Solvent effects on circular dichroism of colominic acid.

Circular dichroism study of polyriboxanthylic acid.

We report in the present paper the circular dichroism spectra of poly(X) at different pH and temperature values. The spectra are characteristic of three stable forms of poly(x) in the pH range of protonation of xanthosine. An electrostatic barrier is proposed to account for the hysteresis and metastability observed in a certain pH range. Some results on oligo(X) at basic pH are also presented. ...

Solvent Induced Circular Dichroism in Conformational Analysis: Bile Pigments

The applicability of solvent induced circular dichroism (SICD) for the conformational analysis of bile pigments has been investigated. The S-(—)-ethyl lactate induced rotational strengths for octaethylbilindion (4) and its dihydroderivative 5 are remarkably high. Related compounds, e.g. the isomeric purpurines 1 and 2 and formyltripyrrinon 3 exhibit an optical activity which is smaller by more ...

Chiral cooperativity and solvent-induced tautomerism effects in electronic circular dichroism spectra of [2.2]paracyclophane ketimines.

[2.2]Paracyclophanes with chiral ketimine side chains constitute a class of highly versatile and enantioselective ligands for catalytic carbon-carbon bond forming reactions. Proper matching of the side chain and [2.2]paracyclophane configurations induces chiral cooperativity, which is key to high selectivities. Here we show that the absolute configuration of both chirotropic elements may be ful...

Circular Dichroism of Protein

Circular Dichroism of the Polyoximic Acid Moiety in Polyoxins

Polyoxins are antifungal antibiotics isolated from Streptomyces cocaoi var. asoensis.1) They are unique dior tripeptides which can be designated as the 'pep tidic nucleoside' composed of characteristic L-amino acids such as polyoximic acid (I), polyoxamic acid (II) and polyoxin C or its analogues (III) with a nucleoside moiety2) Among them the circular dichroism (CD) of the pyrimidine nucleosid...