593-81-7Relevant academic research and scientific papers
Migration of methyl groups between aliphatic amines in water
Callahan, Brian P.,Wolfenden, Richard
, p. 310 - 311 (2003)
Glycine undergoes spontaneous decarboxylation in dilute aqueous solution at elevated temperatures to form methylamine. During that process, we noticed the appearance of dimethylamine and trimethylamine in smaller amounts that increased gradually with time. These observations suggested the existence of disproportionation reactions of methylamines in water, for which there appears to be no direct precedent in the literature. Every member of the methylamine series is found to yield other members of the methylamine series. When the total concentration of amine was held constant and the rate of reaction was examined as a function of changing pH using the amine itself as the buffer, the initial rate of appearance of the products was found to reach a maximum when the conjugate acid and the conjugate base were present at equivalent concentrations. Near this equivalence point, the rate of reaction varied with pH as expected for a second-order reaction between the protonated and the unprotonated species. Under similar conditions, methyl groups were also found to migrate between the nitrogen atoms of N,N-dimethyl-1,3-propanediamine in a first-order process. With dimethylamine as a common acceptor, tetramethylammonium ion at ambient temperature. Copyright
Manganese-Catalyzed Hydroborations with Broad Scope
Ghosh, Pradip,Jacobi von Wangelin, Axel
supporting information, p. 16035 - 16043 (2021/06/16)
Reductive transformations of easily available oxidized matter are at the heart of synthetic manipulation and chemical valorization. The applications of catalytic hydrofunctionalization benefit from the use of liquid reducing agents and operationally facile setups. Metal-catalyzed hydroborations provide a highly prolific platform for reductive valorizations of stable C=X electrophiles. Here, we report an especially facile, broad-scope reduction of various functions including carbonyls, carboxylates, pyridines, carbodiimides, and carbonates under very mild conditions with the inexpensive pre-catalyst Mn(hmds)2. The reaction could be successfully applied to depolymerizations.
Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
supporting information, p. 13122 - 13135 (2021/08/31)
Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
DRUG ELUTING POLYMER COMPOSED OF BIODEGRADABLE POLYMERS APPLIED TO SURFACE OF MEDICAL DEVICE
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, (2021/06/22)
This present invention relates to drug eluting polymers, including novel biodegradable drug eluting polymers, which are added to the surface of a medical device to treat device associated complications and to deliver drug locally around the device. Methods of making polymers, for example, drug-eluting polymers, polymer compositions, and materials used therewith also are provided. The drug eluting polymers are obtained from the polymerization of macromonomers made of a connecting moiety, a biodegradable moiety and a cross-linkable moiety that are liquids at a temperature of 10° C. to 40° C.
La[N(sime3)2]3-catalyzed deoxygenative reduction of amides with pinacolborane. scope and mechanism
Barger, Christopher J.,Dicken, Rachel D.,Weidner, Victoria L.,Motta, Alessandro,Lohr, Tracy L.,Marks, Tobin J.
supporting information, p. 8019 - 8028 (2020/05/27)
Tris[N,N-bis(trimethylsilyl)amide]lanthanum (LaNTMS) is an efficient and selective homogeneous catalyst for the deoxygenative reduction of tertiary and secondary amides with pinacolborane (HBpin) at mild temperatures (25-60 °C). The reaction, which yields amines and O(Bpin)2, tolerates nitro, halide, and amino functional groups well, and this amide reduction is completely selective, with the exclusion of both competing inter- and intramolecular alkene/alkyne hydroboration. Kinetic studies indicate that amide reduction obeys an unusual mixed-order rate law which is proposed to originate from saturation of the catalyst complex with HBpin. Kinetic and thermodynamic studies, isotopic labeling, and DFT calculations using energetic span analysis suggest the role of a [(Me3Si)2N]2La-OCHR(NR′2)[HBpin] active catalyst, and hydride transfer is proposed to be ligand-centered. These results add to the growing list of transformations that commercially available LaNTMS is competent to catalyze, further underscoring the value and versatility of lanthanide complexes in homogeneous catalysis.
Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation
Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
supporting information, p. 159 - 162 (2019/01/04)
A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F2-C6H3)3 in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation. The reaction displays broad substrate scope for tertiary benzoic acid amides and α-branched carboxamides.
Catalytic Hydrogenation for the Preparation of Amines from Amide Acetals, Ketene N,O-Acetals or Ester Imides
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Paragraph 0150; 0152, (2016/10/04)
The present invention relates to a process for the preparation of amines, comprising the following steps: Reaction of a (i) amide acetal of the general formula (I), or (ii) ketene N,O-acetal of the general formula (II), or (iii) ester imide of the general formula (III) with H2 in the presence of a hydrogenation catalyst, where catalyst and amide acetal or ketene N,O-acetal or ester imide are used in a molar ratio of from 1:10 to 1:100 000 and where a hydrogen pressure of from 0.1 bar to 200 bar is established and where a temperature in the range of from 0° C. to 250° C. is established.
Selective Synthesis of Trimethylamine by Catalytic N-Methylation of Ammonia and Ammonium Chloride by utilizing Carbon Dioxide and Molecular Hydrogen
Beydoun, Kassem,Thenert, Katharina,Streng, Emilia S.,Brosinski, Sandra,Leitner, Walter,Klankermayer, Jürgen
, p. 135 - 138 (2016/01/26)
The synthesis of trimethylamine (TMA) through a multicomponent combination of ammonia with carbon dioxide and molecular hydrogen by using a homogeneous ruthenium catalyst was explored. The use of [Ru(triphos)(tmm)] [triphos: 1,1,1-tris(diphenylphosphinomethyl)ethane, tmm: trimethylene methane] together with aluminum trifluoromethanesulfonate as a co-catalyst resulted in high ammonia conversion and excellent selectivity for TMA in organic solvents. Aqueous solutions of ammonium chloride were methylated almost quantitatively to the corresponding hydrochloride salt (i.e., TMA·HCl) in a biphasic solvent system by using the same Ru complex without the need for any co-catalyst.
Magnesium-catalyzed mild reduction of tertiary and secondary amides to amines
Lampland, Nicole L.,Hovey, Megan,Mukherjee, Debabrata,Sadow, Aaron D.
, p. 4219 - 4226 (2015/11/11)
The first example of a catalytic hydroboration of amides for their deoxygenation to amines is reported. This transformation employs an earth-abundant magnesium-based catalyst. Tertiary and secondary amides are reduced to amines at room temperature in the presence of pinacolborane (HBpin) and catalytic amounts of ToMMgMe (ToM = tris(4,4-dimethyl-2-oxazolinyl)phenylborate). Catalyst initiation and speciation is complex in this system, as revealed by the effects of concentration and order of addition of the substrate and HBpin in the catalytic experiments. ToMMgH2Bpin, formed from ToMMgMe and HBpin, is ruled out as a possible catalytically relevant species by its reaction with N,N-dimethylbenzamide, which gives Me2NBpin and PhBpin through C-N and C-C bond cleavage pathways, respectively. In that reaction, the catalytic product benzyldimethylamine is formed in only low yield. Alternatively, the reaction of ToMMgMe and N,N-dimethylbenzamide slowly gives decomposition of ToMMgMe over 24 h, and this interaction is also ruled out as a catalytically relevant step. Together, these data suggest that catalytic activation of ToMMgMe requires both HBpin and amide, and ToMMgH2Bpin is not a catalytic intermediate. With information on catalyst activation in hand, tertiary amides are selectively reduced to amines in good yield when catalytic amounts of ToMMgMe are added to a mixture of amide and excess HBpin. In addition, secondary amides are reduced in the presence of 10 mol % ToMMgMe and 4 equiv of HBpin. Functional groups such as cyano, nitro, and azo remain intact under the mild reaction conditions. In addition, kinetic experiments and competition experiments indicate that B-H addition to amide C-O is fast, even faster than addition to ester C=O, and requires participation of the catalyst, whereas the turnover-limiting step of the catalyst is deoxygenation.
N-Methylation of Amines with Methanol at Room Temperature
Tsarev, Vasily N.,Morioka, Yuna,Caner, Joaquim,Wang, Qing,Ushimaru, Richiro,Kudo, Akihiko,Naka, Hiroshi,Saito, Susumu
supporting information, p. 2530 - 2533 (2015/05/27)
N-Methylation of amines with methanol proceeds at room temperature in the presence of a silver-loaded titanium dioxide (Ag/TiO2) photocatalyst under UV-vis light irradiation. This method allows facile synthesis/isolation of N-methylamines bearing various functional groups including N-benzyl, N-allyl, N-Boc, hydroxyl, ether, acetal, carboxamide, formamide, and olefin groups. (Chemical Presented)
