Azolopyrimidines and pyrimidoquinazolines from 4-chloropyrimidines

5-Cyano-3,4-dihydro-6-phenyl-2-substitutedpyrimidin-4-ones 1a-c reacted with phosphorus oxychloride to give the corresponding 4-chloropyrimidine derivatives IIa-c . Compounds IIa-c reacted with aniline and hydrazine to yield the 4-anilino, IIIa,e , and 4-hydrazino, IIIb-d derivatives. The 4-hydrazino analogues IIIb,c could be converted into the triazolo[4,3-c] and tetrazolo[4,5-c]pyrimidines IV and V by the action of carbon disulphide and nitrous acid, respectively. The reaction of IIb,c with phenylhydrazine afforded directly the 5-amino-4,6-diphenyl-6H-2-substitutedpyrazolo[3,4-d]pyrimidines VIa,b . The 4-chloro derivative IIa reacted with antrhanilic acid to form the 5-cyano-2,4-diphenyl-6-(o-carboxyphenylamino)pyrimidine VIII , which could be cyclised into the 4-cyano-1,3-diphenyl-10H-pyrimido[6,1-b]quinazolin-10-one IX by heating with acetic anhydride.     

Theoretical calculation of the temperature coefficient of surface excess entropy of pure liquid metals

The temperature coefficient of surface excess entropy dS_s/dT of pure liquid metals (Al, Ga and Bi) has been calculated in the framework of Skapski's nearest-neighbor interaction-broken-bond model. It is found that this coefficient varies by 47.2%, 69% and 85% for pure liquids Al, Bi and Ga, respectively, in the temperature range between the melting temperature T_m and T_m + 400 K. The value of the coefficient for pure liquid Ga is an order of magnitude larger than that of Al and Bi. The largest increase in dS_S/dT with temperature occurs in the first 100 K away from T_m, being the largest for liquid Ga which is about 43%. This variation is experimentally inaccessible and therefore lacking in the literature and has never been reported.     

Formulation and analysis of two energy-consistent methods for nonlinear elastodynamic frictional contact problems

Energy-conserving algorithms are necessary to solve nonlinear elastodynamic problems in order to recover long term time integration accuracy and stability. Furthermore, some physical phenomena (such as friction) can generate dissipation; then in this work, we present and analyse two energy-consistent algorithms for hyperelastodynamic frictional contact problems which are characterised by a conserving behaviour for frictionless impacts but also by an admissible frictional dissipation phenomenon. The first approach permits one to enforce, respectively, the Kuhn–Tucker and persistency conditions during each time step by combining an adapted continuation of the Newton method and a Lagrangean formulation. In addition the second method which is based on the work in [P. Hauret, P. Le Tallec, Energy-controlling time integration methods for nonlinear elastodynamics and low-velocity impact, Comput. Methods Appl. Mech. Eng. 195 (2006) 4890–4916] represents a specific penalisation of the unilateral contact conditions. Some numerical simulations are presented to underscore the conservative or dissipative behaviour of the proposed methods.     

Antibacterial sphingolipid and steroids from the black coral Antipathes dichotoma

From the black coral Antipathies dichotoma, a sphingolipid (2S*,3S*,4E,8E)-2N-[tetradecanoyl]-4(E),8(E)-icosadiene-1,3-diol (1) and a steroid (22E)-methylcholesta-5,22-diene-1α,3β,7α-triol (2) were isolated. Other known compounds, 3β,7α-dihydroxy-cholest-5-ene (3), (22E,24S),5α,8α-epidioxy-24-methylcholesta-6,22-dien-3β-ol (4) and (22E,24S),5α,8α-epidioxy-24-methylcholesta-6,9(11),22-trien-3β-ol (5). The structures were established on the basis of NMR spectroscopic analysis and comparison with literature. The antibacterial activity of five compounds was evaluated.     

Surface energies of metals in both liquid and solid states

Although during the last years one has seen a number of systematic studies of the surface energies of metals, the aim and the scientific meaning of this research is to establish a simple and a straightforward theoretical model to calculate accurately the mechanical and the thermodynamic properties of metal surfaces due to their important application in materials processes and in the understanding of a wide range of surface phenomena. Through extensive theoretical calculations of the surface tension of most of the liquid metals, we found that the fraction of broken bonds in liquid metals (f) is constant which is equal to 0.287. Using our estimated f value, the surface tension (γ_m), surface energy (γ_SV), surface excess entropy (−dγ/dT), surface excess enthalpy (H_s), coefficient of thermal expansion (α_m and α_b), sound velocity (c_m) and its temperature coefficient (−dc/dT) have been calculated for more than sixty metals. The results of the calculated quantities agree well with available experimental data.     

New cytotoxic isoprenoid derivatives from the Red Sea soft coral Sarcophyton glaucum

Chemical investigation of the soft coral Sarcophyton glaucum collected from the Red Sea led to isolation of 11 isoprenoidal metabolites (1–11). A new sesquiterpenoid, 6-oxo-germacra-4(15),8,11-triene (1), a new natural cembranoid, sarcophinediol, along with two known sesquiterpenoids (2 and 3) and seven known cembranoids (5–11) was obtained. The structures of the compounds were established based on their NMR, MS, IR and UV spectral data. All compounds were evaluated for their cytotoxicity employing three cancer cell lines (HepG2, MCF-7 and HCT116). Compounds 4 and 6 showed significant cytotoxicity towards HepG2 with IC₅₀ values of 18.8 ± 0.07 and 19.9 ± 0.02 μM; respectively. Compounds 5–7 exhibited potent cytotoxicity against MCF-7 cells with IC₅₀ values of 9.9 ± 0.03, 2.4 ± 0.04 and 3.2 ± 0.02 μM, respectively. Compounds 1, 4 and 5 showed significant activities towards HCT116 cells with IC₅₀ values of 29.4 ± 0.03, 19.4 ± 0.02 and 25.8 ± 0.03 μM, respectively.     

New Cytotoxic Laurene‐, Cuparene‐, and Laurokamurene‐Type Sesquiterpenes from the Red Alga Laurencia obtusa

Three new sesquiterpene alcohols, laur‐2‐ene‐3,12‐diol ( 1 ), cuparene‐3,12‐diol ( 2 ), and 8,11‐dihydro‐1‐methoxylaurokamuren‐12‐ol ( 3 ), along with one known diterpene, kahukuen‐10‐ol ( 4 ) have been isolated from the organic extract of the red alga Laurencia obtusa. The chemical structures were elucidated on the basis of spectroscopic analysis. The cytotoxicity of the isolated compounds were evaluated against three cancer cell lines, i.e., KB, HepG2, and MCF‐7. Compound 4 exhibited a wide range of cytotoxic activity against KB, HepG2, and MCF‐7 cell lines with IC₅₀ of 0.100, 0.057, and 0.054 μm, respectively. In addition, 1 showed moderate activities towards KB and MCF‐7 cell lines with IC₅₀ values of 0.171 and 0.184 μM , respectively and 2 exhibited a moderate activity against KB cell line at a concentration of 0.213 μg/ml. On the other hand, compound 3 exhibited no cytotoxic activity against any of the three cell lines.     

Direct synthesis of a macroscopic array of naked Ag nanoparticles

A 2-D array of naked Ag nanoparticles has been synthesized through interfacial reduction of Ag(+) under hydrothermal conditions. The process bestows the synthesis, nucleation, growth and self-assembly of the nanoparticles in a simple one-pot reaction and makes use of no additive or capping agent. The resulting macroscopic liquid silver mirror is highly stable and composed of tightly packed naked Ag nanoparticles (17 (3) nm diameter, with interparticle gaps of 1.3 (1.0) nm) which can be easily transferred to a given substrate for application.     

Phthalazine-1,4-dione derivatives as non-competitive AMPA receptor antagonists: design,synthesis, anticonvulsant evaluation,ADMET profile and molecular docking

Molecular Diversity - In view of the anticonvulsant activity reported for phthalazine derivatives as non-competitive AMPA receptor antagonists, a new series of phthalazine-1,4-diones (2–12)...     

Test of the des Cloiseaux Law by Membrane Osmometry on Pullulan

The des Cloiseaux law Π ∼︁ C^9/4 describing the scaling relation between osmotic pressure and concentration in semi‐dilute solutions of neutral polymers in athermal solvent (good solvent) was tested on pullulan, which is a linear polysaccharide, using membrane osmometry. The experimentally determined exponent is 2.2865 ± 0.026, which agrees well with this power law and disagrees with the theoretical value of 2 based on the mean field approximation.