- Engineering Orthogonal Methyltransferases to Create Alternative Bioalkylation Pathways
-
S-adenosyl-l-methionine (SAM)-dependent methyltransferases (MTs) catalyse the methylation of a vast array of small metabolites and biomacromolecules. Recently, rare carboxymethylation pathways have been discovered, including carboxymethyltransferase enzymes that utilise a carboxy-SAM (cxSAM) cofactor generated from SAM by a cxSAM synthase (CmoA). We show how MT enzymes can utilise cxSAM to catalyse carboxymethylation of tetrahydroisoquinoline (THIQ) and catechol substrates. Site-directed mutagenesis was used to create orthogonal MTs possessing improved catalytic activity and selectivity for cxSAM, with subsequent coupling to CmoA resulting in more efficient and selective carboxymethylation. An enzymatic approach was also developed to generate a previously undescribed co-factor, carboxy-S-adenosyl-l-ethionine (cxSAE), thereby enabling the stereoselective transfer of a chiral 1-carboxyethyl group to the substrate.
- Bennett, Matthew R.,Cronin, Victoria A.,Herbert, Abigail J.,Micklefield, Jason,Shepherd, Sarah A.,Sung, Rehana
-
supporting information
p. 14950 - 14956
(2020/07/04)
-
- Iron-catalysed enantioselective Suzuki-Miyaura coupling of racemic alkyl bromides
-
The first iron-catalysed enantioselective Suzuki-Miyaura coupling reaction has been developed. In the presence of catalytic amounts of FeCl2 and (R,R)-QuinoxP?, lithium arylborates are cross-coupled with tert-butyl α-bromopropionate in an enantioconvergent manner, enabling facile access to various optically active α-arylpropionic acids including several nonsteroidal anti-inflammatory drugs (NSAIDs) of commercial importance. (R,R)-QuinoxP? is specifically able to induce chirality when compared to analogous P-chiral ligands that give racemic products, highlighting the critical importance of transmetalation in the present asymmetric cross-coupling system.
- Iwamoto, Takahiro,Okuzono, Chiemi,Adak, Laksmikanta,Jin, Masayoshi,Nakamura, Masaharu
-
supporting information
p. 1128 - 1131
(2019/01/28)
-
- Synthesis of [13C3]-B6 vitamers labelled at three consecutive positions starting from [13C3]-propionic acid
-
[13C3]-labelled vitamers (PN, PL and PM) of the B6 group were prepared starting from [13C3]-propionic acid. [13C3]-PN was synthesized in ten linear steps with an overall yield of 17%. Hereby, higher alkyl homologues of involved esters showed a positive impact on the reaction outcome of the intermediates in the chosen synthetic route. Oxidation of [13C3]-PN to [13C3]-PL was undertaken using potassium permanganate and methylamine followed by acid hydrolysis of the imine derivative. [13C3]-PM could be prepared from the oxime derivative of [13C3]-PN by hydrogenation with palladium.
- Bachmann, Thomas,Rychlik, Michael
-
-
- USE OF PYRAZOLOPYRIMIDINE DERIVATIVES FOR THE TREATMENT OF PI3K-DELTA RELATED DISORDERS
-
The present application provides methods of treating PI3Kδ related disorders using compounds of Formula I: or pharmaceutically acceptable salts thereof.
- -
-
Paragraph 0368
(2014/09/16)
-
- Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
-
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
- Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
-
supporting information
p. 17662 - 17668
(2015/02/02)
-
- Novel ibuprofen prodrugs with improved pharmacokinetics and non-ulcerogenic potential
-
In the present study, we evaluated the anti-inflammatory activity with pharmacokinetic, ulcerogenic properties of various synthesized prodrugs of ibuprofen in experimental animals. Prodrugs 2, 6, 9, 10, 12, and 14 were found to possess significant anti-inflammatory activity with almost non-ulcerogenic potential than standard drug ibuprofen 1a in both normal and inflammation-induced rats. Metabolic stability of prodrugs 2, 6, 9, 10, 12, and 14 were also studied in rat liver microsomes and oral bioavailability was determined by estimating area under curve (AUC) and plasma concentration of these prodrugs at various time intervals. The experimental findings elicited higher AUC and plasma concentration at 1 and 2 h indicating improved oral bioavailability as compared to parent ibuprofen. These prodrugs are found to have least gastric ulceration with retain anti-inflammatory activity observed in experimental animals. Therefore, present experimental findings demonstrated significant improvement of various pharmacokinetic properties with least ulcerogenic potential of ester prodrugs of ibuprofen an anti-inflammatory agent
- Dhakane, Valmik D.,Chavan, Hemant V.,Thakare, Vishnu N.,Adsul, Laxman K.,Shringare, Sadanand N.,Bandgar, Babasaheb P.
-
p. 503 - 517
(2014/03/21)
-
- HETEROCYCLYLAMINES AS PI3K INHIBITORS
-
The present invention provides heterocyclylamine derivatives of Formula I: wherein the variables are defined herein, that modulate the activity of phosphoinositide 3-kinases (PI3Ks) and are useful in the treatment of diseases related to the activity of PI3Ks including, for example, inflammatory disorders, immune-based disorders, cancer, and other diseases.
- -
-
Paragraph 1063
(2013/03/26)
-
- Study of the lanthanide-catalyzed, aqueous, asymmetric Mukaiyama aldol reaction
-
The development of efficient methods for the asymmetric Mukaiyama aldol reaction in aqueous solution has received great attention. We have developed a new series of chiral lanthanide-containing complexes that produce Mukaiyama aldol products with outstanding enantioselectivities. In this paper, we describe an optimized ligand synthesis, trends in stereoselectivity that result from changing lanthanide ions, and an exploration of substrate scope that includes aromatic and aliphatic aldehydes and silyl enol ethers derived from aromatic and aliphatic ketones.
- Mei, Yujiang,Averill, Derek J.,Allen, Matthew J.
-
scheme or table
p. 5624 - 5632
(2012/09/05)
-
- Highly selective synthesis of α-bromoesters using molecular bromine catalyzed by phosphorus
-
A series of α-bromoesters have been synthesized by applying Hell-Volhard-Zelinsky reaction catalyzed by phosphorus instead of usual phosphorus tribromide. An excellent regioselectivity to good yields are achieved at comparatively mild reaction conditions of an operational simplicity.
- Sun, Zhaoyun,Peng, Xinhua,Dong, Xiongzi,Shi, Wenwen
-
scheme or table
p. 929 - 930
(2012/07/30)
-
- Efficient procedures to prepare primary and secondary alkyl halides from alkanols via the corresponding sulfonates under mild conditions
-
The study presented herein shows that sulfonate/halide exchange can be advantageously performed in THF to avoid several side reactions such as elimination and epimerization when the reaction is performed from a chiral alkyl sulfonate or a substrate having a C-H acidic chiral center. The main limitation of this procedure was found to be the conversion of secondary alkyl sulfonates to alkyl chlorides. In this case, the addition of a catalytic amount of manganese chloride clearly accelerates the rate and the efficiency of the reaction. Copyright
- Cahiez, Gerard,Gager, Olivier,Moyeux, Alban,Delacroix, Thomas
-
supporting information; experimental part
p. 1519 - 1528
(2012/07/03)
-
- A new class of ligands for aqueous, lanthanide-catalyzed, enantioselective Mukaiyama aldol reactions
-
The development of aqueous methods for generating enantiopure β-hydroxy carbonyl compounds is an important goal because these subunits compose many bioactive compounds and the ability to synthesize these groups in water has environmental and cost benefits. In this communication, we report a new class of ligands for aqueous, lanthanide-catalyzed, asymmetric Mukaiyama aldol reactions for the synthesis of chiral β-hydroxy ketones. Furthermore, we have used luminescence-decay measurements to unveil mechanistic information regarding the catalytic reaction via changes in water-coordination number. The precatalysts presented here yielded β-hydroxy carbonyls from aliphatic and aryl substrates with outstanding syn:anti ratios and enantiometric excesses of up to 49:1 and 97%, respectively.
- Mei, Yujiang,Dissanayake, Prabani,Allen, Matthew J.
-
supporting information; experimental part
p. 12871 - 12873
(2010/11/16)
-
- Enantioselectivity of haloalkane dehalogenases and its modulation by surface loop engineering
-
In the loop: Engineering of the surface loop in haloalkane dehalogenases affects their enantiodiscrimination behavior. The temperature dependence of the enantioselectivity (lnE versus 1/T) of β-bromoalkanes by haloalkane dehalogenases is reversed (red data points) by deletion of the surface loop; the selectivity switches back when an additional single-point mutation is made. This behavior is not observed for -bromoesters.
- Prokop, Zbynek,Sato, Yukari,Brezovsky, Jan,Mozga, Tomas,Chaloupkova, Radka,Koudelakova, Tana,Jerabek, Petr,Stepankova, Veronika,Natsume, Ryo,Van Leeuwen, Jan G. E.,Janssen, Dick B.,Florian, Jan,Nagata, Yuji,Senda, Toshiya,Damborsky, Jiri
-
supporting information; experimental part
p. 6111 - 6115
(2010/11/05)
-
- Enantiodiscrimination of racemic electrophiles by diketopiperazine enolates: asymmetric synthesis of methyl 2-amino-3-aryl-butanoates and 3-methyl-aspartates
-
Enolates of (S)-N,N′-bis-(p-methoxybenzyl)-3-iso-propylpiperazine-2,5-dione exhibit high levels of enantiodiscrimination in alkylations with (RS)-1-aryl-1-bromoethanes and (RS)-2-bromoesters, affording substituted diketopiperazines containing two new stereogenic centres in high de. Deprotection and hydrolysis of the resultant substituted diketopiperazines provides a route to the asymmetric synthesis of homochiral methyl 2-amino-3-aryl-butanoates and 3-methyl-aspartates in high de and ee.
- Bull, Steven D.,Davies, Stephen G.,Epstein, Simon W.,Garner, A. Christopher,Mujtaba, Nadeam,Roberts, Paul M.,Savory, Edward D.,Smith, Andrew D.,Tamayo, Juan A.,Watkin, David J.
-
p. 7911 - 7925
(2007/10/03)
-
- Privileged structure based ligands for melanocortin-4 receptors-Aliphatic piperazine derivatives
-
Aliphatic carbocyclic replacement of the benzyl group of compound 1 yielded compounds with high affinity for the melanocortin-4 receptor (MC4R). Compounds with a cyclohexyl group showed a consistent high affinity, while different polar groups with less basicity were good replacements for the original diethyl amines. Substitution of the polar group found in these privileged structures with an aliphatic moiety produced compounds with high affinity for MC4R.
- Briner, Karin,Collado, Iván,Fisher, Matthew J.,García-Paredes, Cristina,Husain, Saba,Kuklish, Steven L.,Mateo, Ana I.,O'Brien, Thomas P.,Ornstein, Paul L.,Zgombick, John,de Frutos, óscar
-
p. 3449 - 3453
(2007/10/03)
-
- Inclusion complexes of EMPO derivatives with 2,6-di-O-methyl-β- cyclodextrin: Synthesis, NMR and EPR investigations for enhanced superoxide detection
-
The free radical trapping properties of eight 5-alkoxycarbonyl-5-methyl-1- pyrroline N-oxide (EMPO) type nitrones and those of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) were evaluated for trapping of superoxide anion radicals in the presence of 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD). 1H-NMR titrations were performed to determine both stoichiometries and binding constants for the diamagnetic nitrone-DM-β-CD equilibria. EPR titrations were then performed and analyzed using a two-dimensional EPR simulation program affording 1: 1 and 1: 2 stoichiometries for the nitroxide spin adducts with DM-β-CD and the associated binding constants after spin trapping. The nitroxide spin adducts associate more strongly with DM-β-CD than the nitrones. The ability of the nitrones to trap superoxide, the enhancement of the EPR signal intensity and the supramolecular protection by DM-β-CD against sodium l-ascorbate reduction were evaluated. The Royal Society of Chemistry 2006.
- Bardelang, David,Rockenbauer, Antal,Karoui, Hakim,Finet, Jean-Pierre,Biskupska, Inga,Banaszak, Karol,Tordo, Paul
-
p. 2874 - 2882
(2008/02/08)
-
- Design and synthesis of aromatic inhibitors of anthranilate synthase
-
Anthranilate synthase catalyses the conversion of chorismate to anthranilate, a key step in tryptophan biosynthesis. A series of 3-(1-carboxy-ethoxy) benzoic acids were synthesised as chorismate analogues, with varying functionality at C-4, the position of the departing hydroxyl group in chorismate. Most of the compounds were moderate inhibitors of anthranilate synthase, with inhibition constants between 20-30 μM. The exception was 3-(1-carboxy-ethoxy) benzoic acid, (C-4 = H), for which K1 = 2.4 μM. These results suggest that a hydrogen bonding interaction with the active site general acid (Glu309) is less important than previously assumed for inhibition of the enzyme by these aromatic chorismate analogues. The Royal Society of Chemistry 2005.
- Payne, Richard J.,Bulloch, Esther M.M.,Abell, Andrew D.,Abell, Chris
-
p. 3629 - 3635
(2007/10/03)
-
- Preparation of a mannich base intermediate for 2-[(4-heterocyclic-phenoxymethyl)-phenoxy]-alkanoates
-
A Mannich base intermediate for 2-[(4-heterocyclic-phenoxymethyl)-phenoxyl]-alkanoates and methods for its preparation are provided. A method for preparation of an alkyl 2-[2-(secondary amino methyl)-5-alkylphenoxy]-alkanoate comprises the steps of: reacting a mixture of m-alkyl phenol, a secondary amine, and an aldehyde, with or without a catalyst, in a first solvent at reflux temperatures to form a 2-[(secondary amino)methyl]-5-alkylphenol. That product is then reacted with an alkyl 2-haloalkanoate, and an alkali metal carbonate, with or without a second catalyst in a second solvent at reflux temperatures to form the 2-[2-(secondary amino methyl)-5-alkylphenoxy]-alkanoate. The aldehyde may be paraformaldehyde, aqueous formaldehyde, formaldehyde, or polymerized acetal derivatives thereof. The first solvent may be acetonitrile or toluene. The catalyst may be an acid catalyst or a base catalyst. In the preferred embodiment the Mannich base is a 2-[(secondary amino)-methyl]-5-alkylphenol, or a 2-[2-(secondary amino methyl)-5-alkylphenoxy]-alkanoate.
- -
-
-
- Enantioselective synthesis of α-bromo acid derivatives and bromohydrins from tartrate derived bromoacetals
-
Bromination of the acetals 4 derived from aryl alkyl ketones, ArCOR, and (2R,3R)-tartaric acid results in bromoacetals 5 with 78-90% de. Hydrolysis of those compounds with Ar = 4-methoxyphenyl or 3-bromo-4-methoxyphenyl results, after recrystallisation, in α-bromoketones 8 with 66-98% ee which are shown to undergo the Baeyer-Villiger oxidation to α-bromoesters 9 with minimal racemisation, α-Bromoketone 8d is shown to undergo carbonyl reduction to threo-bromohydrin 15 with retention of stereochemistry.
- Boyes, Scott A.,Hewson, Alan T.
-
p. 2759 - 2765
(2007/10/03)
-
- Esterification of carboxylic acid salts
-
Mono- or polycarboxylic acid esters are prepared by reacting a salt of such carboxylic acid with an organic halocompound, e.g., a (cyclo)alkyl, (cyclo)alkenyl, aryl or aralkyl halide, in an aqueous reaction medium, in the presence of a catalytically effective amount of a phase transfer catalyst, for example an onium salt.
- -
-
-
- Difference in the behavior of methyl (S)-α-bromopropionate in its addition to trimethylvinylsilane depending on the method of initiation
-
The addition of methyl (S)-2-bromopropionate to trimethylvinylsilane initiated by systems based on iron pentacarbonyl affords a racemic adduct and is accompanied by racemization of the unreacted chiral ester. In the presence of benzoyl peroxide, the reaction proceeds similarly, but no racemization of the starting chiral ester occurs.
- Terentiev,Vasilieva,Kuz'mina,Orlova,Ikonnikov,Mysov,Kolehmainen,Laihia,Belokon'
-
p. 676 - 679
(2007/10/03)
-
- Racemization of Methyl (S)-2-Bromopropionate in the Presence of Pentacarbonyliron-Based Systems
-
Heating of a benzene solution of methyl (S)-2-bromopropionate in the presence of metal complex systems based on pentacarbonyliron results in racemization with a noticeable induction period. In the addition to vinyltrimethylsilane, the degree of racemization decreases with increasing monomer concentration.
- Terent'ev,Vasil'eva,Kuz'mina,Orlova,Ikonnikov,Belokon'
-
p. 943 - 945
(2007/10/03)
-
- Process for the preparation of brominated compounds, especially from alcohols
-
A process for the preparation of a brominated compound which comprises the step of reacting at least one compound selected from the group consisting of a chloroformate, a chlorosulfite and a chlorophosphite with a brominating agent for a time sufficient to obtain at least one brominated compound. In particular, an alcohol is converted into a chloroformate, chlorosulfite or a chlorophosphite, which is then brominated to obtain the desired product. In another embodiment, a brominating agent is reacted with a reactant selected from the group consisting of thionyl chloride, phosgene and phosphorous oxychloride, followed by contacting the reaction product obtained with an alcohol to be brominated.
- -
-
-
- REACTIONS OF HALOGEN FLUORIDES. XIII. NEW POSSIBILITIES FOR OXIDATIVE NUCLEOPHILIC FLUORINATION OF BROMINE-SUBSTITUTED ESTERS BY THE HEXACHLOROMELAMINE-HYDROGEN FLUORIDE SYSTEM
-
Primary, secondary, and tertiary bromine atoms in bromine-substituted esters, including the bromine atoms of the CBr2 group at the α position to the ester group, are substituted effectively by a bromine atom in the hexachloromelamine-liquid hydrogen fluoride system under normal conditions.New methods were developed for the production of alkyl and fluoroalkyl 2,3-dihalogeno-2-fluoropropionates, which are key compounds in the synthesis of α-fluoroacrylates.
- Chuvatkin, N. N.,Panteleeva, I. Yu.,Kurskii, Yu. A.,Boguslavskaya, L. S.
-
p. 1450 - 1456
(2007/10/02)
-
- A new simple and industrial process for bromination of alcohols
-
Alcohols treated with thionylchloride, followed by chlorine/bromine exchange using gaseous hydrobromic acid and thermal decomposition in the presence of a tertiary amine give the corresponding brominated compounds. The process is regio/stereo selective.
- Mas,Metivier
-
p. 2187 - 2191
(2007/10/02)
-
- Synthesis of a Chiral, Nonracemic Aziridinone (α-Lactam)
-
(S)-tert-Leucine is diazotized affording a mixture of the expected α-chloro and α-hydroxy acids (S)-15 and (S)-16 and the rearranged β-chloro and β-hydroxy acids (R)-12 and (S)-11.Separation produces a 51percent yield of pure (S)-15 (e.e. >= 97.4percent) which is converted via the acid chloride (S)-17 into the α-chloro amides (S)-18a and b (e.e. = 99.0 and 95.2percent, respectively).On treatment with tBuOK, the latter is converted into the α-lactam (R)-22b (59percent, e.e. >= 91.0percent, D20 = -293.7), which is accompanied by small amounts of its ring opening product (R)-23b.Only the α-amino ester (R)-23a is formed from the α-chloro amide (S)-18a and tBuOK.While the enantiomers of the halo amides 13, 18a, b, 24a, b and of the 3-pentyl esters of the hydroxy acid 16 are separated by GC on chiral columns, the α-lactam 22b and the α-amino esters 23a, b require conversion into separable derivatives without involving the stereogenic center.Thus, alkaline hydrolysis of 22b as well as acidic cleavage of 23 yield the α-amino acids 25 which are cyclized to the oxazolidine-2,5-diones 26 by means of bis(trichloromethyl)carbonate ("triphosgene").As shown by the high enantiomeric excess of the products derived from (S)-tert-leucine none of the reactions described results in a considerable degree of racemization.Authentic samples of 11 and 12 are synthesized from the Reformatzky product 21.The absolute configurations of the major enantiomers derived from (S)-14 are based on the retention on chiral GC columns, the signs of optical rotations, and CD spectra.The mechanism of the rearrangement leading to the β-hydroxy and β-chloro acids (S)-11 and (R)-12 is interpreted in terms of a stereospecific 1,2-methyl shift occurring simultaneously with the ring cleavage of the (protonated) α-lactone (R)-2 (R = tBu) which is the crucial intermediate formed in the diazotization of (S)-14.
- Quast, Helmut,Leybach, Holger
-
p. 849 - 859
(2007/10/02)
-
- Nucleophilic Substitution Reactions of Alkyl Halides By Using New Polymer-Supported Reagents Containing Hemin
-
A new polymer reagent consisting of hemin, divinylbenzene, and 2-methyl-5-vinylpyridine was synthesized by suspension copolymerization.Substitution reactions of primary, secondary, and tertiary alkyl halides with the hemin copolymer combined with cyanide, azide, and thiocyanate ions were given satisfactory yields.This reaction mechanism was revealed to be a SNi type on the basis of stereochemical study.The hemin copolymer was not only a polymer-supported reagent with functional capabilities, but also served to separate the product from the reaction mixture.
- Saito, Kiyoshi,Harada, Kaoru
-
p. 2562 - 2566
(2007/10/02)
-
- Resolution of racemic mixtures of aliphatic acid esters
-
Racemic mixtures of partially water-soluble esters defined by the formula STR1 wherein R and R1 represent hydrogen and C1 -C4 alkyl; R2 represents C1 -C4 alkyl and X represents halogen, aliphatic or aromatic groups and substituted derivatives thereof wherein R, R1 and X are different can be resolved by reducing the water solubility of a racemic mixture of said esters by means other than changing the chemical composition of the ester, contacting the racemic mixture of esters of reduced water solubility with a lipase enzyme from Candida cylindracea capable of stereospecifically resolving the racemic mixture of hydrolysis and stereospecifically resolving the racemic mixture.
- -
-
-
- Process for producing α-arylalkanoic acid ester
-
A process for producing an α-arylalkanoic acid ester represented by the general formula STR1 wherein Ar represents an aryl group which may optionally be substituted, and R1 and R2, independently from each other, represent a lower alkyl group, which comprises reacting a Grignard reagent prepared from an aryl halide of the general formula wherein Ar is as defined above and X1 represents a halogen atom, and magnesium, with an α-haloalkanoic acid ester of the general formula STR2 wherein R1 and R2 are as defined above, and X2 represents a halogen atom, said reaction of the Grignard reagent with the α-haloalkanoic acid ester of general formula (III) being carried out in the presence of a nickel compound.
- -
-
-
- Chemical Ionization Mass Spectra of Selected C3H6O Compounds
-
The chemical ionization mass spectra of five isomers of C3H6O (acetone, propionaldehyde, oxetane, propylene oxide and allyl alcohol) have been determined using a variety of reagent gases (H2, D2, N2/H2, CO2/H2 and CO/H2).The + ions produced by protonation of these isomers undergo very similar reactions to those reported for analogous + metastable ions; however, decomposing ions generated by chemical ionization appear to have somewhat higher internal energies.The results of 2H labelling studies (D2 reagent gas or labelled analogues of C3H6O) indicate that protonation occurs mainly on oxygen and are consistent with previous investigations of metastable oxonium ions.The protonated acetone ion is particularly stable, in agreement with the higher activation energies for fragmentation of this isomer than for other + structures.As the calculated heat of protonation of C3H6O is reduced by changing the reagent gas, so the extent to which fragmentation occurs decreases.This is discussed in the context of competition between fragmentation and collisional stabilization of the excited +* ion.It is concluded that on average a large fraction (approching 1) of the exothermicity of the protonation reaction resides in the +* ions produced initially.
- Bowen, Richard D.,Harrison, Alex G.
-
p. 159 - 166
(2007/10/02)
-
- Synthesis and Herbicidal Activity of the D- and L-Methyl 2--propionate Enantiomers
-
The D- and L-enantiomers of the wild oat herbicide diclofop-methyl (title compound) were prepared utilizing resolution operations and by synthetic routes with optically active compounds as starting material.The dextro-rotatory product which the D(R)-configuration can be attributed to, was found to be the herbicidally active species. - Keywords: Phenoxy-phenoxy-propionic Acid Ester, Diclofop-methyl, Stereoisomers, Grass Herbicide
- Nestler, Hans Juergen,Bieringer, Hermann
-
p. 366 - 371
(2007/10/02)
-
- Synthesis of the 2-ethyl-3-methylsuccinic acids via a stereospecific malonic ester alkylation
-
Reaction of (-)-(S)-methyl 2-bromopropionate (4) (obtained from L-alanine) with dibenzyl ethylmalonate gave stereospecifically in four steps (+)-(2R,3S)-2-ethyl-3-methylsuccinic acid (8a) and its diastereoisomer (8b).The malonic ester alkylation proceeded with Walden inversion.The chiroptical properties of the acids and the intermediates are in conformity with the known absolute configurations.
- Leeuwen, F. F. van,Noordam, A.,Maat, L.,Beyerman, H. C.
-
-
- Haloacetanilides as microbicidal active substances
-
Compounds of the formula STR1 wherein Z1 represents methyl or chlorine, Z2 represents chlorine or bromine, Z3 represents hydrogen or C1 -C3 alkyl, and X represents fluorine, chlorine, bromine or iodine, exhibit microbicidal activity, preferably against phytopathogenic fungi.
- -
-
-