7613-16-3Relevant academic research and scientific papers
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 1618 - 1629 (2021/01/25)
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
Understanding the binding properties of phosphorylated glycoluril-derived molecular tweezers and selective nanomolar binding of natural polyamines in aqueous solution
Heilmann, Michael,Knezevic, Melina,Piccini, Giovannimaria,Tiefenbacher, Konrad
supporting information, p. 3628 - 3633 (2021/05/04)
A modular synthetic platform for the construction of flexible glycoluril-derived molecular tweezers was developed. The binding properties of four exemplary supramolecular hosts obtained via this approach towards 16 organic amines were investigated by means of 1H NMR titration. In this work, we compare the Ka values obtained this way with those of three structurally related molecular tweezers and provide a computational approach towards an explanation of the observed behavior of those novel hosts. The results showcase that certain structural modifications lead to very potent and selective binders of natural polyamines, with observed binding of spermine below 10 nM. This journal is
A Modular Phosphorylated Glycoluril-Derived Molecular Tweezer for Potent Binding of Aliphatic Diamines
Heilmann, Michael,Tiefenbacher, Konrad
supporting information, p. 12900 - 12904 (2019/11/05)
A molecular tweezer based on a glycoluril-derived framework bearing four phosphate groups was synthesized and shown to be capable of binding organic amines in aqueous solution. This work reports the Ka values for 30 complexes of this molecular tweezer and amine guests, determined by means of 1H NMR titrations. Both the hydrophobic cavity and the phosphate groups contribute to the binding. Bulkier molecules and molecules bearing negatively charged groups like carboxylates in amino acids bind less tightly due to a steric clash and coulombic repulsion. The narrow cavity and the strong ionic interactions of the phosphate groups with ammonium guests favor binding of aliphatic diamines. These binding properties clearly distinguish this system from structurally related molecular clips and tweezers.
Design, synthesis, and solution behaviour of small polyamines as switchable water additives
Mercer, Sean M.,Robert, Tobias,Dixon, Daniel V.,Chen, Chien-Shun,Ghoshouni, Zahra,Harjani, Jitendra R.,Jahangiri, Soran,Peslherbe, Gilles H.,Jessop, Philip G.
supporting information; experimental part, p. 832 - 839 (2012/04/23)
The practice of adding salt to water to induce salting out of contaminants or to break emulsions and suspensions is generally avoided industrially because of the expense of the necessary treatment of the salty water afterwards. However, the use of switchable water, an aqueous solvent with switchable ionic strength, allows for reversible generation and elimination of salts in aqueous solution, through the introduction and removal of CO2. In the effort to improve the efficiency of these switchable salts, a physical study modeling their reactivity and solution behaviour has been performed, resulting in a set of design principles for future switchable water additives. The resulting polyamines synthesized using this template show the highest efficiency recorded for a switchable water additive. The Royal Society of Chemistry 2012.
Synthesis of poly(galactaramides) from alkylene- and substituted alkylenediammonium galactarates
Kiely, Donald E.,Vishwanathan, Arvind,Jarman, Bevan P.,Manley-Harris, Merilyn
experimental part, p. 348 - 368 (2010/01/16)
Polyhydroxypolyamides (PHPAs) represent a class of synthetic polyamides derived from aldaric acid and diamine monomer units. This paper describes the synthesis of some poly(galactaramides), a class of polyhydroxypolyamides, that employs alkylene and subst
Interactions between protonated Amine, aza crown ether, and cryptand with dibenzocrown ether studied by a new spectrophotometric technique
Buschmann,Cleve,Mutihac,Schollmeyer
, p. 755 - 759 (2007/10/03)
The stability constants for the complexation of a diprotonated diamine, a diaza crown ether, and a cryptand with dibenzo-18-crown-6 and dibenzo-24-crown-8, have been studied in aqueous solution using a new spectrophotometric technique. Because of the complex formation, the solubility of the dibenzocrown ethers increases. Complex formation is possible between diamines and dibenzocrown ethers with both 1:1 and 2:1 stoichiometry. However, experimental data are insufficient to decide on the actual stoichiometry of the complexes formed. By computing the stability constants and comparing them with the corresponding results for monoamines, it is possible to decide on the actual stoichiometry of the complexes. Under the experimental conditions only 1:1 complexes with diamines are formed.
