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New organotin(IV) derivatives of dipeptides as models for metal–protein interactions: in vitro anti‐tumour activity
Author(s) -
Nath Mala,
Pokharia Sandeep,
Song Xueqing,
Eng George,
Gielen Marcel,
Kemmer Martine,
Biesemans Monique,
Willem Rudolph,
de Vos Dick
Publication year - 2003
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.451
Subject(s) - chemistry , trigonal bipyramidal molecular geometry , denticity , ligand (biochemistry) , stereochemistry , medicinal chemistry , dipeptide , monomer , metal , mössbauer spectroscopy , crystallography , tin , peptide , crystal structure , organic chemistry , receptor , biochemistry , polymer
New organotin(IV) derivatives with general formulae R 2 SnL, where R = n −Bu and L is the dianion of glycyltyrosine (H 2 L‐ 1 ), glycyltryptophane (H 2 L‐ 2 ), leucyltyrosine (H 2 L‐ 3 ), leucylleucine (H 2 L‐ 4 ), valylvaline (H 2 L‐ 5 ) and alanylvaline (H 2 L‐ 6 ) have been synthesized in 1 : 1 molar ratio by the reaction of Bu 2 SnO with the respective dipeptide under azeotropic removal of water. Triphenyltin glycylleucinate was obtained by reacting Ph 3 SnCl and sodium glycylleucinate with filtration of NaCl formed. The bonding and coordination behaviour in these derivatives are discussed on the basis of IR, multinuclear 1 H, 13 C and 117 Sn magnetic resonance and 119 Sn Mössbauer spectroscopic studies. These investigations suggest that all the ligands in R 2 SnL act as dianionic tridentates coordinating through the COO − , NH 2 and N peptide groups, whereas in Ph 3 Sn(HL) the ligand acts as a bidentate coordinating through the COO − and NH 2 groups. The 119 Sn Mössbauer studies, together with the NMR data, indicate that, for the 1 : 1 monomeric derivatives, the polyhedron around tin in R 2 SnL is a trigonal bipyramid with the butyl groups and N peptide in the equatorial positions, while the axial positions are occupied by a carboxylic oxygen and the amino nitrogen atom. In Ph 3 Sn(HL) the structure is intermediate between pseudotetrahedral and cis ‐trigonal bipyramidal, with the N amino and two phenyl groups in the equatorial plane and the carboxylate oxygen and the third phenyl group in axial positions. All the complexes have been screened against seven cancer cell lines of human origin, viz. MCF‐7, EVSA‐T, WiDr, IGROV, M19, MEL A498 and H226. Ph 3 Sn(HL) displays the lowest ID 50 values of the tin compounds tested and reported in this paper. Its activity is comparable to those of methotrexate and 5‐fluorouracil. All the di‐ n ‐butyltin compounds exhibit lower in vitro anti‐tumour activities than Ph 3 Sn(HL); however, they do provide significantly better activities than etoposide and cis ‐platin. Copyright © 2003 John Wiley & Sons, Ltd.