TAUTOMERISM AND STEREOCHEMISTRY OF DIHYDROXYPERYLENEQUINONES - FORCE-FIELD INVESTIGATIONS

被引:19
作者
ETZLSTORFER, C [1 ]
FALK, H [1 ]
MULLER, N [1 ]
机构
[1] JOHANNES KEPLER UNIV, INST CHEM, A-4040 LINZ, AUSTRIA
来源
MONATSHEFTE FUR CHEMIE | 1993年 / 124卷 / 04期
关键词
DIHYDROXYPERYLENEQUINONES; CERCOSPORIN; FORCE FIELD CALCULATIONS; TAUTOMERISM; INTERCONVERSION BARRIER;
D O I
10.1007/BF00814139
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Stereochemistry and tautomerism of cercosporin and several of its partial structure models were investigated using an MM2 derived force field method. Besides the ''propeller'' type conformer, which was found before by X-ray crystallography, the complicated energy hypersurface was shown to contain a novel ''double-butterfly'' conformer of similar stability. The interconversion barrier between these conformers and their enantiomers was found to be unusually high due to buttressing effects of neighbor substituents. Judged from the calculations, the 4,9-tautomer of cercosporin could also be present in favoring instances besides the 3,10-tautomer, whereas the 3,9-tautomer is strongly destabilized.
引用
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页码:431 / 439
页数:9
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