Synthesis of S-monofluoromethyl phosphorothioates from PⅤ-H compounds and PhSO2SCH2F

S-Monofluoromethyl phosphorothioates represent an important class of organofluorine compounds and are re ported here for the first time.A series of S-monofluoromethyl phosphorothioates are conveniently synthesized from different P^Ⅴ-H compounds and PhSO₂SCH₂F under mild conditions.The method is compatible with common functional groups and provides potential opportunities to synthesize new bioactive molecules for medicinal chemistry.     

北电区CDMA话务统计与实时监控系统

本文介绍了中国联通青岛分公司为提高CDMA网络质量、提高网络维护效率,开发并投入使用的一套话务统计与实时报警软件(CAS)。     

Posaconazole (Noxafil, SCH 56592), a new azole antifungal drug, was a discovery based on the isolation and mass spectral characterization of a circulating metabolite of an earlier lead (SCH 51048)

Posaconazole (SCH 56592) is a novel triazole antifungal drug that is marketed in Europe and the United States under the trade name 'Noxafil' for prophylaxis against invasive fungal infections. SCH 56592 was discovered as a possible active metabolite of SCH 51048, an earlier lead. Initial studies have shown that serum concentrations determined by a microbiological assay were higher than those determined by HPLC from animals dosed with SCH 51048. Subsequently, several animals species were dosed with (3)H-SCH 51048 and the serum was analyzed for total radioactivity, SCH 51048 concentration and antifungal activity. The antifungal activity was higher than that expected based on SCH 51048 serum concentrations, confirming the presence of active metabolite(s). Metabolite profiling of serum samples at selected time intervals pinpointed the peak that was suspected to be the active metabolite. Consequently, (3)H-SCH 51048 was administered to a large group of mice, the serum was harvested and the metabolite was isolated by extraction and semipreparative HPLC. LC-MS/MS analysis suggested that the active metabolite is a secondary alcohol with the hydroxyl group in the aliphatic side chain of SCH 51048. All corresponding monohydroxylated diastereomeric mixtures were synthesized and characterized. The HPLC retention time and LC-MS/MS spectra of the diastereomeric secondary alcohols of SCH 51048 were similar to those of the isolated active metabolite. Finally, all corresponding individual monohydroxylated diasteriomers were synthesized and evaluated for in vitro and in vivo antifungal potencies, as well as pharmacokinetics. SCH 56592 emerged as the candidate with the best overall profile.     

高功率无铝半导体激光器

ＩｎＧａＡｓＰ／ＧａＡｓ激光器抑制暗线缺陷的形成,器件的突然失效及缓慢退化有所减少。研究表明,高功率无铝半导体激光器比有铝ＡｌＧａＡ／ＧａＡｓ激光器具有更高的可靠性。文章分析比较了高功率有铝和无铝半导体激光器的优缺点,介绍了波长为８０８ｎｍ的高功能无铝半导体激光器的发展及国内外目前的研究状况。     

高功率808nm InGaAsP—GaAs分别限制结构的半导体激光器

介绍了研究分别限制结构ＩｎＧａＡｓＰ－ＧａＡｓ半导体激光器所得到的最新成果。利用引进的俄国技术，基于量子阱结构的ＩｎＧａＡｓＰ－ＧａＡｓ激光器，可用短时间液相外延技术制造。在ＧａＡｓ衬底上制成的ＩｎＧａＡｓＰ－ＧａＡｓ分别限制结构的激光器，主要参数如下：发射波入λ＝８０８ｎｍ，阈值电流密度Ｊ＝３００Ａ／ｃｍ＾２，对于条宽ω＝１００μｍ的激光器，连续功率为１－２Ｗ。     

簇合物[Et4N]2[Mo2S4(SCH2CH2S)2]的合成及其结构研究

以(NH4)2MoS4,Et4NBr,HSCH2CH2SH为原料,合成出[Et4N]2[Mo2S4(SCH23CH2S)2]簇合物,用X射线衍射法测定了晶胞结构.其晶胞参数为a=1.0304(8)nm,b=1.4158(8)nm,c=1.1417(1)nm,V=1.63801nm3,Z=4,晶体属单斜晶系,晶体结构经块状矩阵最小二乘法修正后,最终偏离因子R=0.089.此外还进行了红外光谱,紫外可见光谱的测定.     

GSM公共信道中SCH自适应均衡解调算法研究

针对移动信道多径效应造成的严重的码间干扰(ISI)问题,研究了基于最大似然序列估计(MLSE)的GSM公共信道中SCH自适应均衡解调算法,并对这种自适应均衡解调算法在Jakes移动信道模型环境下的性能进行了分析和计算机仿真,仿真结果表明该自适应均衡解调算法能够很好地克服码间干扰(ISI)问题,性能良好。     

Pleosporin A,an antimalarial cyclodepsipeptide from an elephant dung fungus (BCC 7069)

Cyclodepsipeptides SCH 217048 (1), SCH 218157 (2), and a new analog, pleosporin A (3), were isolated from cultures of an unidentified elephant dung fungus of the family Pleosporaceae. The structure of 3 was elucidated on the basis of detailed spectroscopic interpretation. The absolute configurations of 1–3 were determined by chiral column HPLC analysis and Marfey’s method. Cyclodepsipeptides 1–3 exhibited antimalarial activity against Plasmodium falciparum K1 with respective IC₅₀ values of 1.6, 6.4, and 1.6 μg/mL, while they did not show cytotoxicity against KB, MCF-7 and NCI-H187 cell-lines or non-cancerous Vero cells at 50 μg/mL.     

The Proper Forcing Axiom, Prikry forcing, and the Singular Cardinals Hypothesis

The purpose of this paper is to present some results which suggest that the Singular Cardinals Hypothesis follows from the Proper Forcing Axiom. What will be proved is that a form of simultaneous reflection follows from the Set Mapping Reflection Principle, a consequence of PFA. While the results fall short of showing that MRP implies SCH, it will be shown that MRP implies that if SCH fails first at κ then every stationary subset of reflects. It will also be demonstrated that MRP always fails in a generic extension by Prikry forcing.     

Spectrophotometric Assay of Penem (SCH 29482) by Reaction with Imidazole

Abstract

A rapid method is described for the determination of SCH 29482. This is based on the spectrophotometric measurement at 386 nm of the product of reaction with imidazole formed at 35°Cin a 1.5 M imidazole and 2×10^?3M mercuric chloride solution at pH 7.50. The method, which permits detection of concentrations of SCH 29482 as low as to 2.8, μg/ml, is reproducible and specific for intact SCH 29482 in the presence of degradation products. The molar absorptivity for the chromophore formed is 2.54×l0⁴ I mol^?1cm^?1.