O. A. Lodochnikova

The structure of 1-phenyl-3-benzoylamino-4-benzoylpyrazol-2-in-5-one

Abstract Crystal and molecular structure of 1-phenyl-3-benzoylamino-4-benzoylpyrazol-2-in-5-one as a product of the benzoylation of 1-phenyl-3-benzoylaminopyrazol-2-in-5-one was characterised by X-ray single crystal diffraction. It is shown that 1-phenyl-3-benzoylamino-4-benzoylpyrazol-2-in-5-one exists in the solid phase in an NH-tautomeric form, which is stabilised by two intramolecular hydrogen bonds and one intermolecular bond with the solvate dioxane molecule, the latter being used as a solvent for recrystallisation.

Bis-phosphonium salts of pyridoxine: the relationship between structure and antibacterial activity.

A series of 23 novel bis-phosphonium salts based on pyridoxine were synthesized and their antibacterial activities were evaluated in vitro. All compounds were inactive against gram-negative bacteria and exhibited the structure-dependent activity against gram-positive bacteria. The antibacterial activity enhanced with the increase in chain length at acetal carbon atom in the order n-Pr>Et>Me. Further increasing of length and branching of alkyl chain leads to the reduction of antibacterial activity. Replacement of the phenyl substituents at the phosphorus atoms in 5,6-bis(triphenylphosphonio(methyl))-2,2,8-trimethyl-4H-[1,3]-dioxino[4,5-c]pyridine dichloride (compound 1) with n-butyl, m-tolyl or p-tolyl as well as chloride anions in the compound 1 with bromides (compound 14a) increased the activity against Staphylococcus aureus and Staphylococcus epidermidis up to 5 times (MICs=1-1.25 μg/ml). But in practically all cases chemical modifications of compound 1 led to the increase of its toxicity for HEK-293 cells. The only exception is compound 5,6-bis[tributylphosphonio(methyl)]-2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine dichloride (10a) which demonstrated lower MIC values against S. aureus and S. epidermidis (1 μg/ml) and lower cytotoxicity on HEK-293 cells (CC(50)=200 μg/ml). Compound 10a had no significant mutagenic and genotoxic effects and was selected for further evaluation. It should be noted that all bis-phosphonium salt based on pyridoxine were much more toxic than vancomycin.

New synthetic method for 2,3,4-tris(hydroxymethyl)- 6-methylpyridin-5-ol

Vitamin Β6 and its derivatives are included into the composition of over fifty enzymes taking part in the biosynthesis of amino acids, in the metabolism of carbohydrates, fatty acids, and membrane unsaturated lipids. The pyridoxine, pyridoxal, and pyridoxamine derivatives also attract close attention because of their pharmacological and biological action [1–3]. In this study we developed a new method of the synthesis of pyridoxine IV hydroxymethylated in the position 6. The previously reported five-stage synthesis of compound IV [4, 5] involving preliminary formation of the pyridine ring with its subsequent functionalization is relatively labor-consuming and is not sufficiently effective (the yield of the target product does not exceed 18%). The newly developed preparation procedure includes three stages: the acetonide protection of hydroxymethyl groups in the positions 4, 5 of pyridoxine, the hydroxymethylation of the seven-membered cyclic pyridoxine

New synthesis of diterpenoid (16S)-dihydrosteviol

A new procedure has been developed for the synthesis of diterpenoid (16S)-dihydrosteviol [(16S)-13-hydroxy-ent-kauran-19-oic acid] by acid hydrolysis (0.7% hydrochloric acid) of SWETA food sweetener and subsequent reduction of the resulting mixture of caurenoids with hydrazine hydrate over Raney nickel. The molecular geometry of (16S)-dihydrosteviol, as well as of Δ15-steviol (13-hydroxy-ent-kaur-15-en-19-oic acid), was determined for the first time by X-ray analysis.

Theoretical and experimental study on cyclic 6-methyl-2,3,4-tris(hydroxymethyl)pyridin-5-ol acetonides

Methods for the preparation of three cyclic 2,3,4-tris(hydroxymethyl)-6-methylpyridin-5-ol acetonides have been developed by variation of the reaction conditions. The six-membered acetonide turned out to be thermodynamically more stable than the seven-membered acetonide and bis-acetonide. The experimental data were consistent with the results of quantum-chemical calculations. The structure of the isolated compounds was proved by X-ray analysis.

Study of “Racemic Compound-Like” Behavior of Diastereomeric Mixture of Pinanyl Sulfoxides by X-Ray Diffraction, IR Spectroscopy, and DFT Calculations

Abstract The oxidation of a β-hydroxysulfide in the pinane series by use of m-chloroperbenzoic acid resulted in the formation of the corresponding β-hydroxysulfoxide as a mixture of two diastereomers in 4:5 ratio. According to single-crystal X-ray diffraction (XRD) results, it is established that the diastereomeric mixture of sulfoxides crystallizes in the “racemic compound-like” manner under formation of asymmetric dimers through S=O··H–O interactions. This asymmetric dimer formed from diastereomeric molecules is a structural unit in both crystal modifications, the triclinic and the monoclinic one. The behavior of the diastereomeric mixture of pinane derived sulfoxides in crystals, melts and in tetrachloromethane solutions was studied by IR spectroscopy. The density functional theory (DFT) method with 6-31G (d, p) basis set was used to calculate the optimized geometrical parameters and vibrational frequencies of different associates in solutions. The calculated vibrational frequencies are compared with experimental IR spectra. GRAPHICAL ABSTRACT

A new polymorph of methimazole: Single crystal and powder X-ray diffraction study

A new polymorph of 1-methyl-4-imidazoline-2-thione has been first discovered and studied by X-ray diffraction. The crystal of the new polymorph is monoclinic, the asymmetric part of the cell contains three independent molecules. In the crystal, the key compound is in the form of planar hydrogen-bonded dimers due to the interactions of the N-H…S type. The new modification is of an intensely yellow color in contrast to the previously known colorless forms, is characterized by a lower density but stronger hydrogen bonds; it is formed as a minor impurity to main triclinic polymorph.

Synthesis and antifungal activity of sulfides, sulfoxides, and sulfones based on (1S)-(-)-β-pinene

Attachment of 2-mercaptoethanol and thioglycolic acid methyl ester to the double bond of (1S)-(-)-β-pinene yielded pinane sulfides with the cis configuration. Oxidation of sulfides with m-chloroperbenzoic acid yielded the corresponding sulfoxides and sulfones. The resulting compounds were screened for antimycotic activity and the dynamics of changes in antifungal properties in sulfides-sulfoxide-sulfone series were studied.

Reactions of 2-sulfanylethanol with mucochloric acid and its derivatives

Mucochloric acid reacted with 2-sulfanylethanol in the presence of triethylamine to give 3-chloro-5-hydroxy-4-(2-hydroxyethylsulfanyl)furan-2(5H)-one which underwent acid-catalyzed cyclization to 7-chloro-2,3,4a,6-tetrahydrofuro[2,3-b][1,4]oxathiin-6-one. Likewise, reactions of 5-alkoxy-3,4-dichlorofuran-2(5H)-ones with 2-sulfanylethanol in the presence of triethylamine involved replacement of chlorine in position 4 of the furan ring with formation of the corresponding 4-(2-hydroxyethylsulfanyl) derivatives. The reaction of mucochloric acid with 2-sulfanylethanol in excess aqueous potassium hydroxide resulted in the formation of an acyclic product, 3-(2-hydroxyethylsulfanyl)-2-chloroprop-2-enoic acid. The structure of 7-chloro-2,3,4a,6-tetrahydrofuro[2,3-b][1,4]oxathiin-6-one and 3-(2-hydroxyethylsulfanyl)-2-chloroprop-2-enoic acid was proved by X-ray analysis.

Sulfides, sulfones, and sulfoxides of the furan-2(5H)-one series. synthesis and structure

A number of 4- and 5-R-sulfanylfuran-2(5H)-one derivatives were synthesized, and their oxidation with various reagents was studied. The corresponding sulfones were obtained using hydrogen peroxide in acetic acid. 4-R-sulfanyl derivatives were selectively oxidized to sulfoxides with m-chloroperoxybenzoic acid. The molecular and crystal structures of some new sulfones and sulfoxides were determined by X-ray analysis.