Asymmetric\ Synthesis of Chiral Cyclic Amino Acids by Diels-Alder Reactions of (2S)- and (2R)-4-Methyleneoxazolidin-5-ones

1993 ◽  
Vol 46 (1) ◽  
pp. 73 ◽  
Author(s):  
SG Pyne ◽  
B Dikic ◽  
PA Gordon ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Single Crystal ◽  
Asymmetric Synthesis ◽  
Enantiomeric Purity ◽  
Diels Alder ◽  
X Ray ◽  
Cyclic Dienes ◽  
Ray Methods ◽  
Cyclic Amino Acids

The synthesis of chiral (2S)- and (2R)-4-methyleneoxazolidin-5-ones, in high enantiomeric purity from (S)-S- methylcysteine, and their highly exo-selective Diels -Alder reactions with cyclic dienes are described. (1R,2S,4S)-2-Aminobicyclo[2.2.1]heptane-2-carboxylic acid has been prepared in 92% e.e. by these methods. A number of the products have been characterized by single-crystal X-ray methods, and their structure systematics examined.

ChemInform Abstract: Asymmetric Synthesis of Chiral Cyclic Amino Acids by Diels-Alder Reactions of (2S)- and (2R)-4-Methyleneoxazolidin-5-ones.

ChemInform ◽  
2010 ◽  
Vol 24 (20) ◽  
pp. no-no
Author(s):  
S. G. PYNE ◽  
B. DIKIC ◽  
P. A. GORDON ◽  
B. W. SKELTON ◽  
A. H. WHITE
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Diels Alder ◽  
Cyclic Amino Acids

Asymmetric Synthesis of Protected 2-Substituted Cyclopropane Amino Acids

1998 ◽  
Vol 51 (2) ◽  
pp. 127 ◽  
Author(s):  
Stephen G. Pyne ◽  
Karl Schafer ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Amino Acids ◽  
Structural Analysis ◽  
Single Crystal ◽  
Asymmetric Synthesis ◽  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Ring Opening ◽  
Cyclopropane Ring ◽  
X Ray ◽  
Sulfur Ylide

The cyclopropanation reactions of (1a) with ethyl and t-butyl (dimethylsulfuranylidene)acetate proceeded with good diastereoselectivity and resulted in the formation of three diastereoisomeric products. The major diastereoisomeric product ((2a) and (2b), respectively) could be isolated in pure form by simple recrystallization. The stereochemistry of the major cyclopropane product (2b) has been determined by single-crystal X-ray structural analysis. These cyclopropanation products were susceptible to ring opening of the cyclopropane ring upon reduction with sodium borohydride or acid hydrolysis. The reaction of (1b) with ethyl (dimethylsulfuranylidene)acetate gave a mixture of four diastereoisomeric cyclopropanation products. The reactions of (1a) and (1b) with the sulfur ylide derived from 3-methoxycarbonylallyldimethylsulfonium bromide were less successful in terms of product diastereoselectivities.

Pigments of Fungi. XLVII. Cardinalic Acid, a New Anthraquinone Carboxylic Acid from the New Zealand Toadstool Dermocybe cardinalis and the Synthesis and X-Ray Crystal Structure of Methyl 1,7,8-Tri-O-methylcardinalate

1998 ◽  
Vol 51 (3) ◽  
pp. 213 ◽  
Author(s):  
Melvyn Gill ◽  
Peter M. Morgan ◽  
Jin Yu ◽  
Jonathan M. White
Keyword(s):  
Crystal Structure ◽  
New Zealand ◽  
Carboxylic Acid ◽  
Single Crystal ◽  
Natural Product ◽  
Carboxylic Acids ◽  
Structure Analysis ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
X Ray

Cardinalic acid (1,7,8-trihydroxy-6-methoxy-3-methyl-9,10-dioxoanthracene-2-carboxylic acid) (4) and the known anthraquinone carboxylic acids endocrocin (1), dermolutein (2) and cinnalutein (3) have been isolated from the New Zealand toadstool Dermocybe cardinalis. Methyl 1,7,8-tri-O-methylcardinalate (5) has been prepared both by permethylation of the natural product (4) and from 2,6-dichloro-1,4-benzoquinone by two consecutive regioselective Diels–Alder cycloaddition reactions. A single-crystal X-ray structure analysis of the ester (5) corroborates the structure of the natural product (4) and confirms the outcome of both cycloaddition reactions.

Structural Study of an Unusual Diels-Alder Adduct

1992 ◽  
Vol 45 (12) ◽  
pp. 2089 ◽  
Author(s):  
EL Ghisalberti ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
Structural Study ◽  
Spectroscopic Studies ◽  
Diels Alder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Chemical Evidence ◽  
Alder Adduct

The structure of the compound obtained on heating the naturally occurring clerodane furanoditerpene (1) had been formulated as (2) on the basis of spectroscopic studies. A single-crystal X-ray diffraction study on the dihydro derivative of (2) has confirmed this and provides support for the stereochemistry previously assigned to (1) on the basis of chemical evidence.

scholarly journals Synthesis and Optoelectronic Properties of Iptycene–Naphthazarin Dyes

Synlett ◽  
2018 ◽  
Vol 30 (01) ◽  
pp. 54-58 ◽  
Author(s):  
Timothy Swager ◽  
Cagatay Dengiz ◽  
You-Chi Wu
Keyword(s):  
Single Crystal ◽  
Electronic Properties ◽  
Diels Alder ◽  
Optoelectronic Properties ◽  
Synthesis And Characterization ◽  
Nmr Analysis ◽  
X Ray ◽  
Vis Spectroscopy

We report the synthesis and characterization of iptycene–naphthazarin dyes by using a sequential Diels–Alder approach. The tautomerization of naphthazarin was used as the key step in the synthesis, with structures confirmed by single-crystal X-ray and NMR analysis. The systematic trends in electronic properties were investigated by UV/Vis spectroscopy. BF2 complexes of the dyes were prepared by reaction with BF3·OEt2 in CH2Cl2.

New, Homochiral Synthons Obtained through Simple Manipulations of Enzymatically Derived 3-Halo-cis-1,2-dihydrocatechols

2015 ◽  
Vol 68 (10) ◽  
pp. 1467 ◽  
Author(s):  
Lorenzo V. White ◽  
Ping Lan ◽  
Brett D. Schwartz ◽  
Anthony C. Willis ◽  
Martin G. Banwell
Keyword(s):  
Single Crystal ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
X Ray

The bromoepoxide 5a, which is obtained from the homochiral and enzymatically derived cis-1,2-dihydrocatechol 1a, is readily and efficiently transformed into either isomer 8a or the corresponding methoxymethyl-ether 2a. Though both of these products can be fully characterized, they are somewhat unstable, with the former being converted into the crystalline enone 3a on standing and the latter readily participating in a Diels–Alder cycloaddition reaction with the potent dienophile N-phenyl-1,2,4-triazoline-3,5-dione to give adduct 7a. The single-crystal X-ray structures of compounds 3a and 7a are reported. Using the related chemistry the chloro-analogue, 3b, of enone 3a can be obtained.

Redetermination of Co4Nb2O9 by single-crystal X-ray methods

2006 ◽  
Vol 62 (5) ◽  
pp. i117-i119 ◽  
Author(s):  
María A. Castellanos R. ◽  
Sylvain Bernès ◽  
Marina Vega-González
Keyword(s):  
Single Crystal ◽  
High Precision ◽  
Cation Distribution ◽  
Crystal Data ◽  
Space Group ◽  
X Ray ◽  
Ray Methods

A high-precision structure of tetracobalt diniobium nonaoxide, Co4Nb2O9, is presented, based on X-ray single-crystal data. The space group and cation distribution previously obtained from powder data [Bertaut, Corliss, Forrat, Aleonard & Pauthenet (1961). J. Phys. Chem. Solids, 21, 234–251] are confirmed.

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.

Notizen: Die Kristallstruktur von Rb2Ca(N3)4 · 4 H2O / The Crystal Structure of RB2Ca(N3)4 · 4 H2O

1988 ◽  
Vol 43 (4) ◽  
pp. 497-498
Author(s):  
Franz A. Mautner ◽  
Harald Krischner ◽  
Christoph Kratky
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Ray Methods

Abstract The crystal structure of Rb2Ca(N3)4 · 4H2O has been determined by single crystal X-ray methods. The compound is isotypic with K2Ca(N3)4 · 4 H2O and crystallizes in the orthorhombic space group Ccca, Z = 4, a = 1949.1(12) pm, b = 1099.5(3) pm, c - 622.2(1) pm.

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