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.

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.

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

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.

Constituents of Endiandra species. I. Endiandric acid, a novel carboxylic acid from Endiandra introrsa (Lauraceae), and a derived lactone

1981 ◽  
Vol 34 (8) ◽  
pp. 1655 ◽  
Author(s):  
WM Bandaranayake ◽  
JE Banfield ◽  
DSC Black ◽  
GD Fallon ◽  
BM Gatehouse
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Crystallographic Analysis ◽  
X Ray

X-ray crystallographic analysis shows that endiandric acid and a derived lactone have the respective structures 2-(6'- phenyltetracyclo[5,4,2,03,13,010,12]trideca-4',8'-dien-11'-yl)acetic acid and 12-phenyl-3-oxapentacyclo[7,5,2,02,6,07,15,013,16]hexadecan-4-one.

(4R)-Thiazolidine-4-carboxylic acid: ligand specificity and the synthesis and X-ray structure of a cobalt(III) complex

1980 ◽  
Vol 33 (6) ◽  
pp. 1213 ◽  
Author(s):  
GJ Gainsford ◽  
WG Jackson ◽  
AM Sargeson ◽  
AD Watson
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Carboxylate Ligand ◽  
Ligand Specificity ◽  
X Ray ◽  
Acid Ligand ◽  
Carboxylic Acid Ligand

The N,O mode of bonding of the thiazolidine-4-carboxylate ligand and the structure of the Δ-bis-(ethane-1,2-diamine)[(3R,4R)-thiazolidine-4- carboxylato-N,O]cobalt(2+) ion have been determined. The stereospecificity induced by the chiral amino acid between the A and A forms is discussed in relation to analogous proline chemistry.

scholarly journals Synthetic Studies on Potent Marine Drugs: Synthesis and the Crystal Structure of 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hui-Jing Li ◽  
Jun-Li Wang ◽  
Rui Wang ◽  
Dong-Hui Luo ◽  
Yan-Chao Wu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Methyl Ester ◽  
Crystallographic Analysis ◽  
Antitumor Antibiotic ◽  
Stacking Interactions ◽  
X Ray ◽  
Structural Activity Relationship ◽  
Derivatives Of

4H-Chromene-2-carboxylic acid ester derivatives of renieramycin M might be of use for the structural-activity relationship studies of antitumor antibiotic tetrahydroisoquinoline natural products. Accordingly, 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic acid, one key intermediate, was synthesized via the condensation of (3E)-2-oxo-4-phenylbut-3-enoate methyl ester with 4-tert-butylphenol in the presence of AuCl3/3AgOTf (5 mol%), followed by cyclodehydration and aqueous hydrolysis. The product was unambiguously shown to the 4H-chromene-2-carboxylic acid by spectroscopy and X-ray crystallographic analysis. A packing diagram of the crystal structure shows that aromaticπ-stacking interactions and O–H⋯O hydrogen bond stabilize the structure in the solid.

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.

Revised Absolute Configurations of Latifolic Acid and the Pyrrolizidine Alkaloid Latifoline

1988 ◽  
Vol 41 (11) ◽  
pp. 1781 ◽  
Author(s):  
JN Roitman ◽  
RY Wong
Keyword(s):  
Carboxylic Acid ◽  
Single Crystal ◽  
Pyrrolizidine Alkaloid ◽  
Crystallographic Analysis ◽  
Side Chain ◽  
X Ray ◽  
The Absolute ◽  
Absolute Stereochemistry

The absolute stereochemistry of (+)- latifolk acid has been determined by single-crystal X-ray crystallographic analysis to be (2S,3R,4R)-3- hydroxy-2,4-dimethyl-5-oxotetrahydrofuran-3-carboxylic acid. The configuration of the three chiral centres is opposite to that presently recorded in the literature. Accordingly, the configuration of the pyrrolizidine alkaloid, latifoline, which includes a latifolic acid side chain, must be revised.

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