L. Yu. Izotova

Synthesis, Structure, and Membrane Activity of New Glycyrrhetic Acid Derivatives

Derivatives of 3-O-acetyl-18-βH-glycyrrhetic acid were synthesized. Their structures and membrane activities were studied.

Polymorphism of Inclusion Complexes and Unsolvated Hosts. III. Dimorphism of the Alkaloid Colchicine Hydrate. The Structure of Colchicine Monohydrate

The alkaloid colchicine forms, in addition to the previously known dihydrate host–guest complex, a monohydrate complex. The crystal structure of the monohydrate was determined by direct methods and refined to a final R value of 0.046 for 1425 observed reflections. Crystal data are: orthorhombic, space group P2 12 12 1, a = 9.145(2) Å; b = 13.270(3) Å; c = 17.942(4) Å, V = 2177(1) Å3, Z= 4, Dx = 1.22 g cm-3, T = 293 K. The conformation of the molecule is practically identical with the conformation in the dihydrate inclusion complex. Water molecules show proton donor as well as proton acceptor properties and are hydrogen bonded with the three colchicine molecules giving rise to the three dimensional H-bonded network.

1,2,4-Thiadiazol derivatives of cytisine alkaloid: solvate formation and phase transitions

Abstract1,2,4-Thiadiazol derivatives of cytisine alkaloid—N-(3-methylthio-1,2,4-thiadiazol-5-yl-aminocarbonylmethyl) (1), N-(3-ethylthio-1,2,4-thiadiazol-5-yl-aminocarbonylmethyl) (2), N-(3-hexylthio-1,2,4-thiadiazol-5-yl-aminocarbonylmethyl) (3) cytisine have been crystallized from different solvents and by X-ray and TG–DSC method were studied. By X-ray analysis the structures of the crystal solvate of 2 with dioxane have been determined. By topology represented solvate belongs to tabulate type. In the crystal structure two conformers of the host molecules were determined. By TG–DSC method has been shown, that methyl-, ethyl-, and hexyl cytisine derivatives can exist in two phase forms. But, unlike methyl- and ethyl-derivatives, hexyl-derivative of cytisine not form inclusion compounds.

Molecular and crystal structures of the complex of 18-dehydroglycyrrhetic acid with dimethyl sulfoxide

The crystal structure of the complex of 18-dehydroglycyrrhetic acid (GLD) with DMSO (C30H41O4·C2H6OS) has been determined by x-ray structural analysis. Syntex P21 diffractometer, CuKα radiation, 1309 reflections, R = 0.080. A conformational analysis has been made of the GLD molecule in comparison with that of glycyrrhetic acid. The conformations of rings A and B in the GLD molecule do not differ from the conformations of the corresponding rings of glycyrrhetic acid. Differences arise in ringsC,D, andE because of the presence of the double bond between the C18 and C19 atoms.

Crystal and Molecular Structure of β-(N-Benzothiazoline-2-One)Propionic Acid and Its Ethylenediammonium Salt

The crystal and molecular structure of β-(N-benzothiazoline-2-one)propionic acid and its ethylenediammonium salt is studied. In the latter structure, amine groups of ethylenediamine are involved in the deprotonation of two molecules of β-(N-benzothiazoline-2-one)propionic acid. The geometry of the molecules and weak intermolecular hydrogen and dative bonds in the crystals are analyzed. The asymmetric unit of the unit cell in both structures contains two molecules of β-(N-benzothiazoline-2-one)propionic acid.

Crystal and molecular structure of β-(N-benzoxazoline-2-thione) propionic acid and its salts

The crystal and molecular structures of β-(N-benzoxazoline-2-thione)propionic acid, its monoethanolammonium (NН2(CH2)2OH) and ethylenediammonium (NН2(CH2)2NH2) salts are studied. In the salts the monoethyleneamine amine group participates in the deprotonation of one ethylenediamine–two β-(N-benzthiazolin-2-one)propionic acid molecules. The geometry of the molecules and intermolecular hydrogen and donor-acceptor bonds in crystals are analyzed. In the crystal structures weak interactions form a two-dimensional layer whose thickness corresponds to unit cell sizes.

Stereochemistry of Samarcandin-Type Sesquiterpenoid Coumarins. Crystal Structures of Feshurin and Nevskin

The crystal and molecular structures of the sesquiterpenoid coumarins feshurin and nevskin were determined by x-ray crystal structure analyses. The absolute configuration of feshurin was established as (1′R,2′R,6′S,9′R and C10′S); of nevskin, (1′R,2′R,6′R,C9′R and C10′S). The absolute configurations of eight diastereomers of the samarcandin-type sesquiterpenoid coumarins were refined. Channel-type cavities (35.4% of the total volume) along the crystallographic a axis formed as a result of intermolecular H-bonds and contained disordered solvates in the crystal packing of nevskin

Crystal structure of three solvates of 1,1′-binaphthyl-2,2′-bicarboxylic acid with 2-picoline

From solutions in 2-picoline (2-methylpyridine), depending on the temperature of crystallization, the universal clathratogen — 1,1′-binaphthyl-2,2′-bicarboxylic acid (BBA) — precipitates as crystals of three types with different composition and structure. Under normal conditions (room temperature), the precipitate is crystals of BBA disolvate with 2-picoline; a temperature reduction of 20°C results in the crystallization of monosolvate dihydrate; and a temperature increase of the same level results in the precipitation of monosolvate. That is, as the temperature of crystallization rises, the number of included guest molecules gradually decreases and the space where they are located becomes more closed. In 1:1:2 BBA/2-picoline/H2O solvate (space group P21/n, a = 11.991(2) Å, b = 9.317(2) Å, c = 22.283(5) Å, β = 99.77(3)○, V = 2453.3(9) Å3, Z = 4), the carboxyl groups of the BBA molecule at the C21 atom are deprotonated and the released proton goes to the nitrogen atom of 2-picoline. BBA molecules interact with those of 2-picoline and water via H bonds to form infinite chains in direction [111], which, in their turn, join together into infinite two-dimensional sheets parallel to plane (−101). 2-Picoline molecules are located in the channels. In BBA/2-picoline disolvate (space group C2/c, a = 11.7523(11) Å, b = 13.8563(13) Å, c = 17.9615(13) Å, β = 108.044(9)○, V = 2781.1(4) Å3, Z = 4), one BBA molecule and two H bond 2-picoline molecules form a 0-dimensional associate of the type G-H-G. The solvent molecules are also located in the channels. In BBA/2-picoline monosolvate (space group P21/c, a = 9.299(5) Å, b = 12.727(5) Å, c = 19.011(5) Å, β = 95.248(5)○, V = 2240.5(16) Å3, Z = 4), each BBA molecule is H-bonded with a 2-picoline molecule to form a 0-dimensional associate of the type H-G. Guest molecules are located in closed cavities.

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) Å, b = 30.5957(13) Å, c = 17.0824(4) Å, γ = 94.153(2)°, V = 5901.5(3) Å3, 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.

Gossypol clathrates: Structure and thermal behavior of gossypol solvates with two picoline isomers

Gossypol forms stable solvates with 4- and 2-picolines at room temperature. The solvates are investigated by single crystal X-ray diffraction and thermal analysis. Solvate crystals of gossypol with 4-picoline (1) have the 1:3 composition (gossypol:4-picoline) and crystallize in the P21/c space group. This substance is isostructural to a trisolvate of gossypol with pyridine. Solvate crystals of gossypol with 2-picoline (2) have the 1:4 composition (gossypol:2-picoline) and crystallize in the P-1 space group. The unit cell parameters for the investigated structures are as follows: 1 monoclinic crystals, C30H30O8·3C6H7N, a = 10.7530(1) Å, b = 20.7834(3) Å, c = 19.1166(2) Å, β = 95.537(1)°, V = 4252.32(9) Å3, M = 797.92, Z = 4, dx = 1.246 g/cm3, and R = 0.0489 for 4102 reflections; 2 triclinic crystals, C30H30O8·4C6H7N, a = 11.467(1) Å b = 14.962(2) Å, c = 15.570(3) Å, α = 75.62(1)°, β = 69.83(1)°, γ = 79.58(1)°, V = 2414.6(7) Å3, M = 891.04, Z = 2, dx = 1.226 g/cm3, and R = 0.0528 for 3779 reflections. The results of the single crystal XRD and thermal analysis confirm that gossypol with 4-picoline forms a trisolvat, and a tetrasolvate with 2-picoline. The transition from 4-picoline to 2-picoline proves to change the type of the host-guest association from one-dimensional to zero-dimensional, i.e., to lead to a new crystal structure. Desolvation of compound 2 begins at a lower temperature than that for compound 1, which is explained by their different crystal structures. Keywords: gossypol, 4-picoline, 2-picoline, clathrate formation, crystal structure.