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Your search keyword '"Xiu R Bu"' showing total 13 results
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13 results on '"Xiu R Bu"'

1. The readily available tert-pentyl group as a most effective simple directing group for asymmetric synthesis: a case study on Salen–Mn(III)-catalyzed epoxidation

Author

Xiu R. Bu, Sidney Liang, Anne Gaquere, and Fu-Lian Hsu

Subjects
Inorganic Chemistry, Chemistry, Stereochemistry, Group (periodic table), Organic Chemistry, Enantioselective synthesis, General Medicine, Physical and Theoretical Chemistry, Medicinal chemistry, Catalysis
Abstract

The tert -pentyl group has been found to produce a pronounced stereodirecting effect, which is manifested in a study on Salen–Mn(III) complexes bearing such groups.

Published
2002

2. Y-shaped two-photon absorbing molecules with an imidazole–thiazole core

Author

Cleber Renato Mendonça, Xiu R. Bu, Lino Misoguti, Ke Feng, Fu-Lian Hsu, Leonardo De Boni, and Michael A. Meador

Subjects
Sulfonyl, chemistry.chemical_classification, Stereochemistry, Imidazoles, Metals and Alloys, General Medicine, General Chemistry, Catalysis, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Core (optical fiber), Thiazoles, chemistry.chemical_compound, Crystallography, Absorptiometry, Photon, Two-photon excitation microscopy, chemistry, Group (periodic table), Materials Chemistry, Ceramics and Composites, Nitro, Imidazole, Photon absorptiometry, Molecule, Thiazole
Abstract

Two new classes of two-photon absorbing Y-shaped molecules have been developed to possess an imidazole-thiazole core and a stilbene-type conjugation pathway with either nitro or sulfonyl as terminal electron-accepting group.

Published
2004

3. ChemInform Abstract: A Modified Synthesis of o-Hydroxyaryl Aldehydes

Author

Xiao Z. You, Qing J. Meng, Xiu R. Bu, Rei X. Wang, and Eric A. Mintz

Subjects
Hexamethylphosphoric Triamide, chemistry.chemical_compound, chemistry, Formaldehyde, Organic chemistry, Modified method, General Medicine, Triethylamine
Abstract

A modified method for the synthesis of o-hydroxyaryl aldehydes in moderate yields has been developed by treating aryloxymagnesium bromides with formaldehyde using triethylamine in place of hexamethylphosphoric triamide (HMPA).

Published
2010

5. ChemInform Abstract: Unsymmetric Chiral Salen Schiff Bases: A New Chiral Ligand Pool from Bis-Schiff Bases Containing Two Different Salicylaldehyde Units

Author

Sidney Liang, Xiu R. Bu, and Jose Lopez

Subjects
Steric effects, chemistry.chemical_compound, Schiff base, chemistry, Salicylaldehyde, Steric factor, Polymer chemistry, Chiral ligand, General Medicine, Stepwise approach
Abstract

An efficient and facile synthesis of a new class of novel chiral Salen Schiff base ligands has been developed via a stepwise approach. An important feature of these new Salen ligands is that they possess two different salicylaldehyde units, therefore, while steric factor or electronic factor can be fixed on one side, electronic or/and steric factors can be tuned from the other side with different substituents.

Published
2010

6. ChemInform Abstract: Novel Unsymmetric Chiral Schiff Bases Possessing Two Different Donor Moieties: Unique Tetradentate Ligands from Combination of Salicylaldehyde and Acetylacetone Units

Author

Jose Lopez, Fu-Liang Hsu, Xiu R. Bu, and Eric A. Mintz

Subjects
chemistry.chemical_compound, Schiff base, chemistry, Salicylaldehyde, Acetylacetone, General Medicine, Condensation reaction, Combinatorial chemistry, Stepwise approach
Abstract

A new class of novel chiral Schiff base ligands has been developed using a stepwise approach. The key feature of these new ligands is that they possess two different donor units, one of them is aromatic while the other is non-aromatic.

Published
2010

7. ChemInform Abstract: Phase Transfer Catalysis and Ultrasound in Tandem Alkylation of Azo Dyes for Bifunctional Molecules

Author

Javier Santos, Xiang Li, and Xiu R. Bu

Subjects
chemistry.chemical_compound, endocrine system diseases, Tandem, Chemistry, Bromide, Phase (matter), Molecule, General Medicine, Alkylation, Photochemistry, Bifunctional, Derivative (chemistry), Catalysis
Abstract

Ultrasound has been found to enhance N -substitution against elimination in the reaction of carbazole-containing bromide with disperse orange 3 derivative under PTC conditions.

Published
2010

8. ChemInform Abstract: Tertiary Pentyl Groups Enhance Salen Titanium Catalyst for Highly Enantioselective Trimethylsilylcyanation of Aldehydes

Author

Sidney Liang and Xiu R. Bu

Subjects
chemistry.chemical_classification, Steric effects, chemistry, Enantioselective synthesis, chemistry.chemical_element, General Medicine, Cyanation, Aldehyde, Medicinal chemistry, Catalysis, Titanium
Abstract

tert-Pentyl groups are recognized to be highly effective steric groups that can enhance enantioselectivity of salen titanium complexes when they are used in asymmetrical cyanation of aromatic aldehydes. High ee (92-97%) has been obtained with several aldehyde substrates. Compared to its tert-butyl analogue, the tert-pentyl group has been found to improve enantioselectivity and in some cases quite dramatically.

Published
2010

9. Highly Efficient and Direct Heterocyclization of Dipyridyl Ketone to N,N-Bidentate Ligands

Author

Richard Mason, Xiu R. Bu, Prince Amoyaw, Jie Wang, and Leon Dyers

Subjects
chemistry.chemical_classification, Aldehydes, Denticity, Ketone, Molecular Structure, Ligand, Organic Chemistry, General Medicine, Ligands, Aldehyde, Medicinal chemistry, Acetic acid, chemistry.chemical_compound, 2,2'-Dipyridyl, chemistry, Cyclization, Organic chemistry, Molecule, Ammonium acetate
Abstract

[reaction: see text] Reaction of various aromatic aldehydes with 2,2'-dipyridyl ketone and ammonium acetate in hot acetic acid provides ready access to a series of substituted 1-pyridylimidazo[1,5-a]pyridines, a class of ligands possessing an N,N-bidentate feature, in good yields.

Published
2005

10. Convenient Preparation of a Novel Class of Imidazo[1,5-a]pyridines: Decisive Role by Ammonium Acetate in Chemoselectivity

Author

Xiu R. Bu, Ke Feng, Jie Wang, Richard Mason, and Don VanDerveer

Subjects
Diketone, chemistry.chemical_classification, Class (computer programming), Ketone, Bicyclic molecule, Chemistry, Organic Chemistry, General Medicine, Aldehyde, Chemical synthesis, Combinatorial chemistry, chemistry.chemical_compound, Organic chemistry, Chemoselectivity, Ammonium acetate
Abstract

A facile and one-pot straightforward methodology has been developed to prepare a novel class of imidazo[1,5-a]pyridines. A key role played by ammonium acetate in chemoselectivity has been examined.

Published
2003

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