- SiO2 catalysed expedient synthesis of [E]-3-alkenoic acids in dry media
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Aliphatic aldehydes with α-hydrogens and malonic acid undergo decarboxylative condensation on the surface of SiO2 when subjected to microwave irradiation generating βγ-unsaturated acids in high yields.
- Kumar, H.M. Sampath,Reddy, B.V. Subba,Reddy, E. Jagan,Yadav
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- β-alanine-DBU: A highly efficient catalytic system for knoevenagel-doebner reaction under mild conditions
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A mild and efficient Knoevenagel-Doebner reaction from malonic acid and a wide range of aldehydes was catalyzed by a catalytic system consisting of β-alanine and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), affording the corresponding (E)-α,β-unsaturated carboxylic acids in good to excellent yields and with high stereoselectivity. The advantage of the method is that the reaction could proceed smoothly at ambient temperature so that it can tolerate a variety of functional groups and avoid unnecessary side reactions. Copyright
- Zhu, Lingjian,Lei, Ning,Miao, Zhenyuan,Sheng, Chunquan,Zhuang, Chunlin,Yao, Jianzhong,Zhang, Wannian
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- Base-Catalyzed Reactions of α,β-Unsaturated Esters and Nitriles. 4. Dimerization of β-Alkyl-Substituted Acrylates
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2-Butenoates 1-C4 alkyl, cyclohexyl, or 1-bornyl> and higher β-alkyl-substituted acrylates 2-C9 n-alkyl> undergo highly selective (>95percent) dimerization in the presence of promoted potassium or sodium catalysts to yield corresponding 2-alkylidene-3-alkylglutarates (3).The reaction involves metalation of the β-alkylacrylate at the C-2 position, followed by addition at C-3 of a second monomeric molecule.Changes in the relative extent of dimerization (Kr) as a function of structural and experimentalvariables were determined.Kr is strongly dependent upon the inductive and steric characteristics of the alcoholic (R) group and of the β-alkyl substituent (R').For an n-alkyl group as R' the Kr value increases with increase in chain length from C1 to C4 but then decreases for longer substituents (C5-C9).Among the two geometric isomers in the dimeric product 3, the isomer with an α-vinylic hydrogen cis to the carboalkoxy group is predominant in all cases, but its relative concetration decreases with an increase in the size of R'.Branched or cyclic β-substituents in 2 prevent dimerization due to steric hindrance in the rate-determining addition step.Promoted potassium or sodium catalysts show much higher dimerization activity compared to supported alkali metals or to alkoxides.For conversions of up to 60percent, Kr values in proton-exchanging alkylbenzene solvents and in nonexchanging alkylcyclohexanes are closely similar, indicating faster abstraction of an α-vinylic hydrogen from the monomer, rather than a benzylic hydrogen from the solvent, in the chain regeneration step of the reaction.
- Shabtai, Joseph,Ney-Igner, Eva
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- Studies in Decarboxylation. Part 13. The Incursion of a Stepwise Mechanism in the Gas-phase Decarboxylation of Cyclopropylacetic Acids
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The cyclopropylacetic acids (I)-(IV) have been decarboxylated in the temperature range 720-820 K.It is demonstrated that at 725 K, 2',2'-dimethylcyclopropylacetic acid is decarboxylated by both concerted and stepwise mechanisms.The latter is favoured by higher temperature.Cyclopropylacetic acid is decarboxylated by the concerted mechanism at 725 K, but also exhibits the stepwise mechanism at higher temperature.
- Bigley, David B.,Fetter, Clive L.,Clarke, Michael J.
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- MODIFIED KNOEVENAGEL CONDENSATIONS. SYNTHESIS OF (E)-3-ALKENOIC ACIDS.
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Condensation of aliphatic aldehydes with a three molar excess of malonic acid and 0.001 mole piperidinium acetate in refluxing xylene, with continuous removal of the water formed, gave almost exclusively (E)-3-alkenoic acids, in good yield (60-85percent) and of high stereochemical purity (95-99percent).
- Ragoussis, Nikitas
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- Inhibitors of Thermus thermophilus isopropylmalate dehydrogenase
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In an attempt to use mechanism-based design for the discovery of inhibitors of the isopropylmalate dehydrogenase from T. thermophilus, we have prepared and studied a number of potential mimics for an intermediate in the oxidative decarboxylation of isopropyl malate, the enol or enolate of α-ketoisocaproate. Because hydroxamate and dicarboxylate enolate mimics are strong, uncompetitive inhibitors of the enzyme and vinyl fluoride enol mimics are weak, competitive inhibitors, it is suggested that the reaction involves the enolate. The uncompetitive inhibition by a number of anionic compounds suggests, in combination with previous studies in other laboratories, that they mimic the enolate product of the decarboxylation. An explanation for the potency of the inhibition of IMDH by these compounds is proposed based on the electrostatic interaction of product and cofactor.
- Pirrung,Han,Ludwig
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- Palladium-Catalyzed Low Pressure Carbonylation of Allylic Alcohols by Catalytic Anhydride Activation
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A direct carbonylation of allylic alcohols has been realized for the first time with high catalyst activity at low pressure of CO (10 bar). The procedure is described in detail for the carbonylation of E-nerolidol, an important step in a new BASF-route to (?)-ambrox. Key to high activities in the allylic alcohol carbonylation is the finding that catalytic amounts of carboxylic anhydride activate the substrate and are constantly regenerated with carbon monoxide under the reaction conditions. The identified reaction conditions are transferrable to other substrates as well.
- Schelwies, Mathias,Paciello, Rocco,Pelzer, Ralf,Siegel, Wolfgang,Breuer, Michael
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- Enantioselective conjugate addition of a lithium ester enolate catalyzed by chiral lithium amides
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(Diagram presented) Mixed aggregates of chiral lithium amide and lithium ester enolate have been employed in the enantioselective conjugate addition on α,β-unsaturated esters. Michael adducts were obtained in ee's up to 76% combining a lithium enolate and a chiral 3-aminopyrrolidine lithium amide. The sense of the induction was found to be determined by both the relative configuration of the stereogenic centers borne by the amide and the solvent in which the reaction was conducted.
- Duguet, Nicolas,Harrison-Marchand, Anne,Maddaluno, Jacques,Tomioka, Kiyoshi
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- Chemoselective γ-Oxidation of β,γ-Unsaturated Amides with TEMPO
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A chemoselective and robust protocol for the γ-oxidation of β,γ-unsaturated amides is reported. In this method, electrophilic amide activation, in a rare application to unsaturated amides, enables a regioselective reaction with TEMPO resulting in the title products. Radical cyclisation reactions and oxidation of the synthesised products highlight the synthetic utility of the products obtained.
- Heindl, Sebastian,Lemmerer, Miran,Malzer, Nicolas,Matyasovsky, Ján,Maulide, Nuno,Riomet, Margaux
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- COVALENT RAS INHIBITORS AND USES THEREOF
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The disclosure features compounds, or pharmaceutically acceptable salts thereof, alone and in combination with other therapeutic agents, pharmaceutical compositions, and protein conjugates thereof, capable of modulating biological processes including Ras, and their uses in the treatment of cancers.
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- RAS INHIBITORS
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The disclosure features macrocyclic compounds, and pharmaceutical compositions and protein complexes thereof, capable of inhibiting Ras proteins, and their uses in the treatment of cancers.
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Paragraph 1636-1637
(2021/05/07)
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- METHOD FOR THE SYNTHESIS AND PRODUCTION OF ALKENYL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing an efficient alkenyl compound conveniently and inexpensively. SOLUTION: A first compound represented by formula (1) reacts with a second compound represented by formula (3), in the presence of amino acid, in solvent containing amine, in a range of 50-200°C, to produce an alkenyl compound represented by formula (A) [where R1 is hydrogen or an optionally substituted C1-C30 alkyl group, R2 is a carboxyl group or the like, R3 and R4 are hydrogen, an optionally substituted C1-C30 alkyl group or the like]. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0083
(2018/09/20)
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- Chiral integrated catalysts composed of bifunctional thiourea and arylboronic acid: Asymmetric aza-Michael addition of α,β-unsaturated carboxylic acids
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The first intermolecular asymmetric Michael addition of nitrogen-nucleophiles to α,β-unsaturated carboxylic acids was achieved through a new type of arylboronic acid equipped with chiral aminothiourea. The use of BnONH2 as a nucleophile gives a range of enantioenriched β-(benzyloxy)amino acid derivatives in good yields and with high enantioselectivity (up to 90% yield, 97% enantiomeric excess (ee)). The obtained products are efficiently converted to optically active β-amino acid and 1,2-diamine derivatives.
- Hayama, Noboru,Azuma, Takumi,Kobayashi, Yusuke,Takemoto, Yoshiji
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p. 704 - 717
(2016/07/19)
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- Application of chiral ligands: Carbohydrates, nucleoside-lanthanides and other Lewis acid complexes to control regio- and stereoselectivity of the dipolar cycloaddition reactions of nitrile oxides and esters
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Chiral Lewis acid mediated 1,3-dipolar cycloaddition reactions of 4-trifluoromethylbenzonitrile oxide to methyl crotonate as well to β-substituted acrylates and (Z)-pent-2-en-1-yl esters were examined. Excellent enantioselectivities with moderate to good regioselectivities were achieved for crotonates with complexes of BiBr3 with (+)-(4,6-benzylidene)methyl-α-d-glucopyranoside C, with the l-ascorbic acid I-FeCl3 system, and with lipase Candida antarctica. High enantiomeric excess was observed for isopropyl ester and benzyl ester. The outstanding ee values were achieved for acrylates with β-t-butyl, cyclohexyl, and 1,3-benzodioxol-5-yl groups in cycloadditions catalyzed by C-Yb(OTf)3 and the (+)-2-hydroxy-3-pinanone N-TiCl4 system. High enantioselectivities were found in reactions of (Z)-pent-2-en-1-yl esters mediated by complexes N-Mg(OTf)2 and N-TiCl4.
- Gucma, Miroslaw,Golbiewski, W. Marek,Krawczyk, Maria
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p. 13112 - 13124
(2015/02/19)
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- Synthetic approaches to the daucane sesquiterpene derivatives employing the intramolecular Buchner cyclisation of α-diazoketones
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The use of the intramolecular Buchner cyclisation of an α-diazoketone as an approach to the synthesis of daucane sesquiterpenes is described; in particular the synthesis of the cis-fused analogue of dihydro CAF-603. The key step in the synthesis is the intramolecular Buchner cyclisation, which provides the bicyclo[5.3.0]decane framework with the required stereochemistry at the quaternary centre generated in the cyclisation. A synthetic route enabling access to an asymmetric synthesis is also outlined.
- Foley, David A.,O'Leary, Patrick,Buckley, N. Rachael,Lawrence, Simon E.,Maguire, Anita R.
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p. 1778 - 1794
(2013/03/13)
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- Asymmetric synthesis of cis-7-methoxycalamenene via the intramolecular buchner reaction of an α-diazoketone
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The asymmetric synthesis of cis-7-methoxycalamenene 1 has been accomplished using the intramolecular Buchner reaction of α-diazoketone 7 as the key step in the synthetic route. Upon reduction of the equilibrating azulenone structure 8, the resulting azulenol 9 rearranges to dihydronaphthalene 10 containing the 6,6-membered bicyclic ring system characteristic of 1, by means of an acid-catalyzed aromatization process. Transformation of 10 to 1 is accomplished through a three-step reaction sequence.
- McDowell, Paul A.,Foley, David A.,O'Leary, Patrick,Ford, Alan,Maguire, Anita R.
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experimental part
p. 2035 - 2040
(2012/05/04)
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- Discovery of 4-[4-({(3R)-1-butyl-3-[(R)-cyclohexyl(hydroxy)methyl]-2,5- dioxo-1,4,9-triazaspiro[5.5]undec-9-yl}methyl)phenoxy]benzoic acid hydrochloride: A highly potent orally available CCR5 selective antagonist
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Based on the original spirodiketopiperazine design framework, further optimization of an orally available CCR5 antagonist was undertaken. Structural hybridization of the hydroxylated analog 4 derived from one of the oxidative metabolites and the new orally available non-hydroxylated benzoic acid analog 5 resulted in another potent orally available CCR5 antagonist 6a as a clinical candidate. Full details of a structure-activity relationship (SAR) study and ADME properties are presented.
- Nishizawa, Rena,Nishiyama, Toshihiko,Hisaichi, Katsuya,Minamoto, Chiaki,Murota, Masayuki,Takaoka, Yoshikazu,Nakai, Hisao,Tada, Hideaki,Sagawa, Kenji,Shibayama, Shiro,Fukushima, Daikichi,Maeda, Kenji,Mitsuya, Hiroaki
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experimental part
p. 4028 - 4042
(2011/08/21)
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- METHOD FOR THE DECARBOXYLATIVE HYDROFORMYLATION OF ALPHA, BETA- UNSATURATED CARBOXYLIC ACIDS
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The present invention relates to a process for preparing aldehydes by reacting an α,β-unsaturated carboxylic acid or a salt thereof with carbon monoxide and hydrogen in the presence of a catalyst comprising at least one complex of a metal of transition group VIII of the Periodic Table of the Elements with at least one compound of the formula (I), where Pn is pnicogen; W is a divalent bridging group having from 1 to 8 bridge atoms between the flanking bonds; R1 is a functional group capable of forming at least one intermolecular, noncovalent bond with the —X(═O)OH group of the compound of the formula (I); R2, R3 are each in each case optionally substituted alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl or together with the pnicogen atom and together with the groups Y2 and Y3 if present form an optionally fused and optionally substituted 5- to 8-membered heterocycle; a, b and c are each 0 or 1; and Y1,2,3 are each, independently of one another, O, S, NRa or SiRbRc, where Ra,b,c are each H or in each case optionally substituted alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl; and the use of the above-described catalyst for the decarboxylative hydroformylation of α,β-unsaturated carboxylic acids.
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(2011/02/25)
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- Method for regio- and stereoselective synthesis of (E)-Β,γ- unsaturated acids from aldehydes under solvent-free conditions
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Synthesis of (E)-β,-γunsaturated acids from aldehydes with malonic acid has been explored under solvent-free conditions. The modified Knoevenagel condensation reaction with N-methyl morpholine (NMM) as catalyst exhibits highly β,-γ regioselectivity and exclusively E-stereoselectivity. A mechanism accounting for both regio- and stereoselectivity has been proposed and preliminarily studied. Copyright Taylor & Francis Group, LLC.
- Zhang, Shi-Jie,Hu, Wei-Xiao
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experimental part
p. 3093 - 3100
(2010/12/19)
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- Combined transition-metal- and organocatalysis: An atom economic C3 homologation of alkenes to carbonyl and carboxylic compounds
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A combination of regioselective room-temperature/ambient-pressure hydroformylation (transitionmetal catalysis) and decarboxylative Knoevenagel reactions (organocatalysis) allowed for the development of an efficient, one-pot C3 homologation of terminal alkenes to (E)-α,β-unsaturated acids and esters, (E)-β,γ-unsaturated acids, (E)-α-cyano acrylic acids, and α,β-unsaturated nitriles. All reactions proceed under mild conditions, tolerate a variety of functional groups, and furnish unsaturated carbonyl compounds in good yields and with excellent regioand stereocontrol. Further, an iterative C2 homologation of (E)-α,β-unsaturated carboxylic acids is possible through a combination of decarboxylative hydroformylation employing a supramolecular catalyst followed by decarboxylative Knoevenagel condensation with an organocatalyst.
- Kemme, Susanne T.,Smejkal, Tomas,Breit, Bernhard
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supporting information; experimental part
p. 3423 - 3433
(2010/06/21)
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- A supramolecular catalyst for the decarboxylative hydroformylation of α,β-unsaturated carboxylic acids
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(Chemical Equation Presented) Head 'em up, move 'em out, aldehyde! A catalytic transformation of α,β-unsaturated carboxylic acids into aldehydes through a hydroformylation-decarboxylation process has been developed (see scheme; Do = donor ligand, FG1 and FG2 = complementary functional groups). The reaction proceeds at mild conditions, tolerates many functional groups, and liberates CO2 as the only stoichiometric by-product.
- Smejkal, Tomas,Breit, Bernhard
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p. 3946 - 3949
(2008/12/23)
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- Organocatalysis in conjugate amine additions. Synthesis of β-amino acid derivatives
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Conjugate addition of O-protected hydroxylamines to pyrazole-derived enoates proceeds with high efficiency and enantioselectivity when chiral thioureas are used as activators. A wide variety of substrates undergo conjugate amine addition providing access to enantioenriched β-amino acid derivatives. Structural requirements for the optimal thiourea catalyst have been established, and the results suggest that it operates as a bifunctional catalyst. Copyright
- Sibi, Mukund P.,Itoh, Kennosuke
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p. 8064 - 8065
(2008/02/09)
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- Mild zinc-promoted Horner-Wadsworth-Emmons reactions of diprotic phosphonate reagents
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We report the development of a mild protocol for the Horner-Wadsworth- Emmons reaction of diprotic phosphonates that makes use of a zinc triflate promoter in the presence of mild ter-tiary amine bases to produce α,β-unsaturated carboxylic acids and amides. Georg Thieme Verlag Stuttgart.
- Schauer, Douglas J.,Helquist, Paul
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p. 3654 - 3660
(2008/03/13)
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- Structure-activity relationships of pregabalin and analogues that target the α2-δ protein
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Pregabalin exhibits robust activity in preclinical assays indicative of potential antiepileptic, anxiolytic, and antihyperalgesic clinical efficacy. It binds with high affinity to the α2-δ subunit of voltage-gated calcium channels and is a substrate of the system L neutral amino acid transporter. A series of pregabalin analogues were prepared and evaluated for their α2-δ binding affinity as demonstrated by their ability to inhibit binding of [3H]gabapentin to pig brain membranes and for their potency to inhibit the uptake of [3H]leucine into CHO cells, a measure of their ability to compete with the endogenous substrate at the system L transporter. Compounds were also assessed in vivo for their ability to promote anxiolytic, analgesic, and anticonvulsant actions. These studies suggest that distinct structure activity relationships exist for α2-δ binding and system L transport inhibition. However, both interactions appear to play an important role in the in vivo profile of these compounds.
- Belliotti, Thomas R.,Capiris, Thomas,Ekhato, I. Victor,Kinsora, Jack J.,Field, Mark J.,Heffner, Thomas G.,Meltzer, Leonard T.,Schwarz, Jacob B.,Taylor, Charles P.,Thorpe, Andrew J.,Vartanian, Mark G.,Wise, Lawrence D.,Zhi-Su, Ti,Weber, Mark L.,Wustrow, David J.
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p. 2294 - 2307
(2007/10/03)
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- Competitive formation of β-amino acids, propenoic, and ylidenemalonic acids by the Rodionov reaction from malonic acid, aldehydes, and ammonium acetate in alcoholic medium
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The Rodionov reaction of 49 available aliphatic and aromatic aldehydes with malonic acid and ammonium acetate in alcoholic medium, resulting in formation of β-amino acids, propenoic, and ylidenemalonic acids, was studied. Certain regioselectivity regularities of the reaction were revealed. Among the variety of ketones studied, cyclohexanone is the only whose reaction yields a β-amino acid. Unusual dehydrofluorination of 6-chloro-2-fluorocinnamic acid under the Rodionov reaction was discovered. 2005 Pleiades Publishing, Inc.
- Lebedev,Lebedeva,Sheludyakov,Kovaleva,Ustinova,Kozhevnikov
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p. 1113 - 1124
(2007/10/03)
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- Two-carbon homologation of aldehydes via silyl ketene acetals. 2. Study of the stereochemical control in the formation of (E)-alkenoic acids
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The condensation of C,O,O-tris(trimethylsilyl)ketene acetal 1 with aldehydes 2 in the presence of catalytic amounts of mercuric iodide at room temperature affords syn and anti β-trimethylsiloxy α-trimethylsilyl alkanoic acid silyl esters 3 in good yields. These new compounds gave, under acidic or basic conditions, E and (or) Z enoic acids 4. The paths for the formation of these alkenoic acids are discussed.
- Bellassoued,Mouelhi,Lensen
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p. 5054 - 5057
(2007/10/03)
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- Two-carbon homologation of aldehydes via silyl ketene acetals: A new stereoselective approach to (E)-alkenoic acids
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Aldehydes are converted into (E)-α,β-unsaturated carboxylic acids using C,O,O-tris(trimethylsilyl)ketene acetal 1. This organosilicon reagent is easily generated from trimethylsilyl acetate, LDA, and chlorotrimethylsilane. The effectiveness of the reaction has been explored for a large variety of aldehydes with Lewis acids and fluorides as catalysts.
- Bellassoued, Moncef,Lensen, Nathalie,Bakasse, Mina,Mouelhi, Sinda
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p. 8785 - 8789
(2007/10/03)
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- Total asymmetric synthesis of highly constrained amino acids β-isopropyl-2',6'-dimethyl-tyrosines
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All four stereoisomers of the highly constrained aromatic α-amino acid β-isopropyl-2',6'-dimethyltyrosine have been asymmetrically synthesis on a large scale. A catalytic asymmetric Michael addition of an organocuprate to a chiral α,β-unsaturated acyloxazolidinone and subsequent direct or indirect stereoselective electrophilic azidation of the α-position of the resulting product was followed by hydrolysis, hydrogenation and finally deprotection of the phenol group to afford the desired amino acids. The reactions generally proceeded in good stereoselectivities (75-95% ee/de) and yields (70-90%), making these optically pure amino acids available in large scale practical for the synthesis of peptides and other studies.
- Han, Yinglin,Liao, Subo,Qiu, Wei,Cai, Chaozhong,Hruby, Victor J.
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p. 5135 - 5138
(2007/10/03)
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- Efficient chemoenzymatic synthesis of (2S,3S)-3-hydroxyleucine mediated by immobilised penicillin G acylase
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Immobilised penicillin G acylase (EC 3.5.1.11) has been used in the key step to obtain optically pure (2S,3S)-(+)-hydroxyleucine (ee >99%).
- Fadnavis, Nitin W.,Sharfuddin,Vadivel, S. Kumara,Bhalerao, Uday T.
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p. 3577 - 3578
(2007/10/03)
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- Investigations on the Selectivity of the β-Scission of Alkyl-Radicals, II - Selectivity of the β-Fragmentation of α-(Methoxycarbonyl)alkyl Radicals
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The rate of β-scission of α-(methoxycarbonyl)alkyl radicals 3 and 9, generated by addition of cycloalkyl radicals to appropriate methyl 2-methylenealkanoates 1 and methyl (E)-2-alkenoates 8, resp., has been measured relative to the hydrogen transfer from cycloalkanes.The rate of β-scission increases with increasing stability of the leaving radical R*.Polar effects reversing the stability sequence have also been observed, e.g. the more stable (methoxycarbonyl)methyl radical leaves more slowly than a less stable secondary alkyl radical.
- Metzger, Juergen O.,Klenke, Kurt
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p. 875 - 879
(2007/10/02)
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- STEREOSELECTIVE SYNTHESIS OF (E)-α,β-UNSATURATED ACIDS FROM C,O,O-TRI(TRIMETHYLSILYL) KETENE ACETAL AND ALDEHYDS
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Aldehydes are converted into (E)-α,β-unsatured carboxylic acids by means of C,O,O-tri(trimethylsilyl) ketene acetal and a catalytic a mount of ZnBr2.
- Bellasoued, Moncef,Gaudemar, Marcel
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p. 4551 - 4554
(2007/10/02)
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- OXIDATION OF ALCOHOLS BY ELECTROCHEMICALLY REGENERATED NICKEL OXIDE HYDROXIDE. SELECTIVE OXIDATION OF HYDROXYSTEROIDS
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Primary alcohols, α,ω-diols and secondary alcohols are easily transformed into carboxylic acids, dicarboxylic acids or ketones, respectively, by heterogeneous oxidation with nickel oxide hydroxide electrochemically regenerated at a nickel hydroxyde electrode.The results are discussed in comparison to those of the nickel peroxide and chromic acid oxidation.The oxidation rate decreases with increasing steric hindrance of the alcohol, thus allowing the selective oxidation of the 3-position in hydroxysteroids.
- Kaulen, Johannes,Schaefer, Hans-J.
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p. 3299 - 3308
(2007/10/02)
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- STEREOCHEMISTRY OF THE ADDITION OF SECONDARY AMINES TO VINYLACETYLENIC YNAMINES
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The addition of allylic and propargyl secondary amines and aliphatic-aromatic amines to 1-dialkylamino-3-penten-1-ynes under acid catalysis conditions proceeds regioselectively at the acetylenic bond and stereospecifically as a cis process.
- Tolchinskii, S. E.,Maretina, I. A.
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p. 1034 - 1038
(2007/10/02)
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- Synthesis of E-4-Methyl-4-hydroxypenten-2-oic Acid
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Isobutanal on condensation with malonic acid yields Δα-isohexenoic acid (II), the ester (III) of which on NBS bromination furnishes ethyl 4-bromo-4-methylpenten-2-oate (IV).Treatment of IV with moist silver oxide yields the corresponding 4-hydroxyester which on hydrolysis with 5 percent KOH gives the title acid (I), identical (m.m.p, co-TLC and IR) with a natural sample.
- Agarwal, S. G.,Thappa, R. K.,Dhar, K. L.,Atal, C. K.
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p. 164 - 165
(2007/10/02)
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