The Synthesis of Carbohydrate α-Amino Acids Utilizing the Corey - Link Reaction

2004 ◽  
Vol 57 (8) ◽  
pp. 723 ◽  
Author(s):  
Adrian Scaffidi ◽  
Brian W. Skelton ◽  
Robert V. Stick ◽  
Allan H. White
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Single Crystal ◽  
Sodium Azide ◽  
Similar Sequence ◽  
X Ray ◽  
Tertiary Alcohols ◽  
Amino Esters

Various carbohydrate ketones (uloses) have been treated with chloroform under strongly basic conditions to yield trichloromethyl tertiary alcohols. These alcohols, when subjected to the conditions of the modified Corey–Link reaction (sodium azide and 1,8-diazabicyclo[5.4.0]undec-7-ene in methanol), generally gave the expected azido ester with complete stereocontrol. Subsequent transformations on these azido esters provided amino esters, azido acids, and, in one case, the amino acid. A similar sequence applied to a protected d-glucono-1,5-lactone was only partly successful. Single-crystal X-ray structures are reported for 1,2:5,6-di-O-isopropylidene-3-C-trichloromethyl-α-d-allose, (3S)-3-C-azido-3-C-carboxy-3-deoxy-1,2:5,6-di-O-isopropylidene-α-d-ribo-hexose, 1,2:5,6-di-O-cyclohexylidene-3-C-trichloromethyl-α-d-gulose, (3S)-3-C-amino-1,2:5,6-di-O-cyclohexylidene-3-deoxy-3-C-methoxycarbonyl-α-d-xylo-hexose, methyl 2-O-benzyl-4,6-O-benzylidene-3-C-trichloromethyl-α-d-alloside, methyl (2S)-2-C-azido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-2-C-methoxycarbonyl-α-d-arabino-hexoside, methyl 2,3-di-O-benzyl-6-deoxy-4-C-trichloromethyl-β-d-galactoside, 3,4,5,7-tetra-O-benzyl-1,1,1-trichloro-1-deoxy-α-d-gluco-hept-2-ulose, and 5-O-benzyl-1,2-O-isopropylidene-3-C-trichloromethyl-α-d-ribose.

An Alternative Synthesis of Some Carbohydrate α-Amino Acids

2004 ◽  
Vol 57 (1) ◽  
pp. 25 ◽  
Author(s):  
Grant S. Forman ◽  
Adrian Scaffidi ◽  
Robert V. Stick
Keyword(s):  
Amino Acids ◽  
Sodium Azide ◽  
Subsequent Treatment ◽  
Amino Ester ◽  
Alternative Synthesis ◽  
Tertiary Alcohols ◽  
Amino Esters

Several carbohydrate ketones have been converted into their trichloromethyl-branched tertiary alcohols. A subsequent treatment of these alcohols under Corey–Link conditions (base, sodium azide, methanol) has given rise to α-azido esters, transformable into azido acids, amino esters, and amino acids. An amino ester and an azido acid have been coupled to form a dipeptide.

Sorption of α-amino-acids by copper montmorillonite

Clay Minerals ◽  
1967 ◽  
Vol 7 (2) ◽  
pp. 167-176 ◽  
Author(s):  
W. Bodenheimer ◽  
L. Heller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Complex Formation ◽  
Glutamic Acid ◽  
Acid Complex ◽  
X Ray ◽  
Ray Methods

AbstractSorption of an acidic, amphoteric, sulphur containing and basic α-amino-acid (glutamic acid, glycine, methionine and lysine) by copper montmorillonite was studied by chemical and X-ray methods. With glutamic acid complex formation occurs only in solution but increasing basicity of the aminoacid favours complex formation in the clay interlayers.

X-ray studies on crystalline complexes involving amino acids and peptides. XL. Conformational variability, recurring and new features of aggregation, and effect of chirality in the malonic acid complexes of DL- and L-arginine

2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Crystal Structures ◽  
Malonic Acid ◽  
Conformational Flexibility ◽  
X Ray ◽  
Conformational Variability ◽  
Aggregation Pattern ◽  
Positively Charged

The crystal structures of the complexes of malonic acid with DL- and L-arginine, which contain positively charged argininium ions and negatively charged semimalonate ions, further demonstrate the conformational flexibility of amino acids. A larger proportion of folded conformations than would be expected on the basis of steric consideration appears to occur in arginine, presumably because of the requirements of hydrogen bonding. The aggregation pattern in the DL-arginine complex bears varying degrees of resemblance to patterns observed in other similar structures. An antiparallel hydrogen-bonded dimeric arrangement of arginine, and to a lesser extent lysine, is a recurring motif. Similarities also exist among the structures in the interactions with this motif and its assembly into larger features of aggregation. However, the aggregation pattern observed in the L-arginine complex differs from any observed so far, which demonstrates that all the general patterns of amino-acid aggregation have not yet been elucidated. The two complexes represent cases where the reversal of the chirality of half the amino-acid molecules leads to a fundamentally different aggregation pattern.

scholarly journals Hydrogels formed from Fmoc amino acids

CrystEngComm ◽  
2015 ◽  
Vol 17 (42) ◽  
pp. 8047-8057 ◽  
Author(s):  
Emily R. Draper ◽  
Kyle L. Morris ◽  
Marc A. Little ◽  
Jaclyn Raeburn ◽  
Catherine Colquhoun ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Single Crystal ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Single Crystal Structures

A number of Fmoc amino acids can be effective low molecular weight hydrogelators; we compare single crystal structures to fibre X-ray diffraction data.

scholarly journals Constrained Dipeptide Surrogates: 5- and 7-Hydroxy Indolizidin-2-one Amino Acid Synthesis from Iodolactonization of Dehydro-2,8-diamino Azelates

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 67
Author(s):  
Ramakotaiah Mulamreddy ◽  
William D. Lubell
Keyword(s):  
Amino Acids ◽  
Acid Synthesis ◽  
Ring System ◽  
Dihedral Angles ◽  
Type Ii ◽  
Amino Ester ◽  
Amino Acid Synthesis ◽  
X Ray ◽  
Amino Esters ◽  
Peptide Mimicry

The constrained dipeptide surrogates 5- and 7-hydroxy indolizidin-2-one N-(Boc)amino acids have been synthesized from L-serine as a chiral educt. A linear precursor ∆4-unsaturated (2S,8S)-2,8-bis[N-(Boc)amino]azelic acid was prepared in five steps from L-serine. Although epoxidation and dihydroxylation pathways gave mixtures of hydroxy indolizidin-2-one diastereomers, iodolactonization of the ∆4-azelate stereoselectively delivered a lactone iodide from which separable (5S)- and (7S)-hydroxy indolizidin-2-one N-(Boc)amino esters were synthesized by sequences featuring intramolecular iodide displacement and lactam formation. X-ray analysis of the (7S)-hydroxy indolizidin-2-one N-(Boc)amino ester indicated that the backbone dihedral angles embedded in the bicyclic ring system resembled those of the central residues of an ideal type II’ β-turn indicating the potential for peptide mimicry.

Synthesis of functionalized pyrazole derivatives by regioselective [3+2] cycloadditions of N-Boc-α-amino acid-derived ynones

2018 ◽  
Vol 73 (7) ◽  
pp. 467-480 ◽  
Author(s):  
Eva Pušavec Kirar ◽  
Uroš Grošelj ◽  
Amalija Golobič ◽  
Franc Požgan ◽  
Sebastijan Ričko ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Amino Acid ◽  
Ring Opening ◽  
Pyrazole Derivatives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Catalyzed ◽  
Azomethine Imines

Abstract [3+2] cycloadditions of ynones derived from glycine and (S)-alanine and some other dipolarophiles with azomethine imines, nitrile oxides, diazoacetate, and azidoacetate were studied. The dipolarophiles were obtained from α-amino acids, either by the reduction of the carboxy function with ethynylmagnesium bromide or by propiolation of the amino function. Cu-catalyzed cycloadditions of ynones to azomethine imines were regioselective and gave the expected cycloadducts as inseparable mixtures of diastereomers. In some instances, further oxidative hydrolytic ring-opening took place to afford 3,3-dimethyl-3-(1H-pyrazol-1-yl)propanoic acids. Acid-catalyzed cycloadditions of 3-butenone were also regioselective and provided mixtures of diastereomeric cycloadducts, which were separated by chromatography. In the reactions of title ynones with alkyl diazoacetates, in situ-formed benzonitrile oxides, and tert-butyl azidoacetate, all cycloadducts were obtained as single regioisomers. The structures of all novel compounds were established by nuclear magnetic resonance and X-ray diffraction.

scholarly journals Synthesis and Characterization of Various Amino Acid Derived Thiohydantoins

Proceedings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 37
Author(s):  
Petar Stanić ◽  
Marija Živković ◽  
Biljana Šmit
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Allyl Isothiocyanate ◽  
Structural Diversity ◽  
Biologically Active ◽  
Reaction Conditions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sulfur Containing

Hydantoins and their sulfur containing analogues, thiohydantoins, are cyclic ureides that have attracted huge attention ever since their discovery. Most of them are biologically active compounds and several points of structural diversity have made them very synthetically attractive. Although substituents can be introduced to the hydantoin nucleus, most substituted hydantoins are synthesized from substrates already containing these groups, while forming the hydantoin nucleus. This is a common route to the synthesis of hydantoins and one of them is employed in this study. A series of 3-allyl-2-thiohydantoins is synthesized from various α-amino acids in a reaction with allyl isothiocyanate. The substitution of the acquired thiohydantoin depends on the structure of the starting α-amino acid. The residual group of the α-amino acid becomes the substituent at the C5-position, while N-monosubstituted amino acids give rise to a substituent in the N1-position. The reaction is carried out in a two-step process and the reaction conditions generally depend on the nature of the amino acid itself. All thiohydantoins are obtained in a good yield and fully characterized by NMR and IR spectroscopy, as well as X-ray crystallography.

Transformation of the Carboxyl Group of an Amino Acid to Variously Substituted Imidazoles through a Davidson-Type Heterocyclization

Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 1961-1968 ◽  
Author(s):  
Jim Küppers ◽  
Michaela Hympánová ◽  
Tim Keuler ◽  
Andreas Schneider ◽  
Gregor Schnakenburg ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Amino Acid ◽  
Carboxylic Acid ◽  
Building Blocks ◽  
Carboxyl Group ◽  
Amino Group ◽  
Combinatorial Approach ◽  
X Ray ◽  
Imidazole Derivatives

The modification of amino acids leads to valuable building blocks for the synthesis of bioactive compounds. By keeping the amino group protected, the carboxylic acid functionality can be converted in two steps into an imidazole moiety via a Davidson-like heterocyclization. This reaction allows for a combinatorial approach, in which two positions at the heterocycle can be modified. Herein, we report the synthesis of such imidazole derivatives by employing N-protected cyclohexylalanine as the starting material. Different α-halo ketones were used and two points of diversity, positions 4 and 5, were examined. The structure of the final imidazole derivatives was confirmed by three X-ray crystal structure analyses and their protease inhibiting activities were evaluated.

An Expansion of the Role of the Corey - Link Reaction for the Synthesis of α-Substituted Carboxylic Acid Esters

2006 ◽  
Vol 59 (7) ◽  
pp. 426 ◽  
Author(s):  
Adrian Scaffidi ◽  
Brian W. Skelton ◽  
Robert V. Stick ◽  
Allan H. White
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Methyl Ester ◽  
Single Crystal ◽  
X Ray ◽  
Structure Determinations ◽  
Acid Esters

The treatment of 1,2:5,6-di-O-isopropylidene-α-d-ribo-hexos-3-ulose with chloroform under basic conditions has yielded the normal 3-C-trichloromethyl-α-d-allofuranose derivative. Under the conditions of the modified Corey–Link reaction but with a nucleophile different from the usual azide, a range of α-substituted carboxylic acid esters (and one amide) has been obtained. A similar addition of bromoform to the ulose has formed the α-bromo methyl ester. Two attempts at forming an ‘inositol α-amino acid’ from a polyhydroxylated cyclohexanone failed. Single-crystal X-ray structure determinations are reported for (3S)-1,2:5,6-di-O-isopropylidene-3-C-methoxycarbonyl-3-S-phenyl-3-thio-α-d-ribo-hexose, (3S)-1,2:5,6-di-O-isopropylidene-3-S-phenyl-3-C-(phenylthio)carbonyl-3-thio-α-d-ribo-hexose, 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methoxycarbonyl-α-d-erythro-hex-3-enofuranose, 4,6-di-O-benzyl-2-C-trichloromethyl-scyllo-inositol 1,3,5-orthoformate, 2,2'-anhydro-4,6-di-O-benzyl-2-C-dichlorohydroxymethyl-scyllo-inositol 1,3,5-orthoformate, 1,3,4,5,6-penta-O-benzyl-2-C-trichloromethyl-myo-inositol, and 2-amino-1,3,4,5,6-penta-O-benzyl-2-C-cyano-2-deoxy-myo-inositol.

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