- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- Synthesis of 4-Substituted N-Alkyl-1,3-dithiolan-2-imines
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Abstract: S-(2-Thiocyanatopropyl) N-alkyl-N-methylcarbamothioates were synthesized from N-alkyl-1,3-oxathiolan-2-imines by reaction with potassium thiocyanate, and their reactions with alcohols under the Ritter conditions afforded 4-substituted N-alkyl-1,
- Borisova, I. A.,Shiryaev, A. K.,Shiryaev, V. A.
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p. 1084 - 1088
(2021/09/08)
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- Selective formylation and methylation of amines using carbon dioxide and hydrosilane catalyzed by alkali-Metal carbonates
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The formylation and methylation of amines with carbon dioxide and hydrosilanes are emerging yet important types of transformations for CO2. Catalytic methods effective for both reactions with wide substrate scopes are rare because of the difficulty in controlling the selectivity. Herein, we report that simple and readily available inorganic bases alkali-metal carbonates, especially cesium carbonatecatalyze both the formylation and methylation reactions efficiently under mild conditions. The selectivity can be conveniently controlled by varying the reaction temperature and silane. A “cesium effect” on both reactions was observed by comparing the catalytic activity of various alkali-metal carbonates. Combined experimental and computational studies suggested the following reaction mechanism: (i) activation of Si?H by Cs2CO3, (ii) insertion of CO2 into Si?H, (iii) formylation of amines by silyl formate, and (iv) reduction of formamides to methylamines.
- Fang, Chi,Lu, Chunlei,Liu, Muhua,Zhu, Yiling,Fu, Yao,Lin, Bo-Lin
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p. 7876 - 7881
(2018/05/23)
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- Tris(dialkylamide)aluminum compound, and method for producing aluminum-containing thin film using same
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The present invention relates to a tris(dialkylamide)aluminum compound, and a method for producing an aluminum-containing thin film using the aluminum compound, the tris(dialkylamide)aluminum compound being represented by the formula (1): wherein R represents a linear alkyl group having 1 to 6 carbon atoms; andR1, R2 and R3 may be the same as, or different from each other, and each independently represents hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms, or R1, R2 and R3 may be joined together to form a ring, with the proviso that the compounds in which two or more of R1, R2 and R3 are hydrogen atoms are excluded, and three dialkylamide ligands may be the same as, or different from each other.
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Page/Page column 22
(2015/12/05)
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- Catalytic hydrogenation of amides to amines under mild conditions
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Under (not so much) pressure: A general method for the hydrogenation of tertiary and secondary amides to amines with excellent selectivity using a bimetallic Pd-Re catalyst has been developed. The reaction proceeds under low pressure and comparatively low temperature. This method provides organic chemists with a simple and reliable tool for the synthesis of amines. Copyright
- Stein, Mario,Breit, Bernhard
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supporting information
p. 2231 - 2234
(2013/03/28)
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- Hindered ureas as masked isocyanates: Facile carbamoylation of nucleophiles under neutral conditions
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Bigger is better: Sterically hindered dialkyl ureas undergo nucleophilic substitution at dramatically faster rates than their less hindered counterparts (see scheme). Steric decompression upon the formation of an intermediate isocyanate can explain this c
- Hutchby, Marc,Houlden, Chris E.,Gair Ford,Tyler, Simon N. G.,Gagne, Michel R.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
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supporting information; experimental part
p. 8721 - 8724
(2010/01/16)
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- 2,3,4,5-TETRAHYDRO-1H-1,5-BENZODIAZEPINE DERIVATIVE AND MEDICINAL COMPOSITION
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The present invention has its object to provide a 2,3,4,5-tetrahydro-1H-1,5-benzodiazepine derivative represented with the Formula (1) , or the pharmaceutically acceptable salt, which is effective as a therapeutic and prophylactic agent for diabetes, diabetic nephropathy, or glomerulosclerosis.
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- PHOSPHONIUM DIAZA-DIYLIDS AND AZA-YLDIID AS NEW AND EFFICIENT REAGENTS FOR PRIMARY AND SECONDARY AMINES SYNTHESIS
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Metallated aminophosphonium ylids, diaza-diylids and aza-yldiid, are investigated as reagents for primary and secondary amines synthesis.
- Cristau, Henri-Jean,Garcia, Chantal,Kadoura, Jumah,Torreilles, Eliane
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p. 151 - 154
(2007/10/02)
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- Reactions of Carbonyl Compounds in Basic Solutions. Part 15. The Alkaline Hydrolysis of N-Methyl, N-Phenyl and Bicyclo Lactams, Penicillins and N-Alkyl-N-methylacetamides
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The rate coefficients for the alkaline hydrolysis of a series of N-methyl, N-phenyl and bicyclo lactams, penicillins and N-alkyl-N-methylacetamides in water or in aqueous dimethyl sulphoxide have been measured at several temperatures.The reactions were first order in both substrates and base.The reactivities are related to the structures of the substrates, especially N-substitution, ring size and fused ring effects.The reactivities, as well as the activation parameters, kinetic solvent and solvent isotope effects, are used to suggest the detailed mechanisms.All the β-lactams appear to react with rate-determining addition of hydroxide anion; while the N-alkyl γ- and δ-lactams and N-alkyl-N-methylacetamides have rate-determining ring fission of the tetrahedral adduct, assisted by water-catalysis.The reactivity of penicillin in alkaline hydrolysis has been analysed by studies of model compounds.These show that the increased reactivity of the penicillin β-lactam ring arises from the direct action of the fused ring structure and the acetylamino side chain.
- Bowden, Keith,Bromley, Keith
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p. 2111 - 2116
(2007/10/02)
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- Ion-Dipole Complexes in the Unimolecular Reactions of Isolated Organic Ions. Effect of N-Methylation on Olefin and Amine Loss from Protonated Aliphatic Amines
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The slow unimolecular fragmentation reactions os 18 gaseous protonated aliphatic amines of general formula R1NH(1+)R2R3 (R1=Prn, Pri, Bun, Bui, Bus, or But; R2,R3=H,CH3) are reported and discussed.Two decomposition routes are observed for a metastable ions R1NH(1+)R2R3.The first involves elimination of a neutral amine, R2R3NH, and formation of a carbocation, R1(1+), via a mechanism involving an incipient cation bound to the developing amine by an ion-dipole attraction.Rearrangement of the cation, to give thermodynamically more stable isomers, is feasible in these ion-dipole complexes.Further reorganization of the complexes leads to a species in which an incipient olefin 1-H> and an amine 2R3NH> are co-ordinated to a common proton.Dissociation of these proton-bound complexes, with retention of the proton by the developing amine, results in olefin loss, which is the secondreaction undergone by metastable ions R1NH(1+)R2R3.The relative abundance of amine expulsion is greater for protonated amines containing a primary alkyl group, R1, than is the case for isomeric ions containing secondary or tertiary alkyl groups.Progressive methylation of the nitrogen atom decreases the relative abundance of amine loss from R1NH(1+)R2R3, regardless of the nature of the principal alkyl group.These two trends are explained in terms of the energetics of the intermediates and products involved in the decomposition of the protonated amines.
- Bowen, Richard D.,Harrison, Alex G.,Reiner, Eric J.
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p. 1009 - 1014
(2007/10/02)
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- BESTIMMUNG DER IONENPAAR-BASIZITAT VON LITHIUM- UND KALIUMAMIDEN
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Ion pair basicities of lithio and potassio salts of some secondary amines were determined by equilibration with benzyl compounds.With these bases it is possible to span a range of about 19 pK-units from pK = 27 up to 46.The structural dependence of thermodynamic as well as kinetic basicity is discussed.Some new effective amide bases for preparative purposes are recommended.For the first time the pK-value of toluene has been determined by direct equilibration.It amounts to 40.7 in tetrahydrofuran.
- Ahlbrecht, Hubertus,Schneider, Gunther
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p. 4729 - 4742
(2007/10/02)
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- A New and Specific Method for the Monomethylation of Primary Amines
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The reduction of monomeric methyleneamines, representing a convenient and highly specific procedure for the title reaction, is studied.
- Barluenga, Jose,Bayon, Ana M.,Asensio, Gregorio
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p. 1334 - 1335
(2007/10/02)
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- THE ELECTROPHILIC AMINATION OF ORGANOLITHIUMS WITH METHYLLITHIUM COMPLEXES OF N-SUBSTITUTED METHOXYAMINES
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Three N-alkyl methoxyamine derivatives are shown to be effective as electrophilic reagents for the conversion of organolithiums to secondary amines.
- Kokko, Bruce J.,Beak, Peter
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p. 561 - 564
(2007/10/02)
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