scholarly journals Triol-promoted activation of C–F bonds: Amination of benzylic fluorides under highly concentrated conditions mediated by 1,1,1-tris(hydroxymethyl)propane

2013 ◽  
Vol 9 ◽  
pp. 2451-2456 ◽  
Author(s):  
Pier Alexandre Champagne ◽  
Alexandre Saint-Martin ◽  
Mélina Drouin ◽  
Jean-François Paquin
Keyword(s):  
Hydrogen Bond ◽  
Secondary Amines ◽  
Organofluorine Compound ◽  
Benzylic Amines

Activation of the C–F bond of benzylic fluorides was achieved using 1,1,1-tris(hydroxymethyl)propane (2) as a hydrogen bond-donating agent. Investigations demonstrated that hydrogen bond-donating solvents are promoting the activation and hydrogen bond-accepting ones are hindering it. However, the reaction is best run under highly concentrated conditions, where solvents cannot interfere with the interaction between the organofluorine compound and the triol. Various benzylic fluorides react with secondary amines or anilines to form benzylic amines in good yields.

Carbon Dioxide-Driven Palladium-Catalyzed C–H Activation of Amines: A Unified Approach for the Arylation of Aliphatic and Aromatic Primary and Secondary Amines

Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 519-524 ◽  
Author(s):  
Michael Young ◽  
Mohit Kapoor ◽  
Pratibha Chand-Thakuri ◽  
Justin Maxwell ◽  
Daniel Liu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Bond Activation ◽  
Secondary Amines ◽  
Activation Process ◽  
Unified Approach ◽  
Benzylic Amines ◽  
Palladium Catalyzed ◽  
Group A ◽  
Directing Group ◽  
Site Selective

Amines are an important class of compounds in organic chemistry and serve as an important motif in various industries, including pharmaceuticals, agrochemicals, and biotechnology. Several methods have been developed for the C–H functionalization of amines using various directing groups, but functionalization of free amines remains a challenge. Here, we discuss our recently developed carbon dioxide driven highly site-selective γ-arylation of alkyl- and benzylic amines via a palladium-catalyzed C–H bond-activation process. By using carbon dioxide as an inexpensive, sustainable, and transient directing group, a wide variety of amines were arylated at either γ-sp3 or sp2 carbon–hydrogen bonds with high selectivity based on substrate and conditions. This newly developed strategy provides straightforward access to important scaffolds in organic and medicinal chemistry without the need for any expensive directing groups.1 Introduction2 C(sp3)–H Arylation of Aliphatic Amines3 C(sp2)–H Arylation of Benzylamines4 Mechanistic Questions5 Future Outlook

scholarly journals TwoN-(2-phenylethyl)nitroaniline derivatives as precursors for slow and sustained nitric oxide release agents

2016 ◽  
Vol 72 (5) ◽  
pp. 405-410 ◽  
Author(s):  
Alec R. Badour ◽  
John A. Wisniewski ◽  
Dillip K. Mohanty ◽  
Philip J. Squattrito
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Molecular Conformation ◽  
Therapeutic Interventions ◽  
Secondary Amines ◽  
Asymmetric Unit ◽  
High Concentration ◽  
Nitric Oxide Release ◽  
Π Interactions

Notwithstanding its simple structure, the chemistry of nitric oxide (NO) is complex. As a radical, NO is highly reactive. NO also has profound effects on the cardiovascular system. In order to regulate NO levels, direct therapeutic interventions include the development of numerous NO donors. Most of these donors release NO in a single high-concentration burst, which is deleterious.N-Nitrosated secondary amines release NO in a slow, sustained, and rate-tunable manner. Two new precursors to sustained NO-releasing materials have been characterized.N-[2-(3,4-Dimethoxyphenyl)ethyl]-2,4-dinitroaniline, C16H17N3O6, (I), crystallizes with one independent molecule in the asymmetric unit. The adjacent amine and nitro groups form an intramolecular N—H...O hydrogen bond. Theanticonformation about the phenylethyl-to-aniline C—N bond leads to the planes of the arene and aniline rings being approximately perpendicular. Molecules are linked into dimers by weak intermolecular N—H...O hydrogen bonds such that each amine H atom participates in a three-center interaction with two nitro O atoms. The dimers pack so that the arene rings of adjacent molecules are not parallel and π–π interactions do not appear to be favored.N-(4-Methylsulfonyl-2-nitrophenyl)-L-phenylalanine, C16H16N2O6S, (II), with an optically active center, also crystallizes with one unique molecule in the asymmetric unit. The L enantiomer was establishedviathe configuration of the starting material and was confirmed by refinement of the Flack parameter. As in (I), there is an intramolecular N—H...O hydrogen bond between adjacent amine and nitro groups. The conformation of the molecule is such that the arene rings display a dihedral angle ofca60°. Unlike (I), molecules are not linkedviaintermolecular N—H...O hydrogen bonds. Rather, the carboxylic acid H atom forms a classic, approximately linear, O—H...O hydrogen bond with a sulfone O atom. Pairs of molecules related by twofold rotation axes are linked into dimers by two such interactions. The packing pattern features a zigzag arrangement of the arene rings without apparent π–π interactions. These structures are compared with reported analogues, revealing significant differences in molecular conformation, intermolecular interactions, and packing that result from modest changes in functional groups. The structures are discussed in terms of potential NO-release capability.

scholarly journals Hydrogen-Bond-Promoted Metal-Free Hydroamination of Alkynes

Synlett ◽  
2019 ◽  
Vol 30 (18) ◽  
pp. 2086-2090
Author(s):  
Janet Bahri ◽  
Nour Tanbouza ◽  
Thierry Ollevier ◽  
Marc Taillefer ◽  
Florian Monnier
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Ethylene Glycol ◽  
Proton Exchange ◽  
Secondary Amines ◽  
Metal Free ◽  
Original Metal

An original metal-free regio- and stereoselective intermolecular hydroamination of alkynes is described. Various (E)-enamines were obtained from arylacetylenes and aliphatic secondary amines in the presence of ethylene glycol as a solvent. The latter is assumed to play a major role in the mechanism through hydrogen bonding and proton exchange.

Analysis of the less common hydrogen bonds involving ester oxygen sp 3 atoms as acceptors in the crystal structures of small organic molecules

2004 ◽  
Vol 60 (4) ◽  
pp. 424-432 ◽  
Author(s):  
Krešimir Molčanov ◽  
Biserka Kojić-Prodić ◽  
Nenad Raos
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Packing ◽  
Noncovalent Interactions ◽  
Secondary Amines ◽  
Structural Function ◽  
Hydroxyl Groups ◽  
Donor Group ◽  
Acta Cryst ◽  
Bifurcated Hydrogen Bond

An analysis of hydrogen bonds involving ester Osp 3 atoms as acceptors has been performed based on the data extracted from the Cambridge Structural Database [Allen (2002). Acta Cryst. B58, 380–388; version 5.25, November 2003], using the ConQuest package to evaluate the stereochemical and electronic properties of the acceptors. Evidence for the existence of this particular type of hydrogen bond and its structural function in crystal packing is presented. Using a cut-off limit on residual indices of R < 0.05 (for the structures with hydrogen bonds involving an oxygen as part of the donor group) and R < 0.085 (for nitrogen as part of the donor group), 230 structures out of the total CSD entries of 298 100 were found to contain hydrogen bonds with the ester Osp 3 atoms as acceptors. The hydrogen-bond donors include water molecules, hydroxyl groups, primary and secondary amines and, in a few cases, imino groups. Four modes of the participation of the ester Osp 3 atoms in hydrogen bonding are detected: as a single acceptor, as a double acceptor, as a single acceptor of a H atom involved in an intermolecular bifurcated hydrogen bond, and as a shared acceptor function with the ester Osp 2 atom in a bifurcated hydrogen bond. The role of such directed noncovalent interactions in crystal packing is demonstrated by a small gallery of selected structures.

Hydrogen-bond basicity pKHB scale of secondary amines

2001 ◽  
pp. 2130 ◽  
Author(s):  
Jérôme Graton ◽  
Michel Berthelot ◽  
Christian Laurence
Keyword(s):  
Hydrogen Bond ◽  
Secondary Amines ◽  
Hydrogen Bond Basicity

Reactions of secondary amines with triosmium decacarbonyl bis(acetonitrile): room-temperature carbon-hydrogen bond activation and transalkylation

1990 ◽  
Vol 9 (8) ◽  
pp. 2214-2217 ◽  
Author(s):  
Edward Rosenberg ◽  
Shariff E. Kabir ◽  
Kenneth I. Hardcastle ◽  
Michael Day ◽  
Erich Wolf
Keyword(s):  
Hydrogen Bond ◽  
Room Temperature ◽  
Bond Activation ◽  
Secondary Amines ◽  
Carbon Hydrogen Bond Activation
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