François Kayser

Diorganotin difluorobenzoates: synthesis, spectroscopic characterization and in vitro antitumour activity. X-Ray structure determination of bis[di-n-butyl(2,6-difluorobenzoato)tin] oxide

The synthesis and spectroscopic characterization of diorganotin(IV) bis(difluorobenzoates) [F2C6H3COO]2SnR2 [type a] and bis[diorgano(difluorobenzoato)tin(IV)] oxides {[(F2C6H3COO)R2Sn]2O}2 [type b] are described. An X-ray structure study has revealed compound 3b, {[(2,6-F2C6H3COO)(n-C4H9)2Sn]2O}2, to be dimeric and built around a planar Sn2O2 ring. The crystals are triclinic P1BAR with the cell dimensions a=11.935(13), b=12.3675(14), c=12.974 angstrom, alpha=92.89(8), beta=84.32(7), gamma=67.49(9)-degrees; Z=1, with the dimer being centro-symmetric. Selected compounds have been tested in vitro against two human tumour cell lines, MCF-7 (a mammary tumour) and WiDr (a colon carcinoma), and exhibit promising cytotoxicities.

Synthesis, Characterization and In vitro Antitumour Activity of Novel Organotin Derivatives of 1,2- and 1,7-Dicarba-Closo-dodecaboranes.

Several organotin derivatives of 1,2- and 1,7-dicarba-closo-dodecaboranes were synthesized and characterized by 119Sn Mössbauer, 1H, 13C and 119Sn NMR spectroscopy. Their antitumour activities in vitro against cancerous cell lines of human origin are reported.

Synthesis, X-ray diffraction analysis and NMR studies of (Z)-2-methyl-3-triphenylstannyl-3-pentene-2-ol

Abstract The synthesis of (Z)-2-methyl-3-triphenylstannyl-3-pentene-2-ol and its characterization by an X-ray diffraction study and multinuclear NMR are reported. The tin atom exhibits a distorted tetrahedral SnC 4 geometry with the four SnC bond distances experimentally equivalent. The slight distortion from the ideal tetrahedral geometry is because of the presence of a weak intramolecular HO → Sn interaction of 3.012(3) A which produces a loose four-membered ring. The title compound was characterized in solution by 1 H, 13 C and 119 Sn NMR, and the persistence of the weak intramolecular HO → Sn coordination in solution was revealed by 13 C and 119 Sn secondary isotope multiplet of partially labelled entities (SIMPLE-NMR) experiments.

(Z)-1-[2-(Triarylstannyl)vinyl]-1-cycloheptanols: Synthesis, characterization, halodemetallation and crystal structures

The synthesis and characterization by 1H, 13C, 119Sn NMR and 119Sn Mossbauer spectroscopy of (Z)-1-[2-(triphenylstannyl)vinyl]-1-cycloheptanol, CH2(CH2)5C(OH)CHCHSnPh3 (1), and (Z)-1-[2-tri-p-tolylstannyl)vinyl-1-cycloheptanol, CH2(CH2)5C(OH)CHCHSn(p-tol)3 (2), are described, together with their halodemetallation by I2, Br2 and ICIl to yield derivatives of the types CH2(CH2)5C(OH)CHCHSnAr3−nXn (Ar = phenyl or p-tolyl, n = 1, 2; X = I, Br, Cl, respectively). The solid-state structures of four compounds have been determined by X-ray diffraction analysis. In the crystals of CH2(CH2)5C(OH)CHCHSnPh3 (1) and CH2(CH2)5C(OH)CHCHSn(p-tol)3 (2) the Sn atom has a tetrahedral geometry distorted towards trigonal bipyramid as a consequence of a close intramolecular contact with the hydroxyl O(1) atom of 2.742(3) A and 2.768(3) A, respectively. A trigonal bipyramidal geometry is found in CH2(CH2)5C(OH)CH=CHSn(p-tol)Br2 (12) and CH2(CH2)5C(CH)CHCHSn(p-tol)2Cl (4), in which significant SnO(1) interactions are noted [2.437(8) A and 2.407(8) A, respectively].

Tetraethylammonium (diorgano)halogeno(thiosalicylato)stannates : synthesis, characterization and in vitro antitumor activity

Some tetraethylammonium adducts of diorganotin thiosalicylates were prepared and characterized by Mossbauer, 1H, 13C, 19F and 119Sn NMR spectroscopy. Their solution chemistry in DMSO at equilibrium is discussed on the basis of 119Sn NMR data. These data are explained in terms of the complex being six-coordinate with one DMSO ligand and existing as a mixture of at least five isomers. These adducts appear to be only slightly more active in vitro than the parent diorganotin thiosalicylates against MCF-7, a mammary tumor, and especially against WiDr, a colon carcinoma. The ionic character of the species, resulting in higher solubility, did not provide higher antitumor activities.

Characterization by 2D-NMR and chemical properties of (20Z)-3-methoxy-17-[2-(triphenylstannyl)vinyl]estra-1,3,5(10)-trien-17β-ol

The complete solution structure and conformation of the title compound were determined by 2D proton detected 1H–13C HMQC-RELAY and 2D-NOESY build-up experiments. The assignment of the low field resonances of the quaternary carbon atoms was achieved by 1D–13C NMR with selective decoupling of the high field protons. Proton detected 1H–119Sn HMBC 1D and 2D NMR spectroscopy enables the observation of a very weak coupling between the hydroxy proton of the steroid moiety and the 119Sn nucleus. These proton detected experiments as well as 13C and 119Sn SIMPLE NMR provide evidence for a HO → Sn coordination to occur in solution.

A comparative structural study on the steroids [1,2,5]oxadiazolo[3′,4′:3,4]-5α-pregn-16-en-20-one oxime (HS998), [1,2,5]oxadiazolo[3′,4′:3,4]-5α-pregn-16-en-20-one (HS974), and [1,2,5]oxadiazolo[3′,4′:3,4]-5β-pregn-16-en-20-one (HS973) by NMR, molecular modeling, and X-ray investigations

Abstract The molecular structure of the steroids [1,2,5]oxadiazolo[3′,4′:3,4]-5α-pregn-16-en-20-one oxime, [1,2,5]oxadiazolo[3′,4′:3,4]-5α-pregn-16-en-20-one and [1,2,5]oxadiazolo[3′,4′:3,4]-5β-pregn-16-en-20-one has been determined. The proton-proton distances in the solid state from previous crystallographic studies are compared with the corresponding distances from novel and previous solution NMR as well as from novel in vacuo modeling studies.

STUDY OF HALOGEN EXCHANGES IN (Z)-1-2-(BROMOCHLOROPHENYLSTANNYL)VINYL-1-CYCLOHEXANOL BY 2D 119SN EXSY NMR

Abstract The halogen exchange reactions at equilibrium of ( Z )-1-[2-(bromochlorophenylstannyl)vinyl]-1-cyclohexanol were studied by two-dimensional 119 Sn exchange NMR spectroscopy (2D 119 Sn EXSY NMR). A single halogen exchange mechanism was found from a quantitative matrix analysis of the data.

The molecular structure of [1,2,5]oxadiazolo[3′,4′ : 3,4]-5α-pregn-16-en-20-one (HS974). Crystal structure and NMR investigations

The molecular structure of the steroid [1,2,5]oxadiazolo[3′,4′ : 3,4]-5α-pregn-16-en-20-one has been determined by single-crystal X-ray diffraction analysis in the solid state and by 1H and 13C, 1D and 2D homo- and proton-detected-hetero-nuclear NMR spectroscopy in the solution state. The proton–proton distances in solution were derived from a 2D-NOESY build-up experiment and found to be in good agreement with those in the solid-state structure, obtained from X-ray diffraction data.