A facile green synthesis of MgCoFe2O4 nanomaterials with robust catalytic performance in the synthesis of pyrano[2,3-d]pyrimidinedione and their bis-derivatives

Molecular Diversity - In this study, an efficient, rapid and simple plant-mediated green sol–gel auto-combustion procedure was presented to synthesis magnesium–cobalt ferrite...     

Base-free green synthesis of copper(II) oxide nanoparticles using highly cross-linked poly(curcumin) nanospheres: synergistically improved antimicrobial activity

Research on Chemical Intermediates - Antimicrobial activity of metal containing formulas has drawn attention and been widely investigated. In this research, CuO/hc-pCUR nanocomposite composed of...     

BF3·nano SiO2 as a catalytic system for one-pot green synthesis of pyrophthalone derivatives under microwave conditions: 1st Nano Update

The expeditious and solvent-free approach that involves the exposure of neat reactants to microwave (MW) irradiation in conjunction with the use of supported catalysts was described. A simple one-pot and green reaction of methylpyridine derivatives and phthalic anhydride derivatives on the surface of a nano silica gel impregnated with BF₃ as solid supported catalysts under microwave irradiation without any solvent according to green chemistry was developed. The salient features of these high yield protocols are the enhanced reaction rates, greater selectivity and the experimental ease of manipulation.     

Effect of axial ligand on the electronic configuration, spin states, and reactivity of iron oxophlorin

Iron-oxophlorin is an intermediate in heme degradation, and the nature of the axial ligand can alter the spin, electron distribution, and reactivity of the metal and the oxophlorin ring. The structure and reactivity of iron-oxophlorin in the presence of imidazole, pyridine, and t-butyl isocyanide as axial ligands was investigated using the B3LYP and OPBE methods with the 6-31+G* and 6-311+G** basis sets. OPBE/6-311+G** has shown that the doublet state of [(Py)(2)Fe(III)(PO)] (where pyridines are in perpendicular planes and PO is the oxophlorin trianion) is 3.45 and 5.27 kcal/mol more stable than the quartet and sextet states, respectively. The ground-state electronic configuration of the aforementioned complex is π(xz)(2) π(yz)(2) a(2u)(2) d(xy)(1) at low temperatures and changes to π(xz)(2) π(yz)(2) d(xy)(2) a(2u)(1) at high temperatures. This latter electronic configuration is consistently seen for the [(t-BuNC)(2)Fe(II)(PO(?))] complex (where PO(?) is the oxophlorin dianion radical). The complex [(Im)(2)Fe(III)(PO)] adopted the d(xy)(2) (π(xz) π(yz))(3) ground state and has low-lying quartet excited state which is readily populated when the temperature is increased.     

Synthesis of Some New 3-Oxo-2-[(Z)-1-phenylmethylidene]-5H-[1,3]thiazolo[3,2-a]-and N-Acetylated Pyrimidines

3-Oxo-2-[(Z)-1-phenylmethylidene]-5H-[1,3]thiazolo[3,2-a] pyrimidine derivatives 2a–f were synthesized by the reaction of an appropriate 3,4-dihydro-2(H)-pyrimidone 1 , chloroacetic acid, sodium acetate and benzaldehyde. Reaction of 1 with acetic anhydride under heating afforded only 3-N-acetylated 3,4-dihydro-2(H)-pyrimidines 3a–f . The yields of the products after recrystallization from ethanol were of the order of 60–92 %. IR, ¹ H NMR spectroscopy, and elemental analysis were used for the identification of these compounds.     

One-Pot Synthesis of Novel 2-(Thiazol-2-yl)-4,5-dihydropyridazin-3(2H)-one Derivatives Catalyzed by Activated KSF

A series of 2-(thiazol-2-yl)-4,5-dihydropyridazin-3(2H)-one derivatives were synthesized by one-pot multicomponent cyclocondensation of ketoacid, thiosemicarbazide, and phenacyl bromide using catalytical amount of KSF in EtOH under reflux. The straightforward synthesis, presence of two important class of heterocyclic rings in the individual molecule, easy workup of the products, rapid reaction, mild conditions, and good to excellent yields are notable features of this protocol.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Microwave-Promoted Facile and Rapid Synthesis Procedure for the Efficient Synthesis of 5,5-Disubstituted Hydantoins

A fast, general, environmentally friendly, and facile method for preparation of 5, 5-disubstituted hydantoins from the reaction between ketone (or aldehyde) derivatives with KCN and ammonium carbonate under microwave irradiation is presented. The microwaves remarkably accelerated this reaction, the reaction times decreased dramatically, the reaction conditions were milder, and the yields were also greater. Also a comparative study of microwave versus classical conditions has been done. All the products were characterized by infrared, NMR, and CHN analysis, and their melting points are identical to those of the known compounds reported in the literature. This method might be useful in the future for the preparation of similar derivatives.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]     

Rotational Energy Barrier of the Polarized Carbon–Carbon Double Bond in Quinophthalone

 A dynamic NMR effect is observed in the ¹³C NMR spectra of anhydrous quinophthalone (quinoline yellow) and its monohydrate in the vicinity of 47°C and 0°C, respectively, and is attributed to a restricted rotation around the polarized carbon–carbon double bond. The free energy of activation for this process in anhydrous quinophthalone and the monohydrate is 65±2 and 55±2 kJ · mol⁻¹, respectively, in CDCl₃.     

Estimation of thermal lensing effect in the high-power end-pumped direct-cut crystal lasers

At this working, analytical (with Gaussian pump beam profile) and numerical FEM (with super-Gaussian pump beam profile) methods were compared for estimation of thermal lensing effect in the diode-end-pumped solid-state laser rods. These results were applied to the design and realization of a direct-cut (i.e., cut in right-angle ) crystal Nd:YVO₄ laser. The results showed that for such crystal (direct-cut), two methods obtained almost the same results, but slightly different from experimental results. However, estimation of thermal lensing effect led to realization of a diode-end-pumped Nd:YVO₄ cw high-power laser with good optical quality.