Search

The catalytic influences of boric acid have been introduced on dual Friedel‐Crafts reaction between arylamines and aldehydes to install the Csp3‐center that leads to the formation of di‐ or tri‐substituted methanes. The described reaction conditions have directed the transformation to favor the para‐para substitution pattern to deliver the major products rather than the corresponding ortho‐para functionalization process. The devised transformation was examined by DFT calculation, which shows the favorable activation energy of transition states (TS) for the generation of highly substituted molecular scaffolds. The method was applicable over diversely substituted aldehydes and arylamines to afford the final products in excellent yields (60‐92 %) and selectivity. The proposed mechanism is supported by suitable control experiments, GC‐MS studies, and DFT calculations. [ABSTRACT FROM AUTHOR]

An uracil-azo derivative of quinoline, 1,3-dimethyl-5-(8′-quinolinyl-azo)-6-aminouracil (H2L, 1), was synthesized and then converted into its atropisomers, 1,3-dimethyl-8-(8′-quinolinyl)azaxanthine (α-atropisomer (2) and β-atropisomer (3)). It is indeed a notable accomplishment that the atropisomers were synthesized selectively under dissimilar reaction conditions. Additionally, an axially elongated 5-coordinated distorted square pyramidal copper(II)-complex, [CuII(HL)(H2O)2]NO3 (4), was synthesized from H2L, where it acts as a tridentate ligand. Single crystals of compounds 2–4 were analyzed for their stereochemical characterization. The compounds (2 and 3) belong to the same space group P21 with Z = 2. Based on a torsional angle about N3–N2–C1–C9, which is 48.7(2)° for the α-atropisomer (2) and −48.7(2)° for the β-atropisomer (3), respectively, they are revealed to be atropisomers. According to TD-DFT analysis, the α-atropisomer (2) is 0.05 kcal mol−1 more energetically stable than the β-atropisomer (3). The 5-coordinated Cu1 centre adopts a distorted square pyramidal geometry (space group P21/n, Z = 4), wherein the coordination sites were occupied by three-N and two O-donor atoms from the HL− moiety and the two H2O molecules, respectively. The polycrystalline sample of 4 was subjected to direct current (dc) variable-temperature magnetic susceptibility studies over the temperature range of 1.8–300 K. The magnetic study suggests that copper(II) ions in the crystal lattice have a weak antiferromagnetic interaction, demonstrating the complex to be a mononuclear species. According to the EPR study, the distorted square-pyramidal copper(II) complex may have a dx2−y2 orbital as a ground state. All the compounds have shown significant efficacy against the bacterial plant pathogen, Ralstonia solanacearum Smith. and the fungal plant pathogen, Rhizoctonia solani Kuhn., which cause bacterial wilting of solanaceous crops and sheath blight of rice, respectively. Besides, the atropisomers have demonstrated effectiveness against another bacterial plant pathogen, Xanthomonas oryzaepv. oryzae. that causes bacterial blight of rice. The atropisomers thus differ with respect to biological efficacy towards both bacterial and fungal diseases. [ABSTRACT FROM AUTHOR]

The established process proceeds through copper (II)‐catalyzed C(sp3)− functionalization of β‐diketones/β‐ketoesters with 2‐bromobenzaldehyde oximes followed by the intramolecular cyclization of in situ generated acylated intermediates to deliver isoquinoline N‐oxides. The copper(II) acetate catalyzed C−H functionalization showed maximum efficacy at 60 °C in methanol/toluene as solvent. The described reaction conditions were applicable over a wide range of substrates with a variety of functional groups to yield isoquinoline N‐oxides in yields up to 85%. The developed approach was further elucidated by means of control experiments and DFT calculations. [ABSTRACT FROM AUTHOR]

Two chiral Schiff base ligands 2-((1-hydroxy-3-phenylpropan-2-ylimino)methyl)-6-methoxyphenol (L1H2) and 2-(4-hydroxy-3-isopropylbut-1-enyl)-6-methoxyphenol (L2H2) have been synthesized by the condensation of l-phenylalaninol/l-valinol and o-vanillin (2-hydroxy-3-methoxy benzaldehyde). A tetranuclear homometallic Cu(II) complex [Cu4(L1H)2(L1)2] (ClO4)2 (C1) and a hexanuclear heterometallic complex [Cu4(L2)4Na2(DMF)2(H2O)] (ClO4)2 (C2) have been synthesized with the ligands. Both the complexes possess cubane like Cu4O4 core with interesting structural variations and inherit the chirality of their corresponding ligands. The catalytic potential of the complexes has been explored for the oxidative kinetic resolution of racemic benzoin. The electronic, optical and chiroptical properties of the ligands and the complexes have been studied by DFT and TD-DFT calculations. Two chiral tetranuclear Cu(II) complexes have been synthesized from chiral Schiff base ligands. There are structural, spectroscopic and computational evidence of chirality of the complexes. The complexes show moderate activity toward enantioselective kinetic resolution of racemic benzoin with a maximum of 63% enantiomeric excess. [ABSTRACT FROM AUTHOR]