighbor of diene or dienophile may change the stereoselectivity, hence this kind of substitution can be utilized for stereoselective asymmetric synthesis

[en] In order to analyze the monoglyceride compositions of Asterias rollestoni gonad, the derivative methods and chromatographic conditions of monoglycerides were optimized, and the fragmentation rules and mass spectrometry characteristics of monoglyceride derivatives were analyzed and monoglyceride compositions in Asterias rollestoni gonad were also detected in this paper. The results indicated that trimethylsilylation had ideal derivative effects on monoglycerides, and the ideal chromatographic separation effects of monoglyceride derivatives were obtained by the weak-polar glass capillary column (HP-5 MS, 30 m × 0.25 mm × 0.25 μm). Moreover, the characteristic ions of 1-monoglyceride derivatives were m/z 73, m/z 205, [M-103] + (base-peak ion) and [M-15]⁺, while 2-monoglyceride derivatives were m/z 73 (base-peak ion), m/z 129, m/z 218, [M+H-162]⁺ and [M-15]⁺. Gas chromatographic retention time of monoglyceride derivatives displayed certain regularitys, and 2-monoglyceride derivatives were eluted earlier than 1-monoglyceride derivatives. Additionally, eight monoglycerides were identified from Asterias rollestoni gonad, which were mainly consisted of 1-monopalmitin (1-C16:0-MG) and 1-monostearin (1-C18:0-MG), while the contents of 2-monoglycerides were relatively low. This research provides theoretical references for derivatization, chromatographic analysis and mass spectrometric identification of monoglycerides. (authors)

[en] We have concluded that the apparent pKa values of the substrates reflect the differences in the k_H values and k_o values, the hydrolysis reactions of N-benzoyl-4,5-diphenylimidazoles are not catalyzed by the general base, the geometry of the leaving group in the hydroxide ion catalyzed reaction is very important and the substituent effect on the hydroxide ion catalyzed reaction appears very large. Recently, we have reported hydrolysis reactions of three N-acylimidazoles compounds having one phenyl substituent in the imidazole leaving group. In the hydrolysis reaction of N-furoyl- and N-thenoyl-2-phenylimidazole of these three compounds observed a change in rate determining step in acidic region, whereas, that of N-benzoyl-2-phenylimidazole found to be related with the diprotonated species in acidic region. Even though, the change in the structure of N-acylimidazoles, sometimes, give rise to an abnormal reactivity in hydrolysis reaction,2 the feature of the hydrolysis of the above three N-acyl-2-phenylimidazoles compounds was very unique in comparison with the previous obtained results from hydrolysis of N-acylimidazole derivatives

[en] 2-Iminopyrimidines (1a-e) and 2-thioxopyrimidine (2) were synthesized using the Biginelli three component cyclocondensation reaction of an appropriate β-diketone, arylaldehyde, and guanidine (for 1a-e) or thiourea (for 2). The electrochemical properties of the novel systems were investigated by CV and DPV. Moreover, B3LYP/6-31G(d,p) method was applied to the present structures in order to gather some structural and physicochemical data

[en] Substituent chemical shifts were examined for the 2- and 3-thiophene derivatives of chalcone and compared to the thiophene series of derivatives with the phenyl series. The chemical shift values for the α-carbons of the enones showed and inverse correlation with the Hammett σ values, but the correlation coefficients were moderate (r = 0.836 - 0.878). On the other hand, the β-carbons showed a normal correlation with excellent correlation coefficients (r = 0.994). The absolute magnitude of the ρ values for the α-carbon are about half of those of the β-carbon. The observation may be the result of a through-space transition of the electronic effect of the substituents in addition to the through bond transition

[en] The synthesis of novel iminecalix[4]arenes and further modification thereafter is described using a synthetic strategy. The reaction of the benzaldehyde derivatives with tetraamine functions on the calix[4]arene easily afforded the pure compounds in 92.4-95.7% yields, regardless of the effect of the substituents on the benzaldehyde derivatives. These compounds were stable under the conditions to obtain their analogue dialkylated in the narrow rim, with 83.2-89.9% yields. Characterization of the newly synthesized iminecalix[4]arene derivatives by spectroscopic methods revealed that all compounds are in the cone conformations

[en] We have achieved the synthesis of the C3-C9 fragment of soraphen A by recurring use of stereoselective Roush crotylation and subsequent ozonolysis as key transformations. Soraphen A is an 18-membered macrolide isolated from myxobacterium Sorangium Cellulosum. It displays potent antifungal activity against various pathogenic plant fungi because of its highly efficient and specific inhibitory activity on acetyl CoA carboxylase. The structure of soraphen A was well defined by X-ray crystallographic analysis. The presence of an unsubstituted phenyl ring and a hemiketal ring constitutes its structural feature. The first total synthesis of soraphen A was reported by Giese in 1999. We previously reported our synthetic attempt

[en] Laser-induced Raman spectroscopy has been utilized to demonstrate its feasibility for studying the kinetics of imine formation in chloroform solvent. The imine formation, by the nucleophilic addition of primary amine to the carbonyl group of ketone, has been monitored at ten minute intervals for eight hours. The intensity of the C=O stretching mode at 1684 cm^-1 was measured to determine the rate constant of the reaction. In order to correct the sample-to sample fluctuations in Raman peak area, this peak was normalized to the C-Cl bending peak at 666 cm^-1. By the peak area change during the course of reaction, the second order rates at three different temperatures have been determined. The substituent effects on the π conjugations of imine product have also been investigated. On the basis of Raman frequency shifts, the delocalization properties of the aromatic system modified by substitution of a hydrogen atom with -Cl and -CH₃O groups could be clearly understood