NMR Study of the graphite–<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylformamide system after ultrasonication

A suspension formed as a result of ultrasonication of a mixture of graphite with N,N-dimethylformamide has been studied by ¹H NMR spectroscopy. The dependence of the width of the ¹H NMR signal on the N,N-dimethylformamide content of the suspension has been determined.     

Synthesis of 8,16-diarylacridino[4,3-<Emphasis Type="Italic">c</Emphasis>]acridine-1,9-dione derivatives

A number of new acridino[4,3-c]acridinedione derivatives have been synthesized for the first time by condensation of N¹,N⁵-bis(arylmethylidene)naphthalene-1,5-diamines with cyclic 1,3-diketones (cyclohexane-1,3-dione and dimedone). The product structure has been determined by two-dimensional NMR spectroscopy, and a probable reaction mechanism has been proposed.     

Synthesis of new <Emphasis Type="Italic">N</Emphasis>-glycosides based on Valproic acid analogs tetrazole derivatives

New N-glycosides based on valproic acid analogs tetrazole derivatives were synthesized. The bis-tetrazole derived from 1,6-hexandiol was also connected to acetylated glucose and formed bis-N-glycoside. Structures characterizations have been performed using FT IR, ¹H and ¹³C NMR spectroscopy.     

Synthesis of amino acid conjugates of glycyrrhizic acid using <Emphasis Type="Italic">N</Emphasis>-hydroxyphthalimide and <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>'-dicyclohexylcarbodiimide

Synthesis of amino acid conjugates of glycyrrhizic acid with the use of N-hydroxyphthalimide, N,N'-dicyclohexylcarbodiimide, and tert-butyl esters of L-amino acids (valine, isoleucine, phenylalanine, and methionine) was performed followed by deprotection with trifluoroacetic acid. The target amino acid conjugates were isolated by column chromatography on silica gel in 40–45% yield. The structure of the prepared compounds was confirmed by IR and ¹³C NMR spectroscopy.     

Copolymer of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-diallyl-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylammonium chloride with maleic acid as drug carrier

A copolymer of N,N-diallyl-N,N-dimethylammonium chloride with maleic acid of constant composition was prepared under the conditions of radical initiation. The possibility of the functionalization of the copolymer with drugs containing amino groups by polymer-analogous transformations was examined. Conditions were found for preparing conjugates of the copolymer with isoniazid. The structures and the quantitative compositions of the conjugates were determined by ¹³С NMR spectroscopy, and the possibility of preparing conjugates with controlled drug content was demonstrated.     

Dichloro(ethylenediamine-<Emphasis Type="Italic">N,N</Emphasis>-di-3-propionato)zinc: Synthesis and crystal structure

Dichloro(ethylenediamine-N,N-di-3-propionato)zinc (I) has been synthesized for the first time by the reaction between acrylic acid and ethylenediamine coordinated with ZnCl₂ in an aqueous medium. Complex I has been characterized by IR, Raman, and ¹H,¹³C NMR spectroscopy, mass spectrometry, and elemental analysis. The X-ray diffraction analysis of complex I has also been performed. Crystals are monoclinic, а = 9.7792(4) Å, b = 9.9805(4) Å, c = 13.1130(5) Å, β = 101.5620(10)°, space group Р2₁/c, Z = 4, V = 1253.88(9) ų, ρ_calc = 1.804 g/cm³. The coordination polyhedra of Zn atoms in complex I are slightly distorted {ZnCl₂O₂} tetrahedra, each of which are built of two chlorine atoms and the carboxyl oxygen atoms of the two propionic groups of two ligand molecules and form a polymeric layer parallel to crystallographic plant (100). Bond lengths are Zn–О 1.970(1) and 1.976(1); Zn–Cl 2.2600(4) and 2.2693(4) Å. The ligand molecule in complex I has a double betaine structure.     

Rhodium(I) bisaldimine complexes in transfer hydrogenation

The reactions of hydrogen transfer from 2-propanol on acetophenone in the presence of the system [Rh(cod)Cl]₂–L] (L is bisaldimine ligands based on (R,R)-1,2-cyclohexanediimine and pyridine-, quinoline-, and thiophenecarboxaldehyde) were studied. Rhodium(I) complexes with optically active ligand showed a high catalytic activity (up to 345 h^–1) and moderate enantioselectivity [up to 55% ee of (R)-1-phenyethanol]. The structure of rhodium complex with N,N'-(1R,2R)-cyclohexane-1,2-diyl-bis[1-(pyridine-2-yl)methanimine] was determined on the basis of the data of ¹H and ¹³C NMR spectroscopy and quantum chemical calculations.     

Synthesis and antibacterial activity of new <Emphasis Type="Italic">N</Emphasis>-substituted 7-amino-4-methyl-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-ones

N-Substituted 7-amino-4-methyl-2H-chromen-2-ones containing one or two functionalized azole or azine moieties were synthesized. The structures of all synthesized compounds were confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy. Some of the synthesized compounds exhibited weak antibacterial activity against Rhizobium radiobacter, Escherichia coli, and Xanthomonas campestris.     

Synthesis and conformational analysis of 6-[N,N-bis(dihydroxyphosphorylmethyl)amino]methyl-2-hydroxy-2-oxido-1,4,2-oxazaphosphorinane-4-methylphosphonic acid by NMR spectroscopy

The Kabachnik—Fields methylphosphorylation of 1,3-diaminopropan-2-ol affords a mixture of 1,3-diamino-2-hydroxypropane-N,N,N′,N′-tetrakismethylphosphonic acid and its intramolecular cyclic ester. Subsequent heating of this mixture led to the thermal dehydration of the acid with the 1,4,2-oxazaphosphorinane ring closure and the formation of 6-[N,N-bis(dihydroxyphosphorylmethyl)amino]methyl-2-hydroxy-2-oxido-1,4,2-oxazaphosphorinane4-methylphosphonic acid. A predominant chair conformation of the formed six-membered heterocycle was inferred from the data of 2D homonuclear (¹H, ¹H; J-resolved) and heteronuclear (¹H, ¹³C; HSQC, HMBC) NMR correlation spectra.     

(Iodomethyl)fluorosilanes: Synthesis and Reactions

The methods of synthesis of bifunctional (iodomethyl)fluorosilanes of general formula ICH₂SiMe_nF_3–n (n = 0, 2) have been elaborated; the structure was proved by ¹H, ¹³C, ²⁹Si NMR spectroscopy. The reaction of (iodomethyl)dimethylfluorosilane with O-trimethylsilyl derivative of N,N'-dimethylhydrazide of trifluoroacetic acid gives rise to the formation of 2,2,4,4-tetramethyl-6-(trifluoromethyl)-3,4-dihydro-2Н-1,4,5,2-oxadiasilin-4-ium iodide with tetracoordinate silicone atom.     

Stereochemistry of dihydroxylation of <Emphasis Type="Italic">N</Emphasis>-arylbicyclo[2.2.1]-hept-5-ene-<Emphasis Type="Italic">endo</Emphasis>- and -<Emphasis Type="Italic">exo</Emphasis>-2,3-dicarboximides

Stereochemistry of the oxidation of N-arylbicyclo[2.2.1]hept-5-ene-endo-and-exo-2,3-dicarboximides at the double bond with peroxyacetic acid generated in situ in the presence of sulfuric acid and with an anhydrous dioxane solution of peroxyacetic acid was studied. In both cases, the reaction was stereospecific, regardless of the substituent in the N-aryl group and configuration of the imide ring, but the reaction direction depended on the presence of water in the system. In the first case, the corresponding trans-5,6-dihydroxy derivatives were formed, while in the second, exo-5,6-epoxy derivatives. The oxidation of N-arylbicyclo[2.2.1]-hept-5-ene-endo-and-exo-2,3-dicarboximides with a solution of potassium permanganate in aqueous acetone gave the corresponding N-aryl-cis-5,6-dihydroxybicyclo[2.2.1]heptane-endo-and-exo-2,3-dicarboximides. The exo,cis,exo and exo,cis,endo configurations of the synthesized compounds were determined by ¹H NMR spectroscopy.     

Structure and dynamics of eight-membered <Emphasis Type="Italic">P,N</Emphasis>-heterocycles in solution

Conformational analysis of eight-membered P,N-heterocycles (P₂^NR₂^R') in the solution has been performed by means of NMR spectroscopy and quantum chemical calculations. The equilibrium of the С₂-symmetrical (crown, major) and С_s-symmetrical (chair-boat, minor) forms of the compounds has been revealed, the transition barriers being of about 12 kcal/mol. The presence of an aromatic substituent at the nitrogen atom significantly shifts the equilibrium towards the dominating form.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-trimethylsilyl-substituded anililes

N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and ¹H, ¹³C, and ²⁹Si NMR spectroscopy.     

Study of variation in thermophysical properties of RE<Subscript>6</Subscript>UO<Subscript>12</Subscript>(s) along the lanthanide series

The novel ligand N,N,N′′′′,N′′′′-tetrabutyl-N′′′,N′′′-(N″,N″-diethyl)-ethidene bisdiglycolamide (TBEE-BisDGA) and other eight analogous extractants have been synthesized and characterized by NMR and HRMS. The solvent extraction of Th⁴⁺, UO₂ ²⁺ and Eu³⁺ from nitric acid solution using the above BisDGA extractants was investigated in 1-dodecanol at 30 ± 1 °C. The extractants exhibited higher affinity toward Th⁴⁺ than UO₂ ²⁺ and Eu³⁺ in the present system. The maximum value of separation factor SF _Th(IV)/U(VI) and SF _{Th(IV)/Eu(III)} is 78.5 and 53.3 respectively for TBEE-BisDGA, 88.1 and 69.5 respectively in the case of TB ^i-PE-BisDGA at 3 M HNO₃ solution.     

Synthesis and Biological Activity of 4-Aryl-<Emphasis Type="Italic">N</Emphasis>-(5,6-R-benzo[<Emphasis Type="Italic">d</Emphasis>]thiazol-2-yl)- 2-hydroxy-4-oxobut-2-enamides

The interaction of 5-arylfuran-2,3-diones with 5,6-R-benzo[d]thiazole-2-amines has resulted in 4-aryl-N-(5,6-R-benzo[d]thiazol-2-yl)-2-hydroxy-4-oxobut-2-enamides. The products structure has been confirmed by means of IR, NMR, and ¹H NMR spectroscopy as well as mass spectrometry. Analgesic and antimicrobial activities of the prepared compounds have been studied; acute toxicity of the most active compounds has been determined. The relationship between the structure and biological activity of the obtained compounds has been elucidated. The compounds acting comparably or better than the reference drugs have been found.     

Reaction of transsilylation of <Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="Italic">N</Emphasis>-trimethylsilylacetamide with silanes ClCH<Subscript>2</Subscript>SiR<Superscript>1</Superscript>R<Superscript>2</Superscript>Cl

The reaction of N-methyl-N-trimethylsilylacetamide with silanes ClCH₂SiR¹R²Cl (R¹, R² = H, Me; H, Ph; Ph₂) leads to the formation of (O→Si) chelate compounds with pentacoordinate silicon: N-[chloro(methyl)-silyl]methyl-, N-[chloro(phenyl)silyl]methyl-, and N-[chloro(diphenyl)silyl]methyl-N-methylacetamides. From the data of multinuclear NMR spectroscopy, the intermediates of the reaction of N-methyl-N-trimethylsilylacetamide with ClCH₂SiPhHCl and ClCH₂SiPh²Cl are stable in CDCl₃ solution at room temperature during several days and slowly rearrange to the final (O–Si) chelate compounds.     

Syntheses,structures, and electrochemical properties of the tin(IV) complexes based on the 2-hydroxy-4-<Emphasis Type="Italic">N</Emphasis>-(phenyl)-3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-<Emphasis Type="Italic">p</Emphasis>-iminobenzoquinone ligand

A series of the new tin(IV) complexes based on the 2-hydroxy-4-N-(phenyl)-3,6-di-tert-butyl-p-iminobenzoquinone ligand (LH) containing various hydrocarbon substituents R at the metal atom (R = Me, Et, ⁿ Bu, ^t Bu, and Ph) is synthesized. The structures of the synthesized compounds were determined by elemental analysis, IR spectroscopy, and ¹H and ¹¹⁹Sn NMR spectroscopy. The X-ray diffraction analyses are carried out for the LSnPh³ (I) and L²SnEt² (IV) complexes (CIF files CCDC no. 1557840 (I) and 1557839 (IV)). The main electrochemical characteristics in a solution are obtained for the whole series by cyclic voltammetry.     

Kinetics of mechanochemical dissolution of chromium in iron

The kinetics of solid Fe–Cr solution formation has been studied during mechanical alloying of Fe and Cr powders taken in an atomic ratio of 80: 20. X-ray diffraction and Mössbauer spectroscopy data have been analyzed within the framework of the energetic approach. It has been established that, in this system, reaction product yield N is related to mechanical energy dose D and specific surface area S of Fe nanograin boundaries in an ideal manner: N ~ D² at S ~ D and N ~ D at S = const.     

Graphene oxide promoted synthesis of <Emphasis Type="Italic">p</Emphasis>-phenylenediamine antioxidants

Three p-phenylenediamine antioxidants (p-phenylenediamine-N,N,N′,N′-tetrapropionic acid tetramethyl ester, p-phenylenediamine-N,N,N′-tripropionic acid trimethyl ester, and p-phenylenediamine-N, N′-dipropionic acid dimethyl ester) were successfully synthesized via atom-economic aza-Michael addition of pphenylenediamine to methyl acrylate p-romoted by graphene oxide in water. The synthesized compounds were characterized by NMR, ESI-MS spectra, and elemental analyses. The effects of the solvent and graphene oxide on the reaction were investigated.     

Study on the interaction of a palladium complex with DNA

The complex [Pd(bipy)Cl₂] (1) (bipy = 2,2′-bipyridyl) has been synthesized and characterized by NMR spectroscopy, elemental analysis and X-ray diffraction method. The first step hydrolysis reaction kinetics for the complex was studied by UV-absorption spectroscopy; the speed constant (k ₁) was found to be 3.0×10^?4 s^?1. The fluorescence spectra have been collected to investigate the interaction of complex (1) with fish sperm DNA (FS-DNA) and the results indicate that the complex (1) has an effective intercalation within DNA. The reaction of complex (1) with adenine in ethanol/water results in the compound [Pd₂(bipy)₂(ade)₂]Cl₂·3H₂O (2) (ade = adenine) whose crystal structure was determined by X-ray diffraction method. The structure is orthorhombic, Pmmn, a = 12.993(4) Å, b = 14.512(5) Å, c = 9.837(3) Å, V = 1854.8(11) ų, Z = 2 (C₃₀H₃₀Cl₂N₁₄O₃Pd₂), final R ₁ = 0.0675. The palladium complex is a binuclear cation, where two ade ligands bridge two Pd(II) centers, while each Pd(II) is also chelated by one bipy ligand.