Application of organolithium compounds for the preparation of some aliphatic and alicyclic phosphines, phosphine oxides and phosphine sulfides

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Selective catalytic carbanionic ethylation of methylphenols: influence of catalyst and substitution pattern

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New stable, isolable triarylmethyl based dyes absorbing in the near infrared

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Aryllithiums with Increasing Steric Crowding and Lipophilicity Prepared from Chlorides in Diethyl Ether. The First Directly Prepared Room-Temperature-Stable Dilithioarenes

A convenient procedure has been developed for the preparation of synthetically useful, room-temperature-stable aryllithiums starting from aryl chlorides and lithium metal. The method provides a route to aryllithiums which have previously not been accessible cleanly or could only be prepared by using more expensive starting materials

Microwave assisted solid additive effects in simple dry chlorination reactions with n-chlorosuccinimide

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Synthesis of new phosphino amino alcohol ligands via ortho-alkyllithiation reactions. Versatile coordination behavior toward copper(I) and palladium(II)

2-[Methyl(2-methylphenyl)amino]ethanol undergoes an ortho-alkyllithiation reaction with n-butyllithium to lead to a new mixed benzyllithium−lithium alkoxide. This organolithium species reacts with PPh2Cl, with selective P−C bond formation, to afford the ligand 2-[methyl(2-((diphenylphosphino)methyl)phenyl)amino]ethanol L1. The coordination of the ligand L1 to copper(I) leads to the complex [Cu(L1)2](BF4), whose structure has been determined by an X-ray diffraction study. In the solid state, one of the ligands acts as a monodentate phosphine while the other adopts a tridentate P,N,O coordination mode. A variable-temperature 31P NMR study demonstrated the existence of an equilibrium between the two modes in solution, with a coalescence temperature of ca. 0 °C, indicating a double-hemilabile behavior for the nitrogen and the oxygen functions. L1 reacts with [Pd(Me)(Cl)(COD)] to give a dinuclear complex in which the ligand appears to behave as a bridging anionic P,O ligand. Such a complex could serve as a model for a key intermediate in the proposed mechanism for the homogeneous catalysis of the methoxycarbonylation of propyne by certain palladium(II) complexes containing P,N ligands. L1 can undergo a second ortho-alkylmetalation reaction with n-butyllithium which, after addition of PPh2Cl, provides the new ligand 2-{methyl[2-(bis(diphenylphosphino)methyl)phenyl]amino}ethanol (L2) in high yield

New hydroxystilbenoid derivatives endowed with neuroprotective activity and devoid of interference with estrogen and aryl hydrocarbon receptor-mediated transcription

We have synthesized a series of new (E) stilbenoid derivatives containing hydroxy groups at ring positions identical or similar to those of trans-resveratrol and bearing one or two bulky electron donating groups ortho to 4′-OH and we have evaluated their neuroprotective activity using glutamate-challenged HT22 hippocampal neurons to model oxidative stress-induced neuronal cell death. The most active derivatives, 5-{(E)-2-[3,5-bis(1-ethylpropyl)-4-hydroxyphenyl]ethenyl}-1,3-benzenediol (2), 5-[(E)-2-(3,5-di-tert-butyl-4-hydroxyphenylethenyl)]-1,3-benzenediol (4) and 5-{(1E,3E)-4-[3,5-bis(1-ethylpropyl)-4-hydroxyphenyl]-1,3-butadienyl}-1,3-benzenediol (6), had EC50 values of 30, 45 and 12 nM, respectively, and were ca. 100 to 400-fold more potent than resveratrol. Derivatives 2, 4 and 6 lacked cytotoxic activity against HT22 cells and estrogen receptor agonist or antagonist activity in estrogen response element-dependent gene expression and in estrogen-dependent proliferation of MCF-7 human breast cancer cells. In addition, they were incapable of interfering with aryl hydrocarbon receptor-mediated xenobiotic response element-dependent gene expression. Derivatives 2, 4 and 6 might assist in the development of lead candidates against oxidative stress-driven neurodegenerative diseases that will not increase endocrine cancer risk nor affect drug activation and detoxification mechanisms