Synthesis,spectroscopic and antibacterial investigations of new hydroxy ethers and heterocyclic coumarin derivatives

The reactions between oligoethylene glycol diglycidyl ethers 2a‐c with both 7‐hydroxy‐4‐methyl‐2H‐chromen‐2‐one and 4‐hydroxy‐2H‐chromen‐2‐one lead to new hydroxy ethers 3 and 4 containing coumarin moieties in good yield. The synthesis of 3‐(3‐(dimethylamino)acryloyl)‐4‐hydroxy‐2H‐chromen‐2‐one 5 and new heterocyclic compounds 4‐hydroxy‐3‐(1H‐pyrazol‐3‐yl)‐2H‐chromen‐2‐one 6a , 4‐hydroxy‐3‐(1‐phenylpyrazol‐3‐yl)‐2H‐chromen‐2‐one 6b and 4‐hydroxy‐3‐(isoxazol‐3‐yl)‐2H‐chromen‐2‐one 6c is also described. All compounds were characterized by ¹H NMR, ¹³C{¹H} NMR, 2D‐¹H‐¹³C HMBC, 2D‐¹H NOESY NMR, IR, and MS spectroscopy. Additionally, the antibacterial activity of the new products containing coumarin moiety was evaluated. This activity is clearly dependent on the chemical structure of compounds.     

SYNTHESIS OF MELEZITOSE DERIVATIVES

The reactivity of melezitose hydroxyls is studied during tritylation in pyridine. Some novel derivatives of melezitose are prepared. An acetyl is transferred from the 4- to the 6-position after detritylation of 3 and 4. The structures of the products are proved by elemental analysis; ¹ H, ¹³ C, and ¹ H- ¹ H COSY NMR spectra;IR spectra; and fast-atom bombardment mass spectrometry.     

Hydrogenation of the silanone groups (≡Si-O)2Si=0. Experimental and quantum-chemical studies

The reactivity of bis(siloxy)silanone groups (Si-0)₂Si=O stabilized on a silica surface with respect to H₂ molecules was studied. The reaction was found to give the (Si-O)₂SiH(OH) groups. The rate constant for this process was determined. Its activation energy in the 300–580 K temperature range is 13.4±0.3 kcal mol^–1, and the enthalpy is 54±5 kcal mol^–1. The activation energy for the reverse reaction,viz., elimination of a hydrogen molecule, is equal to 65 kcal mol^–1. Quantum-chemical calculations of hydrogenation of F₂Si=O and (HO)₂Si=O, which are the simplest molecular models of the silanone groups, were performed. Data on the geometrical and electronic structures of transition states and on the effects of substituents at the silicon atom on the reactivity of the silanone groups in this process were obtained. The optical absorption band of the surface silanone groups was quantitatively characterized. Its maximum is located at 5.65±0.1 eV; the extinction coefficient at the maximum (220 nm) is (3±0.5) · 10^–18 cm² molec.^–1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1951–1958, August, 1996.     

1H-NMR Studies of the Inclusion Complexes between α-Cyclodextrin and Adamantane Derivatives Using Both Exchangeable Hydroxy Protons and Non-Exchangeable Aliphatic Protons

The inclusion complexes between -cyclodextrin (-CD) and adamantane, 1-adamantanol, 1-(hydroxymethyl)-adamantane, 2-adamantanol, and 1,3-adamantanediol in aqueous solution have been studied by ¹H-NMR spectroscopy using both non-exchangeable and exchangeable protons. The complexation-induced ¹H-NMR shifts (CIS) and NOEs of non-exchangeable protons, as well as the CIS, NOEs, temperature coefficients, and linewidth of signals from exchangeable hydroxy protons have been determined. The stoichiometry of the adamantane/-CD complex could not be determined due to the low solubility of adamantane. However, for 0.11 equivalent of adamantane added, two sets of separate ¹H signals for the free and bound -CD were observed. The signal from O(3)H in the complexed form appeared narrow and upfield shifted with a low-temperature coefficient indicating reduced hydration inside the hydrophobic cavity of -CD. Both 1-adamantanol, and 1-(hydroxymethyl)-adamantane formed 1:1 inclusion complexes with -CD and only one set of NMR signals was observed. The CIS and NOEs suggested that both complexes had similar structures. The O(2)H signal of -CD was broadened at low temperature and became narrower as the temperature raised. The broadening increased with higher concentration of guest suggesting interaction between O(2)H of -CD and the guest molecules. The stoichiometry of the -CD/2-adamantanol complex could not be determined with certainty, but the NMR data suggested equilibrium between 2:1 and 1:1 complex. As with adamantane, a sharp and upfield shifted O(3)H signal with a very low-temperature coefficient was observed. No inclusion complex was formed between 1,3-adamantanediol and -CD. This study showed how the hydroxy protons of -CD could be used to obtain complementary information on the geometry and stability of inclusion complexes of -CD.     

Molecular recognition of α-amino acid esters with arylporphyrin zinc complexes

The recognition ability of 10 arylporphyrin zinc complexes with respect to glycine, -alanine, and leucine methyl esters in toluene at 20°C was studied by spectrophotometric titration. The formation of amino acid-porphyrin associates, depending on the substitution pattern in the macroring, was examined by ¹H NMR spectroscopy. The zinc complex with diarylporphyrin having hydroxy groups in the para positions of the benzene rings was found to be the best recognizing agent with respect to glycine methyl ester, while leucine methyl ester was recognized best by the complex with hydroxy groups in the ortho positions of the benzene rings.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1557–1562.Original Russian Text Copyright © 2004 by G. Mamardashvili, Storonkina, N. Mamardashvili.This revised version was published online in April 2005 with a corrected cover date.     

Charge monotonicity of atomic systems and radial expectation values

A functionf(r) is monotone of orderp if itspth-derivativef ^(p)(r) fulfils that (–1) ^p f ^(p)(r)0. So, e.g. the monotonicity properties of orderp=0, 1, 2 describe the non-negativity (p=0), the monotonic decreasing from the origin (p=1) and the convexity (p=2) of the function, respectively. Here, the monotonicity properties of the electron functiong _n (r; )=(–1) ^{n (n)} (r)r ^– , 0, of the ground state of atomic systems are analysed both analytically and numerically. The symbol (r) denotes the spherically averaged electron density. First of all, the condition which specifies, if exists, a value _np such thatg _n (r; _np ) be monotone of orderp is obtained. In particular, it is found that ₀₁=max {r(r)/(r)}, ₀₂=max {q ₀(r)}, ₁₁=max {r(r)/(r)} and ₁₂=max {q ₁(r)}, whereq ₀(r) andq ₁(r) are simple combinations of the first few derivatives of (r). Secondly, numerical calculations of the first few values _np in a Hartree-Fock framework for all ground-state atoms with nuclear chargeZ54 are performed. In doing so, the pioneering work of Weinstein, Politzer and Srebrenik about the monotonically decreasing behavior of (r) is considerably extended. Also, it is found that Hydrogen and Helium are the only two atoms having the functions (r), –(r) and (r) with the property of convexity. Thirdly, it is analytically shown that the charge functionr ^– (r) with [(1+4Z ²/I)^1/2–1]/2, I being the first ionization potential, is convex everywhere. Finally, the above mentioned monotonicity properties are used to obtain rigorous, simple and universal inequalities involving three radial expectation values which generalize all the similar ones known up to now. These inequalities allow to correlate various statical and dynamical quantities of the atomic system under study, due to the physical meaning of the radial expectation values. It is worth to remember that some of these expectation values may be experimentally measured in experiments of (e, 2e)-type.     

Chemistry of Diazocarbonyl Compounds: XVIII. Synthesis and Spectral Parameters of 1,3-Dialkyl- 3-hydroxy-2-diazoketones

Reduction of the carbonyl groups in cyclic and acyclic 2-diazo-1,3-diketones with sodium tetrahydridoborate in aqueous–alcoholic medium, followed by hydrolysis of the reaction mixture over wet silica gel and chromatographic purification on neutral aluminum oxide, afforded 1,3-dialkyl-3-hydroxy-2-diazoketones in 58–87% yield. Bulky substituents at the carbonyl group considerably reduce the efficiency of the process, and the reduction of cis- and trans-4,6-di-tert-butyl-2-diazocyclohexane-1,3-diones is characterized by low stereoselectivity (de 40–49%). In the IR spectra of 3-hydroxy-2-diazocyclohexanes, absorption bands corresponding to stretching vibrations of free axial hydroxy groups are located at higher frequencies (by 20-45 cm^-1) than those belonging to equatorial hydroxy groups. These parameters may be useful for conformational analysis of cyclic hydroxy diazo ketones. Stabilization of the E conformation of acyclic hydroxy diazo ketones via intramolecular hydrogen bonding is likely to occur only in nonpolar solvents (CCl₄, cyclohexane).     

Laser-Induced Hydrogen Radical Removal in UV MALDI-MS Allows for the Differentiation of Flavonoid Monoglycoside Isomers

Negative-ion matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectra and tandem mass spectra of flavonoid mono-O-glycosides showed the irregular signals that were 1 and/or 2 Da smaller than the parent deprotonated molecules ([M – H]^–) and the sugar-unit lost fragment ions ([M – Sugar – H]^–). The 1 and/or 2 Da mass shifts are generated with the removing of a neutral hydrogen radical (H*), and/or with the homolytic cleavage of the glycosidic bond, such as [M – H* – H]^–, [M – Sugar – H* – H]^–, and [M – Sugar – 2H* – H]^–. It was revealed that the hydrogen radical removes from the phenolic hydroxy groups on the flavonoids, not from the sugar moiety, because the flavonoid backbones themselves absorb the laser. The glycosyl positions depend on the extent of the hydrogen radical removals and that of the homolytic cleavage of the glycosidic bonds. Flavonoid mono-glycoside isomers were distinguished according to their TOF MS and tandem mass spectra.

Formation of Silica/Poly(p‐dioxanone) Microspheres by Surface‐Initiated Polymerization

A polymeric film of a biodegradable poly(p‐dioxanone) was grown from 490 nm silica particles by monolayer formation via self‐assembly of hydroxy‐terminated triethoxysilane and subsequent surface‐initiated ring‐opening polymerization of p‐dioxanone. The resulting silica/poly(p‐dioxanone) hybrid particles were characterized by means of ¹H NMR spectroscopy, IR spectroscopy, thermogravimetric analysis, field‐emission scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy.

     

The investigation on the NH reactivity of pentacoordinate spirophosphoranes by H/D exchange and NMR experiments

Different pentacoordinate spirophosphoranes were investigated by H/D exchange and NMR tracking experiments. The H/D exchanged site of spirophosphoranes was confirmed to be the NH bond instead of the PH bond according to the integration of the signal changes in proton-decoupled, proton-coupled ³¹P NMR and ¹H NMR tracking experiments. The reactivity of NH bond at the spiroring of spirophosphoranes was explored by the rate constant of H/D exchange of different spirophosphoranes. The results demonstrated that the reactivity of NH bond of spirophosphoranes was influenced by steric hindrance and the species of substituent at phosphorus atom, and the electronic effect of the substituent was the main effect factor on the reactivity of the NH bond. The strong electron-withdrawing group at phosphorus resulted in more reactive NH bond of spirophosphoranes. These results are beneficial to further understand and explore the characteristics of pentacoordinate spirophosphoranes.     

Synthesis of branched aminopolysaccharides by acid-catalyzed polymerization of sugar oxazoline monomer

Acid-catalyzed polymerization of a sugar oxazoline monomer 1b having two free hydroxy groups was carried out to produce a branched aminopolysaccharide 2b. The reaction proceeded via the stereoregular glycosylation through oxazoline ring-opening process, giving rise to 2b consisting of β-glycosidic linkages. The structure of 2b was determined by the ¹H NMR, ¹³C NMR, and IR spectra. The molecular weights determined by GPC measurements were 4200-6100. The degrees of branching were estimated by the ¹H NMR spectra of the products by the reaction of 2b with 3,5-dinitrobenzoyl chloride. Deprotection of 2b was carried out by the catalytic hydrogenation in the presence of 10% Pd-C to produce a free branched aminopolysaccharide.     

Variable temperature H and Si NMR of diastereomeric 1,3-dihydroxy-1,3-bis[(2-dimethylaminomethyl)phenyl]-1,3-divinyldisiloxanes

Variable temperature NMR experiments of diastereomeric 1,3-dihydroxy-1,3-bis[(2-dimethylaminomethyl)phenyl]-1,3-divinyldisiloxanes, meso-1 and rac-1 having intramolecular hydrogen bondings were carried out. As temperature increased, the ¹H NMRs of hydroxy groups of 1 resulted in a low frequency and their ²⁹Si NMRs were very slightly shifted to a low frequency. Interestingly, the ¹H NMR of two benzylic protons was split more widely as temperature increased.     

NMR Spectral Assignment of Per-substituted Key-Intermediates of β-Cyclodextrin and Implications in the Structures of the Derivatives

The compounds, 6-per-O-(t-butyldimethylsilyl)--cyclodextrin(1), 2,3-per-O-benzyl-6-per-O-(t-butyldimethylsilyl)--cyclodextrin(2), 2,3-per-O-benzyl--cyclodextrin (3),2,3,6-per-O-benzyl--cyclodextrin (4),2,3,6-per-O-benzoyl--cyclodextrin (5), are used as keyintermediates in the synthesis of selectively substituted -CD derivatives. Simple and assignable ¹H and ¹³C NMR spectra (chemical shifts and coupling constants) were obtained for compounds1–4 indicating C₇ symmetry, ⁴C₁ glucose conformation and major arrangement of H6, H6' atoms at the primary side. The derivative 5, however, gave very broad peaksat room temperature. The peaks could partially be assigned at 270 K, but the broadening was still present at 220 K. This implies that there exist several conformers of similar energyand C₁ symmetry that continuously interchange, since there is not a single type of stabilizing interaction thatpredominates. We attributed this phenomenon to the presence of the carbonyl group, which probablydisfavors - stacking and induces random arrangements of the aromatic rings.     

Mercuration with Mercury(II) Trifluoroacetate of (η6-Aniline)- or (N,N-dimethylaniline)(η5-cyclopentadienyl)iron(II)

The reaction of mercury(II) trifluoroacetate with the hexafluorophosphate of the ⁶-aniline-⁵cyclopentadienyliron(II) cation under reflux in dry ethanol gives rise to N-mono- and N,N-disubstituted mercury-containing salts of this cation. The same mercury-containing salts have been synthesized by the action of mercury(II) trifluoroacetate on the deprotonation product of the (⁶-aniline)(⁵-cyclopentadienyl)iron(II) cation. Direct mercuration of the [⁶-(N,N-dimethylaniline)](⁵-cyclopentadienyl)iron(II) cation into the para position of the benzene ring of the arene ligand has been performed. The reactivity of the compounds obtained has been studied.     

Synthesis of Hydroxy‐Functionalized Cyclic Olefin Copolymer and Its Block Copolymers with Semicrystalline Polyolefin Segments

Synthesis of hydroxy‐functionalized cyclic olefin copolymer (COC) is achieved with remarkably high activity (up to 5.96 × 10⁷ g‐polymer mol‐Ti⁻¹ h⁻¹) and controlled hydroxy group in a wide range (≈17.1 mol%) by using ansa‐dimethylsilylene (fluorenyl)(amido)titanium complex. The catalyst also promotes living/controlled copolymerization to afford novel diblock copolymers consisting of hydroxy‐functionalized COC and semicrystalline polyolefin sequence such as polyethylene and syndiotactic polypropylene, where the glass transition temperature of the norbornene/10‐undecen‐1‐ol segment and each block length are controlled by comonomer composition and copolymerization time, respectively.

     

Synthesis and Reactivity of Functionalized Binary and Ternary Thiometallate Complexes [(RT)4S6], [(RSn)3S4]2−, [(RT)2(CuPPh3)6S6], and [(RSn)6(OMe)6Cu2S6]4− (R=C2H4COOH,CMe2CH2COMe; T=Ge,Sn)

Caged chalcogens : A series of novel, functionalized T_nS_m cages (T=Ge, Sn; n/m=4:6, 3:4) with terminal COO(H) or COMe groups were synthesized and show further reactivity toward Cu^I complexes (an example of which is shown here) and to hydrazines. This led to the generation of functionalized Cu/T/S clusters or the formation of Schiff bases at the C?O groups, respectively, with or without further fragmentation of the T/S core.

     

Pyrrolopyrimidines. 5. Reaction of 6-Amino-1,3-dimethylpyrrolo[3,4-d]pyrimidine-2,4(1H,3H)-diones with 1,3-Diketones

The reaction of 6-amino-1,3-dimethylpyrrolo[3,4-d]pyrimidine-2,4-dione with 1,3-diketones leads to formation of predominantly pyrimido[4',5':3,4]pyrrolo[1,2-b]pyridazine-2,4(1H,3H)-diones and, to a lesser extent, pyrimido[5',4':3,4]pyrrolo[1,2-b]pyridazine-1,3(2H,4H)-diones. The ease and direction of the cyclization reaction suggests a very -electron rich pyrrole ring in the initial state, especially in the position 7.     

Structural Study of Methyl Acrylate in a Nematic Liquid Crystal by 1H NMR with 13C Satellites

The molecular structure and conformation of methyl acrylate have been determined by analyzing the ¹H NMR spectrum with ¹³C satellites of the molecules dissolved in the liquid crystal ZLI 1132. In the structural analysis, direct coupling constants have been corrected for molecular vibrations and converted to those in the r structure. The correlation between reorientational motion and internal rotation has been taken into account by using the mean external potential described in terms of bond interaction tensors. The potential for the internal rotation about the bond has been represented as V() = (V ₁/2) (1 – cos ) + (V ₂/2)(1 – cos 2), where is zero for the s-cis configuration, and the determined values of V ₁ and V ₂ are 2.7(1) and 8.4(13) kJ mol^–1, respectively. The relative abundance of the s-cis conformer, 76(1)%, agrees with a gas-phase value, 67(11)%, determined by electron diffraction within experimental errors.     

Reaction of 3‐aminoquinoline‐2,4‐diones with isocyanates. Synthesis of novel 3‐(3′‐alkyl/arylureido)quinoline‐2,4‐diones and their cyclic carbinolamide isomers

3‐Alkyl/aryl‐3‐amino‐1H,3H‐quinoline‐2,4‐diones react with alkyl/aryl isocyanates to give novel 3‐alkyl/aryl‐3‐ureido‐1H,3H‐quinoline‐2,4‐diones or 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones. In some cases, a mixture of both products was obtained and separated by fractional crystallization. All compounds were characterized by their ¹H, ¹³C, ir and ms data and some of them also by ¹⁵N nmr data.