133055-17-1Relevant articles and documents
Amine-boranes as Dual-Purpose Reagents for Direct Amidation of Carboxylic Acids
Choudhary, Shivani,Hamann, Henry J.,Ramachandran, P. Veeraraghavan
supporting information, (2020/11/13)
Amine-boranes serve as dual-purpose reagents for direct amidation, activating aliphatic and aromatic carboxylic acids and, subsequently, delivering amines to provide the corresponding amides in up to 99% yields. Delivery of gaseous or low-boiling amines as their borane complexes provides a major advantage over existing methodologies. Utilizing amine-boranes containing borane incompatible functionalities allows for the preparation of functionalized amides. An intermolecular mechanism proceeding through a triacyloxyborane-amine complex is proposed.
A Hydroperoxide-Mediated Decarboxylation of α-Ketoacids Enables the Chemoselective Acylation of Amines
Nanjo, Takeshi,Kato, Natsuki,Zhang, Xuan,Takemoto, Yoshiji
supporting information, p. 15504 - 15507 (2019/11/14)
Strategies for the formation of amide bonds, that is, one of the most basic and important transformations in organic synthesis, have so far focused predominantly on dehydration reactions. Herein, we report and demonstrate the practical utility of a novel decarboxylative amidation of α-ketoacids by using inexpensive tert-butyl hydroperoxide (TBHP), which is characterized by high yields, a broad substrate scope, mild reaction conditions, and a unique chemoselectivity. These features enable the synthesis of peptides from amino acid derived α-ketoacids under preservation of the stereochemical information.
Broadly Applicable Ytterbium-Catalyzed Esterification, Hydrolysis, and Amidation of Imides
Guissart, Céline,Barros, Andre,Rosa Barata, Luis,Evano, Gwilherm
supporting information, p. 5098 - 5102 (2018/09/13)
An efficient, broadly applicable, operationally simple, and divergent process for the transformation of imides into a range of carboxylic acid derivatives under mild conditions is reported. By simply using catalytic amounts of ytterbium(III) triflate as a Lewis acid promoter in the presence of alcohols, water, amines, or N,O-dimethylhydroxylamine, a broad range of imides is smoothly and readily converted to the corresponding esters, carboxylic acids, amides, and Weinreb amides in good yields. This method notably enables an easy cleavage of oxazolidinone-based auxiliaries.
Pd(II)-Catalyzed, Picolinamide-Assisted, Z-Selective γ-Arylation of Allylamines to Construct Z-Cinnamylamines
Parella, Ramarao,Babu, Srinivasarao Arulananda
, p. 6550 - 6567 (2017/07/15)
Investigations of Pd(II)-catalyzed, picolinamide-assisted, γ-C(sp2)-H activation and Z-selective arylation of allylamines are reported. The reactions of N-allylpicolinamides with various aryl iodides in the presence of the catalyst Pd(OAc)2 and additive AgOAc have led to the selective γ-arylation of allylamines to construct various cinnamylamines with moderate to good yields and good to high E/Z ratios. To obtain good E/Z ratios, the Pd(II)-catalyzed arylation reaction of N-allylpicolinamides was probed using different additives, directing groups, and reaction conditions. The Pd(II)-catalyzed arylation of an allylamine containing both γ-C(sp2)-H and γ-C(sp3)-H bonds afforded moderate yields of the γ-C(sp2)-H and γ-C(sp3)-H bisarylated cinnamylamines. Although Heck-type γ-arylations of allylamines have generally afforded the E-cinnamylamines, the bidentate directing group picolinamide-directed arylations of allylamines were found to be Z-selective. A plausible mechanism was proposed for the observed regioselectivity and Z-selective arylation of N-allylpicolinamides. Additionally, the Pd(II)-catalyzed arylation of an N-allyl-5-methylisoxazole-3-carboxamide afforded the E-cinnamylamines plausibly via a ligand-free Heck-type reaction mechanism.
Nickel/Photoredox-Catalyzed Amidation via Alkylsilicates and Isocyanates
Zheng, Shuai,Primer, David N.,Molander, Gary A.
, p. 7957 - 7961 (2017/11/10)
A nickel/photoredox, dual-catalyzed amidation reaction between alkylsilicate reagents and alkyl/aryl isocyanates is reported. In contrast to the previously reported reductive coupling process, this protocol is characterized by mild reaction conditions and the absence of a stoichiometric reductant. A mechanistic hypothesis involving a nickel-isocyanate adduct is proposed based on literature precedent and further validation by experimental results.
One-Pot Amide Bond Formation from Aldehydes and Amines via a Photoorganocatalytic Activation of Aldehydes
Papadopoulos, Giorgos N.,Kokotos, Christoforos G.
, p. 7023 - 7028 (2016/08/30)
A mild, one-pot, and environmentally friendly synthesis of amides from aldehydes and amines is described. Initially, a photoorganocatalytic reaction of aldehydes with di-isopropyl azodicarboxylate leads to an intermediate carbonyl imide, which can react with a variety of amines to afford the desired amides. The initial visible light-mediated activation of a variety of monosubstituted or disubstituted aldehydes is usually fast, occurring in a few hours. Following the photocatalytic reaction, addition of the primary amine at room temperature or the secondary amine at elevated temperatures leads to the corresponding amide from moderate to excellent yields without epimerization. This methodology was applied in the synthesis of Moclobemide, a drug against depression and social anxiety.
TEMPO-Catalyzed Oxidative Amidation of Alcohols via Hexafluoroisopropyl Esters
Vatèle, Jean-Michel
, p. 2280 - 2284 (2015/09/28)
Stepwise oxidative amidation of alcohols using trichloroisocyanuric acid, a catalytic amount of TEMPO in combination with pyridine and hexafluoroisopropyl (HFIP) alcohol followed by amines is described. This procedure used HFIP esters as activating esters which were found to be very efficient acylating agents for amide bond formation. This process is compatible with a number of functional groups and acid-sensitive protecting groups.
Direct amidation from alcohols and amines through a tandem oxidation process catalyzed by heterogeneous-polymer-incarcerated gold nanoparticles under aerobic conditions
Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
supporting information, p. 2614 - 2626 (2013/11/19)
We describe herein a highly elegant and suitable synthesis of amide products from alcohols and amines through a tandem oxidation process that uses molecular oxygen as a terminal oxidant. Carbon-black-stabilized polymer-incarcerated gold (PICB-Au) or gold/cobalt (PICB-Au/Co) nanoparticles were employed as an efficient heterogeneous catalyst depending on alcohol reactivity and generated only water as the major co-product of the reaction. A wide scope of substrate applicability was shown with 42 examples. The catalysts could be recovered and reused without loss of activity by using a simple operation. Gold standard: A highly efficient green method for amide synthesis from alcohols and amines catalyzed by gold nanoparticles stabilized by styrene-based copolymers has been developed (see scheme). Two catalysts have been used with high selectivity depending on the combination of substrates. These Au nanoparticle catalysts can be recovered and reused several times by simple operations. Copyright
Semisynthetic cyclopamine analogues as potent and orally bioavailable hedgehog pathway antagonists
Tremblay, Martin R.,Nevalainen, Marta,Nair, Somarajan J.,Porter, James R.,Castro, Alfredo C.,Behnke, Mark L.,Yu, Lin-Chen,Hagel, Margit,White, Kerry,Faia, Kerrie,Grenier, Louis,Campbell, Matthew J.,Cushing, Jill,Woodward, Caroline N.,Hoyt, Jennifer,Foley, Michael A.,Read, Margaret A.,Sydor, Jens R.,Tong, Jeffrey K.,Palombella, Vito J.,McGovern, Karen,Adams, Julian
supporting information; experimental part, p. 6646 - 6649 (2009/11/30)
Herein is reported the synthesis of a novel class of hedgehog antagonists derived from cyclopamine. The acid sensitive D-ring of cyclopamine was homologated utilizing a sequence of chemoselective cyclopropanation and stereoselective acid-catalyzed rearran
CYCLOPAMINE ANALOGUES AND METHODS OF USE THEREOF
-
Page/Page column 61-62, (2010/10/20)
The present invention provides compositions and methods for modulating smoothened-dependent pathway activation. The present invention provides analogs of cyclopamine that can be used to counteract the phenotypic effects of unwanted activation of a hedgeho
