Zur Kenntnis der Triterpene. 140. Mitteilung. Über weitere Abbaureaktionen des Fredelins
作者:G. W. Perold、K. Meyerhans、O. Jeger、L. Ruzicka
DOI:10.1002/hlca.19490320413
日期:——
1. Das aus Friedelin C30H50O (I) zugängliche nor-Friedelen-dion C29H44O2 (II) liefert bei der Oxydation mit Blei(IV)-acetat oder Wasserstoffperoxyd in Eisessiglösung das nor-Friedelen-disäure-anhydrid C29H44O3 (III), welches zu einem gesättigten, tetracyclischen Keton C25H42O (VI) abgebaut wurde.
1.达芬斯C 30 H 50 O(I)左旋弗里德伦丁C 29 H 44 O 2(II)乙氧基(IV)-乙酸酯在Eisessiglösungdas-Friedelen-disäure-中的Wasserstoffperoxyd酸酐C 29 H 44 O 3(III),微熔剂zu einemgesättigten,四环酮Keton C 25 H 42 O(VI),阿布巴特·乌尔德(abgebaut wurde)。
Preparation of ?,?-Dibromocyclobutanones from Olefins: A simple procedure for the regioselective functionalization of olefins
作者:H�l�ne Chaumeil、Claude Le Drian
DOI:10.1002/hlca.19960790416
日期:1996.6.26
of tribromoacetyl bromide in the presence of POCl3. Under these conditions, the cycloaddition of dibromoketene with olefins 5 yields α,α-dibromocyclobutanones 2, which are cleaved with alkoxides to yield β-dibromomethyl esters 4. Several examples are given. For monosubstituted olefins, the functionalization is regioselective, the methoxycarbonyl group being introduced at the terminal C-atom.
作者:E. T. Blues、D. Bryce-Smith、H. Hirsch、M. J. Simons
DOI:10.1039/c29700000699
日期:——
analyses, together with spectroscopic and chemical properties, show silverketenide, Ag2C2O (I), to have an unusual covalent layer structure in which strong directed bonds exist between metal atoms and the terminal carbon atoms of linear ketenide groups: the distance between adjacent silver atoms in a layer is 2·84 Å, slightly less than in silver metal (2·88 Å), and the interlayer separation is 5·846 Å.
X射线和电子衍射分析以及光谱和化学性质显示,酮化银Ag 2 C 2 O(I)具有不寻常的共价层结构,其中金属原子与碳的末端碳原子之间存在强的定向键线性酮基团:一层中相邻银原子之间的距离为2·84Å,略小于金属银中的2·88Å,层间间距为5·846Å。
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作者:V. S. Bogachev、P. A. Ulanov
DOI:10.1023/a:1022282503476
日期:——
5'-phosphate with trichloroacetic anhydride, trichloroacetyl chloride, and tribromoacetyl bromide was studied in dimethylformamide and acetonitrile in the presence of tertiary amines. The first two reactions gave the mixed anhydride of trichloroacetic and thymidylic acids (acyl phosphate) as the major product and P1, P2-dithymidine 5'-pyrophosphate as the byproduct. The third reaction proceeded by a more complicated
HeI photoelectron spectra of unstable molecules: mono- and di-halogenoketenes
作者:David Colbourne、Nicholas P. C. Westwood
DOI:10.1039/p29850002049
日期:——
HeIPhotoelectronspectra are reported for the mono- and di-chloro- and -bromo-ketenes (XHCCO and X2CCO, X Cl, Br) generated in high yield as unstablemolecules from thermolysis of acid halides. The spectra are discussed and assigned by reference to the parent ketene molecule, orbital trends, and comparison with theoretical calculations.
据报道,由于酰卤的热解,不稳定的分子以高收率产生了单氯乙烯和二氯乙烯和溴乙烯酮(XHC C O和X 2 C C O,X Cl,Br)的He I光电子能谱。通过参考母体乙烯酮分子,轨道趋势以及与理论计算的比较来讨论和分配光谱。