Complexes Of Gossypol Research Articles

PREPARATION AND PHYSICO-CHEMICAL CHARACTERISTICS OF THE WATER-SOLUBLE COMPLEX OF THE GOSSYPOL DERIVATIVE

The article is devoted to the study of the process of obtaining a new water-soluble complex of the imino derivative of gossypol, its physicochemical and structural parameters. N-polyvinylpyrrolidone (N-PVP, M.m. 8000) for medical use was chosen to obtain the complex of the imino derivative of gossypol. During the study, we tested the methods for obtaining several complexes, which are proposed in the classical literature and information resources. The following method was used to obtain the complex: the imino derivative of gossypol was mixed with the polymer at room temperature for 24 hours in a solvent system (acetone : water 3 : 1). Thus, a water-soluble complex of gossypol with N-PVP was obtained, which was purified and dried. The yield of the final product was 75.35%.
 To study the spectral properties of the obtained substances, modern UV and IR spectroscopy instruments were used. The results were analyzed and compared with data presented in the scientific literature. The proposed structure of the resulting water-soluble supramolecular complex is proposed.

Structures of Complexes of Gossypol with Ferrous Sulfate Based on High‐Performance Liquid Chromatography Separation, Spectroscopic Analysis, and PM3 calculations

AbstractThe complexes of gossypol with Fe2+ were prepared by using methanol as solvent in the presence of CO2 atmosphere. The results from FT‐IR spectra analysis indicated that the aromatic aldehyde groups in gossypol molecules were entirely involved in coordination with Fe2+. UV‐Vis absorption spectrum of the complexes in methanol solution displays blue‐shift in comparison with that of gossypol. Five compounds from the complexes were isolated by high performance liquid chromatography. The structures of the complexes are consistent with PM3 calculations. Two compounds were formed by coordination of gossypol with Fe2+ at 1:2 molar ratio, other three compounds were formed by chelation of gossypol with Fe2+ at molar ratio by 1:1, 1:3, and 1:4 respectively.

Gossypol clathrates: Structure and thermal behavior of the gossypol acridine complex

The natural compound gossypol forms a stable clathrate with acridine. The composition of the clathrate is C30H30O8·0.5C13H9N. The unit cell is monoclinic, C2/c space group, a = 11.3213(3) A, b = 30.5957(13) A, c = 17.0824(4) A, γ = 94.153(2)°, V = 5901.5(3) A3, M = 1153.24, Z = 8, dx = 1.369 g/cm3, and R = 0.0413 for 4726 reflections. The structure of the clathrate allows one to refer this compound to the ethyl acetate isomorphic host-guest group of gossypol complexes.

The interaction of PVP complexes of gossypol and its derivatives with an artificial membrane lipid matrix

In this paper, we present the results of a study on the membrane-active properties of gossypol, its derivatives and their polyvinylpyrrolidone complexes as assessed by differential scanning calorimetry and by the fluorescent probe method. The latter revealed the change in polarization of the incident radiation caused by the action of the polyphenol on the artificial membrane lipid matrix.

Inclusion Complexes of Gossypol with 2-Pentanone, 3-Pentanone, and 2-Hexanone

Inclusion complexes of gossypol with 2-pentanone, 3-pentanone, and 2-hexanone were prepared by crystallization from the corresponding ketone and hexane, and their structures were determined by low-temperature X-ray diffraction. All three compounds crystallize in monoclinic systems and have a 2:1 gossypol-to-solvent molar ratio. Both gossypol–pentanone complexes crystallize in C2/c space groups, and the solvent cavities in these structures have C2 symmetry. The 3-pentanone molecule, which has C2 symmetry, sits symmetrically within the cavity, while the 2-pentanone molecule, which lacks C2 symmetry, takes two equally probable orientations within the cavity. Both structures are similar to previously reported gossypol inclusion complexes formed with small esters and 3-hexanone. The distal positioning of the carbonyl group in 2-hexanone does not allow it to fit into the same solvent cavity that exists in the pentanone structures. In the gossypol-2-hexanone complex, the solvent cages are skewed, and the C2 site symmetry is lost. As a result, the structure crystallizes in a Cc space group and has a larger asymmetric unit and unit cell. Although the 2-hexanone structure retains many of the features of the gossypol–pentanone complexes, this is the first report of a gossypol inclusion compound with this extended structure.

Clathrate formation of gossypol: The structure of the complex of gossypol with tropolone

The clathrate of gossypol with tropolone is prepared for the first time and studied by X-ray diffraction. The structure is determined and refined using 7307 reflections (Siemens SMART/CCD diffractometer). The crystals are monoclinic, C30H30O8 · 2C7H6O2, a = 35.5892(1) A, b = 12.8893(2) A, c = 18.5910(2) A, β = 118.54(3)°, Z = 8, space group C2/c, and R = 0.058. Each gossypol molecule is linked to two tropolone molecules through hydrogen bonds. The host (gossypol) and guest (tropolone) molecules form separate bilayers that are parallel to the bc plane and alternate along the a-axis.

Spectroscopic and semiempirical studies of gossypol complexes with Fe 2+ and Fe 3+ cations

The complexes of gossypol with Fe 2+ and Fe 3+ cations were studied in acetonitrile by UV–Vis and FT-IR spectroscopy. Very complex equilibria and structural changes were observed for various ratios of gossypol–iron cation mixtures. With the formation of complexes, the ketol–ketol tautomer form of gossypol was favored. With increasing concentration of iron cation in the mixture, the deprotonation of hydroxyl groups was indicated. The semiempirical studies show that the most stable complexes of gossypol with iron cations are 1:4, 1:1 and 2:1. The structures of these complexes are discussed.

Spectroscopic study of gossypol–lanthanide cation complexes in acetonitrile solution

The formation of 1:1 complexes of gossypol with lanthanide(III) cations (M=Dy, Gd, Tb and Eu) was studied by FT- IR- and UV-visible spectroscopy. The FT–IR spectra evidenced the aldehyde–aldehyde tautomer change to the lactol–lactol tautomer of gossypol upon the complexation. This result was also confirmed by UV-visible absorption spectra measurements. On the basis of the Hildebrant Benessi equation, the formation constants K for gossypol–lanthanide(III) cations complexes in acetonitrile were determined to be in the range of 3.5×10 4 mol dm −3.

Polymorphism of Inclusion Complexes and Unsolvated Hosts. I. Trimorphism of the Host-Guest Complex of Gossypol with Dichloromethane. The Structure of the β-Phase

The formation of host-guest complexes of gossypol at different temperatures has been investigated for the same pressure and concentration. Gossypol forms three different clathrates with dichloromethane within the temperature interval of 22-36 °C. Single crystals of these three modifications (phases) were obtained and their crystallographic parameters measured. The structure of the α-phase has been determined previously and the γ-phase is isostructural to the inclusion complex of gossypol with benzene, while the structure of the β-phase has been solved during the present research. Crystals of C30H30O8·CH2Cl2 are triclinic, space group P1, a = 8.604(1), b = 11.858(2), c = 14.405(2) (A), α = 84.60(1), β = 89.14(1), γ = 89.73(1)°, V = 1463(1) A3, Z = 2, R = 0.089 for 2419 observed reflections.

X-ray structural investigation of gossypol and its derivatives XXV. Structure of the clathrate of gossypol with isopropyl alcohol

With isopropyl alcohol, gossypol forms a clathrate isostructural with the complexes of gossypol formed by ketones (acetone), aldehydes (butyraldehyde),or alcohols (propyl alcohol). The hydroxy group of isopropyl alcohol acts as the proton acceptor in a hydrogen bond of the host-guest type.

Inclusion complexes of the natural product gossypol. Recognition by gossypol of halogeno methanes. Structure of the dichloromethane complex of gossypol and single crystal conservation after decomposition

The structures of gossypol complexes are extremely sensitive to the halogenomethane present as the guest; e.g. changing the number of Cl atoms in chloromethane derivatives changes the structure of the gossypol complex. The crystals of C30H30O8·CH2Cl2 are monoclinic, space groupC2/c,a=21.320(4),b=19.199(6),c=15.765(2)A, β=113.05(2)o,V=5916(2)A3,Z=8,D x=1.35 g/cm3,T=295 K. The structure has been solved by direct methods and refined to the finalR value of 0.084 for 1828 reflections. In the structure H-bonded gossypol molecules form columns, generating channels in the structure which are filled by guest molecules. After decomposition (desolvation) monocrystals of the complexes are conserved without destruction, in which there are rather wide and empty channels though slightly smaller than in the complex. An attempt is made to explain some peculiarities of the behavior of the gossypol polymorph formed on the basis of its structure with empty channels.

X-ray structural investigation of gossypol and its derivatives XXIII autoclathrates based on a mixed gossypol — 1,4-Dioxane matrix

Gossypol forms various complexes with the isomeric dioxanes. The clathrate with 1,4-dioxane is the only complex of gossypol in which the intrinsic symmetry of the gossypol molecule — the symmetry of a twofold axis — is retained. In this complex, two out of the three 1,4-dioxane molecules belonging to each gossypol molecule participate in the construction of a mixed H-bound gossypol -dioxane matrix, while the third molecule plays the part of guest, the guest molecules having no H-bonds with the host matrix and undergoing desolvation at 108–110°C.

X-ray structural investigation of gossypol and its derivatives XXII. Structure of the H-clathrate of gossypol with dimethyl sulfoxide

In crystals obtained from solutions in DMSO, gossypol molecules are again present in the aldehyde tautomeric form. These crystals are H-clathrates with the channel type of structure which has much in common with the structure of the complexes of gossypol with methanol and with formic acid.

The tautomerization of gossypol as a function of the presence of Ni 2+, Cu 2+ or Zn 2+ cations

1 : 1 Complexes of gossypol with Ni(AuCl 4) 2, Cu(AuCl 4) 2 and Zn(AuCl 4) 2 were studied in acetonitrile using FT-IR spectroscopy. With this complexation the tautomeric equilibrium of gossypol is completely shifted from the aldehyde-aldehyde to the lactol-lactol tautomer in the case of Ni 2+ and Cu 2+ complexes, and to the ketol-ketol tautomer with the Zn 2+ complex. The nature of the interaction of these ions with gossypol, especially that of the Zn 2+ ion, is explained in detail. Furthermore, all changes concerning hydrogen bond formation and the reasons for it are discussed.

X-ray investigation of gossypol and its derivatives

The first four homologues of the carboxylic acid series and first two homologues of the monohydric alcohol series with gossypol give equimolar H-clathrates with the channel-type structure that are isostructural with gossypolacetic acid. Formic and acetic acids are capable of forming with gossypol a continuous series of solid substitution solutions. The desolvation of the unstable H-clathrates of carboxylic acids and monohydric alcohols form one and the same polymorph of gossypol. By x-ray structural analysis, the structures have been determined of two complexes of gossypol: an H-clathrate with methanol and a solid solution on the replacement of formic acid by acetic acid in a gossypol matrix.

The structure of Gossypol as a function of the presence of HAuCl 4 and of Be 2+ ions

Solutions of gossypol with HAuCl 4 and Be(AuC1 4) 2 have been studied by FT-IR spectroscopy. Addition of HAuCl 4 shifts the tautomeric equilibrium of gossypol completely from the aldehyde—aldehyde to the ketol-ketol tautomer. On addition of Be(AuCl 4) 2, 1:1 Be 2+ gossypol complexes are formed. With this complexation the tautomeric equilibrium of gossypol is completely shifted from the aldehyde—aldehyde to the lactol—lactol form. An IR continuum in the region 1100-500 cm −1 indicates that the Be 2+ ion fluctuates within the gossypol molecule between four O acceptor atoms. A four minima Be 2+ potential is present with steep slopes at the acceptor O atoms. The complex shows so-called “Be 2+polarizability” since the Be 2+ can easily be shifted within this potential.

Inclusion complexes of the natural product gossypol. Crystal structures of gossypol complexes with benzene and chloroform as guests

The crystal structures of the lattice inclusion complexes of gossypol with benzene and chloroform have been determined by X-ray structure analysis. The crystals of (C30H30O8)2 · C6H6 (GPBNZ) are triclinic, space groupPI,a = 11.241(3),b = 14.986(4),c = 17.380(4) A, α = 98.89(2), β = 99.86(2), γ = 98.91(2)°,V = 2800(2) A3,Z = 2,Dx = 1.32 g cm−3, μ(CuKα) = 7.35 cm−1. The structure has been refined to a finalR value of 0.050 for 6146 observed reflections. The crystals of C30H30O8·CHCl3 (GPCLF) are monoclinic, space groupC2/c,a = 28.464(4),b = 8.948(1),c = 26.480(4) A, β = 108.93(2)°,V = 6380(2) A3,Z = 8,Dx = 1.33 g cm−3, μ(CuKα) = 30.42 cm−1. The structure has been refined to a finalR value of 0.100 for 1980 observed reflections.

ChemInform Abstract: 1H NMR Studies of Gossypol and Its Complexes with Some Organic Compounds

Abstract The 1H NMR spectra of gossypol and its complexes with some organic compounds in various solvents have been analyzed. In CDCl3 solution gossypol exists as the (±) aldehyde tautomer. In other solvents, aldehyde and lactol tautomers are in equilibrium, depending on the nucleophilicity of solvent (B). In the case of complexes of gossypol with organic compounds, the equilibrium is shifted to the aldehyde form, and the (±) diastereoisomers were observed in the 1H NMR spectrum due to asymmetric nonspecific interactions. Two types of tetrabutylammonium complexes of gossypol, 2:1 and 4:1 have been prepared. The spectrum of the 2:1 salt points to a very complex equilibrium in solution without a ketol tautomer. In this case a new type of intramolecular hydrogen bond is formed. Ketol is the main tautomeric form of the 4:1 salt, which shows a very strong intermolecular OHO− type hydrogen bond.

Inclusion complexes of the natural product gossypol. Crystal structure of the 1 : 1 complex of gossypol with isovaleric acid

The crystal structure of the 1 : 1 lattice inclusion complex of gossypol with isovaleric acid has been determined by X-ray structure analysis. The crystals of C30H30O8⁗C5H10O2 are monoclinic, space groupC2/c,a=28.835(7),b=9.063(2),c=26.880(4)A, β=109.66(1)°,V=6615(2) A3,Z=8,Dx = 1.25 g cm−3, μ(CuKα) = 7.14 cm−1,T = 295 K. The structure was solved by direct methods and refined with isotropic thermal parameters to the finalR value of 0.132 for 1114 observed reflections. Hydrogen bonded gossypol molecules form columns along the [1 0 1] direction. These columns pack into layers parallel to the (101) plane. The layers of gossypol molecules are separated by the layers of isovaleric acid. The acid molecules are connectedvia a pair of O-H...O hydrogen bonds forming centrosymmetric dimers. There is no hydrogen bond interaction between the carboxylic acid dimers and gossypol molecules.

Inclusion complexes of the natural product gossypol. Crystal structure of the 2:1 complex of gossypol with amyl acrylate

The crystal structure of the 2: 1 inclusion complex of gossypol with amyl acrylate has been determined by X-ray structure analysis. The crystals of (C30H30O8)2⁗C8H14O2 are triclinic, space group P\(\bar 1\),a = 14.425(2),b = 15.519(1),c = 16.409(2) A, α =97.89(1), β = 117.80(1), γ =67.01(1)° (reduced cell:a = 14.425(2),b = 15.519(2),c = 16.017(2)A, α = 92.19(1), β = 115.01(l), γ =67.01(1)°],V = 2986.7(5) A3,Z = 2,Dx = 1.31 g cm−3, μ(CuKα) = 7.40 cm−1,T = 292 K. The structure has been solved by direct methods and refined to the final R value of 0.059 for 5155 observed reflections. The gossypol molecules bonded via several hydrogen bonds form centrosymmetric tetramers. The two independent gossypol molecules, A and B, are related within the tetramer by a local noncrystallographic 2-fold axis. The host molecules in the crystal form cavities in which two guest molecules are placed. The ester molecule interacts via a pair of C-...H-O hydrogen bonds with two gossypol molecules of the same chirality and belonging to the same tetramer unit. The amyloxy group of the ester molecule shows a very large thermal motion. It adopts a non-extended conformation in which it can be fitted into the cavity formed by the host molecules.