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Topic: Diastereoisomer

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	Biphenyl derivatives - United States Patent 4,191,776
		A diastereoisomer or optically active antipode of a compound of the formula ##STR5## wherein R.sub.3 is (alkoxy of 1 to 6 carbon atoms)-carbonyl.
		The diastereoisomers were separated on the basis of their different solubility in glacial acetic acid.
		The ratio of the two diastereoisomers in the product was determined after thin-layer chromatographic separation of their methyl esters by evaluation of the spot intensities under the UV-lamp.
	xrint.com /patents/us/4191776 (7571 words)

	D (Site not responding. Last check: 2007-10-11)
		Diastereoisomers (or diastereomers) are stereoisomers not related as mirror images.
		Diastereoisomers are characterized by differences in physical properties, and by some differences in chemical behavior towards achiral as well as chiral reagents.
		Diastereomeric Ratio - This is defined by analogy with enantiomeric ratio as the ratio of the percentage of one diastereoisomer in a mixture to that of the other.
	www.sdsc.edu /Education/Elemnet/misc/newerglossary/d.html (278 words)

	D and E
		Diastereoisomers are characterised by differences in physical properties, and by some differences in chemical behaviour towards achiral as well as chiral reagents.
		This is defined by analogy with enantiomeric ratio as the ratio of the percentage of one diastereoisomer in a mixture to that of the other.
		Diastereoisomers that have the opposite configuration at only one of two or more tetrahedral stereogenic centres present in the respective molecular entities.
	www.chem.qmul.ac.uk /iupac/stereo/DE.html (1002 words)

	Process for the preparation of 3-substituted derivatives of 1-amino-2-hydroxy-propane - Patent 5391735
		The present invention relates to a new process for the preparation of 3-substituted derivatives of 1-amino-2-hydroxy-propane in the form of single diastereoisomers, to certain of these diastereoisomers, and to compounds which are intermediates in the new process of the invention.
		Accordingly, a (RS,RS) diastereoisomer is intended to be a racemate of (R,R) and (S,S) enantiomers, and a (RS,SR) diastereoisomer is intended to be a racemate of (R,S) and (S,R) enantiomers.
		The epoxidation of the trans-cinnamic alcohol to give the epoxide of formula (II) may be carried out by the use of a suitable oxidizing agent, for instance with vanadic anhydride and hydrogen peroxide, or with a peroxy acid such as, e.g., perbenzoic, m-chloroperbenzoic, peracetic, mono- or di-peroxy-phthalic, or peroxy-trifluoroacetic acid.
	www.freepatentsonline.com /5391735.html (2333 words)

	Cahn-Ingold-Prelog priority rules - Wikipedia, the free encyclopedia
		They should correctly be labelled as stereocenters or prochiral centers.
		When the nucleophile is a chiral molecule diastereoisomers are formed.
		When one face of a molecule is shielded by substituents or geometric constraints compared to the other face the faces are called diastereotopic.
	en.wikipedia.org /wiki/Cahn_Ingold_Prelog_priority_rules (845 words)

	Regio-, Stereo-, and Enantioselectivity of the Paternò-Büchi Reaction on 2-Furylmethanols
		In order to study the effect of large side chain on the regiochemistry of the reaction, we tested the photochemical behavior of 1-(2-furyl)-heptanol (1c): in the presence of benzophenone we obtained only the compound 3e as a single couple of diastereoisomers (Scheme 2, Table 1).
		In this case, the reaction of 1d with benzophenone gave a 9:1 mixture of 3f and 4c (Scheme 2, Table 1).
		the reaction does not feel the effect of the presence of the alcohol: in fact we obtained a 1:1 mixture of two diastereoisomers; b.
	www.photobiology.com /photobiology99/contrib/maurizio (926 words)

	Dissertation
		2:1 mixture of diastereoisomers) deltaH (300MHz, CDCl3) 3.10-1.20(18H, m) 3.42-3.29(2H, m, CH2NBoc), 3.68(1H, s, OCH3 minor diastereoisomer), 3.69(3H, s, OCH3 minor diastereoisomer), 4.42-4.32(1H, m, CHMe), 4.80(0.3H, dd, J=2.5, 11.5Hz, CHNBoc minor diastereoisomer), 4.88(0.6H, dd, J=3.0, 11.0Hz, CHNBoc major diastereoisomer), 5.27-5.23(1H, m, CHSO2Ph), 6.10(0.3H, br.
		Ethyl acetate (30ml) was then added, and the mixture washed sequentially with 2M hydrochloric acid (30ml) and water (3x50ml), then dried over magnesium sulphate and concentrated under reduced pressure.
		The residue was purified by chromatography on silica gel (petroleum ether/ethyl acetate 1:1) to give (2'S, 3R/S)-4-(N-tert-butoxycarbonyl-L-alanylpyrrolidin-2-yl)-4-oxo-3-phenylsulonyl-butanoylglycyl-L-alanine methyl ester (14) (18mg, 62%) as a colourless oil (2:1 mixture of diastereoisomers).
	www.ch.ic.ac.uk /ectoc/papers/59/bl2exp5.html (460 words)

	Abstract List
		The S and R diastereoisomers of cyclodeoxyadenosine on DNA were investigated separately for their ability to block 3' to 5' exonucleases.
		On the S diastereoisomer, pol eta could catalyze the incorporation of one nucleotide opposite the lesion but could not continue elongation.
		It was observed here that both diastereoisomers block primer extension by mammalian and microbial replicative DNA polymerases, using DNA with a site-specific purine cyclodeoxynucleoside residue as template, and consequently appear to be cytotoxic lesions.
	www.pitt.edu /~biohome/dept/frame/faculty/woodabstract.htm (20213 words)

	[No title]
		These diastereomers can be separated and each eliminated to form either the E- or Z-alkene depending on the stereochemistry of the b-hydroxyphosphine oxide.
		(ii) In the Horner-Wittig reaction the syn diastereoisomer of the b-hydroxyphosphine oxide intermediate is the predominant isomer produced.
		To obtain the anti diastereoisomer a two step procedure has to be employed, whereby the a-ketophosphine oxide is generated and reduced with sodium borohydride.
	www.chem.canterbury.ac.nz /courses/tests_exams/1999texams/exams/312.doc (878 words)

	Penn State Research (Site not responding. Last check: 2007-10-11)
		Upon treatment of the lactone 9 with NaH in DMF then allyl bromide, a single diastereoisomer of the allylated lactone 10 is isolated in 65 % yield in addition to recovered lactone 9.
		Furthermore, a similar Heck precursor modeling the effects of the C-ring bromine on the key palladium mediated cyclization was prepared.
		Therefore, all three halogens could be introduced early in a total synthesis of perophoramidine (1) knowing that our key Heck/carbonylation sequence would not be hindered by the presence of the chlorines or bromine.
	rwindigo1.chem.colostate.edu /grouppages/Jerry/Penn_state.html (564 words)

	Azetidinone derivatives for the treatment of atherosclerosis - Patent 6071899
		In these, the terms `diastereoisomer 1` and `diastereoisomer 2` are used for sulfoxide compounds to refer to the diastereoisomers having R,R/S,S and R,S/S,R configurations, respectively.
		Such configurations were obtained initially by X-ray analysis of a limited number of compounds and then extrapolated to the remaning compounds on the basis of their.sup.1 H nmr spectra.
		.sup.1 H NMR demonstrated that this was a 1:1 mixture of diastereoisomers.
	www.freepatentsonline.com /6071899.html (11270 words)

	Stereoselective and Concentration-Dependent Polarized Epithelial Permeability of a Series of Phosphoramidate Triester ...
		The enzymatic cleavage of the methoxy group is considered the first step in the hydrolytic activation of the compounds, with formation of an intermediate metabolite (IM), which is spontaneously converted into the AAM by liberating the phenyl ring through intramolecular nucleophilic attack of the phosphorus by the charged carboxyl moiety.
		Data represent percentage of dose transported in 30 min for the FE (A) and SE (B) diastereoisomers (mean ± S.D. of three monolayers).
		For the p-I derivative (Cf1572) the [B-A/A-B] ratio for the FE diastereoisomer averaged 3.3 and for the SE diastereoisomer 2.3.
	jpet.aspetjournals.org /cgi/content/full/307/3/1112 (5357 words)

	Solution structure of a DNA duplex with a chiral alkyl phosphonate moiety -- Soliva et al. 29 (14): 2973 -- Nucleic ...
		The melting behavior of the two diastereoisomers is very similar.
		Error bars are the RMSD of the helical parameters between the 10 refined structures of each diastereoisomer.
		between both diastereoisomers are small, but not negligible.
	nar.oxfordjournals.org /cgi/content/full/29/14/2973 (5817 words)

	Isosafrole from Piperonal - [www.rhodium.ws]
		The rate of addition is such that the internal temperature is maintained at -78°C. The orange solution is allowed to warm to room temperature over 2 hours and then water (25 ml) is added.
		The first diastereoisomer to be eluted from the column is the (1RS,2SR)-adduct (erythro), microcrystals (2.5 g, 75.8%) mp 137-140°C [recrystallized from ethyl acetate/light petroleum (bp 60-80°C).
		The second diastereoisomer to be eluted from the column is the (1RS,2RS)-adduct (threo) (277 mg, 8.4%), m.p.
	www.erowid.org /archive/rhodium/chemistry/isosafrole.piperonal.html (600 words)

	Removal of oxygen free-radical-induced 5',8-purine cyclodeoxynucleosides from DNA by the nucleotide excision-repair ...
		diastereoisomer was more efficiently repaired than the S isomer.
		The 5'R and 5'S diastereoisomers of 5',8-cyclo-2'-deoxyadenosine in DNA damaged by hydroxyl radicals.
		an abstract that the 5'S diastereoisomer of cyclodeoxyadenosine
	www.pnas.org /cgi/content/full/97/8/3832 (4457 words)

	DNA sequence recognition by the indolocarbazole antitumor antibiotic AT2433-B1 and its diastereoisomer -- Carrasco et ...
		DNA sequence recognition by the indolocarbazole antitumor antibiotic AT2433-B1 and its diastereoisomer -- Carrasco et al.
		DNA sequence recognition by the indolocarbazole antitumor antibiotic AT2433-B1 and its diastereoisomer
		The configuration of the amino sugar distinguishes AT2433-B1 from its diastereoisomer iso-AT2433-B1.
	nar.oxfordjournals.org /cgi/content/full/30/8/1774 (4375 words)

	[No title] (Site not responding. Last check: 2007-10-11)
		as a single diastereoisomer in which the alkyl groups R adopt a gauche conformation, while the two glycolic H-atoms are in an antiperiplanar (ap) and the ester linkages to the fullerene in a gauche relationship (Figs.
		In contrast, in the less favorable diastereoisomer, which should not form, the alkyl groups R adopt an ap and the H-atoms a gauche conformation, while the ester bridges to the fullerene remain, for geometric reasons, locked in a gauche conformation.
		According to the OM2 calculations, the geometry of the fully staggered tether in the free bis-malonates closely resembles the conformation of the tether fragment in the bis-adducts formed.
	www.wiley-vch.de /contents/jc_2217/200012.html (3589 words)

	Introduction to Group Skills, CM 2500
		Each group works on di-methyl cyclohexane and uses organic text-books, chemical data bases and molecular modelling programs to examine the relative stabilities of the diastereoisomers.
		The group allocates each member with his/her own particular diastereoisomer of di-methyl cyclohexane.
		Should there be a 7 member group, two people do the same diastereoisomer.
	mch3w.ch.man.ac.uk /ug/it/pages/intro2002to2003.html (738 words)

	CSIRO PUBLISHING - Australian Journal of Chemistry
		Mixtures of the two kinds of crystals are formed from solutions that contain an excess of the Δ-R/Λ-S diastereoisomer.
		This diastereoisomer predominates in the solid state, but small amounts of the Δ-S/Λ-R diastereoisomer are also present, creating a disordered structure.
		Modelling the disorder to fit the diffraction data gives a diastereoisomeric composition of the crystals that is consistent with the nuclear magnetic resonance data.
	www.publish.csiro.au /nid/51/paper/CH02038.htm (119 words)

	Ephedra - Azarius
		The ephedra alkaloids are similar in structure to epinephrine (or adrenaline).
		Ephedrine and its diastereoisomer, pseudoephedrine, are believed to be responsible for most of the properties of ephedra.
		Ephedrine can be used for the illegal synthesis of methamphetamine.
	www.azarius.at /encyclopedia.php?encyclopediaid=1 (1631 words)

	[No title]
		Therefore, the logical sequence of first identifying the diastereoisomer (via IR, MNR, or MS) and then determining the chirality by crystal tests, IR, melting points, or optical rotation measurements is valid.
		The digoxin content of the medulla, especially the surface of the medulla under the obex, may be useful in confirmation of elevated blood digoxin concentrations.
		I: A Conceptual Reviewchemical analysis, chiral lanthanide shift reagent, chiral stationary phase, diastereoisomer, drug identification, enantiomer, forensic science, isotope ratio, sample differentiation, sampling, toxicologyDifferentiation of drug samples can be based on at least three different approaches.
	www.astm.org /JOURNALS/FORENSIC/JOFS_old.txt (16958 words)

	Introduction to Group Skills
		The group presents the results both in the form of a poster and in the form of a web-based report.
		For a 7 member group, two people do the same diastereoisomer.
		Each group member uses databases (IsisBase and Beilstein) and a Molecular Modelling package (Macromodel) to study his/her diastereoisomer.
	mch3w.ch.man.ac.uk /ug/it/pages/intro.html (680 words)

	Glossary - D (Site not responding. Last check: 2007-10-11)
		It is chemically identical to hydrogen except that it has a neutron in its nucleus where hydrogen does not.
		A diastereoisomer is a molecule with more than one chiral centre in it, where if the chirality of one of the centres is changed, a different molecule is produced.
		Diathermic: A barrier that allows the transfer of heat through it.
	www.everyscience.com /Chemistry/Glossary/D.php (375 words)

	P (Site not responding. Last check: 2007-10-11)
		The term prochirality also applies to achiral molecule or entity which contains a trigonal system and which can be made chiral by the addition to the trigonal system of a new atom or achiral goup.
		The two faces of the trigonal system may be described as Re and Si.
		The chiral molecule CH3CHOHCH2CH3 can be converted into one of the diastereoisomers of CHiCHOHCHDCH3 by the isotopic replacement of one of the two diastereotopic hydrogen atoms 6f the methylene group.
	www.sdsc.edu /Education/Elemnet/misc/newerglossary/p.html (970 words)

	Cyfluthrin (UK PID)
		It is a mixture of eight stereoisomers (four pairs of diastereoisomers).
		Pa at 20°C Diastereoisomer II 1.4 x 10
		Pa at 20°C (Pesticide Manual, 1997) Relative vapour density NIF Flash point 107°C (technical grade) (Pesticide Manual, 1997) Reactivity NIF Uses Cyfluthrin is effective against many pests.
	www.intox.org /databank/documents/chemical/cyflrin/ukpid58.htm (6777 words)

	N to Q
		The term prochirality also applies to an achiral molecule or entity which contains a trigonal system and which can be made chiral by the addition to the trigonal system of a new atom or achiral group.
		For example addition of hydrogen to one of the enantiotopic faces of the prochiral ketone CH gives one of the enantiomers of the chiral alcohol CH ; the addition of CN to one of the diastereotopic faces of the chiral aldehyde shown below converts it into one of the diastereoisomers of the the cyanohydrin.
		The chiral molecule CH can be converted into one of the diastereoisomers of CH by the isotopic replacement of one of the two diastereotopic hydrogen atoms of the methylene group.
	www.chem.qmul.ac.uk /iupac/stereo/NQ.html (1532 words)

	Research - Natural Sciences - University of Newcastle
		Comparative Study of Diastereoisomer Interconversion in Chiral BINOL-ate and Diamine Platinum Complexes of Conformationally Flexible NUPHOS Diphosphines.
		Rate data revealed that this process obeys 1st-order relaxation kinetics, and rate consts.
		for conversion of the minor to the major diastereoisomer were obtained.
	www.ncl.ac.uk /nsci/research/publication/28081 (199 words)

	The Preparation of d-Pseudococaine from l-Cocaine
		d-Pseudococaine, a diastereoisomer of cocaine, is prepared from l-cocaine by the action of strong base that epimerizes the carbomethoxy group at C-2 to the equatorial position and transesterifies the ester at C-3.
		The benzoate ester is regenerated by reaction with benzoyl chloride.
		With these data, a laboratory can eliminate or confirm pseudococaine in such an analysis.
	www.astm.org /JOURNALS/FORENSIC/PAGES/5760.htm (154 words)

	Conformational Preferences of Neurotransmitters: Ephedrine and Its Diastereoisomer, Pseudoephedrine
		Conformational Preferences of Neurotransmitters: Ephedrine and Its Diastereoisomer, Pseudoephedrine
		Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom, and Department of Chemistry, Queen Mary and Westfield College, University of London, Mile End Road, London E1 4NS, United Kingdom
		It is possible that the combination of a relatively weak transition moment and a lack of facile pathways for relaxation from higher lying structures into the "missing" conformer may play a role.
	pubs.acs.org /cgi-bin/abstract.cgi/jpcafh/2001/105/i03/abs/jp002862s.html (286 words)

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