- β-Amino alcohols from anilines and ethylene glycol through heterogeneous Borrowing Hydrogen reaction
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Borrowing Hydrogen (BH), also called Hydrogen Autotransfer (HA), reaction with neat ethylene glycol represents a key step in the preparation of β-amino alcohols. However, due to the stability of ethylene glycol, mono-activation has rarely been achieved. Herein, a combination of Pd/C and ZnO is reported as heterogeneous catalyst for this BH/HA reaction. This system results in an extremely air and moisture stable, and economic catalyst able to mono-functionalize ethylene glycol in water, without further activation of the diol. In this work, different diols and aromatic amines have been explored affording a new approach towards amino alcohols. This study reveals how the combination of two solid species can afford interesting catalytic properties in heterogeneous phase. ZnO activates ethylene glycol while Pd/C is the responsible of the BH/HA cycle. This catalytic system has also been found useful to dehydrogenate indoles affording indolines that undergo in situ BH/HA cycle prior to re-aromatization, representing a tandem heterogeneous process.
- Llabres-Campaner, Pedro J.,Ballesteros-Garrido, Rafael,Ballesteros, Rafael,Abarca, Belén
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supporting information
p. 5552 - 5561
(2017/08/22)
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- One-pot synthesis of unsymmetrical N-heterocyclic carbene ligands from N-(2-iodoethyl)arylamine salts
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Image Presented An approach that provides symmetrical, unsymmetrical, and asymmetric N-heterocyclic carbene (NHC) ligands is reported. Reaction of iodoethanol with aniline provides N-(2-iodoethyl)arylamine salts that are then converted to the corresponding iodide. Reaction with aliphatic or aromatic amines followed by triethyl orthoformate was used to provide 26 different NHC ligands.
- Bhanu Prasad,Gilbertson, Scott R.
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supporting information; experimental part
p. 3710 - 3713
(2011/02/28)
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- Synthesis of titanium(IV) complexes containing 2,6-dimethylaniline substituted amino alcohols and their utilization in ethylene polymerizations
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Two new Ti(IV) complexes of the type [(OCHRCH2N-2,6-Me2Ph)Ti(NMe2)2] 2 (where R=H, or tbutyl) have been synthesized by protonolysis of Ti(NMe2)4 with the corresponding N-substituted amino alcohol ligand. The two complexes were studied as Ziegler-Natta type polymerization catalysts in the presence of an excess of methylaluminoxane (MAO). It was found that ethylene polymerization activity for both catalysts increased by increasing the polymerization temperature from 25 to 70°C. If the catalysts were pretreated with trimethylaluminum, the activities increased at 25°C, but slightly decreased at 70°C. Both complexes were found to be ineffective for the polymerization of propylene. An X-ray crystal structure of [(OCH2CH2N-2,6-Me2Ph)Ti(NMe2) 2]2 shows the complex to be dimeric in the solid state, with bridging through the amino alcohol oxygen atoms. This complex crystallizes in the monoclinic system space group, P21/n with a=9.181(6), b=13.766(3), c=13.002(3), β=93.08(3) and Z=4.
- Rhodes, Barrie,Chien, James C.W.,Wood, John S.,Chandrasekaran,Rausch, Marvin D.
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