One-Pot,Three-Component Uncatalyzed Quantitative Synthesis of New Aminonaphthols (Betti Bases) in Water

One-pot, three-component reaction of 2-naphthol, aromatic aldehyde, and heteroaryl amine in water at room temperature leads to the formation of the corresponding aminonaphthols (Betti bases). Reaction details and study of enantiomeric resolution of 1-(p-methylphenyl (2-pyrazinylamino) methyl) naphthalene-2-ol with the aid of ¹H NMR spectroscopy using chiral europium shift reagent is presented.     

Quantum Discord of 2<Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>-Dimensional Bell-Diagonal States

In this study, using the concept of relative entropy as a distance measure of correlations we investigate the important issue of evaluating quantum correlations such as entanglement, dissonance and classical correlations for 2 ⁿ -dimensional Bell-diagonal states. We provide an analytical technique, which describes how we find the closest classical states(CCS) and the closest separable states(CSS) for these states. Then analytical results are obtained for quantum discord of 2 ⁿ -dimensional Bell-diagonal states. As illustration, some special cases are examined. Finally, we investigate the additivity relation between the different correlations for the separable generalized Bloch sphere states.     

Synthesis of novel symmetrical bis‐schiff bases of 5,5′‐methylenebis(2‐aminothiazole)

Novel symmetrical bis‐Schiff bases have been prepared cleanly and efficiently in the presence of formic acid catalyst in methanol from the reaction of symmetrical primary bis‐amine of 5,5′‐methylenebis(2‐aminothiazole) ( 1 ) and a series of aromatic aldehyde derivatives under mild conditions. The advantages of this reaction are simplicity of the reaction procedure, simple work‐up and pure products with high yields. The structures of all the new synthesized symmetrical bis‐Schiff bases were confirmed by elemental analyses, IR, ¹H‐NMR, ¹³C‐NMR and mass spectra.     

One-pot synthesis of novel (E)-3-(3,8a-dihydro-2H-oxazolo[3,2-a]pyridin-2-ylidene)chroman-2-one derivatives

An efficient synthetic procedure for the preparation of novel (E)-3-(3,8a-dihydro-2H-oxazolo[3,2-a]pyridin-2-ylidene)chroman-2-one derivatives was developed. A sequential one-pot, two-step tandem reaction starting from 3-(2-bromoacetyl)-2H-chromen-2-one derivatives synthesized, pyridine, and naphthols in the presence of triethylamine proceeded smoothly in acetonitrile under reflux conditions. In this process, 2-oxo-2H-chromen-3-yl)ethyl)pyridinium bromide derivatives as intermediate produced in situ, followed by Michael addition of naphthoxide anion and intramolecular cylization, resulted the corresponding products in good to high yields. All of the compounds were obtained in high purity without any use of more purification.     

One-Pot Green Synthesis of Novel Polysubstituted 1,2-Dihydronaphtho[2,1-b]furans

A simple and highly efficient one-pot protocol for the synthesis of novel polysubstituted 1,2-dihydronaphtho[2,1-b] furans has been developed by three-component coupling reaction of 2-aminopyridines, naphthols, and glyoxal in the presence of guanidinium chloride as a polyfunctional organocatalyst under solvent-free conditions. The protocol avoids the use of expensive catalysts, toxic solvents, and chromatographic separation and provides a wide range of novel dihydronaphthofurans in good to excellent yields.     

Organocatalytic approach toward the green one-pot synthesis of novel benzo[<Emphasis Type="Italic">f</Emphasis>]chromenes and 12<Emphasis Type="Italic">H</Emphasis>-benzo[5,6]chromeno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridines

An efficient tandem reaction approach is described to prepare novel benzo[f]chromenes from 2,3-dihydroxynaphthalene, malononitrile and aldehydes using 10 mol% guanidine hydrochloride as the catalyst under solvent-free conditions. The method was also extended to the preparation of novel 12H-benzo[5,6]chromeno[2,3-b]pyridines from 2-aminoprop-1-ene-1,1,3-tricarbonitrile instead of malononitrile under the same reaction conditions. The described one-pot three-component reaction is characterized by short reaction times, high-product yield, mild reaction conditions, simple workup procedure, and simple purification.     

Synthesis of New Multibenzo Oxygen–Sulfur Donor Macrocycles Containing Lactams at Room Temperature

Some new oxygen–sulfur, multibenzo macrocyclic ligands containing amide groups have been prepared using the macrocyclization process with the reaction of 2,2′-thiobis-[4-methyl(2-aminophenoxy)phenyl ether] as a symmetrical diamine with appropriate dicarboxylicacid dichlorides in moderate yields. This macrocyclization led to the formation of di- and tetramide macrocycles. These reactions were routinely carried out at ambient temperature in CH₂Cl₂ as solvent in high dilution without template effect conditions. It is found that sulfur the atom affects the rigidity of the macrocycles and diastereotopicity of nuclei in the ring of these series of macrocyclic compounds.