- Converging and Diverging Synthetic Strategies to Tetradentate (N,N')-Diaminomethyl,(P,P')-Ferrocenyl Ligands: Influence of tert-Butyl Groups on Ferrocene Backbone Conformation
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Hexasubstituted hybrid tetradentate (N,N',P,P')-ferrocenes bearing phosphino and aminomethyl groups, plus hindering tert-butyl moieties, were synthesized by using two different strategies: a "diverging" synthesis involving successive functionalization of preformed di-tert-butylated ferrocene and a "converging" assembly of the species from appropriately substituted cyclopentadienyl rings. While the new cyclopentadienyl salts formed are of interest, their assembly with iron dichloride used as a "converging" way to produce tetradentate ferrocene ligands presented several drawbacks. Conversely, the synthesis of new tert-butylated (aminomethyl)ferrocene derivatives was found convenient to further form (N,N')-aminomethyl,(P,P')-tert-butylated-ferrocenyl diphosphines by N-directed ortho-metalation. The novel N2-didentate and N2P2-tetradentate tert-butylated ferrocene compounds were all synthesized in good to high yields (48-96%) and tolerated aryl, alkyl, and heteroaryl phosphino groups as substituents on nitrogen and phosphorus atoms. They were characterized by X-ray diffraction and multinuclear NMR (1H, 13C, 31P, 15N). We observed the conformation control provided to rac-(N,N')-diaminomethyl-(P,P')-tert-butylated-ferrocenyldiphosphines with in particular the systematic near-eclipsed conformation of aminomethyl groups. This conformation is at the origin of the unexpected formation at RT of a zwitterionic cyclopalladate from an (aminomethyl)ferrocene derivative, arising from intramolecular Cp-proton transfer to the proximate free amino group by simple C-H activation reaction in the presence of palladium dichloride.
- Allouch, Fatima,Dwadnia, Nejib,Vologdin, Nikolay V.,Svyaschenko, Yurii V.,Cattey, Hélène,Penouilh, Marie-José,Roger, Julien,Naoufal, Daoud,Ben Salem, Ridha,Pirio, Nadine,Hierso, Jean-Cyrille
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supporting information
p. 5015 - 5028
(2015/11/09)
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- PTP-1B inhibitors: Cyclopenta[d][1,2]-oxazine derivatives
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A series of novel cyclopenta[d][1,2]-oxazine derivatives was prepared and evaluated for their inhibitory activity toward protein tyrosine phosphatase 1B (PTP-1B). Compound 6s was found to be an inhibitor of PTP-1B with nanomolar IC50 value and
- Cho, Sung Yun,Baek, Ji Yoen,Han, Sang Sub,Kang, Seung Kyu,Ha, Jae Du,Ahn, Jin Hee,Lee, Jae Don,Kim, Kwang Rok,Cheon, Hyae Gyeong,Rhee, Sang Dal,Yang, Sung Don,Yon, Gyu Hwan,Pak, Chwang Siek,Choi, Joong-Kwon
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p. 499 - 502
(2007/10/03)
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- Octachloroazulene
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The title compound, the first perhaloazulene, has been synthesized from hexachlorobutadiene and cyclopentadiene. Further chlorination of 1,3,4,5,6,7-hexachloroazulene results in addition, rot substitution, under electrophilic as well as free radical conditions. Radical chlorination of the hexachloro-azulene affords in good yield a single decachlorotetrahydroazulene. Treatment of this Cl10 compound with one equiv of a phosphazene base gives a nonachlorodihydroazulene, but the addition of a second equiv results in dechlorination to 1,2,3,4,5,6,7-heptachloroazulene as well as dehydrochlorination to octachloro-azulene. The former azulene is obtained cleanly from the Cl9 compound with acid catalysis or by reduction with mercury. In the presence of calcium carbonate, however, the Cl9 intermediate yields the dark green octachloroazulene. Although octachloronaphthalene is readily converted into its octafluoro counterpart, the isomeric octachloroazulene is far too sensitive to undergo the analogous transformation.
- Lou, Yan,Chang, Joanne,Jorgensen, Jeffrey,Lemal, David M.
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p. 15302 - 15307
(2007/10/03)
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- Tautomerism in the solid state and in solution of a series of 6-aminofulvene-1-aldimines
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To study systems able to sustain intramolecular proton-transfer, we have prepared a series of six aminofulvene aldimines including several labeled with 15N and 2H. These compounds show coupling constants through the hydrogen bond, 1hJ(15N-1H) and 2hJ(15N-15N). The position of the tautomeric equilibria, i.e., on what nitrogen atom is the proton, was determined in the solid state and in solution. The crystal structure of N{([5-[(phenylamino)methylene]- 1,3-cyclopentadien-1-yl]methylene})pyrrole-1-amine (3) has been determined by X-ray analysis. In solution, both N-H and C-H tautomers were observed and their structures assigned by NMR spectroscopy. Particularly useful is the value of the 1J(15N-1H) coupling constant.
- Sanz, Dionisia,Perez-Torralba, Marta,Alarcon, Sergio Hugo,Claramunt, Rosa Maria,Foces-Foces, Concepcion,Elguero, Jose
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p. 1462 - 1471
(2007/10/03)
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- 6-Dimethylamino-6-lithiofulvene, a novel 6-fulvenyl anion of potential synthetic utility
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Treatment of 6,6-bis(dimethylamino)fulvene with 2.2 equiv. of lithium naphthalenide in THF generates, via two-electron reduction and deamination, 6-dimethylamino-6-lithiofulvene which is a new 6-fulvenyl anion of potential utility for the synthesis of a variety of 6-aminofulvenes and related compounds.
- Kawase,Fujino,Oda
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p. 545 - 548
(2007/10/02)
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