Asymmetric transformation of .alpha.-amino acids promoted by optically active cobalt(III) complexes. 3. Importance of side-chain intramolecular interligand hydrogen bonding on stereoselectivity

1982 ◽  
Vol 21 (12) ◽  
pp. 4138-4143 ◽  
Author(s):  
Motowo. Yamaguchi ◽  
Yoshiyuki. Masui ◽  
Masahiko. Saburi ◽  
Sadao. Yoshikawa
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Optically Active ◽  
Side Chain ◽  
Asymmetric Transformation

Isoxazolinium Salts in Asymmetric Synthesis. 1. Stereoselective Reduction Induced by a 3’-Alkoxy Stereocentre. A New Approach to Polyfunctionalized β-Amino Acids* [1, 2]

2004 ◽  
Vol 59 (4) ◽  
pp. 451-467 ◽  
Author(s):  
Marco Henneböhle ◽  
Pierre-Yves Le Roy ◽  
Matthias Hein ◽  
Rudolf Ehrler ◽  
Volker Jäger
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Catalytic Hydrogenation ◽  
Optically Active ◽  
Side Chain ◽  
Reduction Step ◽  
One Pot ◽  
New Approach ◽  
Stereoselective Reduction

AbstractA new approach to optically active N-methylamino acids is presented, relying on stereoselective reduction of N-methylisoxazolinium salts with a dioxyethyl side-chain. The diastereoselectivity of the reduction step is studied systematically, in comparison with that of respective isoxazolines. A two-step transformation of isoxazolinium salts - with NaBH3(OAc) and subsequent catalytic hydrogenation as well as a one-pot reduction by catalytic hydrogenation led to high (95:5 and 87:13) diastereomeric ratios of protected erythro-N-methylaminopentanetriols. The hydroxyethyl side-chain is elaborated by oxidation to afford the β -N-methylamino acid 37, exemplifying the potential of this strategy.

Asymmetric transformation of .alpha.-amino acids promoted by optically active cobalt(III) complexes

1980 ◽  
Vol 19 (7) ◽  
pp. 2010-2016 ◽  
Author(s):  
M. Yamaguchi ◽  
S. Yamamatsu ◽  
T. Furusawa ◽  
S. Yano ◽  
M. Saburi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Optically Active ◽  
Asymmetric Transformation

The interaction of dimethyl sulfoxide with N-benzoyl amino acids

1981 ◽  
Vol 34 (9) ◽  
pp. 1869 ◽  
Author(s):  
CW Fong ◽  
HG Grant
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Dimethyl Sulfoxide ◽  
Benzene Ring ◽  
Chemical Shifts ◽  
Side Chain ◽  
Torsional Angle ◽  
Intermolecular Hydrogen Bonding ◽  
Atom Increase ◽  
Self Association

The interaction of dimethyl sulfoxide with N-benzoyl amino acids in deuterochloroform has been investigated by 13C n.m.r. spectroscopy. Examination of the chemical shifts of the benzene ring reveals that intermolecular hydrogen bonding between dimethyl sulfoxide and the amido-hydrogen atom increase the effective steric size of the amino hydrogen, resulting in an increase in the torsional angle between the benzene ring and the C(O)NHCH(R)COOH side chain. Self-association of N- benzoyl amino acids in deuterochloroform occurs largely through two COOH...O=C hydrogen bonds and does not involve intermolecular hydrogen bonding to the N-H proton.

ChemInform Abstract: ASYMMETRIC TRANSFORMATION OF α-AMINO ACIDS PROMOTED BY OPTICALLY ACTIVE COBALT(III) COMPLEXES

1980 ◽  
Vol 11 (41) ◽  
Author(s):  
M. YAMAGUCHI ◽  
S. YAMAMATSU ◽  
T. FURUSAWA ◽  
S. YANO ◽  
M. SABURI ◽  
...  
Keyword(s):  
Amino Acids ◽  
Optically Active ◽  
Asymmetric Transformation

Water Molecules Hydrogen Bonding to Aromatic Acceptors of Amino Acids: the Structure of Tyr-Tyr-Phe Dihydrate and a Crystallographic Database Study on Peptides

1998 ◽  
Vol 54 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Thomas Steiner ◽  
Antoine M. M. Schreurs ◽  
Jan A. Kanters ◽  
Jan Kroon
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Water Molecule ◽  
Side Chain ◽  
Protein Hydration ◽  
Water Molecules ◽  
Database Study ◽  
Wide Variability

The crystal structure of Tyr-Tyr-Phe dihydrate contains a hydrogen bond formed between a water molecule and the Phe side chain. The geometry is centered with a distance of 3.26 Å between the water O atom and the aromatic centroid. In a database study on hydrated peptides, four related examples are found which exhibit a wide variability of hydrogen-bond geometries. The intermolecular surroundings of the water molecules are inspected, showing that they are typically involved in complex networks of conventional and non-conventional hydrogen bonds. Possible relevance for protein hydration is given.

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