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.

Effect of amino group protonation on the carboxyl group in aqueous glycine observed by O 1s X-ray emission spectroscopy

2018 ◽  
Vol 20 (36) ◽  
pp. 23214-23221 ◽  
Author(s):  
Y. Horikawa ◽  
T. Tokushima ◽  
O. Takahashi ◽  
Y. Harada ◽  
A. Hiraya ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Electronic Structures ◽  
Emission Spectroscopy ◽  
Selective Excitation ◽  
Carboxyl Group ◽  
Amino Group ◽  
X Ray ◽  
Excitation Conditions ◽  
Amino Acid Glycine

The valence electronic structures of the amino acid glycine in aqueous solution were investigated in detail through X-ray emission spectroscopy at O 1s excitation under selective excitation conditions of the CO site in the carboxyl group.

Specificity of the transport system for neutral amino acids in the hamster intestine

1962 ◽  
Vol 202 (5) ◽  
pp. 919-925 ◽  
Author(s):  
Edmund C. C. Lin ◽  
Hiroshi Hagihira ◽  
T. Hastings Wilson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Side Chain ◽  
Carboxyl Group ◽  
Amino Group ◽  
Methyl Group ◽  
Neutral Amino Acids ◽  
Active Transport System ◽  
Everted Sacs

The specificity of the active transport system for neutral amino acids has been studied with everted sacs of hamster intestine. Amino acids with modifications or replacements of the carboxyl, amino, or α-hydrogen groups were poorly transported and were poor inhibitors of the transport of other l-amino acids. The carboxyl group must remain free, the amino group must not be in the tertiary or quaternary state, and the α-hydrogen can not be replaced by a methyl group without serious effect on the transport rate. It was concluded that the l-amino acids were distinguished from the d-isomers by the interaction of the carrier with the carboxyl group, the amino group, and the α-hydrogen. The side chain of the amino acid must be nonpolar but there is relatively little restriction on its structure.

scholarly journals 6-Oxyindan-1-ones with dipeptide chains

2019 ◽  
Vol 7 (2) ◽  
pp. 111-119
Author(s):  
Serhiy Shilin ◽  
Olga Shablykina ◽  
Igor Levkov ◽  
Oleksandra Bugera ◽  
Zoia Voitenko
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Amino Acid ◽  
Direct Interaction ◽  
Carboxyl Group ◽  
Amino Group ◽  
Hydroxysuccinimide Esters

Through N-acylation of a- or b-amino acid units by 2-(3-oxo-2,3-dihydro-1H-inden-5-yloxy)acetic acid using the method of N-hydroxysuccinimide esters new dipeptide indan-1-one derivatives were obtained. In general, the direct interaction of the acetic carboxyl group of the substrate with the amino group of the a- or b-dipeptide is a more productive strategy than the sequential peptidic condensation of the two amino acids.

Die Kristallstruktur des Ectoin, einer neuen osmoregulatorisch wirksamen Aminosäure / The Crystal Structure of Ectoine, a Novel Amino Acid of Potential Osmoregulatory Function

1985 ◽  
Vol 40 (11-12) ◽  
pp. 780-784 ◽  
Author(s):  
Willi Schuh ◽  
Heinrich Puff ◽  
Erwin A. Galinski ◽  
Hans G. Trüper
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Carboxylic Acid ◽  
Halophilic Bacteria ◽  
Pyrimidine Ring ◽  
Structural Features ◽  
Compatible Solute ◽  
X Ray ◽  
Ectothiorhodospira Halochloris ◽  
Osmoregulatory Function

Abstract The crystal structure of ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) isolated from the extremely halophilic phototrophic bacterium Ectothiorhodospira halochloris was determined by X-ray analysis. This novel cyclic amino acid forms zwitterionic molecules with delocalized π-bonding in the N-C-N group of the hydrated pyrimidine ring. The molecules are connected by N-H ...O hydrogen bonds. The excellent solubility of ectoine in water can be explained by its structural features which also account for its function as a compatible solute in halophilic bacteria.

scholarly journals Some Stereochemical Aspects of the Strecker Synthesis and the Bucherer - Bergs Reaction

2004 ◽  
Vol 57 (5) ◽  
pp. 461 ◽  
Author(s):  
Urs D. Wermuth ◽  
Ian D. Jenkins ◽  
Raymond C. Bott ◽  
Karl A. Byriel ◽  
Graham Smith
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Crystallographic Analysis ◽  
Amino Group ◽  
Keto Ester ◽  
X Ray ◽  
Strecker Reaction ◽  
Strecker Synthesis

Both the Strecker and Bucherer–Bergs reactions convert the norbornane keto ester methyl bicyclo[2.2.1]hept-6-one-2-endo-carboxylate into the lactam 6-endo-aminobicyclo[2.2.1]heptane-2-endo-carboxylic acid-γ-lactam-6-exo-carboxylic acid. This lactam is unusually stable and cannot be hydrolyzed to the corresponding amino acid. The stereochemistry in the Strecker reaction, in which the amino group is endo, is contrary to that expected from literature precedent. The stereochemistry in the Bucherer–Bergs reaction, in which the amino group is also endo, has been confirmed by X-ray crystallographic analysis of the intermediate spirohydantoin (±)-bicyclo[2.2.1]heptane-2-endo-carboxylic acid-6-spiro-5′-hydantoin.

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

A MOF based on a lead(II) 2-oxido-6-methylpyridine-4-carboxylate network

2020 ◽  
Vol 75 (4) ◽  
pp. 365-369
Author(s):  
Long Tang ◽  
Yu Pei Fu ◽  
Na Cui ◽  
Ji Jiang Wang ◽  
Xiang Yang Hou ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Carboxylic Acid ◽  
Thermogravimetric Analysis ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
X Ray ◽  
Connected Node ◽  
Metal Organic ◽  
Solid State Fluorescence

AbstractA new metal-organic framework, [Pb(hmpcaH)2]n (1), has been hydrothermally synthesized from Pb(OAc)2 · 3H2O and 2-hydroxy-6-methylpyridine-4-carboxylic acid (hmpcaH2; 2), and characterized by IR spectroscopy, elemental and thermogravimetric analysis, and single-crystal X-ray diffraction. In complex 1, each hmpcaH− ligand represents a three-connected node to combine with the hexacoordinated Pb(II) ions, generating a 3D binodal (3,6)-connected ant network. The crystal structure of 2 was determined. The solid-state fluorescence properties of 1 and 2 were investigated.

Isolation from atelia herbert-smithii pittier (sophoreae, leguminosae) and x-ray structure of cis-1-amino-3-hydroxymethyl-cyclobutane-1-carboxylic acid, an achiral non-protein amino acid

Tetrahedron ◽  
1987 ◽  
Vol 43 (8) ◽  
pp. 1857-1861 ◽  
Author(s):  
Geoffrey N. Austin ◽  
Peter D. Baird ◽  
Hak-Fun Chow ◽  
L.E. Fellows ◽  
G.W.J. Fleet ◽  
...  
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Protein Amino Acid ◽  
X Ray
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