AlCl3 as an Efficient Catalyst Toward the Synthesis of 1,6-Dihydropyrazine-2,3-dicarbonitrile Derivatives

Aluminium chloride has been shown to be an efficient catalyst for the multicomponent reactions of diaminomaleonitrile (DAMN), ketones or aldehydes, and isocyanides for the synthesis of 1,6-dihydropyrazine-2,3-dicarbonitrile derivatives using comparative study with various catalysts. Unprecedented use of aromatic and aliphatic aldehydes in this multicomponent reaction (MCR) was demonstrated.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]     

Independent isomeric-yield ratio of 89m,gNb from 93Nb(γ, 4n), natZr(p,xn), and 89Y(α, 4n) reactions

The independent isomeric-yield ratios of ^89m,gNb for the ⁹³Nb(γ, 4n) ^89m,gNb reaction with bremsstrahlung energies of 45-, 50-, 55-, 60-, and 70-MeV were measured by the activation and the off-line γ-ray spectrometric technique at 100 MeV electron linac of the Pohang accelerator laboratory. The isomeric-yield ratios of ^89m,gNb for the ^natZr(p, xn) ^89m,gNb and the ⁸⁹Y(α, 4n) ^89m,gNb reactions were measured by using a stacked-foil activation technique with the proton energies of 19–45 MeV and alpha energies of 38.9-, 40.5-, and 42.5-MeV at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured isomeric-yield ratio of ^89m,gNb from the ⁹³Nb(γ, 4n), ^natZr(p, xn), and ⁸⁹Y(α, 4n) reactions were compared with the similar literature data in the ⁸⁹Y(³He, 3n) reaction. It was found that the isomeric yield ratio of ^89m,gNb increases with projectile energy, which indicate the effect of excitation energy. However, for the similar compound nucleus with the same excitation energy, the isomeric-yield ratios of ^89m,gNb in the ⁸⁹Y(α, 4n) and ⁸⁹Y(³He, 3n) reactions are higher than those in the ⁹³Nb(γ, 4n) and ^natZr(p, xn) reactions, which indicates the role of input angular momentum. The isomeric-yield ratios of ^89m,gNb in the ⁹³Nb(γ, 4n), ^natZr(p, xn), ⁸⁹Y(α, 4n), and ⁸⁹Y(³He, 3n) reactions were also calculated theoretically using computer code TALYS 1.4. The theoretical isomeric-yield ratios of ^89m,gNb from four reactions increase with excitation energy. However, the theoretical value are significantly higher than the experimental data in the ⁹³Nb(γ, 4n) and ^natZr(p, xn) reactions but slightly lower or comparable in the ⁸⁹Y(α, 4n) rand ⁸⁹Y(³He, 3n) reactions.     

Sodium alginate/HPMC/liquid paraffin emulsified (o/w) gel beads,by factorial design approach; and in vitro analysis

The present study involved development of a novel sodium alginate (SA)/HPMC/light liquid paraffin emulsified (o/w) gel beads containing Diclofenac sodium (DS) as an active pharmaceutical ingredient and its site specific delivery by using hard gelatin capsule fabricated by enteric coated Eudragit L-100 polymer. Emulsified gel beads were formulated by 3-level factorial design, ionic gelatin method. The obtained beads were characterized by Fourier transform infrared, X-ray diffraction and Field emission scanning electron microscope analysis. The variables such as SA (X₁), HPMC (X₂), were optimized for drug loading and in vitro drug release with the help of response surface methodology (RSM). The RSM analysis predicted that SA was significant for both drug loading (p = 0.0005) and drug release (p = 0.0041). HPMC was only significant for drug release (p = 0.0154). The cross-product contribution (2FI) and quadratic model were found to be adequate and statistically accurate with correlation value (R²) of 0.9054 and 0.9450 to predict the drug loading and drug release respectively. An increase in concentration of HPMC and SA decreases the drug loading as well as the drug release. The obtained optimum values of drug loading and DS released were 7.43 % and 85.54 % respectively, which were well in agreement with the predicted value by RSM.     

Structural Conformation of a Novel Piperidine-4-One Derivative: 1-Acryloyl-3-Methyl-2,6-Dip-Tolylpiperidine-4-One

Abstract  

The novel 3-methyl-2,6-dip-toylpiperidine-4-one was acylated by 3-chloropropanoychloride and subjected for dehydrohalogenation. The synthesized compound was characterized by spectroscopic techniques and finally confirmed by X-ray diffraction studies. The molecule crystallizes in the monoclinic crystal class in the space group C ₂/c with cell parameters a = 18.538(2) ?, b = 9.9050(1) ?, c = 22.954(2) ?, β = 94.486(8)° and Z = 8. The piperidine ring adopts a twist boat conformation.     

Efficient Aerobic Wacker Oxidation of Styrenes Using Palladium Bis(isonitrile) Catalysts

The palladium‐catalyzed aerobic oxidation of alkenes and especially styrenes (Wacker oxidation) by using chiral pseudo C₂‐symmetrical bis(isonitrile) ligands in the absence of further cocatalysts gives rise to methyl ketones in a highly chemoselective manner. The palladium bis(isonitrile) catalyst was characterized by NMR spectroscopy and X‐ray structure analysis, revealing a dissymmetric coordination of palladium by the two isonitrile moieties.     

Branching fractions for psi(2S)-to-J/psi transitions

We describe new measurements of the inclusive and exclusive branching fractions for psi(2S) transitions to J/psi using e(+)e(-) collision data collected with the CLEO detector operating at CESR. All branching fractions and ratios of branching fractions reported here represent either the most precise measurements to date or the first direct measurements. Indirectly and in combination with other CLEO measurements, we determine B(chi(cJ) --> gamma(J/psi)) and B[psi(2S) --> light hadrons].     

Conformational analysis of methylphenidate: comparison of molecular orbital and molecular mechanics methods

Summary Methylphenidate (MP) binds to the cocaine binding site on the dopamine transporter and inhibits reuptake of dopamine, but does not appear to have the same abuse potential as cocaine. This study, part of a comprehensive effort to identify a drug treatment for cocaine abuse, investigates the effect of choice of calculation technique and of solvent model on the conformational potential energy surface (PES) of MP and a rigid methylphenidate (RMP) analogue which exhibits the same dopamine transporter binding affinity as MP. Conformational analysis was carried out by the AM1 and AM1/SM5.4 semiempirical molecular orbital methods, a molecular mechanics method (Tripos force field with the dielectric set equal to that of vacuum or water) and the HF/6-31G* molecular orbital method in vacuum phase. Although all three methods differ somewhat in the local details of the PES, the general trends are the same for neutral and protonated MP. In vacuum phase, protonation has a distinctive effect in decreasing the regions of space available to the local conformational minima. Solvent has little effect on the PES of the neutral molecule and tends to stabilize the protonated species. The random search (RS) conformational analysis technique using the Tripos force field was found to be capable of locating the minima found by the molecular orbital methods using systematic grid search. This suggests that the RS/Tripos force field/vacuum phase protocol is a reasonable choice for locating the local minima of MP. However, the Tripos force field gave significantly larger phenyl ring rotational barriers than the molecular orbital methods for MP and RMP. For both the neutral and protonated cases, all three methods found the phenyl ring rotational barriers for the RMP conformers/invertamers (denoted as cte, tte, and cta) to be: cte, tte> MP > cta. Solvation has negligible effect on the phenyl ring rotational barrier of RMP. The B3LYP/6-31G* density functional method was used to calculate the phenyl ring rotational barrier for neutral MP and gave results very similar to those of the HF/6-31G* method.