Enantioselective Synthesis and Photoreactivity of a Diazirinyl-substituted (R)-β-Phenylalanine

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1088-1096 ◽  
Author(s):  
Jan-Niklas Schäckermann ◽  
Thomas Lindel
Keyword(s):  
Amino Acid ◽  
Absolute Configuration ◽  
Enantioselective Synthesis ◽  
Thermally Stable ◽  
Standard Laboratory ◽  
Laboratory Conditions ◽  
Quantumchemical Calculations ◽  
Valence Tautomers ◽  
The Absolute

Abstract The first enantioselective synthesis of a photoreactive (R)-β-phenylalanine is described. In the key step, m-diazirinyl-substituted benzaldehyde is converted to a chiral sulfinimine in a Ti(OEt)4- mediated reaction, followed by diastereoselective enolate addition. The absolute configuration of photo (R)-β-phenylalanine was confirmed by Mosher analysis. The photo amino acid proved to be thermally stable under standard laboratory conditions. Irradiation in toluene afforded cycloheptatriene=norcaradiene valence tautomers, together with carbene benzylation. Quantumchemical calculations indicate a small triplet-singlet gap.

Enantioselective synthesis of 1-substituted tetrahydroisoquinoline-1-carboxylic acids

1992 ◽  
Vol 70 (5) ◽  
pp. 1555-1561 ◽  
Author(s):  
Zbigniew Czarnocki ◽  
Dennis Suh ◽  
David B. MacLean ◽  
Philip G. Hultin ◽  
Walter A. Szarek
Keyword(s):  
Amino Acid ◽  
Carboxylic Acids ◽  
Absolute Configuration ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Acid Hydrochloride ◽  
The Absolute

The 3,4-dihydroisoquinolinium salt 1 and its enantiomer have been converted readily and stereoselectively into (+)-and (−)-1,2,3,4-tetrahydro-6,7-dimethoxy-1-methylisoquinoline-1-carboxylic acids. The synthetic route described should be applicable to the enantioselective synthesis of a variety of 1-alkyl- or 1-aryl-1,2,3,4-tetrahydroisoquinoline-1-carboxylic acids. The absolute configuration of the amino acid hydrochloride 11 was established to be as depicted in Scheme 2.

Evaluation of Different Synthetic Routes to (2R,3R)-3-Hydroxymethyl-2-(4-hydroxy- 3-methoxyphenyl)-1,4-Benzodioxane-6-Carbaldehyde

2020 ◽  
Vol 23 (26) ◽  
pp. 2960-2968
Author(s):  
Renáta Kertiné Ferenczi ◽  
Tünde-Zita Illyés ◽  
Sándor Balázs Király ◽  
Gyula Hoffka ◽  
László Szilágyi ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Stereoselective Synthesis ◽  
Cotton Effect ◽  
Enantioselective Synthesis ◽  
Aryl Group ◽  
Target Molecule ◽  
Synthetic Routes ◽  
The Absolute

The reported enantioselective synthesis for the preparation of (+)-(2R,3R)-2-(4- hydroxy-3-methoxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-carbaldehyde, precursor for the stereoselective synthesis of bioactive flavanolignans, could not be reproduced. Thus, the target molecule was prepared via the synthesis and separation of diastereomeric O-glucosides. TDDFT-ECD calculations and the 1,4-benzodioxane helicity rule were utilized to determine the absolute configuration. ECD calculations also confirmed that the 1Lb Cotton effect is governed by the helicity of the heteroring, while the higher-energy ECD transitions reflect mainly the orientation of the equatorial C-2 aryl group.

scholarly journals Rapid Organocatalytic Chirality Analysis of Amines, Amino Acids, Alcohols, Amino Alcohols and Diols with Achiral Iso(thio)cyanate Probes

2021 ◽  
Author(s):  
Eryn Nelson ◽  
Jeffrey S. S. K. Formen ◽  
Christian Wolf
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Rapid Determination ◽  
Amino Alcohols ◽  
Enantioselective Synthesis ◽  
Widespread Occurrence ◽  
Chiral Compounds ◽  
New Methods ◽  
The Absolute

The widespread occurrence and significance of chiral compounds does not only require new methods for their enantioselective synthesis but also efficient tools that allow rapid determination of the absolute configuration,...

scholarly journals Absolute Stereochemistry of the β-Hydroxy Acid Unit in Hantupeptins and Trungapeptins

2016 ◽  
Vol 11 (1) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Deepak Kumar Gupta ◽  
Gary Chi Ying Ding ◽  
Yong Chua Teo ◽  
Lik Tong Tan
Keyword(s):  
Amino Acid ◽  
Structural Feature ◽  
Absolute Configuration ◽  
Hydroxy Acid ◽  
Hplc Analysis ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Common Structural Feature ◽  
Acid Unit

The β-hydroxy/amino acid unit is a common structural feature of many bioactive marine cyanobacterial depsipeptides. In this study, the absolute stereochemistry of the β-hydroxy acid moieties in hantupeptins and trungapeptins were determined through their synthesis and HPLC analysis of the Mosher ester derivatives. Synthesis of two3-hydroxy-2-methyloctanoic acid (Hmoa) stereoisomers, (2 S,3 R)-Hmoa and (2 S,3 S)-Hmoa, were achieved using diastereoselective asymmetric method and the retention times of all four Hmoa isomers were established indirectly by RPLC-MS analysis of their Mosher ester derivative standards. Based on the retention times of the standards, the absolute configuration of the Hmoa unit in hantupeptin C (3) and trungapeptin C (6) was assigned as (2 R,3 S)- and (2 S,3 R)-Hmoa, respectively. The use of the Mosher's reagents, coupled with HPLC analysis, provided a viable alternative to the absolute stereochemical determination of β-hydroxy acid units in depsipeptides.

scholarly journals A tryptophan C-methyltransferase involved in streptonigrin biosynthesis in Streptomyces flocculus

1984 ◽  
Vol 220 (1) ◽  
pp. 309-313 ◽  
Author(s):  
D L Hartley ◽  
M K Speedie
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Amino Acid ◽  
Stationary Phase ◽  
High Pressure Liquid Chromatography ◽  
Absolute Configuration ◽  
Specific Activity ◽  
Shake Culture ◽  
Methyl Group ◽  
The Absolute

A C-methyltransferase that catalyses the transfer of a methyl group from S-adenosylmethionine to C-3 of tryptophan, resulting in beta-methyltryptophan, has been identified in cell-free extracts of streptonigrin-producing Streptomyces flocculus. The absolute configuration of the product was shown to be (2S,3R)-beta-methyltryptophan by high-pressure liquid chromatography and reactivity with D- and L-amino acid oxidases. In shake culture, maximum specific activity occurs after S. flocculus enters stationary phase, but before significant streptonigrin accumulates.

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