Facial Selectivity
Mostrando 1-6 de 6 artigos, teses e dissertações.
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1. Facial Selectivity between Carbohydrates and Aromatic Amino Acids Explained by a Combination of NCI, NBO and EDA Techniques with NMR Spectroscopy
The influence of electrostatic and dispersion components of intermolecular interactions on the recognition of carbohydrates by aromatic protein residues is important for many biological processes. Interactions between glucose and galactose and aromatic moieties of tryptophan, phenylalanine and histidine were investigated through 1H nuclear magnetic resonance
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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2. Studies on facial diastereoselectivity in Diels-Alder reactions of sulfinyl benzoquinones and in nucleophilic additions to sulfanylated sulfinylcyclohexanones / Estudos de diastereosseletividade facial em reações de Diels-Alder de sulfinil benzoquinonas e em adições nucleofílicas a sulfinil cicloexanonas sulfaniladas
Calcando-se na bem conhecida capacidade que os sulfóxidos apresentam em induzir a quiralidade em uma vasta gama de reações, foram preparadas as (±)-2-p-tolilsulfinil-3,6-dimetil- e a (S)-2-p-tolilsulfinil-3-metil-1,4-benzoquinonas e estudadas as suas reações de Diels-Alder com alguns 1,3-dienos. Bons resultados de quimio- e regiosseletividade foram obt
Publicado em: 2008
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3. Indução assimétrica 1,5-Anti na adição de enolatos de boro de metilcetonas beta-oxigenadas a aldeídos
High levels of substrate-based 1,5-stereoinduction are obtained in the boron-mediated aldol reactions of beta-oxygenated methyl ketones with achiral and chiral aldehydes. Remote induction from the boron enolates gives the 1,5-anti adducts, with the enolate pi-facial selectivity critically dependent upon the nature of the beta-alkoxy protecting group. This 1,
Química Nova. Publicado em: 2007
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4. Adição de nucleofilos de carbono a ions iminio e aciliminio : sintese de B-aminocetonas e enantiosseletiva da base necinica (+) - hastanecina
b-aminoketones 50-58 and 67-70 were prepared in 35-80% yield through the addition of sililenolethers to iminiun ions generated from the corresponding imines (Schiff bases) and 15% mol of TMSOTf or catalytic amount of Lewis acid (Cp2BOTf, BF3 OEt2, Me2AlCI ou TiC4). The diastereoisomeric ratio of the b-aminoketones proved to be dependent on the reaction condi
Publicado em: 1995
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5. Concurrent Bell's palsy and diabetes mellitus: a diabetic mononeuropathy?
In a series of 126 patients with Bell's palsy, chemical or overt diabetes mellitus was found in 39% of the cases. A high frequency of disturbances of taste was found in the patients who had no diabetes (83%), as compared to only 14% of diabetic patients whose taste was affected (p less than 0 .001). Thus, the usual site of facial nerve lesion in diabetics ap
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6. Studies of stereocontrolled allylation reactions for the total synthesis of phorboxazole A
A highly convergent total synthesis of the potent anticancer agent (+)-phorboxazole A (1) is accomplished. Four components (3–6) are assembled with considerations for control of absolute and relative stereochemistry. Iterative asymmetric allylation methodology addresses key stereochemical features in the preparation of the 2,6-cis- and 2,6-trans-tetrahydro
National Academy of Sciences.