The properties of nuclear matter at zero and finite temperatures

The properties of nuclear matter are studied in the frame of the Brueckner theory. The Brueckner-Hartree-Fock approximation plus two-body density-dependent Skyrme potential which is equivalent to three-body interaction are used. Various modern nucleon-nucleon potentials are used in the framework of the Brueckner-Hartree-Fock approximation, e.g.: CD-Bonn potential, Nijm1 potential, and Reid 93 potential. These modern nucleon-nucleon potentials fit the deuteron properties and are phase shifts equivalent. The equation of state at T = 0, pressure at T = 0, 8, and 12 MeV, free energy at T = 8 and 12 MeV, nuclear matter incompressibility, and the symmetry energy calculation are presented. The hot properties of nuclear matter are calculated using T ²-approximation method at low temperatures. Good agreement is obtained in comparison with previous theoretical estimates and experimental data, especially at low densities.     

New Approach to 4‐ and 5‐Aminopyrazole Derivatives

3‐Oxo‐3‐(pyrrol‐2‐yl)‐propanenitrile 1 coupled with aromatic diazonium salts to yield the corresponding 2‐arylhydrazones 2a–c. The latter products reacted with chloroacetonitrile and ethyl chloroacetate to yield 4‐aminopyrazole derivatives 5a–f. Reaction of 2 with hydrazine hydrate led to formation of 5‐amino‐4‐arylazopyrazole 6a–c. Compound 1 reacted also with trichloroacetonitrile to yield enamine 7, which in turn reacted with hydrazine hydrate to yield 5‐amino‐3‐(pyrrol‐2‐yl)‐pyrazole‐4‐carbonitrile 8.     

Nuclear quantum effects in calculated NMR shieldings of benzene; a Feynman path integral study

The Feynman path integral Monte Carlo approach has been coupled to the gauge including atomic orbital formalism in order to analyse the absolute magnetic shieldings of the benzene nuclei under the conditions of thermal equilibrium. The Hamiltonian employed in the derivation of ensemble averaged NMR quantities is of the Hartree-Fock type. The basis set used is of 6–31G quality. The spatial delocalization of the atoms leads to a deshielding of both types of benzene nuclei relative to the shieldings experienced at the minimum of the potential energy surface. This deshielding has to be traced back to bond length elongations in thermal equilibrium. The influence of the nuclear fluctuations on the NMR parameters of benzene is quantum driven up to temperatures of 400 K; classical fluctuations are of minor importance in this low-temperature window.     

Facile synthesis of thiadiazolo [2,3-b] quinazoline derivatives via the Japp-Klingemann Reaction

Diazotized anathranilic acid and its methyl ester react with substituted α-thiocyanatoacetoacetanilides3a–c to give in both cases the corresponding thiadiazolo [2,3-b] quinazolines6a–c, respectively. A mechanism is proposed and it is substantiated by synthesis of6a from N-(2-car?yphenyl)-C-phenylcarbamoyl hydrazidoyl chloride8a or its N-(2-methoxycarbonylcarbonylphenyl) analogue8d.     

A one step synthesis of thiadiazolo[2,3-b]quinazoline derivatives

Diazotized anthranilic acid and its methyl ester react with substituted phenacyl thiocyanates 3 to give in both cases the corresponding thiadiazolo[2,3-b]quinazolines 7a-e . A mechanism is proposed and it is substantiated by alternate synthesis of 7a from the hydrazidoyl chlorides 9a,b and potassium thiocyanate.     

Experimental and theoretical electronic absorption spectra of 2,4‐diphenyl‐1,5‐benzothiazepine and its derivatives: Solvatochromic effect and time dependent density functional theory approach

Electronic spectra of 2,4‐diphenyl‐1,5‐benzothiazepine and some of its derivatives in 1,2‐dichloromethane and ethanol are investigated experimentally and theoretically using the time dependent density functional theory (TD‐DFT) method at the B3LYP/6‐311G** level of the theory. The origin of the spectrum of the parent compound is found to be an additive one. The observed ultra violet (UV) spectra in both solvents show two bands S1 in the range between 312–334 nm and S2 in the range between 248–272 nm. The solvent effect is investigated experimentally and theoretically and a blue shift is observed, which is explained in terms of a hydrogen bond model between the solvent and the most negative site of the solute (N atom). This theoretical model is robust in reproducing the experimental blue shift and calculating the hydrogen bond energy and hydrogen bond length. The extent of delocalization and charge transfer processes of the studied compounds is estimated and discussed in terms of natural bond orbital (NBO) analysis and second order perturbation interactions (E²) between donors and acceptors. The effect of substituents of the studied compounds in both solvents shows a noticeable red shift attributed to hyperconjugation effects of the π electron systems of the different moieties.     

Facile one-pot,three-component synthesis of novel bis(heterocycles) incorporating thieno[2,3-b]thiophenes via Michael addition reaction

A synthesis of novel series of bis(2-amino-3-cyano-4H-chromene), bis(2-amino-3-cyanopyrano[3,2-c]chromene), bis(6-amino-5-cyano-1,4-dihydropyrano[2,3-c]pyrazole), and bis(2,7-diamino-3,4,6-tricyanopyrazolo[1,5-a]pyridine) derivatives linked to thieno[2,3-b]thiophene core via ether or ester linkages was reported. The formation of the target compounds presumably proceeds through a three component reaction of the appropriate bis(aldehyde) with 2 M of each of malononitrile and the corresponding active methylene compounds namely; dimedone, 4-hydroxycoumarine, 5-methyl-2,4-dihydro-3H-pyrazol-3-one, or cyanomethylpyrazole in dioxane at reflux in the presence of piperdine as a basic catalyst. The chemical structures of the new compounds were elucidated by several spectral tools.     

A new strategy for the synthesis of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidines and pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines

A series of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidines were prepared via oxidative cyclization of aldehyde N-(1,3-diphenylpyrazolo[3,4-d]pyrimidin-4-yl)hydrazones. Dimroth rearrangement of such a series yielded pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines.