Hidden Heptacyclic Chiral N-Acyl Iminium Ions: A New Entry to Enantioenriched Polycyclic Azepanes and Azocanes by Superacid-Promoted Intramolecular Pictet-Spengler Reaction

Enantioenriched complex fused-tricyclic azepanes or bridged-polycyclic azocanes were constructed via a two-step sequence involving an enantioselective organocascade followed by superacid activation of the domino adduct. The activated oxa-bridged azepane acts as a key hidden heptacyclic chiral N-acyl iminium ion triggering a chemo- and diastereoselective intramolecular mono- or di-arylation.     

Operational Methods and Truncated Exponential-Based Mittag-Leffler Polynomials

This article deals with the introduction of truncated exponential-based Mittag-Leffler polynomials and derivation of their properties. The operational correspondence between these polynomials and Mittag-Leffler polynomials is established. An integral representation for these polynomials is also derived.     

Generalized and mixed type Gegenbauer polynomials

In this paper, a new generalized form of the Gegenbauer polynomials is introduced by using the integral representation method. Further, the Hermite–Gegenbauer and the Laguerre–Gegenbauer polynomials are introduced by using the operational identities associated with the generalized Hermite and Laguerre polynomials of two variables.     

Marilines A–C: Novel Phthalimidines from the Sponge‐Derived Fungus Stachylidium sp.

A marine‐derived fungus of the genus Stachylidium was isolated from the sponge Callyspongia cf. C. flammea. Chemical investigation of the bioactive fungal extract led to the isolation of the novel phthalimidine derivatives marilines A₁ ( 1 a ), A₂ ( 1 b ), B ( 2 ), and C ( 3 ). The absolute configurations of the enantiomeric compounds 1 a and 1 b were assigned by a combination of experimental circular dichroism (CD) investigations and quantum chemical CD calculations. The skeleton of marilines is most unusual, and its biosynthesis is suggested to require uncommon biochemical reactions in fungal secondary metabolism. Both enantiomers, marilines A₁ ( 1 a ) and A₂ ( 1 b ), inhibited human leukocyte elastase (HLE) with an IC₅₀ value of 0.86 μM .     

Synthesis of several new lanthanide Glimepiride complexes for evaluation of microbial activity

The complexation between lanthanide metal ions like Nd(III), Tb(III), and Er(III) with Glimepiride produces 1: 1 molar ratio (metal: Glimepiride) monodentate complexes of general formula: [M(GMP)(H₂O)₄]Cl₃·xH₂O, where: M = Nd, Tb, and Er, x = 1, 10, respectively. The structures of obtained compounds were assigned by IR, ¹H NMR and UV/Vis spectra. Themogravimetric analysis and kinetic thermodynamic parameters have proved the thermal stability of Glimepiride complexes. Obtained lanthanide complexes showed significant effect against some bacteria and fungi.     

Synthesis and surface modification of mesoporous mcm-41 silica materials

Surface modification offers a great opportunity to adjust both the pore diameter and surface properties of MCM-41 type organic–inorganic hybrid materials which result in materials of improved hydrothermal and mechanical stability. Therefore, MCM-41 silica, surface modified with organic ligands, are promising systems with engineered properties and attractive for advanced applications. In the present study, after optimization of the reaction conditions highly ordered MCM-41 silica spheres with uniform mesopores were prepared by the pseudomorphic transformation route. The effect of functionality and alkyl chain length of the alkyl ligands during surface modification was probed by using butyl and octylsilanes with two different functionalities. Due to steric hindrance, the longer chains are assumed to bind only on the outer silica surface and near the entrance of the pores, while the shorter chains are also able to bind to the interior mesopore walls. The resulting materials were comprehensively characterized before and after surface modification using nitrogen sorption techniques, XRD, SEM, solid-state NMR spectroscopy and FTIR spectroscopy. From chromatographic test measurements it was found that the separation power primarily depends on surface coverage and alkyl chain length. On the basis of the present data, surface modified mesoporous silica of MCM-41 type are very promising candidates for future chromatographic applications.     

Efficient catalytic cyclizations of three and two imine assemblies: direct access to tetrahydroimidazo[1,5-c]imidazol-7-ones and imidazoles

A cascade cyclization involving union of three imines by an organocatalyst proline is established to afford new fused-tetrahydroimidazo[1,5-c]imidazol-7-ones with excellent regio- and stereoselectivity. Another dehydrogenative cyclization by union of two imines is developed using the Cu(OTf)(2)-Ag(2)O combo catalyst to furnish functionalized imidazoles.     

Generalized Bessel Functions and Lie Algebra Representation

The generalized Bessel functions (GBF) are framed within the context of the representation Q(ω,m ₀) of the three-dimensional Lie algebra . The analysis has been carried out by generalizing the formalism relevant to Bessel functions. New generating relations and identities involving various forms of GBF are obtained. Certain known results are also mentioned as special cases.Mathematics Subject Classifications (2000) 33C10, 33C80, 33E20.