- “On-water” reduction of α-keto amide by Hantzsch ester: A chemoselective catalyst- and additive-free way to α-hydroxy amide
-
An efficient and practical method for chemoselective “on-water” reduction of α-keto amide by Hantzsch ester without using any catalysts and additives was developed. Control experiments indicated that the intramolecular hydrogen bond of α-keto amide was cr
- Fang, Zhong-Bing,Yu, Ru-Rong,Hao, Fei-Yue,Jin, Zheng-Neng,Liu, Gu-Yue,Dai, Guo-Liang,Yao, Wu-Bing,Wu, Jia-Shou
-
supporting information
(2021/11/18)
-
- Manganese Catalyzed Direct Amidation of Esters with Amines
-
The transition metal catalyzed amide bond forming reaction of esters with amines has been developed as an advanced approach for overcoming the shortcomings of traditional methods. The broad scope of substrates in transition metal catalyzed amidations remains a challenge. Here, a manganese(I)-catalyzed method for the direct synthesis of amides from a various number of esters and amines is reported with unprecedented substrate scope using a low catalyst loading. A wide range of aromatic, aliphatic, and heterocyclic esters, even in fatty acid esters, reacted with a diverse range of primary aryl amines, primary alkyl amines, and secondary alkyl amines to form amides. It is noteworthy that this approach provides the first example of the transition metal catalyzed amide bond forming reaction from fatty acid esters and amines. The acid-base mechanism for the manganese(I)-catalyzed direct amidation of esters with amines was elucidated by DFT calculations.
- Fu, Zhengqiang,Wang, Xinghua,Tao, Sheng,Bu, Qingqing,Wei, Donghui,Liu, Ning
-
p. 2339 - 2358
(2021/02/03)
-
- Graphene oxide: A convenient metal-free carbocatalyst for facilitating amidation of esters with amines
-
Herein, we report a graphene oxide (GO) catalyzed condensation of non-activated esters and amines, that can enable diverse amides to be synthesized from abundant ethyl esters forming only volatile alcohol as a by-product. GO accelerates ester to amide conversion in the absence of any additives, unlike other catalysts. A wide range of ester and amine substrates are screened to yield the respective amides in good to excellent yields. The improved catalytic activity can be ascribed to the oxygenated functionalities present on the graphene oxide surface which forms H-bonding with the reactants accelerating the reaction. Improved yields and a wide range of functional group tolerance are some of the important features of the developed protocol.
- Patel, Khushbu P.,Gayakwad, Eknath M.,Shankarling, Ganapati S.
-
p. 2661 - 2668
(2020/02/20)
-
- Catalyst- and Additive-Free Chemoselective Transfer Hydrogenation of α-Keto Amides to α-Hydroxy Amides by Sodium Formate
-
A catalyst- and additive-free chemoselective transfer hydrogenation of α-keto amides to α-hydroxy amides is easily achieved by using sodium formate as a hydrogen source. The utility of this method is demonstrated by gram-scale synthesis and transformation of the resultant α-hydroxy amides into polysubstituted acetamides and 2-arylindole derivatives. Control experiments suggest that the NH group of α-keto amides is crucial for the chemoselective reduction through the formation of hydrogen bonds.
- Hao, Feiyue,Gu, Zhenyu,Liu, Guyue,Yao, Wubing,Jiang, Huajiang,Wu, Jiashou
-
p. 5985 - 5991
(2019/09/10)
-
- Homogeneous Hydrogenation with a Cobalt/Tetraphosphine Catalyst: A Superior Hydride Donor for Polar Double Bonds and N-Heteroarenes
-
The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex-catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24 000 TON and 12 000 h-1 TOF) and excellent chemoselectivities with various aldehydes, ketones, imines, and even N-heteroarenes. The preference for 1,2-reduction over 1,4-reduction makes this method an efficient way to prepare allylic alcohols and amines. Meanwhile, efficient hydrogenation of the challenging N-heteroarenes is also furnished with excellent functional group tolerance. Mechanistic studies and control experiments demonstrated that a CoIH complex functions as a strong hydride donor in the catalytic cycle. Each cobalt intermediate on the catalytic cycle was characterized, and a plausible outer-sphere mechanism was proposed. Noteworthy, external inorganic base plays multiple roles in this reaction and functions in almost every step of the catalytic cycle.
- Duan, Ya-Nan,Du, Xiaoyong,Cui, Zhikai,Zeng, Yiqun,Liu, Yufeng,Yang, Tilong,Wen, Jialin,Zhang, Xumu
-
supporting information
p. 20424 - 20433
(2019/12/27)
-
- Method for synthesizing chiral alpha-hydroxy amide by catalyzing prochiral alpha-keto-amide
-
The invention provides a novel method for preparing chiral alpha-hydroxy amide through asymmetric hydrogenation of pro-chiral alpha-keto-amide using a novel tridentate nitrogen phosphine ligand to prepare a series of chiral alpha-hydroxy amide compounds.
- -
-
Paragraph 0064; 0065; 0066
(2017/12/28)
-
- REAGENTS AND METHODS FOR ESTERIFICATION
-
Methods and reagents for esterification of biological molecules including proteins, polypeptides and peptides. Diazo compounds of formula (I): where R is hydrogen, an alkyl, an alkenyl or an alkynyl, RA represents 1-5 substituents on the indicated phenyl ring and RM is an organic group, which includes a label, a cell penetrating group, a cell targeting group, or a reactive group or latent reactive group for reaction to bond to a label, a cell penetrating group, or a cell targeting group, among other organic groups are useful for esterification of biological molecules. Also provided are diazo compounds which are bifunctional and trifunctional coupling reagents as well as reagents for the synthesis of compounds of formula (I).
- -
-
Paragraph 00202-00204
(2016/10/31)
-
- A Heterogeneous Niobium(V) Oxide Catalyst for the Direct Amidation of Esters
-
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
-
p. 2705 - 2710
(2015/09/15)
-
- Optimized Diazo Scaffold for Protein Esterification
-
The O-alkylation of carboxylic acids with diazo compounds provides a means to esterify carboxylic acids in aqueous solution. A Hammett analysis of the reactivity of diazo compounds derived from phenylglycinamide revealed that the (p-methylphenyl)-glycinamide scaffold has an especially high reaction rate and ester/alcohol product ratio and esterifies protein carboxyl groups more efficiently than any known reagent. (Chemical Equation Presented).
- Mix, Kalie A.,Raines, Ronald T.
-
supporting information
p. 2358 - 2361
(2015/06/02)
-
- Metal free chemoselective reduction of α-keto amides using TBAF as catalyst
-
The metal and ligand free chemoselective reduction of the keto group and complete reduction of the both keto and amide groups of α-keto amide with hydrosilanes using tetrabutylammoniumflouride (TBAF) as catalyst have been accomplished. This methodology affords an efficient and economic route for the synthesis of biologically important α-hydroxy amides and β-amino alcohols. The other important advantage of this TBAF catalyst is chemoselective reduction of ketones to corresponding alcohols in the presence of several other sensitive functional groups.
- Mamillapalli, N. Chary,Sekar, Govindasamy
-
p. 61077 - 61085
(2015/02/19)
-
- Chemoselective reduction of α-keto amides using nickel catalysts
-
Ni-catalysts are used for the first time to synthesize highly important α-hydroxy amides and β-amino alcohols from α-keto amides by chemoselective and complete reduction using hydrosilanes. Chemoselective complete reduction of α-keto amides in the presenc
- Mamillapalli, N. Chary,Sekar, Govidasamy
-
supporting information
p. 7881 - 7884
(2014/07/08)
-
- A new chemoenzymatic approach to the synthesis of chiral 4-aryl-1,4-dihydro-2H-isoquinolines via the enzymatic resolution of 2-acetyl-4-phenyl-1,4-dihydro-2H-isoquinolin-3-one
-
A new chemoenzymatic method is proposed for the synthesis of enantiomerically pure 4-phenyl-1,4-dihydro-2H-isoquinolines based on the enzymatic kinetic resolution of 2-acetyl-4-phenyl-1,4-dihydro-2H-isoquinolin-3- one. For the enzymatic resolution of the racemic substrate, readily available 'home made' animal liver acetone powders (LAPs) were used. Excellent enantioselectivity, exceeding 500, was achieved in a short reaction time upon application of turkey liver acetone powder as the biocatalyst. Reduction of obtained product led to the formation of amine (R)-1, which is hardly available using standard procedures. These results show that N-acetyl lactams are a new type of substrate for enzymatic biotransformations.
- Koszelewski, Dominik,Cwiklak, Malgorzata,Ostaszewski, Ryszard
-
p. 1256 - 1261
(2012/11/07)
-
- Palladium-catalyzed double carbonylation using near stoichiometric carbon monoxide: Expedient access to substituted 13C2-labeled phenethylamines
-
A novel and general approach for 13C2- and 2H-labeled phenethylamine derivatives has been developed, based on a highly convergent single-step assembly of the carbon skeleton. The efficient incorporation of two carbon-13 isotopes into phenethylamines was accomplished using a palladium-catalyzed double carbonylation of aryl iodides with near stoichiometric carbon monoxide.
- Nielsen, Dennis U.,Neumann, Karoline,Taaning, Rolf H.,Lindhardt, Anders T.,Modvig, Amalie,Skrydstrup, Troels
-
p. 6155 - 6165
(2012/09/21)
-
- An efficient boric acid-mediated preparation of α-hydroxyamides
-
An efficient methodology for the preparation of α-hydroxyamides via boric acid-mediated addition of isonitriles onto aldehydes has been developed. The reaction of isonitriles with α-boronobenzaldehyde takes place under intramolecular catalysis conditions
- Sravan Kumar,Jonnalagadda, Subash C.,Mereddy, Venkatram R.
-
experimental part
p. 779 - 782
(2010/03/24)
-
- Medium effects on Zwitterionic-biradicaloid intermediates from two phenyl-α-oxoamides. Irradiations in fluid and solid protic media, neat solid phases, and the solid, smectic and isotropic phases of a completely saturated phosphonium salt at different tem
-
The photochemical processes of two N,N-dialkyl phenyl-α-oxoamides, N,N-diisopropyl phenyl-α-oxoamide (1) and N,N-dibenzyl phenyl-α-oxoamide (2), are investigated at different temperatures in methanol and ethylene glycol (to probe the influences of H-bondi
- Chesta, Carlos A.,George, Mathew,Luo, Chuping,Weiss, Richard G.
-
p. 570 - 583
(2008/09/17)
-
- Direct Zn-diamine promoted reduction of C=O and C=N bonds by polymethylhydrosiloxane in methanol
-
Ketones and imines are chemoselectively reduced at room temperature in methanol to the corresponding alcohols and amines in high yields in a one-step procedure using polymethylhydrosiloxane (PMHS) and a simple zinc-diamine catalyst.
- Bette, Virginie,Mortreux, Andre,Lehmann, Christian W.,Carpentier, Jean-Francois
-
p. 332 - 333
(2007/10/03)
-
- Stereoselective formation of optically active 2-oxy-1,3-oxazolidin-4-ones from chiral O-acylmandelamides or lactamides
-
(-)-O-Acyllactamides or mandelamides in the presence of TBSOTf underwent cyclization reaction to give optically active 2-oxy-1,3-oxazolidin-4-ones, a novel nitrogen analog of orthoesters, in good yields. An X-ray analysis and NOE studies indicated that the absolute configuration at the newly formed chiral carbon was S. For their synthetic application, the 1,3-dipolar cycloaddition of nitrile oxide was examined. The cycloadducts were obtained in a stereoselective manner. Subsequent treatment of the adduct with TBAF resulted in the one-step removal of mandelamide, giving optically active 4,5-dihydroisoxazole and mandelamide in good yields.
- Kamimura, Akio,Omata, Yoji,Kakehi, Akikazu,Shirai, Masashi
-
p. 8763 - 8770
(2007/10/03)
-
- Hydrogenation of the carbonyl group in α-ketoesters and α-ketoamides catalyzed by ruthenium clay
-
Ruthenium clay, prepared by reaction of RuCl3·H2O with the 3- phosphinopropyl ligand anchored on Fluka K10 montmorillonite, is an effective catalyst for the reduction of the α-carbonyl group of α-ketoesters and α- ketoamides (50-89% yield).
- Aldea, Raluca,Alper, Howard
-
p. 9425 - 9426
(2007/10/03)
-
- The anticonvulsant activities of functionalized N-benzyl 2-acetamidoacetamides. The importance of the 2-acetamido substituent
-
Recent studies have demonstrated that substituted N-benzyl 2-acetamidoacetamides provide significant protection against maximal electroshock (MES)-induced seizures in mice and rats. In this study, we investigated whether the 2-acetamido moiety was necessary for anticonvulsant activity. Ten derivatives of the known anticonvulsant, N-benzyl 2-acetamido-2-phenylacetamide were prepared in which the 2-acetamido group was replaced by hydrogen, methyl, oxygen, and halogen substituents. Evaluation of these compounds in the MES-induced seizure test demonstrated that both the hydroxy and the methoxy compounds provided full protection against MES-induced seizures in mice given ip at 100 mg/g. Moreover, evaluation of the individual stereoisomers for the hydroxy compound showed that the principal activity resided in the (R)-isomer. These findings demonstrated that the 2-acetamido substituent is important but not obligatory for the prevention of MES-induced seizures. Further supporting evidence was provided by comparing the pharmacological activities of N-benzyl 2,3-dimethoxypropionamide with N-benzyl 2-acetamido-3-methoxypropionamide. The ED50 value for the former in the MES test was 3.0 mg/kg (ip), which compared favorably with phenobarbital (ED50=22 mg/kg), but the ED50 value for N-benzyl 2-acetamido-3-methoxypropionamide was 8.3 mg/kg.
- Choi, Daeock,Stables, James P.,Kohn, Harold
-
p. 2105 - 2114
(2007/10/03)
-
- Base-Promoted Reaction of O-Sulfonylated Hydroxamic Acids with Nucleophiles. A New Mehtod for the Synthesis of α-Substituted Amides
-
Treatment of a series of hydroxamic acids 2 with mesyl chloride in the presence of 2 equiv of triethylamine at 0 deg C gives 2-chloroamides 3 in good yields.Use of a single equivalent of triethylamine gives the N-(mesyloxy)amides 1, which are versatile sy
- Hoffman, Ribert V.,Nayyar, Naresh K.,Chen, Wenting
-
p. 5700 - 5707
(2007/10/02)
-
- Photocyclization of α-keto amides in homogeneous solution and aqueous cyclodextrin media. The role of zwitterions and diradicals in photoinduced electron transfer reactions
-
A mechanistic investigation of the photoreaction of the N,N-disubstituted benzoyl amides, PhCOCONR'R" 1-4 (1: R' = C2H5, R" = Ph; 2: R' = R" = C2H5; 3: R' = R" = CH2Ph; 4: R' = R" = i-C3Hs
- Chesta, Carlos A.,Whitten, David G.
-
p. 2188 - 2197
(2007/10/02)
-
- New Reduction Method of α-Diketones, Oxo amides, and Quinones with Zn-EtOH in the Presence of a Salt
-
The reagent, Zn-Salt-EtOH effectively reduces α-diketones, oxo amides, and quinones to hydroxy ketones, hydroxy amides, and hydroquinones, respectively.
- Toda, Fumio,Tanaka, Koichi,Tange, Hiroshi
-
p. 1555 - 1556
(2007/10/02)
-
- Direct Aminolysis of Nonactivated and Thermally Unstable Esters at High Pressure
-
The preparation of the amides 3 from a wide variety of nonactivated esters 1 and secondary amines 2 has been achieved at 8 kbar and around 45 deg C; scope and limitations are discussed.The method was also successfully applied for the aminolysis of alkyl 2-arylsulfinylacetates 7 that are relatively sensitive to heat. - Key Words: Aminolysis/ High-pressure synthesis
- Matsumoto, Kiyoshi,Hashimoto, Shiro,Uchida, Takane,Okamoto, Tadashi,Otani, Shinichi
-
p. 1357 - 1364
(2007/10/02)
-
- Reactions of α-Hydroxy Carbonyl Compounds with Azodicarboxylates and Triphenylphosphine: Synthesis of α-N-Hydroxy Amino Acid Derivatives
-
Reaction of aliphatic α-hydroxy esters with azodicarboxylates and triphenylphosphine in the presence of either CbzNHOCH2Ph or trOCNHOCH2Ph provides a direct route to protected α-N-hydroxy amino acids.Similar reactions with aromatic α-hydroxy carbonyl compounds and derivatives result in predominate oxidation to the corresponding α-oxo carbonyl derivatives.
- Kolasa, Teodozyj,Miller, Marvin J.
-
p. 4978 - 4984
(2007/10/02)
-