ChemInform Abstract: THE ABSOLUTE CONFIGURATION OF HYPERFORIN, AN ANTIBIOTIC FROM HYPERICUM PERFORATUM L., BASED ON THE CRYSTAL STRUCTURE DETERMINATION OF ITS P-BROMOBENZOATE ESTER

1983 ◽  
Vol 14 (42) ◽  
Author(s):  
I. BRONDZ ◽  
T. GREIBROKK ◽  
P. GROTH ◽  
A. J. AASEN
1999 ◽  
Vol 23 (9) ◽  
pp. 578-579
Author(s):  
Rainer Schobert ◽  
Hermann Pfab ◽  
Jutta Böhmer ◽  
Frank Hampel ◽  
Andreas Werner

Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.


1985 ◽  
Vol 40 (8) ◽  
pp. 1023-1028 ◽  
Author(s):  
Uwe Klingebiel ◽  
Sabine Pohlmann ◽  
Lutz Skoda ◽  
Cornelia Lensch ◽  
George M. Sheldrick

AbstractThe nature of the products which are formed in the reaction of tris(trimethylsilyl)Methylfluorosilanes (Me3Si)3C -SiF2R with KOH depends on the bulkiness of the substituents R. The condensed siloxane is obtained for R = F . The crystal structure determination of this siloxane (Me3Si)3C -SiF2-O -SiF2-C (SiMe3)3 shows that the Si -O - Si unit is linear. A fluorosilanol as well as a siloxane could be isolated for R = Me. 1,3-Migration of one or two trimethylsilyl groups from the carbon to the oxygen takes place for R = phenyl, rm-butyl or silylamine, with formation of siloxanes which are isomeres o f the expected silanols.


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