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Circular dichroism evidence of the left‐handed conformation adopted by cyclopropylpyrroloindole antitumor antibiotics in solution
Author(s) -
Tayeb Hayet,
Fiallo Marina,
GarnierSuillerot Arlette
Publication year - 1996
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(1996)8:8<585::aid-chir8>3.0.co;2-8
Subject(s) - circular dichroism , chemistry , chirality (physics) , crystallography , vibrational circular dichroism , ring (chemistry) , left handed , stereochemistry , optics , chiral symmetry , organic chemistry , physics , quantum mechanics , nambu–jona lasinio model , quark
The purpose of this work was to determine the conformation adopted in solution by adozelesin, carzelesin, and their derivatives obtained under basic or acidic conditions. Circular dichroism in the 270–330 nm wavelengths region was studied. In solution adozelesin can adopt two different conformations: a left‐handed one which is thermodynamically favoured at low temperature and is mainly present at room temperature, and a right‐handed one which is observed either at high temperature or at room temperature in the presence of DNA. This was ascertained by the presence of circular dichroism signals of the couplet type. The active form of carzelesin, i.e., U‐76074, also exhibited a left‐handed conformation in solution. Carzelesin and the derivatives obtained under acidic conditions that lack the cyclopropyl ring, and cyclopropylpyrroloindole, obtained under basic conditions, cannot adopt such a conformation. Chirality 8:585–589, 1996. © 1997 Wiley‐Liss, Inc.