Chemistry and Structure of Diterpene Compounds of the Kaurane Series: VI. Isosteviol Esters

Esterification with alcohols and diols of (4,8,13)-13-methyl-16-oxo-17-norkaurane-18-carboxylic acid chloride prepared by treatment of the acid (isosteviol) with thionyl chloride yields the corresponding esters. The molecular and crystal structures of a series of esters were determined by single crystal X-ray diffraction. The diethylene glycol diester in the crystal has a tweezer structure with an intramolecular cavity. The supramolecular structure of some isosteviol derivatives in the crystal is characterized by alternation of lipophilic and hydrophilic regions.     

Chemistry and Structure of Diterpene Compounds of the Kaurane Series: VIII. Azomethines Derived from Isosteviol

(4,8,13)-13-Methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) and its methyl ester were reacted with benzylamine and hydroxylamine to obtain the corresponding E-stereoisomeric 16-ketimines. Isosteviol benzylimine and oxime form individual 1:1 H-bonded complexes with methanol and water, respectively.     

Chemistry and Structure of Diterpene Compounds of the Kaurane Series: VII. Chiral Complexes of Isosteviol with Aromatic Compounds

(4,8,13)-13-Methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) forms with aniline, dimethylaniline, and toluene individual 2:1 molecular complexes whose crystals are isostructural. According to X-ray diffraction data, the supramolecular crystal structure of these complexes is formed by chiral double helices with a 4₃ screw axis, consisting of isosteviol molecules. The strands of the helices are linked together by intermolecular hydrogen bonds involving the carboxy and carbonyl groups of two isosteviol molecules of neighboring helices. In their turn, the two hydrogen-bonded isosteviol molecules form head-to-tail pseudocage dimers. The aromatic guests occupy fairly large cavities between the strands of isosteviol helices.     

Chemistry and Structure of Diterpene Derivatives of the Kaurane Series: V. Isosteviol Anhydrides

(4,8,13)-13-Methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) anhydride is synthesized, which is a first representative of bisditerpene compounds of the kaurane series. The structures of the anhydride and isosteviol chloride were studies by X-ray diffraction and quantum chemistry (AM1).     

Chemistry and Structure of Diterpene Compounds of the Kaurane Series: IX. Electrochemical Reactions of Isosteviol and Its Derivatives

The keto group in (4,8,13)-13-methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) is not polarographically reduced in DMF. Isosteviol methyl ester and oximes, too, are not reduced under these conditions. Isosteviol oxime is oxidized electrochemically or with lead dioxide, yielding iminoxyl radical.     

The Reduction of a Natural Diterpene Containing a, B-Unsaturated Keto Group

Hedychenone (1), a diterpene containing a, B-unsaturated keto group, was reduced by aluminum-mercury alloy, and a dimerized product (2) was obtained as the major product. The coupling occurred at B position of the keto group.     

The Reduction of a Natural Diterpene Containing o, β-Unsaturated Keto Group

Hedychenone (1), a diterpene containing α, β-unsaturated keto group, was reduced byaluminum-mercury alloy, and a dimerized product (2) was obtained as the major product. Thecoupling occurred at β position of the keto group.     

Chemistry and Structure of Diterpenoids: X. Isosteviol Amides

Acylation of amino alcohols with isosteviol chloride, depending on the reactant ratio, leads to formation of either bis-isosteviol derivatives or N-acylation products. Reactions of aromatic diamines with 2 equiv of isosteviol chloride give the corresponding N,N′-bis(isostevioyl) derivatives.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 276–281.Original Russian Text Copyright © 2005 by Al’fonsov, Kataev, Strobykina, Korochkina, Kovylyaeva, Bakaleinik, Beskrovnyi, Gubaidullin, Litvinov, Musin.For communication IX, see [1].     

Supplementary Observations on the Chemistry of the Alkaloids of Berberine Series and Related Compounds. III. Fluorescence Spectra of the Alkaloids of Berberine Series and Their Related Compounds

The absorption maxima of the fluorescence spectra of the berberine series alkaloids are broadly distributed between 360 and 560 mμ. The fluorescence spectra of most substances of this series are very monotonous one having a single peak, the spectra of tetrahydrocoptisine and tetrahydroepiberberine are quite exceptional and consist of two wavy bands. The introduction of the auxochrome group into the molecule of “proto” compounds causes the decreasing of the fluorescence intensity and this effect is strongest in case of transition from protoberberine to berberine. That, tetrahydropalmatine does not show the distinct fluorescence spectrum band is the only incomprehensible fact.     

Clerodane and ent‐Kaurane Diterpene Glycosyl and Glycoside Derivatives from the Leaves of Casearia sylvestris

Five new clerodane diterpene glycosyl derivatives, caseariasides A–E ( 1 – 5 , resp.) and three new ent‐kaurane diterpene glucosides, sylvestrisides C–E ( 6 – 8 , resp.) were isolated from the leaves of Casearia sylvestris. Their structures were determined on the basis of chemical and spectroscopic analyses.     

基于学科理解的认识视角研究——以有机物分子组成与结构主题为例

学科理解对教师教学的主要价值在于凝练学科本原性问题、抽提认识视角、厘清认识思路及建构主题概念层级结构,其中认识视角决定了理解问题的深刻程度,能够指引认识思路的发展,具有学科认识论层面的重要价值。本研究探讨学科理解视域下的认识视角是如何抽提并发展的,以有机物分子组成与结构主题为例。通过理解化学史得出抽提认识视角的过程：(1)追溯化学家本原性思想,分析概念的学科功能;(2)基于学科功能抽提认识视角,纵向体会认识视角的发展性;(3)基于矛盾冲突丰富认识视角,横向体会认识视角的多面性;(4)基于认识视角发展结构化、本原性的理解。     

Photochemistry of Organic Compounds.From Concepts to Practice. Postgraduate Chemistry Series. By Petr Klán and Jakob Wirz.

John Wiley & Sons, Hoboken 2009. 582 pp., softcover € 49.90.—ISBN 978‐1405161732

     

Acylation of pyrrolyltricarbonylmanganese. Structure of the acylation product

The acylation of pyrrolyltricarbonylmanganese (PTM) is studied. The reaction proceeds in an unusual manner; introduction of an acetyl group into the α-position of the PTM pyrrolyl ligand is accompanied by extensive rearrangement of bonds resulting in the formation of a binuclear complex (π-C₄H₄N)Mn(CO)₃(CH₃COC₄H₃N)Mn(CO)₃ (I)Coordination of the acetylpyrrolyl ligand to the manganese atom is of the chelate type and involves atoms of heterocyclic nitrogen and of acetyl oxygen. The ligand, therefore, is not a five-electron but a three-electron donor. The manganese atom is additionally coordinated to three carbonyl groups and one molecule of the initial PTM (by a donor—acceptor bond through a nitrogen atom), thus acquiring a 18-electron shell. A scheme for complex I formation is proposed.     

Chemistry of the phenoxathiins IV. Synthesis of 9-substituted 1 -azaphenoxathiins

In an extension of recently reported syntheses of the I-azaphenoxathiin nucleus as well as several 7-substituted analogs, the synthesis of several 9-substituted members of this series is now reported. In addition, the first ¹³C-nmr spectral evidence of an interaction between a sulfur atom and the oxygen of an ortho-nilro group which has been previously observed only in X-ray erystallographic studies is also described. The possible consequences of this interaction on the reaction pathway leading to the cyclization of the 9-substituted J-azaphenoxathiin nucleus is also presented.     

REPS4(RE=Y, La～Lu)系列化合物的合成和结构化学研究

采用高温固相反应合成了稀土硫代磷酸盐ＲＥＰＳ４（ＲＥ＝Ｙ，Ｌａ～Ｌｕ），并通过Ｘ射线粉末衍射测定了晶胞参数以及ＨｏＰＳ４，ＥｒＰＳ４和ＴｍＰＳ４的晶体结构。其中ＲＥＰＳ４（ＲＥ＝Ｙ，Ｌａ～Ｙｂ）系列化合物的结构均属四方晶系，其空间群为Ｉ４１／ａｃｄ，ａ≈１１ｎｍ，ｃ≈１９ｎｍ，Ｚ＝１６。四方结构中的三价稀土离子为反四方棱柱八配位。该结构具有较大的孔洞空间，孔洞直径分别为０６２５ｎｍ（沿ｃ轴方向）和０３５ｎｍ（沿ａ、ｂ轴方向）。ＬｕＰＳ４晶体为单斜晶系，很可能是层状（２Ｄ）结构。研究了镧系收缩效应对四方结构稳定性的影响，发现对ＲＥＡＸ４系列化合物来说，四方结构能稳定存在的前提是２４ｄＡＸ／ｒ１９。