Preparation and properties of glutathion conjugates of 2,4,5,6-tetrachloro-1,3-dicyanobenzene
作者:Zdenko Hameršak、Miklos Hollósi、Darko Kontrec、Branko Ladešié、Zsuzsa Majer、Vitomir Šunjić
DOI:10.1016/0040-4020(94)01090-m
日期:1995.2
Preparation and spectroscopic properties of 2,5,6-trichloro-4-(S-gamma-L-glutamyl-L-cysteinyl-glycine)-1.3-dicyanobenzene (2), 2,5-dichloro-4,6-di-(S-gamma-L-glutamyl-L-cysteinyl-glycine)- 1,3-dicyanobenzene (3), and 5-chloro-2,4,6-tri(S-gamma-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-spectroscapic data allowed unambiguous determination of regioselectivity of conjugation reaction of chlorothalonil with glutathione. UV Spectra of 24 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.