Synthesis of benzothiazolopyrazoloisonicotinohydrazide derivatives and their nitro regioisomers for antitubercular activity

The history of incessant struggle and the current global burden associated with emerging infectious disease especially tuberculosis, guided us to define the scope of this research project, and to identify research gaps in synthesizing some heterocyclic compounds for anti-tubercular activity. In this research project, we have synthesized a series of novel heterocyclic (benzothiazoles) compounds viz N'-((1-(7-chloro-6-fluorobenzo[d]thiazol-2-yl)-3-phenyl-1H-pyrazol-4-yl) methylene)isonicotinohydrazide 12a-c their 5-nitro 15a-c and 4-nitro 18a-c derivatives, by a series of reactions of their respective synthons. The completion of reaction and the purity of the synthesized compounds have been established by chromatographic analysis. All the newly synthesized compounds satisfactorily show acceptable analysis for their anticipated structures, which have been confirmed based on physicochemical and spectral data. These newly synthesized compounds have been primarily evaluated for their in vitro anti-tubercular activity by Ziehl-Neelsen stain method. Compounds 15a, 15b, 15c, 18b and 18c have shown 100% inhibition at 25 mg/ mL and MIC values of around 45 nM against M. tuberculosis H37Rv (ATCC 27294). Cytotoxicity on THP-1 cell line shows that all the tested compounds are safe.

Synthesis of benzothiazolopyrazoloisonicotinohydrazide derivatives and their nitro regioisomers for antitubercular activity

1388-1399The history of incessant struggle and the current global burden associated with emerging infectious disease especially tuberculosis, guided us to define the scope of this research project, and to identify research gaps in synthesizing some heterocyclic compounds for anti-tubercular activity. In this research project, we have synthesized a series of novel heterocyclic (benzothiazoles) compounds viz N'-((1-(7-chloro-6-fluorobenzo[d]thiazol-2-yl)-3-phenyl-1H-pyrazol-4-yl) methylene)isonicotinohydrazide 12a-c their 5-nitro 15a-c and 4-nitro 18a-c derivatives, by a series of reactions of their respective synthons. The completion of reaction and the purity of the synthesized compounds have been established by chromatographic analysis. All the newly synthesized compounds satisfactorily show acceptable analysis for their anticipated structures, which have been confirmed based on physicochemical and spectral data. These newly synthesized compounds have been primarily evaluated for their in vitro anti-tubercular activity by Ziehl-Neelsen stain method. Compounds 15a, 15b, 15c, 18b and 18c have shown 100% inhibition at 25 mg/ mL and MIC values of around 45 nM against M. tuberculosis H37Rv (ATCC 27294). Cytotoxicity on THP-1 cell line shows that all the tested compounds are safe

Modulation of the electronic states of 2-D single carrier quantum dots due to presence of hole doped impurity perturbations

We report the effects of on- and off-center attractive impurities on regular parabolic dots and their impact on the level structures as a function of the strength of the transverse magnetic field. Information entropy, probability density and level-spacing distribution are used as keys to monitor the pattern of evolution of electronic states. The level structures are marked by crossings and anticrossings and sharply peaked level-spacing distribution functions, either at low or high field strengths confirming the presence of level repulsion. The anticipated emergence of quantum chaos as a result of hole doping is demonstrated in dots with off-centre impurities

Response dynamics of 2-D quantum dots in the presence of time-varying fields: anharmonicity and pulse shape effects

We explore the pattern of time evolution of different observables in a harmonically confined single carrier 2-D quantum dot when an external time-varying electric field is switched on. A static transverse magnetic field is also present. For given strengths of the confining field, cyclotron frequency, intensity and oscillation frequency of the external field, and pulse shape parameters, the system reveals a long time dynamics that leads to a kind of localization in the unperturbed state space. The presence of cubic anharmonicity in the confining field brings in new features in the dynamics. Frequency dependent linear and non-linear response properties of the dot are analyzed

Linear and non-linear optical response properties of singlet 2-electron quantum dots

We explore the pattern of linear and non-linear optical (NLO) response of 2-electron singlet quantum dots in two dimensions with or without anharmonicity in the confinement potential. The influence of transverse magnetic field strength (β) on linear (α), first (β), and second (γ) NLO response of the system are analyzed. A simple, exactly solvable model involving two interacting harmonic oscillators is exploited to explain some of the observations

Shell structure and paramagnetism of 3-D N-e anisotropic (ellipsoidal) quantum dots: Exact multi-pole expansion of coulomb interaction under fermionic exchange symmetry

As the density of electrons (N=2, 3, 4, 5, 6, 7, 8,.) increases, complexity arises due to coulomb interactions, inclusion of fermionic exchange symmetry and anisotropy. Consequently, Schrödinger equations of anisotropic quantum dots become non-trivial. Recasting such non-relativistic quantum equations into Whittaker-M basis functions unifies coulomb (exchange) correlation and antisymmetric nature of electrons in two-centered integrals of exact, finite, single-summed, terminated and simplest Lauricella functions (F2) via multi-pole expansion and the subsequent Chu-Vandermonde identity. Coulomb correlations interplay with in-plane and out-of-plane electrical and magnetic confinements in their moderate fields. On the other hand, full-scale fermionic exchange symmetry is incorporated through multiple number of Slater determinants, unlike Hartree-Fock method. In this context, both open-shell and restricted closed-shell configurations are considered for trial Hartree-products which are composed of the basis set of oscillator spin-orbitals. Thus optimized bound states can easily capture large number of mixed term symbols. Consequently, level clustering/accidental degeneracies occur in energy level diagram due to competition among strength of anisotropy in electrical confinements, magnetic field, mass of the carrier and dielectric constant. It brings about orbital induced paramagnetism (T∼(0-1)K), signature of fractional quantum Hall effect (FQHE) in chemical potential cusps (μ) and formation of different ′shell structures′ in capacitive energy respectively, spanning over wide dielectric range of materials (atomic like quantum dot, ZnO, GaAs, CdSe (Cadmium Chalcogenide) and PbSe (Lead Chalcogenide) etc)

Quantum adiabatic switching route to the impurity modulated states of 2-D quantum dots with different switching functions

A time-dependent quantum adiabatic switching algorithm is exploited to determine the eigenstates of 2-D quantum dots perturbed by a repulsive scatterer. Several forms of switching functions are explored and optimal forms are suggested. The switching paths are compared for a number of states, using overlap, information entropy and energy as descriptors for possible identification of the optimal switching function

A linear variational route to the polarizability of 2-D artificial atoms: effects of anharmonicity in the confinement potential

Effective mass Schrodinger equation of an artificial atom in two dimensions with anharmonicity in confinement potential is solved by linear variational method using an appropriate harmonic oscillator basis set. Linear response to electric field is computed and correlated with changes in the electronic probability density distribution

Response properties of 2-electron 2-D quantum dots: triplet versus singlet

The linear and non-linear optical response properties of 2-D quantum dots with two interacting carrier electrons having triplet coupling of spins are computed and compared with their singlet counterparts. The significant dependence of the response properties on the spin multiplicity in the high and low field regimes are sought to be rationalized