著名有机化学家R.B.伍德沃德

著名的美国有机化学家,哈佛大学的R.B.伍德沃德教授于1979年7月8日因患心脏病突然逝世了。他是当代有机化学的大师之一,由于对有机合成的重大贡献,曾荣获1965年度诺贝尔化学奖。他的不幸逝世使世界化学界感到极其惋惜,因为他正当盛年,近年来不断有重     

R.B.Woodward和当代有机化学

Woodward 1917年生于美国波士顿,1933年16岁时进入麻省理工学院,1937年获得博士学位。以后,他在伊利诺斯大学的暑期讲习班任教一年,后作为Kohler的同工作者回到波士顿,在哈佛大学渡过一生,并一直工作到生命的最后一刻。1938年他已是哈佛大学研究会的初级研究员,这个身份的职责仅是每星期与其他会员共同进餐一次。1941年提升为讲师,1950年成为教授,1953年被任命为Morris-Loeb衔称的化学教授。1960年为Donner衔称的科学教授。1979年7月在他去世后,人们对他的工作给了极高的评价。在Barton,Wasserman以及其他知名的有机化学家的悼     

An enantiomerically pure bilirubin. Absolute configuration of (αR,α′R)-dimethylmesobilirubin-XIIIα

Enantiomerically pure (+)-(αR,α′R)-dimethylmesobilirubin-XIIIα 1 and its (αS,α′S) enantiomer ent-1 were synthesized in ten steps from simple precursors. Resolution was achieved at an early stage in the synthesis, with a racemic monopyrrole precursor rac-6 being converted to its amides 8 with (1S)-camphor-2,10-sultam. Resolution of 8 to 99% d.e. was accomplished in three crystallizations, and the absolute configuration of the acid 6 was deduced by X-ray crystallography of the more crystalline, diastereomerically pure amide 7. Circular dichroism spectroscopy of 1 showed intense bisignate Cotton effects: Δε^max₄₃₅=+344, Δε^max₃₉₁=−193 (CHCl₃), as expected for a molecular exciton, and consistent with a P-helical intramolecularly hydrogen-bonded ridge-tile conformation. The Cotton effect magnitudes of 1 match almost exactly those found for (−)-(βS,β′S)-dimethylmesobilirubin-XIIIα 11 and (+)-(αR,β′R)-dimethylmesobilirubin-XIIIα. However, the Cotton effect of the pseudo-meso diastereomer (αR,β′S)-dimethylmesobilirubin-XIIIα 12 is not zero. Its large positive exciton couplet and ¹H NMR NOE analysis confirm that an α-CH₃ exerts a greater steric demand than a β-CH₃—by a factor of ∼3.     

Bericht über das Biorheologische Symposion in Providence/R.I. (USA) vom 26.–30. August 1963

Ohne Zusammenfassung     

A NEW GUANIDINE DERIVATIVE FROM ASTRAGALUS COMPLANATUS R.Br.

A new guanidine derivative,complanatin has been isolated from the seedsof Chinese traditional medicine Astragalus complanatus R.Br..Its structure wasestablished on the basis of spectral data and X-ray crystallographic analysis to beN-[3-carboxypropyl]-N-[3-methyl-2-butenyl]guanidine.     

Asymmetric synthesis of (?)-(R)-massoia lactone, (R)-δ-decalactone, and (+)-(3R,5R)-3-hydroxydecano-5-lactone. Formal synthesis of verbalactone

A simple and efficient procedure for the asymmetric synthesis of (?)-(R)-massoia lactone, (R)-??-decalactone, and (+)-(3R,5R)-3-hydroxy-1,5-decanolide is described. Verbalactone was synthesized using Heck allylation at the key stage of construction of the carbon skeleton.     

N.M.R.DETERMINATION OF THE STRUCTURE AND CONFORMATION OF BIOLOGICAL MOLECULES

IntroductionN.M.R.is known to be useful forstructure determination of natural products,but it's main advantage compared with otherphysical techniques like crystallography is     

Die Röntgenkleinwinkelstreuung von dichtgepackten kolloiden Systemen. II. Teil

Ohne Zusammenfassung Fortsetzung und Schlu? aus Kolloid-Z.125, 1, 51 (1952). Die vorliegende Arbeit wurde am Institut für theoretische und physikalische Chemie der Universit?t Graz durchgeführt. Dem Vorstand des Institutes, Herrn Prof. Dr. O. Kratky bin ich für die Anregung zu dieser Arbeit und F?rderung zu aufrichtigem Dank verpflichtet. Mein bester Dank gilt ferner Frau Dr. A. Sekora für die Ausführung der R?ntgenaufnahmen und Herrn Dr. F. Grasenick, Elektronenmikroskopisches Institut Technische Hochsehule Graz, für zwei elektronenmikroskopische Aufnahmen.     

Resolution of racemic R.S-α-arylethylamine by a new resolving agent (R)thiazolidine-2-thione-4-carboxylic acid

Ｔｈｅｏｐｔｉｃａｌｌｙａｃｔｉｖｅαａｒｙｌｅｔｈｙａｍｉｎｅｈａｓｅｘｔｅｎｓｉｖｅｌｙｂｅｅｎｕｓｅｄｔｏｒｅｐｌａｃｅｔｈｅｏｐｔｉｃａｌｌｙａｃｔｉｖｅｎａｔｕｒａｌａｌｋａｌｏｉｄ,ｅｐｈｅｄｒｉｎｅｂｒｕｃｉｎｅａｎｄｑｕｉｎｉｎｅａｓｔｈｅｒｅｓｏｌｖｉｎｇａｇｅｎｔｏｆｒａｃｅｍｉｃａｃｉｄ.Ｔｈｅｙａｒｅａｌｓｏｔｈｅｃｈｉｒａｌｓｏｕｒｃｅｅｍｐｌｏｙｅｄｉｎｔｈｅａｓｙｍｍｅｔｒｉｃｓｙｎｔｈｅｓｉｓ.Ｐｒｅｖｉｏｕｓｌｙｔｈｅｍａｊｏｒｉｔｙｏｆｒｅｓｏｌｕｔｉｏｎｆｏｒ…