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Chiral compound

An example of a chiral compound is lactic acid. Two different forms of lactic acid that are mirror images of each other can be defined (Figure 2-69). These two different molecules are called enantiomers. They can be separated, isolated, and characterized experimentally. They are different chemical entities, and some of their properties arc different (c.g., their optical rotation),... [Pg.77]

The Cahn-Ingold-Prelog (CIP) rules stand as the official way to specify chirahty of molecular structures [35, 36] (see also Section 2.8), but can we measure the chirality of a chiral molecule. Can one say that one structure is more chiral than another. These questions are associated in a chemist s mind with some of the experimentally observed properties of chiral compounds. For example, the racemic mixture of one pail of specific enantiomers may be more clearly separated in a given chiral chromatographic system than the racemic mixture of another compound. Or, the difference in pharmacological properties for a particular pair of enantiomers may be greater than for another pair. Or, one chiral compound may rotate the plane of polarized light more than another. Several theoretical quantitative measures of chirality have been developed and have been reviewed elsewhere [37-40]. [Pg.418]

Twenty-eight chiral compounds were separated from their enantiomers by HPLC on a teicoplanin chiral stationary phase. Figure 8-12 shows some of the structures contained in the data set. This is a very complex stationary phase and modeling of the possible interactions with the analytes is impracticable. In such a situation, learning from known examples seemed more appropriate, and the chirality code looked quite appealing for representing such data. [Pg.424]

The usual physical properties such as density melting point and boiling point are iden tical for both enantiomers of a chiral compound... [Pg.295]

Chirality and Optical Activity. A compound is chiral (the term dissymmetric was formerly used) if it is not superimposable on its mirror image. A chiral compound does not have a plane of symmetry. Each chiral compound possesses one (or more) of three types of chiral element, namely, a chiral center, a chiral axis, or a chiral plane. [Pg.45]

Optically Inactive Chiral Compounds. Although chirality is a necessary prerequisite for optical activity, chiral compounds are not necessarily optically active. With an equal mixture of two enantiomers, no net optical rotation is observed. Such a mixture of enantiomers is said to be racemic and is designated as ( ) and not as dl. Racemic mixtures usually have melting points higher than the melting point of either pure enantiomer. [Pg.47]

A second type of optically inactive chiral compounds, meso compounds, will be discussed in the next section. [Pg.47]

When the asymmetric carbon atoms in a chiral compound are part of a ring, the isomerism is more complex than in acyclic compounds. A cyclic compound which has two different asymmetric carbons with different sets of substituent groups attached has a total of 2 = 4 optical isomers an enantiometric pair of cis isomers and an enantiometric pair of trans isomers. However, when the two asymmetric centers have the same set of substituent groups attached, the cis isomer is a meso compound and only the trans isomer is chiral. (See Fig. 1.15.)... [Pg.47]

Chiral separations are concerned with separating molecules that can exist as nonsupetimposable mirror images. Examples of these types of molecules, called enantiomers or optical isomers are illustrated in Figure 1. Although chirahty is often associated with compounds containing a tetrahedral carbon with four different substituents, other atoms, such as phosphoms or sulfur, may also be chiral. In addition, molecules containing a center of asymmetry, such as hexahehcene, tetrasubstituted adamantanes, and substituted aHenes or molecules with hindered rotation, such as some 2,2 disubstituted binaphthyls, may also be chiral. Compounds exhibiting a center of asymmetry are called atropisomers. An extensive review of stereochemistry may be found under Pharmaceuticals, Chiral. [Pg.59]

Analytically, the inclusion phenomenon has been used in chromatography both for the separation of ions and molecules, in Hquid and gas phase (1,79,170,171). Peralkylated cyclodextrins enjoy high popularity as the active component of hplc and gc stationary phases efficient in the optical separation of chiral compounds (57,172). Chromatographic isotope separations have also been shown to occur with the help of Werner clathrates and crown complexes (79,173). [Pg.75]

Chiral Smectic. In much the same way as a chiral compound forms the chiral nematic phase instead of the nematic phase, a compound with a chiral center forms a chiral smectic C phase rather than a smectic C phase. In a chiral smectic CHquid crystal, the angle the director is tilted away from the normal to the layers is constant, but the direction of the tilt rotates around the layer normal in going from one layer to the next. This is shown in Figure 10. The distance over which the director rotates completely around the layer normal is called the pitch, and can be as small as 250 nm and as large as desired. If the molecule contains a permanent dipole moment transverse to the long molecular axis, then the chiral smectic phase is ferroelectric. Therefore a device utilizing this phase can be intrinsically bistable, paving the way for important appHcations. [Pg.194]

Tbe purpose of tbe bydroxyl group is to acbieve some hydrogen bonding with the nearby carbonyl group and therefore hinder the motion of the chiral center. Another way to achieve the chiral smectic Cphase is to add a chiral dopant to a smectic Chquid crystal. In order to achieve a material with fast switching times, a chiral compound with high spontaneous polarization is sometimes added to a mixture of low viscosity achiral smectic C compounds. These dopants sometimes possess Hquid crystal phases in pure form and sometimes do not. [Pg.200]

Use ofMethanesulfonyl Chloride (MSC) in the Synthesis of Chiral Compounds, Technical Bulletin A-70-11, Elf Atochem North America, Philadelphia, Pa., 1992. [Pg.160]

The remarkable stereospecificity of TBHP-transition metal epoxidations of allylic alcohols has been exploited by Sharpless group for the synthesis of chiral oxiranes from prochiral allylic alcohols (Scheme 76) (81JA464) and for diastereoselective oxirane synthesis from chiral allylic alcohols (Scheme 77) (81JA6237). It has been suggested that this latter reaction may enable the preparation of chiral compounds of complete enantiomeric purity cf. Scheme 78) ... [Pg.116]

The presence of asymmetric C atoms in a molecule may, of course, be indicated by diastereotopic shifts and absolute configurations may, as already shown, be determined empirically by comparison of diastereotopic shifts However, enantiomers are not differentiated in the NMR spectrum. The spectrum gives no indication as to whether a chiral compound exists in a racemic form or as a pure enantiomer. [Pg.56]

It is possible to obtain pure enantiomers of chiral compounds. One property of separated enantiomers is to cause the rotation of the plane of polarized light by opposite... [Pg.75]

Scheme 2.1. Chiral Compounds with Stereogenlc Centers at Sulfur and Phosphorus... Scheme 2.1. Chiral Compounds with Stereogenlc Centers at Sulfur and Phosphorus...
Wood, W.M.L., 1997. Crystal science techniques in the manufacture of chiral compounds. Cli. 7 in Chirality in Industry II. Eds. N.A. Collins, G.N. Sheldrake and Crosby. New York J. Wiley Sons. [Pg.327]

For developing osmium-catalyzed oxidation methods for preparing chiral compounds of high optical purity, Professor K. Barry Sharpless (Scripps Research Institute) shared the 2001 Nobel Prize in chemistry. [Pg.635]

The main strategy for catalytic enantioselective cycloaddition reactions of carbonyl compounds is the use of a chiral Lewis acid catalyst. This approach is probably the most efficient and economic way to effect an enantioselective reaction, because it allows the direct formation of chiral compounds from achiral substrates under mild conditions and requires a sub-stoichiometric amount of chiral material. [Pg.151]

A large amount of fuel and environmentally based analysis is focused on the determination of aliphatic and aromatic content. These types of species are often notoriously difficult to deconvolute by mass spectrometric means, and resolution at the isomeric level is almost only possible by using chromatographic methods. Similarly, the areas of organohalogen and flavours/fragrance analysis are dominated by a need to often quantify chiral compounds, which in the same way as aliphatic... [Pg.57]

D. Jukelka, A. Steil, K. Witt and A. Mosandl, Chiral compounds of essential oils. XX. Cliirality evaluation and authenticity profiles of neroli and petitgrain oils , ]. Essential Oil Res. 8 487-497 (1996). [Pg.246]

HPLC separations are one of the most important fields in the preparative resolution of enantiomers. The instrumentation improvements and the increasing choice of commercially available chiral stationary phases (CSPs) are some of the main reasons for the present significance of chromatographic resolutions at large-scale by HPLC. Proof of this interest can be seen in several reviews, and many chapters have in the past few years dealt with preparative applications of HPLC in the resolution of chiral compounds [19-23]. However, liquid chromatography has the attribute of being a batch technique and therefore is not totally convenient for production-scale, where continuous techniques are preferred by far. [Pg.4]

V. M. L. Wood, Crystal science techniques in the manufacture of chiral compounds in Chirality and Industry II. Developments in the Manufacture and applications of optically active compounds, A. N. Collins, G. N. Sheldrake, J. Crosby (Eds.), John Wiley Sons, New York (1997) Chapter 7. [Pg.19]

The majority of the original chiral selectors for brush-type CSPs were derived from natural chiral compounds. Selectors prepared from amino acids, such as phenyl... [Pg.59]


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1,3-Dicarbonyl compounds chiral metal complexes

2-Cyclopentenone, 2-methylconjugate additions chiral organocopper compounds

Addition of Chiral Enolates to Achiral Carbonyl Compounds

Alcohol dehydrogenases chiral compound production

Allyl organometallic compounds chiral

Allyl organometallic compounds reactions with chiral C=N electrophiles

Arsenic compounds chiral

Asymmetric Autocatalysis Triggered by Chiral Organic Compounds

Asymmetric chiral sulfur-containing compounds

Asymmetric synthesis from chiral pool compounds

Autocatalysis chiral organic compounds

Auxiliary compounds, chiral

Available Chiral Compounds

Axial chiral compounds

Axial chiral compounds hydrogenation

Axial chiral compounds ligands

Axially chiral compounds

Benzylic chiral compounds

Benzyllithium compounds chiral

Biaryl compounds chirality

Boron compounds, allylconfigurational stability reactions with chiral a-methyl aldehydes

Boron compounds, crotylreactions with chiral a-methyl aldehydes

Carbonyl compounds chiral acyclic

Carbonyl compounds chiral auxiliaries

Carbonyl compounds, a-alkoxy chiral

Carbonyl reduction chiral compound stereoselective synthesis

Centrally chiral compounds of carbon and silicon

Centrally chiral compounds of nitrogen and phosphorus

Centrally chiral compounds of sulphur

Chiral Compounds Are Optically Active

Chiral Compounds without Asymmetric Atoms

Chiral Isocyanides, Carboxylic Acids and Carbonyl Compounds

Chiral Recognition in Organometallic and Coordination Compounds

Chiral aroma compounds in cherries

Chiral binaphthyl compounds

Chiral bioactive compounds

Chiral bioactive fluoroorganic compounds

Chiral carbonyl compounds

Chiral carbonyl compounds, electrophilic

Chiral chalcogen compounds

Chiral compound stereoselective synthesis

Chiral compound stereoselective synthesis reduction products

Chiral compound stereoselective synthesis whole-cell biocatalysts

Chiral compound synthesis dehydrogenases

Chiral compound, circular dichroism

Chiral compounds 1728 INDEX

Chiral compounds 2,2 -Dihydroxy-1,1 -binaphthyl

Chiral compounds 2,3]-Wittig rearrangement

Chiral compounds 3,3]-sigmatropic rearrangement

Chiral compounds 8-Phenylmenthol

Chiral compounds Alcohols

Chiral compounds Aldehydes

Chiral compounds Alicyclics

Chiral compounds Amides

Chiral compounds Amino acids

Chiral compounds Camphor- 10-sulfonic acid

Chiral compounds Evans aldol reaction

Chiral compounds Lewis acids

Chiral compounds Mannich reactions

Chiral compounds Mitsunobu reaction

Chiral compounds Organotitanium reagents

Chiral compounds absolute configuration, enantiopurity

Chiral compounds activation

Chiral compounds activation, enantioselective

Chiral compounds active moiety

Chiral compounds adamantanes

Chiral compounds alcohol-amine conversion

Chiral compounds aldols

Chiral compounds allenes

Chiral compounds allylborations

Chiral compounds allylic amination

Chiral compounds amination

Chiral compounds amines

Chiral compounds amino alcohol-derived bases

Chiral compounds analysis

Chiral compounds analysis pollutants

Chiral compounds asymmetric hydroformylation

Chiral compounds asymmetric reaction products

Chiral compounds asymmetric variants

Chiral compounds asymmetry

Chiral compounds atoms

Chiral compounds atropisomers

Chiral compounds auxiliary removal

Chiral compounds background

Chiral compounds base catalysts

Chiral compounds biaryls

Chiral compounds biocatalytic synthesis methods

Chiral compounds capillary electrophoresis

Chiral compounds carbons

Chiral compounds carboxylic acids, absolute

Chiral compounds catalyst controlled stereoselectivity

Chiral compounds catalytic reactions

Chiral compounds chemistry

Chiral compounds chirality

Chiral compounds chromatography

Chiral compounds compared

Chiral compounds complexes

Chiral compounds compound names

Chiral compounds configuration

Chiral compounds crotylation

Chiral compounds crown ether

Chiral compounds cyclooctene

Chiral compounds cyclophanes

Chiral compounds determination

Chiral compounds diastereomers

Chiral compounds diastereoselective reductive

Chiral compounds dimeric

Chiral compounds diphosphines

Chiral compounds drugs

Chiral compounds electrophoresis

Chiral compounds enamines

Chiral compounds enantiomer differentiation

Chiral compounds enantiomers

Chiral compounds enantioselective Michael addition

Chiral compounds enantioselective synthesis

Chiral compounds enzymatic

Chiral compounds enzymatic resolution

Chiral compounds epoxides

Chiral compounds epoxy alcohols

Chiral compounds formed during

Chiral compounds glyceraldehyde

Chiral compounds guanidines

Chiral compounds hydrogenation

Chiral compounds imines, reductive amination

Chiral compounds iridium catalysts

Chiral compounds liquid crystals

Chiral compounds meso form

Chiral compounds metallocenes

Chiral compounds monodentate ligands

Chiral compounds morpholines

Chiral compounds natural

Chiral compounds nomenclature

Chiral compounds nomenclature systems

Chiral compounds nonaromatic

Chiral compounds olefins

Chiral compounds optical resolution

Chiral compounds optically active nature

Chiral compounds oxetanones

Chiral compounds paracyclophanes

Chiral compounds phase-transfer catalysts

Chiral compounds phenols

Chiral compounds quaternary ammonium catalysts

Chiral compounds reactions

Chiral compounds recent innovations

Chiral compounds resolution, optically active products

Chiral compounds screening

Chiral compounds secondary amine catalysts

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Chiral compounds sourcing

Chiral compounds stereoselectivity

Chiral compounds sulfoxides

Chiral compounds sulfur ylides

Chiral compounds surfactants, capillary electrophoresis

Chiral compounds synthetic utility

Chiral compounds system

Chiral compounds tertiary alcohols

Chiral compounds that do not have a tetrahedral atom with four different groups

Chiral compounds transformation

Chiral compounds transition metal carbon-hydrogen

Chiral compounds with cyclodextrin

Chiral compounds with cyclodextrin mobile phase

Chiral compounds with multiple stereogenic

Chiral compounds, Amino acids B-3-Pinanyl-9-borabicyclo nonane

Chiral compounds, Amino acids Camphor

Chiral compounds, Amino acids Camphor-10-sulfonic acid

Chiral compounds, Amino acids Cyanohydrins

Chiral compounds, Amino acids Dienes

Chiral compounds, Amino acids Diols

Chiral compounds, Amino acids Epoxides

Chiral compounds, Amino acids Esters

Chiral compounds, Amino acids Ethers

Chiral compounds, Amino acids Heterocycles

Chiral compounds, Amino acids pyrrolidine

Chiral compounds, Amino acids tartrate

Chiral compounds, docking

Chiral compounds, spiranes

Chiral compounds, synthesis

Chiral crown compounds

Chiral dialkylzincs compounds

Chiral dirhodium compounds

Chiral glycine compounds

Chiral host compound

Chiral molecules cyclic compounds

Chiral nitrogen compounds

Chiral organic compounds

Chiral organic host compound

Chiral organoboron compound

Chiral organofluorine compounds

Chiral organolithium compounds

Chiral organosilicon compounds

Chiral organotin compounds

Chiral phosphorus compounds

Chiral pool compounds from

Chiral recognition compounds

Chiral silicon compounds

Chiral sulphur compounds

Chiral sulphur compounds chirality

Chiral sulphur compounds types

Chiral vinyllithium compound

Chiral, auxiliary compounds catalysts

Chirality at Metal Half-sandwich Compounds

Chirality centers compounds other than carbon with

Chirality centers meso compounds

Chirality centers naming compounds with

Chirality compounds without asymmetric

Chirality in Supramolecular Coordination Compounds

Chirality phosphino compounds

Chirality quaternary nitrogen compounds

Chirality spiro compounds

Chirality, also compounds

Classification of Chiral Nematic Liquid Crystalline Compounds

Cluster compounds, chiral

Cluster compounds, chiral iridium, osmium, rhodium, and ruthenium

Cluster compounds, chiral molybdenum-sulfur

Cluster compounds, chiral transition metal

Compounds chiral nematics

Compounds with Two Chiral Centres

Coordination compounds, chirality

Copper compounds, as chiral catalysts for

Copper compounds, as chiral catalysts for Diels-Alder reaction

Divergent chiral compounds

Drugs, chiral selected single compounds

Dynamic kinetic resolution chiral compounds

Enantioselective Synthesis Mediated by Chiral Crystals of an Achiral Organic Compound in Conjunction with Asymmetric Autocatalysis

Essential oils chiral compounds analysis

Ether compounds asymmetric reactions, chiral auxiliaries

Europium compounds, chiral

Europium compounds, chiral shift reagents

Fluoroorganic compounds via chiral organoboranes

Fungicides chiral compounds

Glycosylamines as Auxiliaries in Stereoselective Syntheses of Chiral Amino Compounds

Helical-chiral compounds

Hydroxy carbonyl compounds chiral

IUPAC nomenclature chiral compounds

Inclusion compounds, chiral separation

Inclusion compounds, chiral separation through

Intermediate compounds chiral sulfoxides

Keto esters chiral compound stereoselective synthesis

Lattice inclusion compounds chiral structures

Macrocyclics chiral compounds

Metal Modified by a Soluble Chiral Compound

Monofunctional Epoxides as Chiral Building Blocks for the Synthesis of Biologically Active Compounds

Natural products enone chiral compounds

Nitroso compounds, chiral, asymmetric

Nuclear magnetic resonance chiral compounds

Of chiral compounds

Optically active compounds reduction with chiral hydrides

Organocopper compounds chiral

Organometallic compounds chiral auxiliaries

Organosulfur Compounds, Chiral (Mikolajczyk and Drabowicz)

Other Chiral Compounds

P-chiral compound

P-chiral hydroxy phosphoryl compounds

Palladium compounds, as chiral catalysts for Subject inde

Planar chiral compounds

Planar chiral compounds bidentate ligands

Planar chiral compounds hydrogenation

Preparation of chiral compounds

Racemic compounds chiral resolution

Racemic compounds chirally labile

Racemic compounds, fragments chirality

Reactions with Chiral Non-Racemic Carbonyl Compounds

Recent Michael-Type Reactions Using Chirally Modified ,-Substituted Carbonyl Compounds

Ruthenium compounds with chiral ligand

Separation of chiral compounds

Spiro compounds chiral

Stereochemistry chiral compounds without

Stereoelectronics reactions of chiral carbonyl compounds with

Stereoselectivity chiral organolithium compounds

Substrate Control with Chiral Carbonyl Compounds

Sulfur compounds, vinylic chiral

Suppliers chiral compounds

Synthesis of Chiral Compounds

Titanium reagents, chirally modified carbonyl compounds

Transition metal compounds chiral manganese complex

Use of naturally occurring chiral compounds as building blocks

Ylide compounds chiral ylides

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