- Synthesis of (±)-eusynstyelamide A
-
The synthesis of (±)-eusynstyelamide A has been accomplished in six steps in 13% overall yield from 6-bromoindole, methyl glycidate, and Boc-protected agmatine. If oxygen is carefully excluded from the reaction, the key NaOH-catalyzed aldol dimerization of the α-ketoamide proceeded efficiently to give Boc-protected eusynstyelamide A.
- Barykina, Olga V.,Snider, Barry B.
-
-
Read Online
- Facile synthesis of glycidates via oxidation of acrylates with aqueous solution of naocl in the presence of ammonium salts
-
Various glycidates were obtained in high yields via green oxidation of acrylates with aqueous solution of NaOCl in the presence of ammonium salts. The appropriate choice of ammonium salts fitting to the polarity of the substrates and the reaction under slightly basic conditions were essential for efficient reactions.
- Ochiai, Bungo,Hirano, Taiki
-
-
Read Online
- Synthesis of the fungal macrolide berkeleylactone A and its inhibition of microbial biofilm formation
-
The fungal macrolide berkeleylactone A was synthesised in 13 steps and 24% yield using (R)-propylene oxide and an asymmetric Noyori hydrogenation of a β-ketoester to install the stereogenic centres. A domino addition-Wittig olefination of a 13-hydroxytetradecanal intermediate with the cumulated ylide Ph3PCCO closed the macrocyle by establishing the α,β-unsaturated ester group, necessary for the attachment of the sidechain thiol via a thia-Michael reaction. The synthetic berkeleylactone A inhibited the formation of Staphylococcus aureus biofilms and showed significant dispersive effects on preformed biofilms of Candida albicans by at least 45% relative to untreated controls at concentrations as low as 1.3 μg mL-1.
- Schobert, Rainer,Schrey, Hedda,Schriefer, Manuel G.,Stadler, Marc,Zeng, Haoxuan
-
p. 4743 - 4751
(2021/06/11)
-
- Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
-
Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
- Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
-
supporting information
p. 513 - 518
(2019/01/14)
-
- Poly(Alkyl Glycidate Carbonate)s as Degradable Pressure-Sensitive Adhesives
-
Insertion of CO2 into the polyacrylate backbone, forming poly(carbonate) analogues, provides an environmentally friendly and biocompatible alternative. The synthesis of five poly(carbonate) analogues of poly(methyl acrylate), poly(ethyl acrylate), and poly(butyl acrylate) is described. The polymers are prepared using the salen cobalt(III) complex catalyzed copolymerization of CO2 and a derivatized oxirane. All the carbonate analogues possess higher glass-transition temperatures (Tg=32 to ?5 °C) than alkyl acrylates (Tg=10 to ?50 °C), however, the carbonate analogues (Td≈230 °C) undergo thermal decomposition at lower temperatures than their acrylate counterparts (Td≈380 °C). The poly(alkyl carbonates) exhibit compositional-dependent adhesivity. The poly(carbonate) analogues degrade into glycerol, alcohol, and CO2 in a time- and pH-dependent manner with the rate of degradation accelerated at higher pH conditions, in contrast to poly(acrylate)s.
- Beharaj, Anjeza,Ekladious, Iriny,Grinstaff, Mark W.
-
supporting information
p. 1407 - 1411
(2019/01/14)
-
- NOVEL 3-INDOL SUBSTITUTED DERIVATIVES, PHARMACEUTICAL COMPOSITIONS AND METHODS FOR USE
-
A compound of Formula I is provided: or pharmaceutically acceptable enantiomers, salts or solvates thereof. The 5 invention further relates to the use of the compounds of Formula I as TDO2 inhibitors. The invention also relates to the use of the compounds of Formula I for the treatment and/or prevention of cancer, neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and Huntington's disease, chronic viral infections such as HCV and HIV, depression, and obesity. The invention also 10 relates to a process for manufacturing compounds of Formula I.
- -
-
Page/Page column 195; 196
(2016/10/04)
-
- The asymmetric total synthesis of (+)-salvianolic acid A
-
An asymmetric synthesis of (+)-salvianolic acid A with cardioprotective properties, has been accomplished in a convergent manner in eight steps and 10.6% overall yield. This synthesis features an asymmetric addition of organometallics to optically pure 2,3-epoxypropionate in the presence of BF3·Et2O, Ru(III)-catalyzed directed [Formula presented] olefination, and I2-catalyzed isomerization reaction.
- Zheng, Yong,Song, Wei-Bin,Xuan, Li-Jiang
-
supporting information
p. 5047 - 5050
(2016/07/25)
-
- Epoxide manufacturing method
-
Method for producing epoxides of formula (I), where R stands for an organic group with 1-10 C atoms, by reaction of compounds of formula (II) with an oxidation agent, characterized in that the production takes place continuously in a tube reactor.
- -
-
Paragraph 0049-0056
(2016/10/20)
-
- Α coccidiosis production of acrylic acid ester
-
PROBLEM TO BE SOLVED: To provide a production method with which α-acyloxy acrylate can be obtained at high yield using commodity chemicals as raw materials and which is thereby suitable to be used industrially as a method for producing the α-acyloxy acrylate. SOLUTION: The method for producing the α-acyloxy acrylate includes a process for obtaining the α-acyloxy acrylate, which has a specific structure, using glycidic esters that have a specific structure. COPYRIGHT: (C)2012,JPOandINPIT
- -
-
Paragraph 0048
(2016/12/16)
-
- A broadly applicable and practical oligomeric (salen)Co catalyst for enantioselective epoxide ring-opening reactions
-
The (salen)Co catalyst (4a) can be prepared as a mixture of cyclic oligomers in a short, chromatography-free synthesis from inexpensive, commercially available precursors. This catalyst displays remarkable enhancements in reactivity and enantioselectivity relative to monomeric and other multimeric (salen)Co catalysts in a wide variety of enantioselective epoxide ring-opening reactions. The application of catalyst 4a is illustrated in the kinetic resolution of terminal epoxides by nucleophilic ring-opening with water, phenols, and primary alcohols; the desymmetrization of meso epoxides by addition of water and carbamates; and the desymmetrization of oxetanes by intramolecular ring opening with alcohols and phenols. The favorable solubility properties of complex 4a under the catalytic conditions facilitated mechanistic studies, allowing elucidation of the basis for the beneficial effect of oligomerization. Finally, a catalyst selection guide is provided to delineate the specific advantages of oligomeric catalyst 4a relative to (salen)Co monomer 1 for each reaction class.
- White, David E.,Tadross, Pamela M.,Lu, Zhe,Jacobsen, Eric N.
-
supporting information
p. 4165 - 4180
(2014/06/09)
-
- 2-oxo-1,3-dioxolane-4-carboxamide building blocks, their preparation and use
-
The present invention suggests a 2-oxo-1,3-dioxolane-4-carboxamide of formula (I), wherein R is an n-valent radical, n is an integer from 2 to 10 and x is an integer from 1 to n-1. The invention furthermore suggests a process for the preparation of the 2-oxo-1,3-dioxolane-4-carboxamide of formula (I) from 2-oxo-1,3-dioxolane-4-carboxylic acid of formula (II) with a polyisocyanate of the formula R(NCO)n, where R and n have the meanings given, and the use of the 2-oxo-1,3-dioxolane-4-carboxamide of formula (I) for the preparation of a 2-oxo-1,3-dioxolane-4-carboxamide-substituted prepolymer.
- -
-
Paragraph 0035; 0036
(2014/08/19)
-
- 2-OXO-1,3-DIOXOLANE-4-CARBOXAMIDE BUILDING BLOCKS, THEIR PREPARATION AND USE
-
The present invention suggests a 2-oxo-1,3-dioxolane-4-carboxamide of formula (I), wherein R is an n-valent radical, n is an integer from 2 to 4, preferably from 2 to 3, and x is an integer from 1 to n-1. The invention furthermore suggests a process for the preparation of the 2-oxo-1,3-dioxolane-4-carboxamide of formula (I) from 2-oxo-1,3- dioxolane-4-carboxylic acid of formula (II), with a polyisocyanate of the formula R(NCO)n, where R and n have the meanings given, the use of the 2-oxo-1,3-dioxolane-4-carboxamide of formula (I) for the preparation of a 2-oxo-1,3-dioxolane-4-carboxamide-substituted prepolymer, and the 2-oxo-1,3-dioxolane-4-carboxamide-substituted prepolymer thus obtainable.
- -
-
Page/Page column 10; 11
(2014/08/19)
-
- PROCESS FOR PREPARING EPOXYCARBOXYLIC ESTERS
-
Process for preparing epoxides of the formula I where R is an organic group having from 1 to 10 carbon atoms, by reacting compounds of the formula II with an oxidant, wherein the preparation is carried out continuously in a tube reactor.
- -
-
Paragraph 0047-0057; 0062
(2013/08/14)
-
- 2-OXO-1,3-DIOXOLANE-4-CARBOXAMIDES, THEIR PREPARATION AND USE
-
The present invention relates to 2-oxo-1,3-dioxolane-4-carboxamides of formula (I), in which F? can be, inter alia, an n-valent radical (n > 1), which is substituted with n-1 further 2-oxo-1,3-dioxolane-4-carboxamide groups of general formula (II), to processes for the preparation of these 2-oxo-1,3-dioxolane-4-carboxamides, to processes for the preparation of the 2-oxo-l,3-diox-olane-4-carboxylic acids of formula (III), which are suitable starting materials for the above processes, and to the use of said 2-oxo-1,3-dioxolane-4-carboxamides for the preparation of (poly)hydroxyurethanes, -hydroxycarbonates and -hydroxysulfanylformates, and also as end groups for the blocking of amines.
- -
-
Page/Page column 13; 14
(2013/07/05)
-
- Enantioselective, chromatography-free synthesis of β3-Amino acids with natural and unnatural side chains
-
β3-Amino acids are key components of some pharmaceuticals, excellent surrogates for metabolically labile α-amino acids, and building blocks for chiral heterocycles. Unfortunately they are not easily accessible in enantiomerically pure form, especially when possessing unnatural side chains. A flexible, chromatography-free process for the synthesis of enantiopure β3-amino acids possessing natural and unnatural side chains is described. The procedure uses inexpensive starting materials and reagents and offers a good alternative to the hazardous and expensive Arndt-Eistert homologation of enantiopure α-amino acids. Its utility has been demonstrated with the preparative scale synthesis of two valuable β3-amino acids possessing unnatural side chains.
- Gerfaud, Thibaud,Chiang, Ying-Ling,Kreituss, Imants,Russak, Justin A.,Bode, Jeffrey W.
-
scheme or table
p. 687 - 696
(2012/07/13)
-
- 2-Oxo-1, 3-dioxolane-4-carboxylic Acid and Derivatives Thereof, Their Preparation and Use
-
2-Oxo-1,3-dioxolane-4-carboxylic acid and derivatives thereof, according to the following formula, in which R1 represents a negative charge, hydrogen or may be methyl or ethyl or an n-valent radical, which may be substituted with at most n?1 further 2-oxo-1,3-dioxolane-4-carboxyl groups, as well as a process for their preparation by means of carboxylation of the corresponding epoxides, a process for their transesterification and their use for the preparation of hydroxyurethanes and as end groups for the blocking of amines.
- -
-
Page/Page column 4
(2012/01/13)
-
- 2-OXO-1,3-DIOXOLANE-4-CARBOXYLIC ACID AND DERIVATIVES THEREOF, THEIR PREPARATION AND USE
-
Proposed are 2-Oxo-1,3-dioxolane-4-carboxylic acid and derivatives thereof, according to the following formula, in which R1 represents a negative charge, hydrogen or can be preferably Me or Et or an n-valent radical, which may be substituted with at most n-1 further 2-oxo-1,3-dioxo- lane-4-carboxyl groups, as well as a process for their preparation by means of carboxylation of the corresponding epoxides, a process for their transesterification and their use for the preparation of hydroxyurethanes and as end groups for the blocking of amines.
- -
-
Page/Page column 9
(2012/01/06)
-
- NEW CHIRAL SALEN CATALYSTS AND METHODS FOR THE PREPARATION OF CHIRAL COMPOUNDS FROM RACEMIC EPOXIDES BY USING THEM
-
The present invention relates to new chiral salen catalysts and the preparation method of chiral compounds from racemic epoxides using the same. More specifically, it relates to new chiral salen catalysts that have high catalytic activity due to new molecular structures and have no or little racemization of the generated target chiral compounds even after the reaction is completed and can be also reused without catalyst regeneration treatment, and its economical preparation method to mass manufacture chiral compounds of high optical purity, which can be used as raw materials for chiral food additives, chiral drugs, or chiral crop protection agents, etc., using the new chiral salen catalysts.
- -
-
Page/Page column 39; 40
(2009/01/24)
-
- Hydrolytic kinetic resolution of epoxides catalyzed by chromium(III)-endo, endo-2,5-diaminonorbornane-salen [Cr(III)-DIANANE-salen] complexes. Improved activity, low catalyst loading
-
The hydrolytic kinetic resolution (HKR) of terminal epoxides, using chiral chromium(III)-salen catalysts based on DIANANE (endo,endo-2,5-diaminonorbornane) , was studied. A broad substrate scope was found for the chromium(III)-DIANANE catalysts, and very low loadings (down to 0.05 mol%) were needed to achieve high enantiomeric purities of both the remaining epoxides and the product diols (up to >99% ee). Besides monosubstituted epoxides, 2-methyl-2-n-pentyloxirane, which is an example for 2,2-disubstituted epoxides, could be ring-opened in an asymmetric fashion with water in the presence of an electronically tuned chromium-(III)-DIANANE complex.
- Berkessel, Albrecht,Ertuerk, Erkan
-
p. 2619 - 2625
(2007/10/03)
-
- Inhibition of the severe acute respiratory syndrome 3CL protease by peptidomimetic α,β-unsaturated esters
-
The proteolytic processing of polyproteins by the 3CL protease of severe acute respiratory syndrome coronavirus is essential for the viral propagation. A series of tripeptide α,β-unsaturated esters and ketomethylene isosteres, including AG7088, are synthesized and assayed to target the 3CL protease. Though AG7088 is inactive (IC50 > 100 μM), the ketomethylene isosteres and tripeptide α,β-unsaturated esters containing both P1 and P2 phenylalanine residues show modest inhibitory activity (IC50 = 11-39 μM). The Phe-Phe dipeptide inhibitors 18a-e are designed on the basis of computer modeling of the enzyme-inhibitor complex. The most potent inhibitor 18c with an inhibition constant of 0.52 μM is obtained by condensation of the Phe-Phe dipeptide α,β-unsaturated ester with 4-(dimethylamino)cinnamic acid. The cell-based assays also indicate that 18c is a nontoxic anti-SARS agent with an EC50 value of 0.18 μM.
- Shie, Jiun-Jie,Fang, Jim-Min,Kuo, Tun-Hsun,Kuo, Chih-Jung,Liang, Po-Huang,Huang, Hung-Jyun,Wu, Yin-Ta,Jan, Jia-Tsrong,Cheng, Yih-Shyun E.,Wong, Chi-Huey
-
p. 5240 - 5252
(2007/10/03)
-
- Mechanistic Investigation Leads to a Synthetic Improvement in the Hydrolytic Kinetic Resolution of Terminal Epoxides
-
The mechanism of the hydrolytic kinetic resolution (HKR) of terminal epoxides was investigated by kinetic analysis using reaction calorimetry. The chiral (salen)Co-X complex (X = OAc, OTs, Cl) undergoes irreversible conversion to (salen)Co-OH during the course of the HKR and thus serves as both precatalyst and cocatalyst in a cooperative bimetallic catalytic mechanism. This insight led to the identification of more active catalysts for the HKR of synthetically useful terminal epoxides. Copyright
- Nielsen, Lars P. C.,Stevenson, Christian P.,Blackmond, Donna G.,Jacobsen, Eric N.
-
p. 1360 - 1362
(2007/10/03)
-
- New oligomeric catalyst for the hydrolytic kinetic resolution of terminal epoxides under solvent-free conditions
-
The solvent-free hydrolytic kinetic resolution of terminal epoxides catalyzed by a new oligomeric (salen)Co complex 2 is described. Extremely low loadings of catalyst were used to provide all epoxides examined in good yields and >99% ee under ambient conditions within 24 h.
- White, David E.,Jacobsen, Eric N.
-
p. 3633 - 3638
(2007/10/03)
-
- Highly selective hydrolytic kinetic resolution of terminal epoxides catalyzed by chiral (salen)CoIII complexes. Practical synthesis of enantioenriched terminal epoxides and 1,2-diols
-
The hydrolytic kinetic resolution (HKR) of terminal epoxides catalyzed by chiral (salen)CoIII complex 1·OAc affords both recovered unreacted epoxide and 1,2-diol product in highly enantioenriched form. As such, the HKR provides general access to useful, highly enantioenriched chiral building blocks that are otherwise difficult to access, from inexpensive racemic materials. The reaction has several appealing features from a practical standpoint, including the use of H2O as a reactant and low loadings (0.2-2.0 mol %) of a recyclable, commercially available catalyst. In addition, the HKR displays extraordinary scope, as a wide assortment of sterically and electronically varied epoxides can be resolved to ≥ 99% ee. The corresponding 1,2-diols were produced in good-to-high enantiomeric excess using 0.45 equiv of H2O. Useful and general protocols are provided for the isolation of highly enantioenriched epoxides and diols, as well as for catalyst recovery and recycling. Selectivity factors (krel) were determined for the HKR reactions by measuring the product ee at ca. 20% conversion. In nearly all cases, krel values for the HKR exceed 50, and in several cases are well in excess of 200.
- Schaus, Scott E.,Brandes, Bridget D.,Larrow, Jay F.,Tokunaga, Makoto,Hansen, Karl B.,Gould, Alexandra E.,Furrow, Michael E.,Jacobsen, Eric N.
-
p. 1307 - 1315
(2007/10/03)
-
- Process for preparing hydroxychomanones and CIS-aminochromanols
-
Enantiomerically enriched hydroxychromanones are obtained by the AlCl3-catalyzed intramolecular Friedel-Crafts acylation of the corresponding 3-phenoxy-2-alkylcarbonyloxy-propionic acid followed by cleavage of the carboxylate in the presence of an alkali metal peroxide or hydroperoxide. Enantiomerically enriched cis-aminochromanols can then be prepared by treating the hydroxychromanones with a hydroxylamine and hydrogenating the resulting oxime. The cis-aminochromanols can be employed as intermediates in the production of HIV protease inhibitors which are useful for treating HIV infection and AIDS.
- -
-
-
- Asymmetric synthesis of cis-aminochromanol
-
An efficient asymmetric synthesis of cis-aminochromanol was achieved in seven steps. The absolute stereochemistry of cis-aminochromanol was derived from (salen)Co(III)-catalyzed phenol opening of methyl glycidate.
- Hansen, Karl B.,Rabbat, Philippe,Springfield, Shawn A.,Devine, Paul N.,Grabowski, Edward J.J.,Reider, Paul J.
-
p. 8743 - 8745
(2007/10/03)
-
- Synthesis and application of novel catalytically active polymers containing 1,4,7-triazacyclononanes
-
New polymers containing 1,4,7-triazacyclononanes have been synthesised by means of ring opening metathesis polymerisation (ROMP); their complexes with Mn(II) catalyse the oxidation of simple olefins by hydrogen peroxide.
- Grenz,Ceccarelli,Bolm
-
p. 1726 - 1727
(2007/10/03)
-
- Mn-trimethyltriazacyclononane/ascorbic acid: A remarkably efficient catalyst for the epoxidation of olefins and the oxidation of alcohols with hydrogen peroxide
-
The system comprised of manganese(II) acetate or sulfate, 1,4,7-trimethyl-1,4,7-triazacyclononane (TMTACN) and ascorbic acid efficiently catalyzes the epoxidation of olefins and the oxidation of alcohols with hydrogen peroxide. For example, in the presence of as little as 0.03 mol% of Mn2+, methyl acrylate is converted to its epoxide in 97% yield. Under the same conditions, 2-pentanol yielded 2-pentanone in almost quantitative yield. With E- and Z-1-deuterio-1-octene as substrates, the epoxidation was shown to proceed with almost exclusive (94±2%) retention of configuration.
- Berkessel, Albrecht,Sklorz, Christoph A.
-
p. 7965 - 7968
(2007/10/03)
-
- Biotransformation and clearance of 3-(phenylamino)propane-1,2-diol, a compound present in samples related to toxic oil syndrome, in C57BL/6 and A/J mice
-
In May 1981, a massive food-borne intoxication occurred in Spain. The so-called toxic oil syndrome (TOS) was associated with the consumption of aniline-denatured and refined rapeseed oil that was illegally sold as edible olive oil. Fatty acid anilides and fatty acid derivatives of 3- (phenylamino)propane-1,2-diol were detected in oils and implicated as potential toxic agents and markers of toxic oil batches. Epidemiological evidence points to 3-(phenylamino)propane-1,2-diol derivatives as the putative toxic agents, which were generated during the refining process at the ITH refinery. Here we present the biotransformation and clearance of 3- (phenylamino)propane-1,2-diol (PAP) administered intraperitoneally to A/J and C57BL/6 mice that have been proposed as a murine model for the immunological features of TOS. Mice eliminated 6 μCi of [U-14C]PAP during a 24 h period, mostly in urine. Animals exhibited urine elimination rates of 70 and 36% in A/J and C57BL/6 strains, respectively. A/J mice exhibited no increase in the elimination rate when induced with β-naphthoflavone, whereas C57BL/6 did increase the rate of elimination to 57%. Feces contributed to a lesser extent to the elimination rate (0.6 and 3.3% in A/J and C57BL/6 mice, respectively). Radioactivity remaining in organ tissues was lower than 1% (liver, lung, kidney, spleen, heart, and muscle). Metabolic species in urine were identified by HPLC coupled to UV and radioisotope detectors and further GC/MS analyses. 2-Hydroxy-3-(phenylamino)propanoic acid metabolite was the major chemical species excreted in urine in both strains, in both control and induced animal groups. This compound was the main urinary metabolite of PAP, and unmetabolized PAP excreted in urine constituted less than 1% of the total administered dose. Two additional highly polar metabolites also detected in urine were identified as 3-[(4'-hydroxyphenyl)amino]propane-1,2-diol and 2- hydroxy-3-[(4'-hydroxyphenyl)amino]propanoic acid. These findings are the first reported on PAP metabolism and clearance in mice strains and suggest that PAP can be extensively metabolized in vivo and potential reactive species can be generated.
- Ladona, Margarita G.,Bujons, Jordi,Messeguer, Angel,Ampurdanes, Coral,Morato, Anna,Corbella, Jacint
-
p. 1127 - 1137
(2007/10/03)
-
- An efficient route to α,β-epoxy ketones of high enantiomerical purity
-
Acylepoxides were obtained in high enantiomeric purity (ee = 92-99%) by addition of organolithium or Grignard reagents to enantiomerically pure methyl or ethyl 2,3-epoxypropanoates at low temperature (-85°C).
- Pegorier,Petit,Mambu,Larcheveque
-
p. 1403 - 1405
(2007/10/02)
-
- ALTERNATIVE ROUTES TO VINCAMINE
-
The preparation of vincamine (1a) via indoloquinolizine propionic esters (7) is discussed.A new synthesis of the starting material methyl 2-acetoxyacrylate and an oxidative transformation of 7b to 1a are described and an alternative, more efficient route is reported.
- Nemes, Andras,Czibula, Laszlo,Visky, Gyorgy,Farkas, Maria,Kreidl, Janos
-
p. 2329 - 2338
(2007/10/02)
-
- Preparation d'α-hydroxyesters et d'α-hydroxyaldehydes enantiomeriquement purs. Application a la synthese enantiospecifique de la pheromone sexuelle de la cochenille Pseudococcus comstocki
-
Enantiomerically pure glycidic esters may be obtained in good yields by nitrous deamination of (S) or (R) serine; 2-bromo-3-hydroxy propionic acid is obtained and cyclized with alcoholic potash to give potassium glycidate; by reacting this salt with a sulfate, a primary iodide or an active bromide in acetonitrile in the presence of 18-crown-6, various glycidic esters were prepared.The ethyl glycidate reacts with lithiocuprates (alkyl or vinyl) but also with magnesiocuprates to afford a totally regiospecific reaction with the exclusive formation of α-hydroxyesters.The reaction is also possible with acetylides but it is necessary to use aluminium acetylides.With organolithium compounds reaction with the ester function of methyl glycidate occurs, leading to the formation of α-epoxyketones.The reduction of α-hydroxyesters (as protected form) with DIBAL-H at -70 deg C affords the corresponding α-hydroxyaldehydes in nearly quantitative yields.These reactions were applied to the synthesis of (R)-(+)-2,6-dimethyl-1,5-heptadien-3-ol acetate, the sex pheromone of the Comstock Mealybug, Pseudococcus comstocki.
- Larcheveque, Marc,Petit, Yves
-
p. 130 - 139
(2007/10/02)
-
- A SIMPLE PREPARATION OF R OR S GLYCIDIC ESTERS; APPLICATION TO THE SYNTHESIS OF ENANTIOMERICALLY PURE α-HYDROXYESTERS
-
The simple preparation of enantiomerically pure α-hydroxyesters by the regioselective reaction of lithio and magnesiocuprates with glycidic esters 3 or 3' readily available from serine is described.
- Larcheveque, Marc,Petit, Yves
-
p. 1993 - 1996
(2007/10/02)
-