Alum as an efficient catalyst for the multicomponent synthesis of functionalized piperidines

An effective approach to the synthesis of functionalized piperidines via a one-pot multicomponent reaction of aniline, β-ketoester and aldehyde in the presence of alum as an efficient catalyst has been reported. The present procedure offers advantages such as simple workup, short reaction time and offers rapid access to a variety of functionalized piperidines.     

A non-overlapping domain decomposition dual reciprocity method for solving the forward–backward heat equation in two-dimension

We apply a boundary element dual reciprocity method (DRBEM) to the numerical solution of the forward–backward heat equation in a two-dimensional case. The method is employed for the spatial variable via the fundamental solution of the Laplace equation and the Crank–Nicolson finite difference scheme is utilized to treat the time variable. The physical domain is divided into two non-overlapping subdomains resulting in two standard forward and backward parabolic equations. The subproblems are then treated by the underlying method assuming a virtual boundary in the interface and starting with an initial approximate solution on this boundary followed by updating the solution by an iterative procedure. In addition, we show that the time discrete scheme is unconditionally stable and convergent using the energy method. Furthermore, some computational aspects will be suggested to efficiently deal with the formulation of the proposed method. Finally, two forward–backward problems, for which the exact solution is available, will be numerically solved for two different domains to demonstrate the efficiency of the proposed approach.     

Selective O-deallylation of dihydropyrazoles by molecular iodine in the presence of active N-allyl and formyl groups

Selective O-deallylation of dihydropyrazoles has been achieved by use of iodine (10 mol%) in PEG-400 as ecofriendly solvent. Iodine (10 mol%) in dimethyl sulfoxide at 100 °C also afforded O-deallylation with aromatization compatible with highly reactive N-allyl and formyl groups. The function of iodine in the synthesis of substituted pyrazoles under different conditions is described.     

Liquid crystalline polymers V. Thermotropic liquid crystalline poly(azomethine-ether)s containing a cycloalkanone moiety in the polymer backbone

A new homologous series of thermotropic liquid crystalline poly(azomethine-ether)s was synthesized by solution polycondensation of various diformyl-alpha,omega-diphenoxyalkanes, I-VIII with 2,5-bis(m-aminobenzylidene)cyclopentanone, XI and 2,6-bis(m-aminobenzylidene)cyclohexanone, XII. The inherent viscosities of the polymers were in the range 0.34-0.75 dI g^-1. The mesomorphic properties were studied as a function of the diphenoxyalkane spacer length. Analyses by DSC and optical polarized microscopy demonstrated that the poly(azomethine-ether)s form nematic mesophases over wide temperature ranges. The poly(azomethine-ether)s based on the cyclohexanone moiety had better thermal stabilities than the corresponding poly(azomethine-ether)s based on cyclopentanone.     

Glabridin,a Stable Flavonoid of Glycyrrhiza glabra: HPTLC Analysis of the Traditional Formulation

JPC – Journal of Planar Chromatography – Modern TLC - A novel HPTLC method has been developed for the estimation of glabridin in Licorice rhizome and its Unani polyherbal formulation...     

Quantum dynamics of heavy light heavy reactions: Application to (F + CH4 → FCH3 + H) reaction

We apply the time-dependent theory to the collinear exchange reaction F + CH₄ → FCH₃ + H. We have performed detailed calculations on two-dimensional potential surfaces representing the ground electronic potentials of the collinear F + CH₄ → FCH₃ + H reaction, at incident energies. Transmission coefficients range from zero to unity, depending upon the incident energy. Normal modes of vibrations are displayed along the reaction path.     

The quintessential exotic X(3872)

The experimental evidence for the exotic meson, X(3872), is summarized and the various proposed theoretical models for it are reviewed. It is pointed out that several important experimental measurements have marginal statistical significance and disagreements between different sources. Until these problems are resolved, the understanding of the structure of X(3872) is likely to remain controversial.     

Base-free monosulfonylation of amines using tosyl or mesyl chloride in water

A mild and efficient procedure has been developed for the monosulfonylation of various amines using mesyl or tosyl chlorides in water at room temperature to afford the corresponding sulfonamides in high yields.