- A practical catalytic reductive amination of carboxylic acids
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We report reductive alkylation reactions of amines using carboxylic acids as nominal electrophiles. The two-step reaction exploits the dual reactivity of phenylsilane and involves a silane-mediated amidation followed by a Zn(OAc)2-catalyzed amide reduction. The reaction is applicable to a wide range of amines and carboxylic acids and has been demonstrated on a large scale (305 mmol of amine). The rate differential between the reduction of tertiary and secondary amide intermediates is exemplified in a convergent synthesis of the antiretroviral medicine maraviroc. Mechanistic studies demonstrate that a residual 0.5 equivalents of carboxylic acid from the amidation step is responsible for the generation of silane reductants with augmented reactivity, which allow secondary amides, previously unreactive in zinc/phenylsilane systems, to be reduced.
- Andrews, Keith G.,Denton, Ross M.,Hirst, David J.,Stoll, Emma L.,Tongue, Thomas,Valette, Damien
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p. 9494 - 9500
(2020/10/02)
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- Direct Catalytic Reductive N-Alkylation of Amines with Carboxylic Acids: Chemoselective Enamine Formation and further Functionalizations
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Direct reductive N-alkylation of secondary amines with carboxylic acids using molybdenum hexacarbonyl (5 mol %) as catalyst and diethoxymethylsilane as reducing agent generate enamines in a straightforward fashion in high yields. The formed enamines are without the need for isolation or purification further reacted with trimethylsilyl cyanide in the same reaction flask to yield α-amino nitriles in good yields. In the optimized reaction conditions equimolar amounts of carboxylic acid and amine are reacted under neat conditions, and a catalytic amount of trifluoroethanol (0.1 mol %) is added along with TMSCN for the cyanation step. The reductive N-alkylation reaction is demonstrated to be highly chemoselective, tolerating a multitude of different functional groups present in the starting carboxylic acids and amines. The reaction is scalable and the generated α-amino nitriles are converted to other useful compounds, e.g., α-amino acids or amino-tetrazoles. In addition, the intermediate enamines are further transformed into triazolines, sulfonylformamidines, pyrimidinediones, and TMS-propargylamines, respectively, in high yields under mild reaction conditions. Benzoic acids react with secondary amines under similar conditions to give tertiary amines in high yields, and using this methodology, the biologically active compound Piribedil was isolated in 80% yield in a direct one-pot reaction setup.
- Trillo, Paz,Adolfsson, Hans
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p. 7588 - 7595
(2019/08/20)
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- Borinic Acid Catalysed Reduction of Tertiary Amides with Hydrosilanes: A Mild and Chemoselective Synthesis of Amines
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A reduction of various aryl, alkyl, and α,β-unsaturated amides with phenylsilane, catalysed by a borinic acid, is reported. The unprecedented reaction was carried out under very mild conditions and led to useful amines. Furthermore, the reaction tolerates a variety of functional groups. Initial investigations implicated that an intermediate diarylhydroborane is involved in the reaction mechanism.
- Chardon, Aurélien,Mohy El Dine, Tharwat,Legay, Rémi,De Paolis, Micha?l,Rouden, Jacques,Blanchet, Jér?me
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p. 2005 - 2009
(2017/02/19)
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- Orally bioavailable factor Xa inhibitors containing alpha-substituted gem-dimethyl P4 moieties
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In an effort to identify a potential back-up to apixaban (Eliquis), we explored a series of diversified P4 moieties. Several analogs with substituted gem-dimethyl moieties replacing the terminal lactam of apixaban were identified which demonstrated potent
- Orwat, Michael J.,Qiao, Jennifer X.,He, Kan,Rendina, Alan R.,Luettgen, Joseph M.,Rossi, Karen A.,Xin, Baomin,Knabb, Robert M.,Wexler, Ruth R.,Lam, Patrick Y.S.,Pinto, Donald J.P.
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p. 3341 - 3345
(2014/07/22)
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- 3-(4-PIPERIDINE-1YLMETHYL-PHENYL)-PROPION ACID-PHENYLAMIDE-DERIVATIVES AND RELATED COMPOUNDS USED IN THE FORM OF MCH ANTAGONISTS (MELANINE CONCENTRATING HORMONE) FOR TREATING EATING DISORDERS
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The invention relates to amid compounds of general formula (I), wherein groups and residuals A, B, b, W, X, Y, Z, R1, R2 and R3 have significances given in a claim 1. In addition, said invention relates to drugs containing at least one type of inventive amid. Because of the antagonist activity of an MCH-receptor, the inventive drugs are suitable for treating metabolic disturbances and/or eating disorders, in particular adiposity, bulimia, anorexia, hyperphagia and diabetes.
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Page/Page column 78-79
(2008/06/13)
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