- Design, synthesis and antimalarial evaluation of novel thiazole derivatives
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As part of our medicinal chemistry program's ongoing search for compounds with antimalarial activity, we prepared a series of thiazole analogs and conducted a SAR study analyzing their in vitro activities against the chloroquine-sensitive Plasmodium falciparum 3D7 strain. The results indicate that modifications of the N-aryl amide group linked to the thiazole ring are the most significant in terms of in vitro antimalarial activity, leading to compounds with high antimalarial potency and low cytotoxicity in HepG2 cell lines. Furthermore, the observed SAR implies that non-bulky, electron-withdrawing groups are preferred at ortho position on the phenyl ring, whereas small atoms such as H or F are preferred at para position. Finally, replacement of the phenyl ring by a pyridine affords a compound with similar potency, but with potentially better physicochemical properties which could constitute a new line of research for further studies.
- Bueno, José María,Carda, Miguel,Crespo, Benigno,Cu?at, Ana Carmen,de Cozar, Cristina,León, María Luisa,Marco, J. Alberto,Roda, Nuria,Sanz-Cervera, Juan F.
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- Novelty of immobilized enzymatic synthesis of 3-ethyl-1,3-oxazolidin-2-one using 2-aminoalcohol and dimethyl carbonate: Mechanism and kinetic modeling of consecutive reactions
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Oxazolidinones are multifunctional compounds possessing diverse biological and pharmacological activity. Enzymatic synthesis of oxazolidin-2-one was studied using 2-aminoalochol and dimethyl carbonate and synthesis of 3-ethyl-1,3-oxazolidin-2-one was chosen as the model reaction using a variety of immobilized lipases; among which Candida antarctica lipase B (Novozyme 435) was the best catalyst. The reaction leads to the final product oxazolidin-2-one via methyl ethyl (2-hydroxyethyl) carbamate as the intermediate. The parameters affecting rate of reaction and the conversion of both steps were studied systematically and covered effects of agitation speed, solvent, catalyst loading and reaction temperature. A reaction mechanism was proposed wherein the coproduct methanol is generated in the first step leading to the formation of methyl ethyl (2-hydroxyethyl) carbamate as the intermediate which rearranges itself leading to the final products 3-ethyl-1,3-oxazolidin-2-one and methanol. The kinetic constant and activation energy were determined for each step of the reaction. The study was further extended to other 2-aminoalochols under optimized reaction conditions to prepare different oxazolidinones. This is a first report of its kind describing kinetics and mechanism of bimolecular consecutive enzyme catalyzed reactions.
- Yadav, Ganapati D.,Pawar, Sandip V.
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- Self-immolative polymers containing rapidly cyclizing spacers: Toward rapid depolymerization rates
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Self-immolative polymers containing 4-hydroxybenzyl alcohol alternating with either N-methylaminoethanol or 2-mercaptoethanol spacers were synthesized and demonstrated to controllably depolymerize in response to the cleavage of a stabilizing end-cap from
- Chen, Eric K. Y.,McBride, Ryan A.,Gillies, Elizabeth R.
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- Facile formation of N-alkyl-oxazolidin-2-ones from N-alkyl- nitroxyethylamines and carbonate anion in biphasic media
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Nitration of N-alkyl ethanolamines (1) followed by treatment of their corresponding N-alkyl-N-(2-nitroxyethyl)amine salts (2) in a biphasic CH2Cl2/aqueous Na2CO3 or NaHCO3 mixture at 25°C gives N-alkyl- oxazolidin-2-ones (3). This represents a new method that allows the preparation of oxazolidinones at ambient temperature with the use of aqueous carbonate.
- Sitzmann, Michael E.,Kenar, James A.,Trivedi, Nirupam J.
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- Damage and Repair in Informational Poly(N-substituted urethane)s
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The degradation and repair of uniform sequence-defined poly(N-substituted urethane)s was studied. Polymers containing an ω-OH end-group and only ethyl carbamate main-chain repeat units rapidly degrade in NaOH solution through an ω→α depolymerization mechanism with no apparent sign of random chain cleavage. The degradation mechanism is not notably affected by the nature of the side-chain N-substituents and took place for all studied sequences. On the other hand, depolymerization is significantly influenced by the molecular structure of the main-chain repeat units. For instance, hexyl carbamate main-chain motifs block unzipping and can therefore be used to control the degradation of specific sequence sections. Interestingly, the partially degraded polymers can also be repaired; for example by using a combination of N,N′-disuccinimidyl carbonate with a secondary amine building-block. Overall, these findings open up interesting new avenues for chain-healing and sequence editing.
- Charles, Laurence,Lutz, Jean-Fran?ois,Mondal, Tathagata
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supporting information
p. 20390 - 20393
(2020/09/21)
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- Visible-Light-Mediated Liberation and In Situ Conversion of Fluorophosgene
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The first example for the photocatalytic generation of a highly electrophilic intermediate that is not based on radical reactivity is reported. The single-electron reduction of bench-stable and commercially available 4-(trifluoromethoxy)benzonitrile by an organic photosensitizer leads to its fragmentation into fluorophosgene and benzonitrile. The in situ generated fluorophosgene was used for the preparation of carbonates, carbamates, and urea derivatives in moderate to excellent yields via an intramolecular cyclization reaction. Transient spectroscopic investigations suggest the formation of a catalyst charge-transfer complex-dimer as the catalytic active species. Fluorophosgene as a highly reactive intermediate, was indirectly detected via its next downstream carbonyl fluoride intermediate by NMR. Furthermore, detailed NMR analyses provided a comprehensive reaction mechanism including a water dependent off-cycle equilibrium.
- Petzold, Daniel,Nitschke, Philipp,Brandl, Fabian,Scheidler, Veronica,Dick, Bernhard,Gschwind, Ruth M.,K?nig, Burkhard
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supporting information
p. 361 - 366
(2018/11/23)
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- Synthesis and kinetics of disassembly for silyl-containing ethoxycarbonyls using fluoride ions
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In this study, a series of silyl-containing ethoxycarbonates and ethoxycarbamates on electron poor anilines and phenols were synthesized and their kinetics of disassembly determined in real-time upon exposure to fluoride ion sources at room temperature. The results provide a greater understanding of stability and kinetics for silyl-containing protecting groups that eliminate volatile molecules upon removal, which will allow for simplification of orthogonal protection in complex organic molecules.
- Camerino, Eugene,Daniels, Grant C.,Wynne, James H.,Iezzi, Erick B.
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p. 1884 - 1888
(2018/02/06)
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- Copper(II)-catalysed oxidative carbonylation of aminols and amines in water: A direct access to oxazolidinones, ureas and carbamates
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Copper(II) chloride catalyses the oxidative carbonylation of aminols, amine and alcohols to give 2-oxazolidinones, ureas and carbamates. Reaction proceeds smoothly in water under homogeneous conditions (Ptot = 4 MPa; PO2 = 0.6 MPa, PCO), at 100°C in relatively short reaction times (4 h) and without using bases or any other additives. This methodology represents an economic and environmentally benign non-phosgene alternative for the preparation of these three important N-containing carbonyl compounds.
- Casiello, Michele,Iannone, Francesco,Cotugno, Pietro,Monopoli, Antonio,Cioffi, Nicola,Ciminale, Francesco,Trzeciak, Anna M.,Nacci, Angelo
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- Combining Low-Pressure CO2 Capture and Hydrogenation to Form Methanol
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This paper describes a novel approach to CO2 hydrogenation, in which CO2 capture with aminoethanols at low pressure is coupled with hydrogenation of the captured product, oxazolidinone, directly to MeOH. In particular, (2-methylamino)ethanol or valinol captures CO2 at 1-3 bar in the presence of catalytic Cs2CO3 to give the corresponding oxazolidinones in up to 65-70 and 90-95% yields, respectively. Efficient hydrogenation of oxazolidinones was achieved using PNN pincer Ru catalysts to give the corresponding aminoethanol (up to 95-100% yield) and MeOH (up to 78-92% yield). We also have shown that both CO2 capture and oxazolidinone hydrogenation can be performed in the same reaction mixture using a simple protocol that avoids intermediate isolation or purification steps. For example, CO2 can be captured by valinol at 1 bar with Cs2CO3 catalyst followed by 4-isopropyl-2-oxazolidinone hydrogenation in the presence of a bipy-based pincer Ru catalyst to produce MeOH in 50% yield after two steps.
- Khusnutdinova, Julia R.,Garg, Jai Anand,Milstein, David
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p. 2416 - 2422
(2015/04/14)
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- Novelty of immobilized enzymatic synthesis of 3-ethyl-1,3-oxazolidin-2-one using 2-aminoalcohol and dimethyl carbonate: Mechanism and kinetic modeling of consecutive reactions
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Oxazolidinones are multifunctional compounds possessing diverse biological and pharmacological activity. Enzymatic synthesis of oxazolidin-2-one was studied using 2-aminoalochol and dimethyl carbonate and synthesis of 3-ethyl-1,3-oxazolidin-2-one was chosen as the model reaction using a variety of immobilized lipases; among which Candida antarctica lipase B (Novozyme 435) was the best catalyst. The reaction leads to the final product oxazolidin-2-one via methyl ethyl (2-hydroxyethyl) carbamate as the intermediate. The parameters affecting rate of reaction and the conversion of both steps were studied systematically and covered effects of agitation speed, solvent, catalyst loading and reaction temperature. A reaction mechanism was proposed wherein the coproduct methanol is generated in the first step leading to the formation of methyl ethyl (2-hydroxyethyl) carbamate as the intermediate which rearranges itself leading to the final products 3-ethyl-1,3-oxazolidin-2-one and methanol. The kinetic constant and activation energy were determined for each step of the reaction. The study was further extended to other 2-aminoalochols under optimized reaction conditions to prepare different oxazolidinones. This is a first report of its kind describing kinetics and mechanism of bimolecular consecutive enzyme catalyzed reactions.
- Yadav, Ganapati D.,Pawar, Sandip V.
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- Interaction of substrate and catalyst during the formation of oxazolidinones from 2-aminoalcohols and diethyl carbonate using recyclable 1,3-dichlorodistannoxanes
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An efficient synthesis of oxazolidinone (OXZ) using 2-aminoalcohols (2AAs) and diethyl carbonate (DEC) as reagents in the presence of recyclable catalyst 1,3-dichloro-1,1,3,3-tetraalkyldistannoxane, [(RR′SnCl)2O] 2 (1) is reported. 0.5 mol% (with respect to 2AA) of 1 provides OXZ quantitatively within 1 h at 80 °C with turnover frequency (TOF) of 200 h-1. The observed TOF is much higher than the reported value (4 h-1) of the most convenient and commercially feasible K 2CO3 catalyst. Chiral 2AAs produce OXZs with 99% ee. Molar dependency of 1, DEC and 2AA is found to be 1:2:2. Molar conductivities (Ω-1 cm2 mol-1) in DMSO at 25 °C are 6.41 for 1a (R = R′ = Bu), 5.25 for 1b (R = Bu, R′ = Ph), 2.87 for 1c (R = Ph, R′ = Bu), and 2.21 for 1d (R = R′ = Ph) which reveal the mobility of bridged Cl in 1 during reaction. The study of a broad range of substrates and reaction parameters supports a reaction pathway that begins with initial attack by -OH of the pre-formed 2-ethylcarbamato aminoalcohol (2ECA) of 2AA on Snb of 1 displacing the bridged Cl. Change in the reaction rates resulted due to various alkyl and aryl substituents on Sn provides better understanding of the distannoxane catalysis, which has not been attempted before for the said reaction.
- Pulla, Sharon,Unnikrishnan, Vineed,Ramidi, Punnamchandar,Sullivan, Shane Z.,Ghosh, Anindya,Dallas, Jerry L.,Munshi, Pradip
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experimental part
p. 33 - 43
(2011/05/02)
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- Amidite for synthesizing modified nucleic acid and method for synthesizing modified nucleic acid
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The disclosure provides an excellent amidite for synthesizing a modified nucleic acid, which enables a protective group therein to be removed under a moderate condition, thereby stably producing a hydroxyl group-containing modified nucleic acid. The disclosure also provides a method for synthesizing a modified nucleic acid using the amidite. Specifically, an amidite for synthesizing the modified nucleic acid is expressed by General Formula (I): where X represents a base, Y represents a substituent, Z represents a protective group for protecting a hydroxyl group in the substituent, and Q represents one of a hydrogen atom, a hydroxyl group and a hydroxyl group protected by a protective group, wherein the protective group can be removed in an aprotic solvent, and when the protective group is removed, the hydroxyl group emerges in the substituent.
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Page/Page column 22-24
(2011/04/18)
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- Ceria nanoparticles as heterogeneous catalyst for CO2 fixation by ω-aminoalcohols
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In contrast to γ-Al2O3, TiO2, ZrO2, MgO and Y2O3, CeO2 is a reusable catalyst for the reaction of CO2 with ω-aminoalcohols to form cyclic carbamates; the highest yield (68%) was obtained for the preparation of N-alkyl 1,3-oxazolidin-2-ones from N-alkyl ethanolamines.
- Juarez, Raquel,Concepcion, Patricia,Corma, Avelino,Garcia, Hermenegildo
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experimental part
p. 4181 - 4183
(2010/08/22)
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- Protecting groups for glucuronic acid: Application to the synthesis of new paclitaxel (taxol) derivatives
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To prepare two new glucuronide conjugates, allyl ester and allyl carbonates were used as protecting groups of the glucuronic moiety. In this way, an aniline glycosyl carbamate spacer linked to the 2′-OH of paclitaxel was obtained. By using palladium chemistry, an efficient one-step removal of all the allyl groups at the end of the synthesis afforded the desired compounds in good yields.
- El Alaoui, Abdessamad,Schmidt, Frederic,Monneret, Claude,Florent, Jean-Claude
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p. 9628 - 9636
(2007/10/03)
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- Method for producing cyclic carbamate ester
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A method for producing a cyclic carbamate ester produces the cyclic carbamate ester by reacting an organic compound having at least two halogen atoms per molecule, an amine having at least two hydrogen atoms on a nitrogen atom, and carbon dioxide.
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Page/Page column 4
(2008/06/13)
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- Synthesis of 2-oxazolidinones from CO2 and 1,2-aminoalcohols catalyzed by n-Bu2SnO
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The dehydrative condensation of 1,2-aminoalcohols with CO2 is found to proceed in NMP as solvent; 2-oxazolidinones are obtained in the yields of 53-94% when a commercially available tin compound, n-Bu2SnO is used as catalyst.
- Tominaga, Ken-Ichi,Sasaki, Yoshiyuki
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p. 307 - 309
(2007/10/03)
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- N-carbamylamino alcohols as the precursors of oxazolidinones via nitrosation-deamination reaction
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Oxazolidinones were effectively prepared from N-carbamylamino alcohols by treatment with nitrous acid, via N-nitroso compound as the intermediate. A new route to (R)-4-benzyloxazolidinone was developed starting from DL- phenylalanine, utilizing D-hydantoinase-catalyzed enantioselective hydrolysis of 5-benzylhydantoin under the dynamic kinetic resolution conditions, and the subsequent reduction to the precursor for the above-mentioned cyclization reaction, by taking advantage of the intermediates bearing an N-carbamylamino functionality.
- Suzuki, Masumi,Yamazaki, Takahiro,Ohta, Hiromichi,Shima, Kyoko,Ohi, Katsuhide,Nishiyama, Shigeru,Sugai, Takeshi
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p. 189 - 192
(2007/10/03)
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- Di-tert-butyl dicarbonate and 4-(dimethylamino)pyridine revisited. Their reactions with amines and alcohols
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The reaction of BOC2O in the presence and absence of DMAP was examined with some amines, alcohols, diols, amino alcohols, and aminothiols. Often, unusual products were observed depending on the ratio of reagents, reaction time, polarity of solvent, pK(a) of alcohols, or type of amine (primary or secondary). In reactions of aliphatic alcohols with BOC2O/DMAP, we isolated for the first time carbonic-carbonic anhydride intermediates; this helps explain the formation of symmetrical carbonates in addition to the O-BOC products. In the case of secondary amines, we succeeded to isolate unstable carbamic-carbonic anhydride intermediates that in the presence of DMAP led to the final N-BOC product. The effect of N-methylimidazole in place of DMAP was also examined.
- Basel, Yochai,Hassner, Alfred
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p. 6368 - 6380
(2007/10/03)
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- Spiro-fysed 2-alkoxy-2-amino-Δ3-1,3,4-oxadiazolines. Synthesis and thermolysis to corresponding aminooxycarbenes
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Δ3-1,3,4-Oxadiazolines spiro-fused at C2 to C2 to oxazolidines (12) or to C2 of tetrahydro-1,3-oxazines (13) were synthesized. The oxadiazolines undergo thermolysis in benzene at 90°C with first-order rate constants of (1.6-50) × 10-5 s-1. The dependence of these rate constants on the nature of the substituents present on the oxadiazoline ring is consistent with a mechanism involving a carbonyl ylide intermediate. Substituents on N of the oxazolidine or tetrahydro-1,3-oxazine moieties play a major role in determining the fragmentation pathways. Oxadiazolines with N-carbonyl groups (12c-j, 13d,e) afford essentially quantitative yields of the corresponding aminooxycarbenes, while other fragmentation reactions compete with carbene generation in the case of oxadiazolines with N-methyl (12b, 13c) or N-sulfonyl (12k) groups.
- Couture, Philippe,Warkentin, John
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p. 1264 - 1280
(2007/10/03)
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- Aminoethylation process for production of substituted ethylene diamines
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A process is disclosed for producing a substituted ethylenediamine, the process comprising reacting an oxazolidinone with a secondary amine or an alkanolamine. The process includes, in one aspect, reacting precursors of the oxazolidinone in situ.
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- Palladium-Catalyzed Double and Single Carbonylations of β-Amino Alcohols. Selective Synthesis of Morpholine-2,3-diones and Oxazolidin-2-ones and Applications for Synthesis of α-Oxo Carboxylic Acids
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Catalytic cross double carbonylation of secondary amines and alcohols proceeds in the presence of [PdCl2(MeCN)2] and CuI under carbon monoxide (80 atm) and oxygen (5 atm). Catalytic intramolecular double carbonylation of β-amino alcohols gives morpholine-2,3-diones, which are excellent protecting compounds of amino alcohols and important precursors for biologically active nitrogen compounds. In contrast, catalytic single carbonylation of β-amino alcohols under a mixture (1 : 1) of carbon monoxide and oxygen (1.0 atm) proceeds to give oxazolidin-2-ones selectively. The reaction can be explained by assuming a mechanism which includes intramolecular nucleophilic attack of the hydroxy group of (hydroxyethyl)aminocarbonyl ligands on the CO ligand of the carbamoylpalladium(II) complexes, followed by reductive elimination to give morpholine-2,3-diones. In contrast, direct nucleophilic attack of the hydroxy group to the carbamoyl group affords oxazolidin-2-ones. As a common intermediate for the double and single carbonylations, carbamoylpalladium(II) complex has been isolated by the reaction of [PdCl2(PMe3)2] with β-amino alcohol under CO. The present double carbonylation of amino alcohols provides a novel and convenient method for synthesis of α-oxo carboxylic acids. Thus, the morpholine-2,3-diones obtained undergo reaction with Grignard reagents chemoselectively at the ester positions to give 2-substituted 2-hydroxymorpholin-3-ones, which undergo acid hydrolysis to give α-oxo carboxylic acids.
- Imada, Yasushi,Mitsue, Yo,Ike, Kazuo,Washizuka, Ken-Ichi,Murahashi, Shun-Ichi
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p. 2079 - 2090
(2007/10/03)
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- Carbonylation of β-Aminoethanols, Diols, and Diol Amines
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Oxazolidinones are prepared from the palladium-catalyzed carbonylation of β-aminoethanols under mild conditions.With N-alkyl-substituted substrates, conditions for double carbon monoxide incorporation to give morpholinediones have been discovered.Cyclic carbonates can be prepared from the carbonylation of diols.The carbonylation of N-phenyl-1-aminopropane-2,3-diol can give either the carbonate or oxazolidinone as the major product depending on the reaction conditions.
- Tam, Wilson
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p. 2977 - 2981
(2007/10/02)
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- PREPARATION AND REACTIONS OF NOVEL μ-OXO-BISANTIMONY AMINOALKOXIDE
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Novel μ-oxo-bis(diphenylhydroxyantimony) di (1) was obtained in the reaction of triphenylstibine oxide and 2-(methylamino)ethanol.Cyclic urethane derivatives were obtained by the reaction of 1 with CO2 or CS2 in good yields.
- Nomura, Ryoki,Kori, Masakuni,Matsuda, Haruo
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p. 579 - 580
(2007/10/02)
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