Two New Acidic Diterpenoids from the Heartwood of Pinus massoniana Lamb.

A new abietane diterpene, named abietopinoic acid, and a new podocarpane diterpene, named podopinoic acid, were isolated from the acetone extract of the heartwood of Pinus massoniana. Their structures were established as 12‐hydroxy‐7‐oxoabieta‐8,11,13‐trien‐18‐oic acid ( 1 ) and 13‐hydroxy‐7‐oxopodocarpane ( 2 ) by means of spectroscopic analyses including 2D‐NMR. To the best of our knowledge, this is the second report of a podocarpa‐8,11,13‐trien‐18‐oic acid diterpene, isolated from the genus Pinus.     

Recent Advances in the Chemistry and Synthetic Uses of Amino‐1,3,4‐thiadiazoles

Amino‐1,3,4‐thiadiazoles, although scarce in nature, constitute a group of nitrogen and sulfur heterocyclic compounds that have shown significant biological activities. Their transformations into other biologically active compounds have been exploited. This review describes the work on the synthesis and reactions of amino‐1,3,4‐thiadiazoles as well as their biological evaluation.     

Synthesis of Some New Benzimidazole–Thiazole Derivatives as Anticancer Agents

4‐(1H‐benzo[d]imidazol‐2‐yl)thiazol‐2‐amine and its 1‐methyl derivative ( 1 ) were reacted with different reagents such as acid anhydrides, malononitrile, chloroacetyl chloride, and aromatic aldehydes to produce the corresponding benzimidazole products 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , respectively. Also, 2‐chloro‐N‐(4‐(1‐methyl‐1H‐benzo[d]imidazol‐2‐yl)thiazol‐2‐yl) acetamide ( 6 ) was reacted with diaminoethane, ortho‐substituted aniline, thioglycolic acid, thiosemicarbazide derivatives, secondary amines, and potassium isothiocyanate to afford the corresponding derivatives 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , respectively. The cytotoxic activity of some newly synthesized derivatives was studied against two different cell lines HepG2 and PC12. Compounds 9 and 15b showed promising anticancer activity against both types of the tested cancerous cell lines.     

Synthesis of New Chromeno[4,3‐b]pyrazolo[4,3‐e]pyridines Derivatives with Antimicrobial Evaluation

A series of 2‐oxo‐2,5‐dihydro‐1H‐chromeno[4,3‐b]pyridine derivatives were obtained by using a one‐pot three component reaction of 2,2‐disubstituted chroman‐4‐one with aromatic aldehydes and 2‐cyanoacetamide in the presence of sodium hydroxide under solvent‐free conditions. Heating chromenopyridine derivatives with phosphoryl chloride gave the corresponding chloro derivatives. The reaction of the chloro derivatives with hydrazine hydrate afforded dihydrochromeno[4,3‐b]pyrazolo[4,3‐e]pyridines derivatives. Condensation of the dimethyl derivative compound with the aromatic aldehydes gave 8‐Arylideneamino‐6,6‐dimethyl‐10H‐chromeno[4,3‐b]pyrazolo[4,3‐e]pyridine.     

Chemistry of Phosphonium Ylides. Part 39: Facile Synthesis of Aziridine,Pyridine, Pyrolotriazole Chromenones and Azaphosphinin Chromenones as Antitumor Agents

The reaction of 4‐azido‐2‐oxo‐2H‐chromene‐3‐carbaldehyde with the active nucleophilic phosphacumulenes yielded the corresponding phosphanylidene‐aziridines and chromeno‐pyrolo‐triazoles. On the other hand, the reaction of the allylic phosphonium ylide, hexaphenylcarbodiphosphorane with the azido compound, was also undertaken. In this case, the phosphanylidene‐chromeno‐triazinone was obtained. Further assessment of these new compounds against (breast: MCF‐7 and liver: HPEG2) human solid tumor cell lines is necessary.     

Synthesis of pyranopyrazoles using magnetic Fe3O4 nanoparticles as efficient and reusable catalyst

Magnetic Fe₃O₄ nanoparticles as a heterogeneous catalyst, were found to be efficient for the synthesis of a series of pyranopyrazoles by a four component reaction of a mixture of hydrazine hydrate, ethyl acetoacetate, aldehydes/ketones and malononitrile in water at room temperature. The products were attributed to the nanosize of about 16 nm in which the catalyst could act as a nanoreactor. The present protocol offers the advantages of clean reaction, short reaction time, high yield, easy purification and economic availability of the catalyst.     

Photolysis of Some N‐Arylbenzamidoximes in Acetonitrile

The photolysis of five N‐arylbenzamidoxime derivatives I‐V in dry acetonitrile gives rise to anilides 8 and benzimidazoles 1 as the major products in addition to benzonitrile 4 , arylamines 5 , benzoic acid 6 , and 2‐phenyl benzoxazoles 7 . In the presence of naphthalene, I gave α‐ and β‐naphthols 2 and 3 beside the previous products. The isolated products have been interpreted in the terms of a free radical mechanism involving the homolysis of N‐O and/or C‐N bonds. This photodegradation process can be considered as an alternative method for the synthesis of anilide, benzimidazole and benzoxazole derivatives in addition to other organic compounds.     

Detection of Heavy Metal Ions Using Synthesized Amino Thiol Surfactants Assembled on Gold Nanoparticles

In this work, we synthesized amino thiol surfactants, namely, 10-(4-aminophenoxy)-decane-1-thiol and 12-(4-aminophenoxy)-dodecane-1-thiol. The self-assembling of the synthesized surfactants on gold nanoparticles (AuNPs) was investigated using different techniques such as ultraviolet analysis, x-ray diffraction, and transmission electron microscopy. The synthesized surfactants show the ability to assemble on gold nanoparticles and form stable nanostructure with it. We used the synthesized surfactants and their nanostructures with gold nanoparticles for the detection of Zn and Ni ions in aqueous solution using the ultraviolet spectrophotometer technique. The synthesized amino thiol surfactants showed the ability to detect Zn and Ni ions at low concentration. The results showed that gold nanoparticles can enhance the detection of Zn and Ni ions using the nanostructures of the synthesized surfactants.     

Synergistic extraction of uranium from acidic sulfate leach liquor using D2EHPA mixed with TOPO

Uranium extraction from sulfate leach liquor acid by D₂EHPA and TOPO mixture in kerosene was investigated. The effect of different factors affecting the extraction mechanism such as sulfate leach liquor acid, D₂EHPA and TOPO concentrations and temperature have been studied. The mathematical treatment for the obtained date suggested that the composition of synergistic extraction species is (UO₂(D)₂T). The logarithm of the apparent equilibrium constant, log Kex, of synergistic extraction reaction has been evaluated, to be 3.35 ± 0.1. The effect of temperature on extraction process was investigated and the apparent values of the thermodynamics parameters (?H, ?G and ?S) were 38.2 kJ/mol, ?19.1 kJ/mol and 192.5 J/mol respectively.     

Effect of conductive fillers on the cyclic stress-strain and nano-scale free volume properties of silicone rubber

The effect of carbon black(CB) and graphite(G) powders on the macroscopic and nano-scale free volume properties of silicone rubber based on poly(di-methylsiloxane)(PDMS) was studied through thermal and cyclic mechanical measurements, as well as with positron annihilation lifetime spectroscopy(PALS). The melting temperature of the composites(Tm) and the endothermic enthalpy of melting(?Hm) were estimated by differential scanning calorimetry(DSC). Tm and the degree of crystallinity(χc) of PDMS composites were found to decrease with increasing the CB content. This can be explained due to the increase in physical cross-linking which results in a decrease in the crystallite thickness. Besides, χc was found to be dependent on the filler type. Cyclic stress-strain behavior of PDMS loaded with different contents of filler has been studied. Mullins ratio(RM) was found to be dependent on the filler type and content. It was found that, RM increases with increasing the filler content due to the increase in physical cross-linking which results in a decrease in the size of free volume, as observed through a decrease of the o-Ps lifetime τ3 measured by PALS. Moreover, the hysteresis in PDMS-CB composites was more pronounced than in PDMS-G composites. Furthermore, a correlation was established between the free volume Vf and the mechanical properties of PDMS composites containing different fillers. A negative correlation was observed between Vf and RM.