Novel Synthesis and Structures of Amines and Triazole-Derived Glycoside and Nucleoside Derivatives of Phosphanyl Sugar Analogs

ABSTRACT

3-Methyl-1-phenyl-2-phospholene and 1-phenyl-2-phospholene 1-oxides were converted into 2-bromo-3-hydroxy-3-methyl-1-phenylphospholane and 2-bromo-3-hydroxy-1-phenylphospholane 1-oxide (1-bromo-1,3,4-trideoxy-1,4-C-[(R, S)-phenylphosphinylidene]-glycero-tetrofuranose) by the action of bromine in aqueous medium. The bromo substituent of the phospholane was substituted by treatment with amines or an azide anion to afford novel glycoside derivatives of phosphanyl sugar analogs such as 2-amino-3-hydroxy-1-phenylphospholane (3,4-dideoxy-1,4-C-[(R, S)-phenylphosphinylidene]-glycero-tetrofuranosylamine) and 2-azido-3-hydroxy-3-methyl-1-phenylphospholane 1-oxides with retention of the configuration. The 1,3-dipolar cycloaddition of the 2-azido derivative of the phospholane with alkynes gave 3-hydroxy-3-methyl-1-phenyl-2-(triazol-1′-y1)phospholane 1-oxides as a novel triazole-derived nucleoside of phosphanyl sugar analogs. The structure of the glycoside and nucleoside derivatives of the phosphanyl sugar analogs prepared was deterimined from IR, NMR, and X-ray crystallography analysis.     

Nine compounds containing high‐nuclearity [CunX2n+2]2− (n = 4, 5 or 7; X = Cl or Br) quasi‐planar oligomers

The structures of seven A₂Cu₄X₁₀ compounds containing quasi‐planar oligomers are reported: bis(1,2,4‐trimethylpyridinium) hexa‐μ‐chlorido‐tetrachloridotetracuprate(II), (C₈H₁₂N)₂[Cu₄Cl₁₀], (I), and the hexa‐μ‐bromido‐tetrabromidotetracuprate(II) salts of 1,2,4‐trimethylpyridinium, (C₈H₁₂N)₂[Cu₄Br₁₀], (II), 3,4‐dimethylpyridinium, (C₇H₁₀N)₂[Cu₄Br₁₀], (III), 2,3‐dimethylpyridinium, (C₇H₁₀N)₂[Cu₄Br₁₀], (IV), 1‐methylpyridinium, (C₆H₈N)₂[Cu₄Br₁₀], (V), trimethylphenylammonium, (C₉H₁₄N)₂[Cu₄Br₁₀], (VI), and 2,4‐dimethylpyridinium, (C₇H₁₀N)₂[Cu₄Br₁₀], (VII). The first four are isomorphous and contain stacks of tetracopper oligomers aggregated through semicoordinate Cu...X bond formation in a 4(,) stacking pattern. The 1‐methylpyridinium salt also contains oligomers stacked in a 4(,) pattern, but is isomorphous with the known chloride analog instead. The trimethylphenylammonium salt contains stacks of oligomers arranged in a 4(,) stacking pattern similar to the tetramethylphosphonium analog. These six structures feature inversion‐related organic cation pairs and hybrid oligomer/organic cation layers derived from the parent CuX₂ structure. The 2,4‐dimethylpyridinium salt is isomorphous with the known (2‐amino‐4‐methylpyridinium)₂Cu₄Cl₁₀ structure, in which isolated stacks of organic cations and of oligomers in a 4(,) pattern are found. In bis(3‐chloro‐1‐methylpyridinium) octa‐μ‐bromido‐tetrabromidopentacuprate(II), (C₆H₇ClN)[Cu₅Br₁₂], (VIII), containing the first reported fully halogenated quasi‐planar pentacopper oligomer, the oligomers stack in a 5(,) stacking pattern as the highest nuclearity [Cu_nX_2n+2]²⁻ oligomer compound known with isolated stacking. Bis(2‐chloro‐1‐methylpyridinium) dodeca‐μ‐bromido‐tetrabromidoheptacuprate(II), (C₆H₇ClN)₂[Cu₇Br₁₆], (IX), contains the second heptacopper oligomer reported and consists of layers of interleaved oligomer stacks with a 7[(,)][(−,−)] pattern isomorphous with that of the known 1,2‐dimethylpyridinium analog. All the oligomers reported here are inversion symmetric.     

Synthesis and Antioxidant Activity of Amido‐Linked Benzoxazolyl/Benzothiazolyl/Benzimidazolyl‐Pyrazoles and Isoxazoles

A new class of amido‐linked bis heterocycles‐benzoxazolyl/benzothiazolyl/benzimidazolyl‐pyrazoles and isoxazoles were prepared from benzoxazolyl /benzothiazolyl/benzimidazolyl‐cinnamamides and tested for antioxidant activity.     

One-pot synthesis of novel spiro 2,3,7,8-tetrahydro-benzo[1,2-b:5,4-b′]dipyran-4,6-dione and 2,3,8,9-tetrahydro-benzo[1,2-b:4,3-b′]dipyran-4,10-dione derivatives

An efficient synthesis of novel spiro 2,3,7,8-tetrahydro-benzo[1,2-b:5,4-b′]dipyran-4,6-dione and 2,3,8,9-tetrahydro-benzo[1,2-b:4,3-b′]dipyran-4,10-dione derivatives in high yields under microwave irradiation is described. The reaction was also studied under conventional heating conditions.     

Aza-Michael addition of 1,2-diazoles to structurally diverse enones: Efficient methods toward β-amino ketones

An efficient and mild protocol was realized using 1,2-diazoles and related heterocycles with cyclic and acyclic enones in presence of T3P (2,4,6-tripropyl-1,3,5,2,4,6-trioxatriphosphorinane-2,4,6-trioxide) toward the regioselective formation of N-cycloalkyl heterocycles at room temperature. The developed reaction conditions showcased good selectivity over a wide range of 1,2-diazoles and enones by delivering N-cycloalkyl heterocycles in excellent yields.     

Synthesis,Characterization and Luminescence Sensitivity with Variance in pH,DNA and BSA Binding Studies of Ru(II) Polypyridyl Complexes

Three ruthenium(II) polypyridyl complexes, [Ru(phen)₂(mip)](ClO₄)₂ (1) (phen =1,10-Phenanthroline), [Ru(bpy)₂(mip)](ClO₄)₂ (2) (bpy = 2,2’bipyridyl) and [Ru(dmb)₂(mip)](ClO₄)₂ (3) (dmb = 4, 4′-dimethyl 2, 2′-bipyridine), were synthesized with an intercalative ligand mip (2-morpholino-1H-imidazo[4,5-f][1, 10]phenanthroline) and characterized by ¹H, ¹³C–NMR, IR, UV-vis, mass spectra and elemental analysis. pH effect, ion selectivity (cations, anions) and solvent sensitivity of complexes were studied. The interaction of these complexes with DNA was performed using absorption, emission spectroscopy and viscosity measurements. The experimental results indicated that the two complexes interacted with calf thymus DNA (CT-DNA) by intercalative mode. BSA (Bovine Serum Albumin) protein binding of these complexes was studied by UV-visible and fluorescence techniques. The binding capacity of these complexes was explained theoretically by molecular docking method.     

Green one-pot synthesis of N -bisphosphonates as antimicrobial and antioxidant agents

A straightforward and greener approach has been developed for the synthesis of novel aminomethylene bisphosphonates by one-pot reaction of diverse aryl/heteroaryl amines with dialkyl phosphite and triethyl orthoformate using CuO nanoparticles as catalyst under microwave irradiation and solvent-free conditions. This is an ecofriendly synthetic approach for swift access to a library of diverse aminomethylene bisphosphonates. All the synthesized new compounds were evaluated for their antimicrobial activity by disc diffusion method and antioxidant activity by DPPH, H2O2, and NO methods. The title compounds exhibited significant antioxidant and considerable antimicrobial activities.     

Synthesis of Heteroaryl Thiazolidinones and Azetidinones under Conventional and Ultrasonication Methods

A simple and an efficient protocol for the synthesis of differently substituted thiazolidinones was reported under conventional and also under ultrasonication in one‐step and in two‐step methodologies. Heteroaryl Schiff's bases were also exploited to develop heteroaryl azetidinones under both conventional and ultrasound irradiation.     

Velocity field in isothermal turbulent bubbly gas-liquid flow through a pipe

Velocity field was measured by laser Doppler velocimetry in isothermal, turbulent bubbly gas-liquid flow through a 26.6 mm inner diameter vertical pipe. The measurements were made about 33 diameters downstream from the pipe entrance, gas injection being just upstream of the entrance. The gas phase radial distribution at the measurement plane exhibited influence of the injection device in that higher gas fraction existed in the central region of the pipe. For comparison, velocity field was also measured in isothermal, turbulent single-phase liquid flow through the same pipe at the same axial plane. Measured were the radial distributions of liquid mean axial and radial velocities, axial and radial turbulent intensities, and axial Reynolds shear stress. The radial distributions of gas bubble mean axial velocity and axial velocity fluctuation intensity were also measured by LDV. A dualsensor fiberoptic probe was used at the same time to measure the radial distributions of gas fraction, bubble mean axial velocity and size slightly downstream of the LDV measurement plane.List of Symbols an average gas bubble diameter - f, f _TP friction factor, friction factor for gas-liquid flow - k _L liquid turbulent kinetic energy - , gas, liquid mass flow rate - R inner radius of pipe - r, {sitR}^* radial coordinate; nondimensional radial coordinate (=r/R) - Re _L liquid Reynolds number - U _G mean axial velocity of gas bubble - U _L mean axial velocity of liquid - U _LO mean axial velocity for flow at the total mass velocity with properties of the liquid phase - u _L ⁺ nondimensional mean axial velocity of liquid in wall coordinate - friction velocity - axial velocity fluctuation intensity of liquid - axial velocity fluctuation intensity of gas bubbles - V_L mean radial velocity of liquid - v _L radial velocity fluctuation intensity of liquid - (uv)_L single-point cross-correlation between axial and radial velocity fluctuations of liquid ( axial Reynolds shear stress) - T _in mean liquid temperature at test section inlet - x flow quality - y normal distance from wall - y ⁺ nondimensional normal distance from wall in wall coordinate (=yu/v_L) - _G gas phase residence time fraction - _L rate of dissipation in the liquid - _L Kolmogorov length scale in the liquid - _L liquid kinematic viscosity - _L characteristic turbulence length scale in the liquid - _G, _L density of gas, liquid - _m gas-liquid mixture density This work was partly supported by National Science Foundation, Thermal Transport and Thermal Processing Program, Chemical and Thermal Systems Division, under Grant No. CTS-9411898.     

Unusual Regioselective Electrophilic Substitutions in Quinoline Foldamers: Conceptual DFT and Frontier Molecular Orbital Analysis Reveal the Crucial Role of Folding and Substituents

We carried out a detailed computational investigation of an earlier experimentally observed, unusual, regioselective, electrophilic halogenation in helically folded quinoline oligoamides. In the experimental studies, halogenation occurred selectively at a given monomer of a foldamer substituted with electron‐withdrawing groups at the N terminus, although apparently identical reactive sites were available to react with the incoming electrophile. On the other hand, the selectivity was lost with weakly electron‐donating groups. To gain an insight into the regioselective preference of bromination in quinoline foldamers, conceptual DFT was used to calculate the local nucleophilicity index of various foldamers of different sizes and with different substituents, and it was found that the predicted reaction centers were in line with the experimental results. Frontier molecular orbital analysis was used to understand this behavior. A detailed study of the hypothetical linear conformation of the tetramer for comparison with the folded conformation was carried out. In the case of a linear conformer, the HOMO is localized on specific monomers irrespective of substitution, but upon folding delocalization is observed, which is larger for the weakly electron‐donating groups when compared with the electron‐withdrawing groups. In the case of strongly donating groups there is no delocalization, even upon folding. The behavior remains the same when the size of the helix is increased (octamer). Thus, it is clearly seen in this work that the combined effects of conformations and substituents dictate the regioselectivity in the folded oligoamides; this knowledge will have a profound effect on the field of foldamer chemistry.