- Defunctionalization of sp3 C–Heteroatom and sp3 C–C Bonds Enabled by Photoexcited Triplet Ketone Catalysts
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A general strategy for enabling a light-induced defunctionalization of sp3 C–heteroatom and sp3 C–C bonds with triplet ketone catalysts and bipyridine additives is disclosed. This protocol is characterized by its broad scope without recourse to transition metal catalysts or stoichiometric exogeneous reductants, thus offering a complementary technique for activating σ sp3 C–C(heteroatom) bonds. Preliminary mechanistic studies suggest that the presence of 2,2′-bipyridines improves the lifetime of ketyl radical intermediates.
- An, Juzeng,Gu, Yiting,Martin, Ruben,Wakeling, Matthew,Yin, Hongfei
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p. 1031 - 1036
(2022/01/19)
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- Near-Ambient-Temperature Dehydrogenative Synthesis of the Amide Bond: Mechanistic Insight and Applications
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The current existing methods for the amide bond synthesis via acceptorless dehydrogenative coupling of amines and alcohols all require high reaction temperatures for effective catalysis, typically involving reflux in toluene, limiting their potential practical applications. Herein, we report a system for this reaction that proceeds under mild conditions (reflux in diethyl ether, boiling point 34.6 °C) using ruthenium PNNH complexes. The low-temperature activity stems from the ability of Ru-PNNH complexes to activate alcohol and hemiaminals at near-ambient temperatures through the assistance of the terminal N-H proton. Mechanistic studies reveal the presence of an unexpected aldehyde-bound ruthenium species during the reaction, which is also the catalytic resting state. We further utilize the low-temperature activity to synthesize several simple amide bond-containing commercially available pharmaceutical drugs from the corresponding amines and alcohols via the dehydrogenative coupling method.
- Kar, Sayan,Xie, Yinjun,Zhou, Quan Quan,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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p. 7383 - 7393
(2021/06/30)
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- Iridium-PPh3 Catalysts for Conversion of Amides to Enamines
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Studies on the deactivation mechanism of the reaction of N,N-dialkylamides with TMDS catalyzed by Vaska's complex, IrCl(CO)(PPh3)2 (1a), triggered the discovery of highly active Ir-PPh3 catalysts: Photochemically activated
- Une, Yuta,Tahara, Atsushi,Miyamoto, Yasumitsu,Sunada, Yusuke,Nagashima, Hideo
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supporting information
p. 852 - 862
(2019/03/04)
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- Iron-Catalyzed Amide Formation from the Dehydrogenative Coupling of Alcohols and Secondary Amines
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The five-coordinate iron(II) hydride complex (iPrPNP)Fe(H)(CO) (iPrPNP = N[CH2CH2(PiPr2)]2) selectively catalyzes the dehydrogenative intermolecular coupling of alcohols and secondary amines to form tertiary amides. This is the most productive base-metal catalyst for dehydrogenative amidation reported to date, in some cases achieving up to 600 turnovers. The catalyst works well for sterically undemanding amines and alcohols or cyclic substrates and is particularly effective in the synthesis of formamides from methanol. However, the catalyst performance declines rapidly with the incorporation of large substituents on the amine or alcohol substrate. Variable-temperature NMR spectroscopic studies suggest that the catalyst resting state is an off-cycle iron(II) methoxide species, (iPrPN(H)P)Fe(H)(OCH3)(CO), resulting from addition of methanol across the Fe-N bond of (iPrPNP)Fe(H)(CO). This reversibly formed iron(II) methoxide complex is favored at mild temperatures but eliminates methanol upon heating.
- Lane, Elizabeth M.,Uttley, Katherine B.,Hazari, Nilay,Bernskoetter, Wesley
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p. 2020 - 2025
(2017/06/13)
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- CuCl/TBHP catalyzed synthesis of amides from aldehydes and amines in water
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A CuCl/TBHP catalyzed amidation of aldehydes with amine under aqueous media is described. Both aliphatic and aromatic aldehydes coupled with a variety of amines under the reaction conditions employed.
- Lu, Shao-Yi,Badsara, Satpal Singh,Wu, Yi-Chun,Reddy, Daggula Mallikarjuna,Lee, Chin-Fa
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supporting information
p. 633 - 636
(2016/01/26)
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- Mild and direct conversion of esters to morpholine amides using diisobutyl(morpholino)aluminum: Application to efficient one-pot synthesis of ketones and aldehydes from esters
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Morpholine amide intermediates, which are easily prepared by aminolysis of various esters with diisobutyl(morpholino)aluminum, react with organolithium and reducing agents (DIBALH or LDBMA) without isolation of the aminolysis intermediates to give ketones in 83-95% yields and aldehydes quantitatively.
- Jeon, Ah Ram,Kim, Min Eai,Park, Jae Kyo,Shin, Won Kyu,An, Duk Keun
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p. 4420 - 4424
(2014/06/10)
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- Recyclable hypervalent iodine(III) reagent iodosodilactone as an efficient coupling reagent for direct esterification, amidation, and peptide coupling
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A hypervalent iodine(III) reagent plays a novel role as an efficient coupling reagent to promote the direct condensation between carboxylic acids and alcohols or amines to provide esters, macrocyclic lactones, amides, as well as peptides without racemization. The regeneration of iodosodilactone (1) can also be readily achieved. The intermediate acyloxyphosphonium ion C from the activation of a carboxylic acid is thought to be involved in the present esterification reaction.
- Tian, Jun,Gao, Wen-Chao,Zhou, Dong-Mei,Zhang, Chi
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supporting information; experimental part
p. 3020 - 3023
(2012/08/07)
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- Transamidation of amides with amines under solvent-free conditions using a CeO2 catalyst
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Among various metal oxides, cerium oxide (CeO2) shows the highest catalytic activity for transamidation of picolinamide with n-octylamine. CeO2 acts as a reusable and effective heterogeneous catalyst for transamidation under solvent-free conditions. Transamidation of a variety of amides and amines produced the corresponding N-alkyl amides in high yields. This method provides the first example of a heterogeneous catalyst for transamidation using aliphatic amines as substrates. Characterization of acid-base properties and kinetic studies suggest that the cooperation of the weak Lewis acid sites and adjacent strong base sites play important roles in the transamidation reaction. The Royal Society of Chemistry 2012.
- Tamura, Masazumi,Tonomura, Takuya,Shimizu, Ken-Ichi,Satsuma, Atsushi
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experimental part
p. 717 - 724
(2012/05/07)
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- Synthesis of amides from esters and amines with liberation of H2 under neutral conditions
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Efficient synthesis of amides directly from esters and amines is achieved under mild, neutral conditions with the liberation of molecular hydrogen. Both primary and secondary amines can be utilized. This unprecedented, general, environmentally benign reaction is homogeneously catalyzed under neutral conditions by a dearomatized ruthenium-pincer PNN complex and proceeds in toluene under an inert atmosphere with a high turnover number (up to 1000). PNP analogues do not catalyze this transformation, underlining the crucial importance of the amine arm of the pincer ligand. A mechanism is proposed involving metal-ligand cooperation via aromatization-dearomatization of the pyridine moiety and hemilability of the amine arm.
- Gnanaprakasam, Boopathy,Milstein, David
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supporting information; experimental part
p. 1682 - 1685
(2011/04/22)
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- Highly efficient synthesis of aldenamines from carboxamides by iridium-catalyzed silane-reduction/dehydration under mild conditions
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The combination of IrCl(CO)(PPh3)2 with 1,1,3,3-tetramethyldisiloxane or poly(methylhydrosiloxane) (PMHS) is found to be an efficient catalyst system for the preparation of aldenamines from carboxamides; in particular, facile removal of silicone and iridium residues from the product can be achieved by the use of PMHS.
- Motoyama, Yukihiro,Aoki, Masaharu,Takaoka, Naoki,Aoto, Ryuta,Nagashima, Hideo
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supporting information; experimental part
p. 1574 - 1576
(2009/09/06)
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- Direct dehydrogenative amide synthesis from alcohols and amines catalyzed by γ-alumina supported silver cluster
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The heterogeneously catalyzed reaction of alcohols with amines to form amides and H2 using the easily prepared and inexpensive heterogeneous catalyst, Ag/Al2O3 has been reported. Aromatic and aliphatic amides are functiona
- Shimizu, Ken-Ichi,Ohshima, Keiichiro,Satsuma, Atsushi
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supporting information; experimental part
p. 9977 - 9980
(2010/04/03)
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- Addition of organocerium reagents to morpholine amides: synthesis of important pheromone components of Achaea janata.
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Readily preparable morpholine amides hitch in good yields with organocerium reagents to produce ketones. Even in the presence of substrates and reagents with high steric hindrance, the organometallic compounds prepared from dry cerium(III) chloride and organomagnesium or organolithium compounds at -78 degrees C add cleanly to morpholine amides. The low cost of starting materials makes this new scheme of synthesis very interesting for the preparation of biologically important pheromones.
- Badioli, Michele,Ballini, Roberto,Bartolacci, Massimo,Bosica, Giovanna,Torregiani, Elisabetta,Marcantoni, Enrico
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p. 8938 - 8942
(2007/10/03)
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- Transdermal compositions of 1-oxohydrocarbyl-substituted azacyclohexanes
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This invention provides compositions for enhancing penetration of physiologically active agents through the skin or mucosal membranes and for retaining these agents in body tissues, said composition comprising effective amounts of a physiologically-active agent and a compound represented by the general formula STR1 wherein X may represent sulfur, oxygen or nitrogen; a and b may be 0 or 1, c may be 0, 1 or 2, except that when X is oxygen, a, b and c are 0, when X is nitrogen c is 0 and only one of a or b is 1, and when X is sulfur a and b are 0; A is a branched or a straight chain, divalent aliphatic radical having from 0 to 2 double bonds; R' is selected from the group consisting of H, a lower alkyl group having from 1 to 4 carbon atoms, phenyl, lower alkyl or halogen substituted phenyl, acetamido, halogen, piperidinyl, lower alkyl or halogen substituted piperidinyl, carbalkoxy, carboxamide, and alkanoyl; and R is hydrogen or a lower alkyl group having from 1 to 4 carbon atoms, STR2 wherein R" is H or halogen, and salts, e.g. acid or quaternary derivatives, thereof. These compositions are useful in topical or transdermal applications of the physiologically-active agent.
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