Highly Efficient and Practical Syntheses of Lavendamycin Methyl Ester and Related Novel Quinolindiones

The novel 7-(N-formyl-, 7-(N-acetyl-, and 7-(N-isobutyrylamino)-2-methylquinoline-5,8-diones were synthesized in excellent overall yields in three steps via the nitration of the commercially available 8-hydroxy-2-methylquinoline followed by a reduction-acylation step and then oxidation. Acid hydrolysis of 7-(N-acetylamino)-2-methylquinoline-5,8-dione (14a) afforded the novel 7-aminoquinoline-5,8-dione 7 in excellent yields. Due to our efficient preparation of dione 14a, we now report a short and practical method for the total synthesis of the potent antitumor agent lavendamycin methyl ester (1b) with an excellent overall yield.     

ULTRASONICALLY DISPERSED POTASSIUM AS DEPROTONATING AND COUPLING AGENT──SYNTHESIS OF 1，6－DINITRILES IN SITU

ＵＬＴＲＡＳＯＮＩＣＡＬＬＹ　ＤＩＳＰＥＲＳＥＤ　ＰＯＴＡＳＳＩＵＭ　ＡＳ　ＤＥＰＲＯＴＯＮＡＴＩＮＧ　ＡＮＤ　ＣＯＵＰＬＩＮＧ　ＡＧＥＮＴ──ＳＹＮＴＨＥＳＩＳ　ＯＦ　１，６－ＤＩＮＩＴＲＩＬＥＳ　ＩＮ　ＳＩＴＵＵＬＴＲＡＳＯＮＩＣＡＬＬＹＤＩＳＰ...     

Phase Selectively Soluble Dendritic Derivative of 4-(Dimethylamino)- pyridine: An Easily Recyclable Catalyst for Baylis-Hillman Reactions

Among the reactions in which C-C bonds are formed, the Baylis-Hillman coupling of aldehydes with α, β-unsaturated carbonylic compounds is currently attracting much interest due to the atom economy, the mild conditions and the generation of functional groups1,2. Furthermore, compared to the Heck, Suzuki and other palladium catalyzed C-C bond forming reaction3, the Baylis-Hillman reaction can be promoted by using organic bases in the complete absence of any metal4. However, almost all the …     

一锅法制备全乙酰吡喃溴代糖

将未保护的吡喃糖与醋酸酐在分子碘的催化下制得全乙酰吡喃糖 ,随后不经分离直接与溴化氢的冰醋酸溶液( 4 5 %)反应得到全乙酰吡喃溴代糖 .这种一锅法制备全乙酰吡喃溴代糖操作方便 ,收率高 ,经济实用且对环境友好     

聚电解质──壳聚糖浓溶液流变学性质研究：浓度、温度、溶剂pH值和外加盐对粘度及流动性的影响

本工作用日本岩本ＲＰＸ－７０５多功能流变仪测定了在不同浓度、温度、溶剂ｐＨ值和外加盐浓度对壳聚糖在甲酸水溶液中其浓溶液粘度η随剪切速率γ的变化关系．讨论了浓度、温度等对溶液粘度、流动活化能Ｅ_γ和流动指数ｎ的影响．发现溶剂ｐＨ值减小或溶液中外加盐浓度增加，溶液粘度变小，ｎ增大，表明非牛顿流动性减弱，并且进一步讨论了零剪切粘度η_０和外加盐浓度Ｃ_ｓ的依赖关系．     

Analyzing functional similarity of protein sequences with discrete wavelet transform

This paper applies discrete wavelet transform (DWT) with various protein substitution models to find functional similarity of proteins with low identity. A new metric, 'S' function, based on the DWT is proposed to measure the pair-wise similarity. We also develop a segmentation technique, combined with DWT, to handle long protein sequences. The results are compared with those using the pair-wise alignment and PSI-BLAST.     

钒毒性的研究进展

综述了钒的一般毒性，生殖毒性，胚胎毒性，致畸，致突变，致癌毒性的研究进展。     

Study of Tea Digitized Chromatographic Fingerprint Spectra Using Micellar Electrokinetic Chromatography

IntroductionTeaisthemostwidelyconsumedbeverageinpeople’slife .Theheightenedpopularityofthisbeveragethroughouttheworldinrecentyearsmaybedueinparttotheevidenceofarelationshipbetweenteaconsumptionandpreventionofcertainformsofhumandisease .Themaincomponentsofteaarepolyphenoliccompounds ,commonlyknownascatechins ,whichrepresentagroupofcom poundsbelongingtotheflavonoidfamily .Thesecom poundsarewidelydistributedinthetealeavesandconsti tuteupto 30 %ofthedryleafweight.1Muchinteresthasbeenfocusedoncat…