Reaction of imidazole and its 2-alkyl derivatives with γ-butyrolactone

Reaction of imidazole with -butyrolactone gives N-alkylation and N-acylation products depending upon the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1491–1493, November, 1992.     

Oxidative Coupling Reaction of N,N‐Dialkylanilines with Cerium(IV) Ammonium Nitrate in the Solid State

Oxidative coupling reactions of N,N‐dialkylanilines with cerium(IV) ammonium nitrate can be achieved by grinding at room temperature in the absence of solvents.     

Critical phenomena in the topochemical reaction of water vapor with solid N,N′-ethylenebis (acetylacetoniminato)copper (II)

The effects of water vapor and temperature on the phase transition between anhydrous N,N-ethylenebis(acetylacetoniminato) copper (II) and the monohydrate have been studied by a piezoelectric microbalance method. The presence of a branch point and critical deceleration of the phase transition dynamics near that point have been observed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 29, No. 2, pp. 149–153, March–April, 1993.This work was supported by a fundamental research grant from the State Committee on Science and Technology, Ukraine Council of Ministers.     

Structure of intermediates in the Hantzsch reaction of phenylchloropyruvic acid derivatives with N,N′-diphenylthiourea

The intermediates in the Hantzsch reaction of the methyl ester and diethylamide of phenylchloropyruvic acid with N,N-diphenylthiourea are derivatives of 2-phenylimino-3,5-diphenyl-4-hydroxythiazoline-4-carboxylic acid. They exist as an equilibrium mixture of two diastereomers in solution.A. E. Arbuzov Institute of Organic and Physical Chemistry of the Kazan Scientific Center, Russian Academy of Sciences, Kazan' 420088; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 975–980, July, 1999.     

The synergistic cooperation of NH⋯O and CH⋯O hydrogen bonds in the structures of three new phosphoric triamides

The supramolecular assemblies of three new phosphoric triamides, {(C₆H₅CH₂)(CH₃)N}₂(4-CH₃-C₆H₄C(O)NH)P(O) (1), {(C₆H₁₁)(CH₃)N}₂(4-CH₃-C₆H₄C(O)NH)P(O) (2) and {(C₂H₅)₂N}₂(4-CH₃-C₆H₄C(O)NH)P(O) (3) were studied by single crystal X-ray diffraction as well as by Hirshfeld surface analysis. It was found that a synergistic cooperation of NH?O and CH?O hydrogen bonds occurs in all three structures, but forming unique supramolecular architectures individually. Along with the presence of centrosymmetric dimers in 1, 2 and 3, based on a classical NH?O hydrogen bond, the presence of weak CH?O interactions play an additional and vital role in crystal architecture and construction of the final assemblies, collectively identified as a centrosymmetric dimer (0D), a 1-D array and a 3-D network, respectively. These differences in superstructures are related to the effect of aromatic, bulk and flexible groups used in the molecules designed, with a similar C(O)NHP(O) backbone. The NH?O contacts in 1, 2 and 3 are of the “resonance-assisted hydrogen bond” types and also the anti-cooperativity effect can be considered in the multi-acceptor sites P═O in 1 and 2 and C═O in 3. All three compounds were further studied by 1D NMR experiments, 2D NMR techniques (HMQC and HMBC (H–C correlation)), high resolution ESI–MS, EI–MS spectrometry and IR spectroscopy methods.     

The stereoselective synthesis of γ-lactam derivatives through N(1)-C(4) one carbon ring expansion of β-lactam derivatives

The base induced ring opening of β-lactam derivatives, 3, 5, 7, 9, 11 with LDA gave γ-lactam derivatives, 4, 6, 8, 10, 12 stereoselectively. The γ-lactam derivatives were formed stereoselectively depending on C-3 substituent of β-lactam derivatives.     

Polymerization of α-methylstyrene in the solid (frozen) state

Russian Chemical Bulletin -     

Influence of OH⋯N and NH⋯O inter- and intramolecular hydrogen bonds in the conformational equilibrium of some 1,3-disubstituted cyclohexanes through NMR spectroscopy and theoretical calculations

The analysis of concentration effects in the (1)H NMR data of cis-3-aminocyclohexanol (ACOL) showed that its diequatorial conformer changes from 60% at 0.01 mol L(-1) to 70% at 0.40 mol L(-1) in acetone-d(6). A similar increase was also observed for the diequatorial conformer of cis-3-N-methylaminocyclohexanol (MCOL), from 32% (CDCl(3) 0.01 mol L(-1)) to 55% (CDCl(3) 0.40 mol L(-1)). The increase in solvent basicity leads to a large stabilization effect for the diequatorial conformer of both compounds too. For ACOL, it changes from 47% (ΔG(eqeq-axax)=0.06 kcal mol(-1)) in CCl(4) to 93% (ΔG(eqeq-axax)=-1.53 kcal mol(-1)) in DMSO, while for MCOL it goes from 7% (ΔG(eqeq-axax)=1.54 kcal mol(-1)) in CCl(4) to 82% (ΔG(eqeq-axax)=-0.88 kcal mol(-1)) in pyridine-d(6). These results indicate that the intramolecular hydrogen bonds (IAHB) OH?N and NH?O stabilize the diaxial conformers of these compounds in a non-polar solvent. For cis-3-amino-1-methoxycyclohexane (ACNE) and cis-3-N-methylamino-1-methoxy-cyclohexane (MCNE) no changes were observed in equilibrium with the variation of solvent polarity. These results indicate for the first time that the IAHB NH?O is not strong enough to stabilize the diaxial conformer of these compounds and that the conformation equilibria of the cis isomers of compounds ACOL and MCOL are influenced only by the IAHB OH?N. Moreover, the presence of a secondary amino group (93% of diaxial conformer in CCl(4)) leads to an IAHB OH?N stronger than in primary and tertiary amino-derivatives (53 and 54% of diaxial conformer, respectively) for 1,3-disubstituted cyclohexanes. Values obtained from the theoretical data through the B3LYP functional are in agreement with the experimental results and indicate that the IAHB strength that influences the conformational equilibrium of these compounds is the IAHB OH?N. Thus, the IAHB NH?O do not stabilize the diaxial conformer of the cis isomer of compounds ACNE and MCNE showing that the diequatorial conformer will always be more stable than the diaxial conformer, independent of concentration or solvent.     

Crystal structure of Co(III) α-dimethylglyoximates with imidazole

Two new dimethylglyoximate complexes [Co(DmgH)₂(Im)Cl] (I) and (ImH)[Co(DmgH₂)₂Cl₂] (II), where DmgH^? is the dimethylglyoxime residue and Im is the imidazole molecule, are synthesized. The composition and structure of the crystals are determined from the elemental analysis, IR spectra, and single crystal X-ray diffraction. Complex I is molecular, containing the Im molecule as a coordinated ligand; complex II is of the ionic type with (ImH)⁺ involved as an outer-sphere organic cation. The mode of component packing in the crystals mainly depends on the imidazole position in the compounds.     

Temperature dependence of the ν(OH) bands of hydroxyapatites

The effect of temperature upon the ν(OH) bands of nine hydroxy apatites has been studied and discussed in relation to earlier results.     

New β-amino-α-trifluoromethyl alcohols and their exploration in the synthesis of trifluoromethylated imidazole derivatives

Racemic and enantiomerically pure β-amino-α-trifluoromethyl alcohols were obtained via sequential nucleophilic trifluoromethylation of selected α-imino ketones, derived from arylglyoxals, and subsequent removal of the MeO or Ph(Me)CH substituent, respectively, located at the N-atom. The obtained products, containing a primary amino group, were used for the synthesis of imidazole N-oxides bearing a trifluoromethyl group as a part of the N(1)-alkyl chain. Imidazole N-oxides with an electron-withdrawing ester group at C(4) underwent spontaneous isomerization under the reaction conditions, and the corresponding imidazol-2-ones derivatives were isolated as final products.     

Host–guest complexes of some cucurbit[n]urils with the hydrochloride salts of some imidazole derivatives

Interaction between the normal cucurbit[n]urils (n = 6,7,8; Q[6], Q[7], Q[8]) and a sym-tetramethyl-substituted cucurbit[6]uril derivative (TMeQ[6]) with the hydrochloride salts of some imidazole derivatives N-(4-hydroxylphenyl)imidazole (g1), N-(4-aminophenyl)imidazole (g2), 2-phenylimidazole (g3) in aqueous solution was investigated by using ¹H NMR spectroscopy, electronic absorption spectroscopy and fluorescence spectroscopy, as well as by using a single crystal X-ray diffraction determination. The ¹H NMR spectra analysis established a basic interaction model in which inclusion complexes with a host:guest ratio of 1:1 forms for the Q[6]s and Q[7] cases, while with a host:guest ratio of 1:2 form for the Q[8] cases. It was common that the hosts selectively bound the phenyl moiety of the guests. Absorption spectrophotometric and fluorescence spectroscopic analysis in aqueous solution defined the stability of the host–guest inclusion complexes at pH 5.8 with a host:guest ratio of 1:1 form quantitatively as logK values between 4 and 5 for the smaller hosts Q[6 or 7]s, while with a host:guest ratio of 1:2 form quantitatively as logK values between 11 and 12 for the host Q[8]. Two single crystal X-ray structures of the inclusion complexes TMeQ[6]-g2 · HCl and TMeQ[6]-g3 · HCl showed the phenyl moiety of these two guests inserted into the host cavity, which supported particularly the ¹H NMR spectroscopic study in solution.     

High resolution quantum cascade laser studies of the ν3 band of methyl fluoride in solid para-hydrogen

Spectra of solid para-H(2) doped with CH(3)F at 1.8 K are studied in the ν(3) region (~1040 cm(-1)) using a quantum cascade laser source. As shown previously, residual ortho-H(2) in the sample (~1000 ppm) gives rise to distinct spectral features due to clusters of the form CH(3)F-(ortho-H(2))(N), with N = 0, 1, 2, 3, etc. Brief annealing at 7 K is found to give narrower spectral lines (≥0.006 cm(-1)) than conventional (5 K) annealing, and causes the N = 3 and 4 lines to fragment into two or more components. The N = 3 line is observed to be particularly stable and persistent. The N = 0 line (no ortho-H(2) neighbors) is resolved into two closely spaced (≈0.007 cm(-1)) components which are assigned to the K = 0 and 1 states of CH(3)F rotating around its C(3v) symmetry axis (ortho- and para-CH(3)F, respectively). Similar K-structure is also evident for other lines. Weak but persistent features ("N = 1/2 lines") are observed mid way between N = 0 and 1.     

Characterization of NH overtone and combination bands in the near-infrared absorption spectra of simple cyclic imides

Bands due to overtone and combination vibrational modes attributable to the imide grouping have been elucidated in the near-IR absorption spectra of small-ring cyclic imides, in which the grouping is in a cis, cis conformation. The spectra closely parallel the spectra of cis lactams except that two combination modes involving the carbonyl stretching fundamental, [ν(NH) + ν(CO)] and [2ν(C=O) + imide III], occur at higher wavenumbers in the imide spectra, reflecting the higher frequency at which this fundamental absorbs. This same factor results in a reversal in the wavenumber positions of the [2ν(CO) + imide III] and [ν(NH) + imide III] combination bands in the imide spectra relative to those in the lactam spectra. In addition, in-phase and out-of-phase vibrational coupling between the two carbonyl groups in the imides may compound the band due to the [ν(NH) + ν(CO)] combination mode. These three spectral characteristics serve to distinguish the imides from the lactams in the near-IR.     

Enantioselective synthesis of γ-aminobutyric acid derivatives by Ni(II)-catalyzed reaction of diethyl malonate with nitroalkenes

A new synthetic approach to (3R)-4-amino-3-methylbutyric acid and [(4R)-2-oxo-4-phenylpyrrolidin-1-yl]acetamide [(R)-phenotropil] has been developed. Asymmetric center with a required configuration has been generated via enantioselective addition of diethyl malonate to 1-nitropropene and β-nitrostyrene, catalyzed by Ni(II) complexes with (R,R)- and (S,S)-N,N′-dibenzylcyclohexane-1,2-diamine.     

Computational study of hydrogen-bonded complexes of HOCO with acids: HOCO⋯HCOOH, HOCO⋯H(2)SO(4), and HOCO⋯H(2)CO(3)

Quantum chemistry calculations at the density functional theory (DFT) (B3LYP), MP2, QCISD, QCISD(T), and CCSD(T) levels in conjunction with 6-311++G(2d,2p) and 6-311++G(2df,2p) basis sets have been performed to explore the binding energies of open-shell hydrogen bonded complexes formed between the HOCO radical (both cis-HOCO and trans-HOCO) and trans-HCOOH (formic acid), H(2)SO(4) (sulfuric acid), and cis-cis-H(2)CO(3) (carbonic acid). Calculations at the CCSD(T)∕6-311++G(2df,2p) level predict that these open-shell complexes have relatively large binding energies ranging between 9.4 to 13.5 kcal∕mol and that cis-HOCO (cH) binds more strongly compared to trans-HOCO in these complexes. The zero-point-energy-corrected binding strengths of the cH?Acid complexes are comparable to that of the formic acid homodimer complex (～13-14 kcal∕mol). Infrared fundamental frequencies and intensities of the complexes are computed within the harmonic approximation. Infrared spectroscopy is suggested as a potential useful tool for detection of these HOCO?Acid complexes in the laboratory as well as in various planetary atmospheres since complex formation is found to induce large frequency shifts and intensity enhancement of the H-bonded OH stretching fundamental relative to that of the corresponding parent monomers. Finally, the ability of an acid molecule such as formic acid to catalyze the inter-conversion between the cis- and trans-HOCO isomers in the gas phase is also discussed.     

Interaction of naproxen with α-, β-, and γ-hydroxypropyl cyclodextrins in solution and in the solid state

Solid combinations of naproxen with amorphous hydroxypropyl derivatives of -, -, and -cyclodextrin with an average substitution degree per anhydroglucose unit of 0.6 were investigated for thermal behaviour (differential scanning calorimetry), drug crystallinity (X-ray diffractometry), and dissolution rate (dispersed amount and rotating disc methods). Phase-solubility analysis and computer-aided molecular modelling were carried out to study the inclusion complexation of naproxen with hydroxypropyl cyclodextrins. The cavity size of the host is a selective factor for the solubilizing effect, complexing ability, and dissolution rate enhancement on naproxen, hydroxypropyl -cyclodextrin being markedly the most effective derivative. No relationship was found between the decrease in crystallinity of the drug dispersed in the amorphous carrier matrix and the geometrical features of the cyclodextrin macrocycle.     

Temperature-dependent vibrational spectra of zinc(II) bis-(N,N′-diethyldithiocarbamate) in solid state and solution

The IR spectra of zinc(II) bis-(N,N′-diethyldithiocarbamate) in the solid state (at 20, 80 and 120°C) as well as in solution (20°C) have been recorded and discussed as to the changes in the zinc coordination sphere that may occur upon heating and dissolution. The decreased number of bands in the high-temperature and in the solution specta as compared with the room temperature solid state spectra has been explained by removal of the intermolecular contacts upon dissolution or thermal averaging in the high temperature solid state.     

Reaction of amino acid derivatives with C_(60)

Ammo acid derivatives react with C60 at 110-120℃to form adduct compounds.The products were isolated by column chromatography and were identified by FD-MS,UV-Vis,FT-IR and 13C NMR spectroscopies.