The facile preparation of β-diketiminate gallium amides with general formulas of either LGa(NHR) 2 {L = [HC{C(Me)N-(Ar)} 2 ]-, Ar = 2,6-iPr 2 C 6 H 3 ; R = Et (1), iPr (2), nBu (3), Ph (4)} or LGa(NHR)Cl [R = tBu (5); Et (6)] was accomplished by the reaction of LGaCl 2 with the lithium salt of the corresponding amine in 1:2 (1-4) or 1:1 (5, 6) molar ratios. Compounds 1-6 are useful synthons for further synthesis, as the amide substituents are excellent leaving groups, and the resulting amines can be cleanly and easily removed from the reaction matrix. To demonstrate this, compounds 1 and 5 were treated with ethanol, leading to the alcoholysis products LGa(OEt) 2
Novel oxazolidin-2-one-linked 1,2,3-triazole derivatives () were synthesized by straightforward and versatile azide-enolate (3 + 2) cycloaddition. The series of compounds was screened for antifungal activity against four filamentous fungi as well as six yeast species of spp. According to their efficiency and breadth of scope, they can be ordered as > > > , especially in relation to the activity displayed against ATCC-34138, ATCC-28592 and ATCC-8690, compounds, and showed excellent activity against (MIC 0.12, 0.25 and 0.12 μg mL, respectively), better than that of itraconazole (MIC 1 μg ml). The activity of compound (MIC = 2 μg mL) was higher than that observed for the standard antifungal drug (MIC = 8 μg mL) against , while compound displayed an excellent antimycotic activity against (MIC = 2 μg mL 4 μg mL for itraconazole). In addition, we describe herein a novel mild and eco-friendly synthetic protocol for obtaining β-ketosulfones (adducts to afford compounds ) from α-brominated carbonyls in an aqueous nanomicellar medium at room temperature.
The synthesis of molecular heterometallic alumosilicates in good yields has been achieved by reaction between LAl(OH·thf)(μ‐O)Si(OH)(OtBu)2 (1, L = [HC{C(Me)N(Ar)}2]–, Ar = 2,6‐iPr2C6H3) and group 4 amides. These reactions lead to inorganic cycles (type I) and spirocycles (type II) containing six‐membered rings with unprecedented inorganic cores (O–Al–O–Si–O)nM (n = 1, 2; M = Ti, Zr and Hf). Noteworthy, for the heavier metals, Zr and Hf, higher steric bulk in the alkyl substituent of the amide moiety is required to obtain type I compounds. The solid‐state structures for all compounds were determined and reveal a tetrahedral environment for all metal atoms, dihedral angles close to 90° for spirocyclic compounds, and isomorphous structures for the Zr and Hf derivatives.
The preparation of dinuclear aluminum and gallium complexes with controlled M•••M proximity (intermetal separation of 3.28−4.35 Å) was achieved through direct chelation of the multidentate bis(diphenyl-(1) and bis(diisopropylphosphinoyl)-1,8-diamino naphthalene (2) ligands. The solid-state structure of the dinuclear complexes obtained with 1 suggests that the geometric constraint imposed by the ligand backbone is responsible for the in situ conversion in solution of the kinetic to the thermodynamic isomers. The complexes derived from 1 represent rare examples of linkage isomer couples stable enough to allow their characterization by X-ray diffraction studies, while for 2 only the thermodynamic isomers were stable enough to be characterized by this technique. Kinetic studies revealed a first-order reaction rate for the isomerization process, and an intramolecular mechanism was rationalized in terms of the effects of temperature, solvent, and structural variation. Preliminary catalytic screening on an isomer couple derived from 1 showed that both the kinetic and thermodynamic species are active for the ROP of ε-caprolactone.
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