engleski

Preparation and properties of glutathion conjugates of 2,4,5,6-tetrachloro-1,3-dicyanobenzene

Preparation and spectroscopic properties of 2, 5, 6-trichloro-4(S-γ-L-glutamyl-L-cysteinyl- glycine)-1.3-dicyanobenzene (2), 2, 5-dichloro-4, 6-di-(S-γ-L-glutamyl-L-cysteinyl-glycine)-1, 3- dicyanobenzene (3), and 5-chloro-2, 4, 6-tri(S-γ- L-glutamyl-L-cysteinyl-glycine)-1, 3- dicyanobenzene (4), gluthation conjugates of the general fungicide chlorothalonil (2, 4, 5, 6- tetrachloro-1, 3-dicyanobenzene, 1) are reported. Optimal conditions for preparation and chromatographic separation of the single conjugates are described. NMR-spectroscopic data allowed unambiguous determination of regioselectivity of conjugation reaction of chlorothalonil with glutathione. UV Spectra of 2–4 revealed significant long-wavelength band shift and enhancement of intensity with increasing number of thioalkyl groups attached to the aromatic ring. The UV band assignement is based on the UV-VIS spectra of the model compounds 5–7. The far-UV CD spectra are dominated by the chiral contribution of the amide chromophores. In a trifluoroethanol/water (70:30) mixture the peptide backbone of conjugate 2 likely adopts an ordered (folded) conformation, whereas peptides 3 and 4 show no significant tendency for forming ordered structures.

glutathione ; synthesis ; CD-spectroscopy

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