- N-acylcarbazole as a selective transamidation reagent
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N-acylation reaction offers an opportunity to develop an efficient synthesis of amide group-containing molecules. We found that N-acyl carbazoles showed remarkable selectivity in transamidation. Sterically less hindered primary amines are selectively acylated with N-acyl carbazoles without any additives. Various functional groups such as alcohol, phenol, indole, and aniline moieties are tolerated under mild conditions. The synthetic utility was displayed in one-pot synthesis of an N-acyl polyamine natural product. The terminal amines of spermidine were selectively benzoylated with N-benzoyl carbazole, followed by acetylation reaction accomplished the total synthesis in a highly efficient manner.
- Kang, Bubwoong,Kuse, Masaki,Okamura, Hironori,Sakai, Asumi,Satoh, Tetsuya,Shinada, Tetsuro,Yasuno, Yoko
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p. 993 - 999
(2020/09/22)
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- METHOD FOR PRODUCING ALCOHOL BY HYDROGENATION OF CARBOXYLIC ACID COMPOUND, AND RUTHENIUM COMPLEX FOR USE IN THE PRODUCTION METHOD
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PROBLEM TO BE SOLVED: To provide a method of obtaining an alcohol by efficiently hydrogenating a variety of carboxylic acid compounds under mild conditions using a homogeneous catalyst. SOLUTION: The present invention provides a method of hydrogenating a carboxylic acid compound, in the presence of a ruthenium complex represented by RuXnYpZq, in an atmosphere of hydrogen [X is a group represented by the following formula; Y is a phosphine ligand having a substituted/unsubstituted alkyl group or a substituted/unsubstituted aryl group; Z is a ligand other than X and Y; n is 1 or 2; p is an integer of 1-4; q is an integer of 0-2] {R1 is H, a substituted/unsubstituted alkyl group or a substituted/unsubstituted aryl group; A1 and A2 independently represent O, NR4 (R4 is H, a substituted/unsubstituted alkyl group or a substituted/unsubstituted aryl group) or S; m is an integer of 1 or more; a solid line and a dashed line both represent a single bond or a double bond}]. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0133; 0137; 0138
(2017/02/02)
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- A Heterogeneous Niobium(V) Oxide Catalyst for the Direct Amidation of Esters
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This study reports the first example of a heterogeneous catalytic system for the direct amidation of various esters with amines. Of 25 types of catalyst, Nb2O5 shows the highest activity in the amidation of methyl benzoate with aniline. Nb2O5 gives high yields in the amidation of various esters and amines under solvent-free conditions, is reusable, and shows higher turnover numbers than previously reported homogeneous catalysts such as La(OTf)3. IR spectroscopic studies of ethyl acetate adsorbed on the catalysts show a strong acid-base interaction between the Nb5+ Lewis acid site and carbonyl oxygen, which can result in high reactivity of the ester with a nucleophile (amine) and, thus, high activity of Nb2O5. Kinetic results show that the activity of Nb2O5 does not markedly decrease with increasing aniline concentration, in contrast to reference catalysts TiO2 and La(OTf)3. The relatively low negative impact of basic molecules on the Lewis acid catalysis of Nb2O5 also enables its high activity.
- Ali, Md. Ayub,Siddiki, S. M. A. Hakim,Kon, Kenichi,Shimizu, Ken-Ichi
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p. 2705 - 2710
(2015/09/15)
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- Laccase/2,2,6,6-tetramethylpiperidinoxyl radical (TEMPO): An efficient catalytic system for selective oxidations of primary hydroxy and amino groups in aqueous and biphasic media
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Copper salts/2,2,6,6-tetramethylpiperidinoxyl radical (TEMPO) catalytic systems enable efficient aerobic oxidations of primary alcohols but they generally show a reduced reactivity in aqueous medium. Herein, we report an oxidative catalytic system composed of Trametes versicolor laccase and TEMPO, which is able to work in buffer solutions at room temperature using ambient air. Although this catalytic system displays great efficiency in aqueous systems, the addition of methyl tert-butyl ether allows the reduction of TEMPO loading, also enhancing the solubility of hydrophobic compounds. This practical methodology promotes the chemoselective aerobic oxidation of hydroxy or amino groups, leading to interesting organic derivatives such as aldehydes, lactones, hemiaminals or lactams.
- Díaz-Rodríguez, Alba,Martínez-Montero, Lía,Lavandera, Iván,Gotor, Vicente,Gotor-Fernández, Vicente
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supporting information
p. 2321 - 2329
(2014/07/21)
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- Mesoporous niobium oxide spheres as an effective catalyst for the transamidation of primary amides with amines
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Mesoporous niobium oxide spheres (MNOS), conveniently prepared by a novel antisolvent precipitation approach, have been shown to be an effective catalyst for the transamidation of primary amides with amines. This novel transamidation can be efficiently carried out under solvent-free conditions and is applicable to a wide range of primary amides and amines to provide N-alkyl amides in good to excellent yields. The catalyst is highly stable and reusable. The application of this transamidation reaction has been demonstrated in the synthesis of antidepressant drug moclobemide and other druglike compounds.
- Ghosh, Subhash Chandra,Li, Cheng Chao,Zeng, Hua Chun,Ngiam, Joyce S. Y.,Seayad, Abdul M.,Chen, Anqi
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p. 475 - 484
(2014/05/20)
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- On DABAL-Me3 promoted formation of amides
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The range and utility of DABAL-Me3 couplings of methyl esters and free carboxylic acids with primary and secondary amines under a variety of conditions (reflux, sealed tube, microwave) has been compared for a significant range of coupling partners of relevance to the preparation of amides of interest in pharmaceutical chemistry. Commercial microwave reactors promote the fastest couplings and allow the use of significantly sterically hindered amines (primary and secondary) and carboxylic acids derivatives. The influence of microwave energy on the reaction system was shown to be typically related to thermal effects (over-pressuring and superheating).
- Dubois, Nathalie,Glynn, Daniel,McInally, Thomas,Rhodes, Barrie,Woodward, Simon,Irvine, Derek J.,Dodds, Chris
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supporting information
p. 9890 - 9897
(2013/10/22)
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- Copper-catalyzed oxidative amidation of aldehydes with amine salts: Synthesis of primary, secondary, and tertiary amides
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A practical method for the amidation of aldehydes with economic ammonium chloride or amine hydrochloride salts has been developed for the synthesis of a wide variety of amides by using inexpensive copper sulfate or copper(I) oxide as a catalyst and aqueous tert-butyl hydroperoxide as an oxidant. This amidation reaction is operationally straightforward and provides primary, secondary, and tertiary amides in good to excellent yields for most cases utilizing inexpensive and readily available reagents under mild conditions. In situ formation of amine salts from free amines extends the substrate scope of the reaction. Chiral amides are also synthesized from their corresponding chiral amines without detectable racemization. The practicality of this amide formation reaction has been demonstrated in an efficient synthesis of the antiarrhythmic drug N-acetylprocainamide.
- Ghosh, Subhash Chandra,Ngiam, Joyce S. Y.,Seayad, Abdul M.,Tuan, Dang Thanh,Chai, Christina L. L.,Chen, Anqi
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p. 8007 - 8015,9
(2012/12/12)
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- Copper-catalyzed oxidative amidation of aldehydes with amine salts: Synthesis of primary, secondary, and tertiary amides
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A practical method for the amidation of aldehydes with economic ammonium chloride or amine hydrochloride salts has been developed for the synthesis of a wide variety of amides by using inexpensive copper sulfate or copper(I) oxide as a catalyst and aqueous tert-butyl hydroperoxide as an oxidant. This amidation reaction is operationally straightforward and provides primary, secondary, and tertiary amides in good to excellent yields for most cases utilizing inexpensive and readily available reagents under mild conditions. In situ formation of amine salts from free amines extends the substrate scope of the reaction. Chiral amides are also synthesized from their corresponding chiral amines without detectable racemization. The practicality of this amide formation reaction has been demonstrated in an efficient synthesis of the antiarrhythmic drug N-acetylprocainamide.
- Ghosh, Subhash Chandra,Ngiam, Joyce S.Y.,Seayad, Abdul M.,Tuan, Dang Thanh,Chai, Christina L.L.,Chen, Anqi
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p. 8007 - 8015
(2013/01/15)
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- Protease catalysis mediated by a substrate mimetic: A novel enzymatic approach to the synthesis of carboxylic acid amides
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We present a protease-based method for the coupling of non-coded and non-amino-acid-derived amines with carboxy components. The key feature of this approach is the combination of the substrate-mimetic strategy with the ability of the cysteine protease clostripain to accept a wide spectrum of amines. Firstly, we tested the use of the 4-guanidinophenyl ester leaving group to mediate acceptance of non-coded and non-amino-acid-derived acyl residues. This employed β-amino acid and simple carboxylic acid moieties as acyl donors, and several amino acid and peptide units as acyl acceptors. The study was completed by the use of non-amino-acid-derived acyl acceptors comprising simple amines, amino alcohols, and diamines. The results indicate that the approach presented is a useful strategy for the synthesis of peptide isosteres, peptide analogues, and organic amides. These last open a new range of synthetic applications of proteases completely beyond peptide synthesis, achieving efficient and selective acylations of non-amino-acid-derived amines under extraordinarily mild reaction conditions.
- Guenther, Robert,Bordusa, Frank
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p. 463 - 467
(2007/10/03)
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- Synthesis of oxazines and thiazines by cyclodehydration of hydroxy amides and thioamides
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Dihydro-1,3-oxazines and -thiazines were obtained by cyclodehydration of hydroxy amides and thioamides with PEG-linked Burgess reagent or under Mitsunobu conditions. Yields were generally higher with polymer-Burgess reagent, but both conditions failed to
- Wipf, Peter,Hayes, Gregory B.
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p. 6987 - 6998
(2007/10/03)
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- Ruthenium-catalyzed oxidations for selective syntheses of ketones and acyl cyanides. Selective acylation of amino compounds with acyl cyanides
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Oxidation of alcohols to the corresponding carbonyl compounds with tert-butyl hydroperoxide in the presence of dichlorotris(triphenylphosphine)ruthenium catalyst gives the corresponding carbonyl compounds with high efficiency. This method can be applied to the oxidation of cyanohydrins to give acyl cyanides which are versatile synthetic intermediates. Acylation of amino compounds with acyl cyanides thus obtained proceeds chemoselectively. Thus, the reaction of amino alcohols with acyl cynides gives N-acylated products exclusively. In the similar N-acylation of polyamines primary amines are selectively acylated in the presence of secondary amines. These reactions are highly useful for the synthesis of spermidine and spermine alkaloids such as spermidine alkaloids such as spermidine siderophores. Dimeric cyclocoupling reaction of diacyl cyanides such as iso- and terephthaloyl cyanides with polyamines can be performed under the similar reaction conditions to give the corresponding polyazamacrocycles with high efficiency.
- Murahashi,Naota
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p. 433 - 440
(2007/10/02)
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- Selective synthesis of heterocyclic compounds through the intramolecular substitution of phenylselenonyl group by nitrogen or carbonyl oxygen in amides
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Nitrogen heterocycles were produced by the oxidation of N-[ω-(phenylseleno)alkyl]-p-toluenesulfonamides through the intramolecular substitution of the resultant phenylselenonyl group by the nitrogen atom. By the oxidation of the corresponding benzamides,
- Toshimitsu,Hirosawa,Tanimoto,Uemura
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p. 4017 - 4020
(2007/10/02)
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- RUTHENIUM CATALYZED OXIDATION OF CYANOHYDRINS TO ACYL CYANIDES USEFUL REAGENTS FOR SELECTIVE N-BENZOYLATION OF AMINOALCOHOLS
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Ruthenium catalyzed oxidation of cyanohydrins with tert-butyl hydroperoxide gives the corresponding acyl cyanides in good to excellent yields.Acyl cyanides thus obtained are useful reagents for selective N-benzoylation of aminoalcohols.
- Murahashi, Shun-ichi,Naota, Takeshi,Nakajima, Nobuyuki
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p. 925 - 928
(2007/10/02)
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- ACTIVATION OF CARBOXYL GROUPS BY DIPHENYL 2-OXO-3-OXAZOLINYLPHOSPHONATE. FACILE PREPARATION OF VERSATILE REAGENTS, 3-ACYL-2-OXAZOLONES
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Synthetic utility of the 2-oxazolone moiety as an excellent new leaving group is described.Based on such a function of the heterocycles, diphenyl 2-oxo-3-oxazolinylphosphonate has been newly introduced as a carboxyl-activating reagent which permits a facile direct preparation of 3-acyl-2-oxazolones and amides including peptides from a wide variety of carboxylic acids.The 3-acyl-2-oxazolides also serve as versatile reactive agents for highly chemoselective acyl-transfer to the nucleophilic species such as amines, alcohols and thiols, providing convenient and high-yield routes to amides, esters and thiol esters under mild conditions.They are also useful intermediates for ketones and alcohols.
- Kunieda, Takehisa,Higuchi, Tsunehiko,Abe, Yoshihiro,Hirobe, Masaaki
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p. 3253 - 3260
(2007/10/02)
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