- INTERRELATIONS OF THE ENERGETICS OF AMIDES AND ALKENES: ENTHALPIES OF FORMATION OF N,N-DIMETHYL DERIVATIVES OF PIVALAMIDE, 1-ADAMANTYLCARBOXAMIDE AND BENZAMIDE, AND OF STYRENNE AND ITS α-, TRANS-β AND β,β-METHYLATED DERIVATIVES
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The enthalpies of formation of the condensed phase and gaseous N,N-dimethyl derivatives of pivalamide, 1-adamantylcarboxamide and benzamide were determined by combustion calorimetry and the associated enthalpies of vaporization and sublimation.The enthalpies of formation of styrene and its α-, trans-β- and β,β-methylated derivatives were determined from measurements of their enthalpies of hydrogenation in dilute hydrocarbon solution.Strain and resonance effects of amides and alkenes are discussed in terms of the exo-/endothermicity of the following reactions: CH3CONH2(g)+RC(CH3)=CH2 -> (CH3)2C=CH2(g)+RCONH2(g), CH3CON(CH3)2(g)+RCH=C(CH3)2(g) -> CH3CH=C(CH3)2(g)+RCON(CH3)2(g) and in terms of the difference of enthalpies of formation of the isomeric (Z)- and (E)-RCH=CHCH3.
- Abboud, Jose-Luis M.,Jimenez, Pilar,Roux, M. Victoria,Turrion, Concepcion,Lopez-Mardomingo, Carmen,et al.
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- Direct amidation of acid fluorides using germanium amides
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Amide functional groups are an essential linkage that are found in peptides, proteins, and pharmaceuticals and new methods are constantly being sought for their formation. Here, a new method for their preparation is presented where germanium amides Ph3GeNR2convert acid fluorides directly to amides. These germanium amides serve to abstract the fluorine atom of the acid fluoride and transfer their amide group -NR2to the carbonyl carbon, and so function as amidation reagents.
- Hayatifar, Ardalan,Elifritz, Emily A.,Bloom, Molly B.,Pixley, Kaitlyn M.,Fennell, Christopher J.,Weinert, Charles S.
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supporting information
p. 4490 - 4493
(2021/04/12)
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- A scalable continuous photochemical process for the generation of aminopropylsulfones
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An efficient continuous photochemical process is presented that delivers a series of novel γ-aminopropylsulfones via a tetrabutylammonium decatungstate (TBADT) catalysed HAT-process. Crucial to this success is the exploitation of a new high-power LED emitting at 365 nm that was found to be superior to an alternative medium-pressure Hg lamp. The resulting flow process enabled the scale-up of this transformation reaching throughputs of 20 mmol h-1 at substrate concentrations up to 500 mM. Additionally, the substrate scope of this transformation was evaluated demonstrating the straightforward incorporation of different amine substituents as well as alkyl appendages next to the sulfone moiety. It is anticipated that this methodology will allow for further exploitations of these underrepresented γ-aminopropylsulfone scaffolds in the future. This journal is
- Baumann, Marcus,Bonciolini, Stefano,Di Filippo, Mara
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supporting information
p. 9428 - 9432
(2020/12/15)
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- Iridium-Catalyzed Reductive Strecker Reaction for Late-Stage Amide and Lactam Cyanation
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A new iridium-catalyzed reductive Strecker reaction for the direct and efficient formation of α-amino nitrile products from a broad range of (hetero)aromatic and aliphatic tertiary amides, and N-alkyl lactams is reported. The protocol exploits the mild and highly chemoselective reduction of the amide and lactam functionalities using IrCl(CO)[P(C6H5)3]2 (Vaska's complex) in the presence of tetramethyldisiloxane, as a reductant, to directly generate hemiaminal species able to undergo substitution by cyanide upon treatment with TMSCN (TMS=trimethylsilyl). The protocol is simple to perform, broad in scope, efficient (up to 99 % yield), and has been successfully applied to the late-stage functionalization of amide- and lactam-containing drugs, and naturally occurring alkaloids, as well as for the selective cyanation of the carbonyl carbon atom linked to the N atom of proline residues within di- and tripeptides.
- Fuentes de Arriba, ángel L.,Lenci, Elena,Sonawane, Mahendra,Formery, Odilon,Dixon, Darren J.
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supporting information
p. 3655 - 3659
(2017/03/21)
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- Amide-ligand-controlled highly para-selective arylation of monosubstituted simple arenes with arylboronic acids
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Pd-catalyzed highly para-selective arylations of monosubstituted simple arenes with arylboronic acids to widely existed biaryls have been developed. Inspired by requisite amide-directing groups in reported selective oxidative couplings, amide ligands, especially DMF, are designed and found to be critical for the selectivity control in current arylations.
- Luan, Yu-Xin,Zhang, Tao,Yao, Wei-Wei,Lu, Ke,Kong, Lu-Yao,Lin, Yu-Tong,Ye, Mengchun
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supporting information
p. 1786 - 1789
(2017/02/15)
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- α-Arylation of Saturated Azacycles and N-Methylamines via Palladium(II)-Catalyzed C(sp3)-H Coupling
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Pd(II)-catalyzed α-C(sp3)-H arylation of pyrrolidines, piperidines, azepanes, and N-methylamines with arylboronic acids has been developed for the first time. This transformation is applicable to wide arrays of pyrrolidines and boronic acids, including heteroaromatic boronic acids. A diastereoselective one-pot heterodiarylation of pyrrolidines has also been achieved.
- Spangler, Jillian E.,Kobayashi, Yoshihisa,Verma, Pritha,Wang, Dong-Hui,Yu, Jin-Quan
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supporting information
p. 11876 - 11879
(2015/10/05)
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- Easy access to amides through aldehydic C-H bond functionalization catalyzed by heterogeneous Co-based catalysts
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A novel synthesis strategy for amides by oxidative amidation of aldehydes is developed using a heterogeneous Co-based catalyst. The Co composite was prepared by simple pyrolysis of a Co-containing MOF, to obtain well-dispersed Co nanoparticles enclosed by carbonized organic ligands. The catalysts were characterized by powder X-ray diffraction (PXRD), N2 physical adsorption, atomic absorption spectroscopy (AAS), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The small Co nanoparticles embedded in the N-doped carbons were highly dispersed with an average size of ca. 7 nm. The Co@C-N materials exhibited significantly enhanced catalytic activity in the oxidative amidation of aldehydes in comparison to those of commercial sources. A series of amides can be easily obtained in good to excellent yields. It was found that the reaction proceeded via radicals under mild conditions, and the carbonyl group in the amide product was from the aldehyde. Moreover, the catalyst could be easily separated by using an external magnetic field and reused several times without significant loss in catalytic efficiency under the investigated conditions. (Chemical Equation Presented).
- Bai, Cuihua,Yao, Xianfang,Li, Yingwei
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p. 884 - 891
(2015/02/19)
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- Bromination of enamines from tertiary amides using the petasis reagent: A convenient one-pot regioselective route to bromomethyl ketones
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An original one-pot synthesis of bromomethyl ketones is achived using the Petasis reagent (dimethyltitanocene) as a key for enamine generation. Several amides were used to test the limits of the procedure by changing either the alkyl chain R or the amino portion of the starting materials. The enamines generated in situ were allowed to react with bromine at low temperature followed by hydrolysis to yield bromomethyl ketones in excellent yields (85 to 95%). Mechanistic details and optimum conditions for the reaction are briefly discussed. The present approach offers several advantages such as regioselectivity in enamine formation, good yields, mild reaction conditions, and ease of experimentation.
- Kobeissi, Marwan,Cherry, Khalil,Jomaa, Wissam
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supporting information
p. 2955 - 2965
(2013/09/02)
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- N-directed aliphatic C-H borylation using borenium cation equivalents
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Highly electrophilic boron cations derived from hindered amine borane complexes have been shown to undergo intramolecular aliphatic C-H borylation.
- Prokofjevs, Aleksandrs,Vedejs, Edwin
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supporting information; experimental part
p. 20056 - 20059
(2012/02/05)
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- Can relief of ring-strain in a cyclopropylmethyllithium drive the Brook rearrangement?
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α-Cyclopropyl-α-trialkylsilyl alkoxides were formed either by addition of cyclopropyllithiums to acylsilanes or by addition of organolithiums to a cyclopropylformylsilane. [1,2]-Brook rearrangement led to α-silyloxy organolithiums which on warming underwent cyclopropane ring opening and [1,5]-retro-Brook rearrangement to yield γ-silyl ketones. Despite the favourability of the cyclopropane ring opening, the Brook rearrangement still required the presence of an anion stabilising group to proceed. β-Silylketones were similarly formed by Brook-retro-Brook rearrangement on warming acylsilanes with a vinyllithium.
- Clayden, Jonathan,Watson, David W.,Chambers, Mark
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p. 3195 - 3203
(2007/10/03)
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- The extraordinary reactions of phenyldimethylsilyllithium with N,N-disubstituted amides
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The reactions of the silyllithium reagent with tertiary amides was discussed. The enediamines were easily isomerized from cis to trans, easily oxidized to dienediamines and were hydrolyzed to α-aminoketones. If the two equivalents of the silyllithium reagent were used, the product was an α-silylamine. The results show that each member of the homologous series of amides gives rise to a substantially different product.
- Buswell, Marina,Fleming, Ian,Ghosh, Usha,Mack, Stephen,Russell, Matthew,Clark, Barry P.
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p. 3006 - 3017
(2007/10/03)
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- A chiral axis due to an acyclic imide-Ar bond: A study of steric effects of acyl groups on racemization
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Studies on the racemization in a series of optically active compounds 3a-e, including the steric effect of their acyl groups, are described. The first example of optically active compounds 3c and 3d, which possess axial chirality based on an acyclic imide-Ar bond, has been reported. A quite interesting result has been revealed, namely, that 3a bearing a bulky acyl group rather than a relatively small one racemized more easily. To explain this observed phenomenon, 13C NMR experiments and the reaction with benzylamine of 3a-e were undertaken. These results suggested that the t-BuCO-N bond in 3a which racemized easily, is more twisted, compared with the RCO-N bonds in 3b-e which are relatively stable to racemization. Furthermore, the absolute configuration of 3b and 3c has been determined to be R by the CD spectrum and the X-ray crystallographic analysis of racemic 3f has been accomplished. (C) 2000 Published by Elsevier Science Ltd.
- Kondo, Kazuhiro,Iida, Takeko,Fujita, Hiroko,Suzuki, Tomoko,Yamaguchi, Kentaro,Murakami, Yasuoki
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p. 8883 - 8891
(2007/10/03)
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- Process for the preparation of imidazolyl macrolide immunosuppressants
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Imidazolmethyloxy-substituted tricyclo-macrolide immunosuppressants are prepared by reacting a tricyclo-macrolide with an imidazolmethyl trichloroacetimidate in the presence of an acid. The invention further provides a crystalline salt of imidazolmethyloxy-substituted tricyclo-macrolide, as well as novel compounds useful in the process of the present invention.
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- Reactions of the "Naked" Fluoride Ion: Syntheses and Structures of SeF6(2-) and BrF6(1-)
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1,1,3,3,5,5-Hexamethylpiperidinium fluoride (pip(1+)F(1-)) and 1,2-dimethylpropyltrimethylammonium fluoride have been prepared.They dissolve in fluorohydrocarbons (CH2F2, CF3-CHF-CF3, CHF3) even at very low temperatures.The nature of these solutions is indicated by the crystal structure of the adduct pip(1+)F(1-)*4CH2F2, which shows (C)H...F bridging.The high fluoride activity is exemplified by the previously unknown reaction between SeF5(1-) and F(1-) to yield SeF6(2-).The salt pip(1+)BrF6(1-) is obtained by a metathesis reaction of Cs(1+)BrF6(1-) with pip(1+)F(1-).The distortion of the SeF6(2-) structure from octahedral symmetry is intermediate between IF6(1-) (strongly distorted) and BrF6(1-) (octahedral).The electron-pair repulsion model is checked against these results. - Keywords: crystal structure; fluorides; hexafluorobromate(V); hexafluoroselenate(IV); naked fluoride
- Mahjoub, Ali Reza,Zhang, Xiongzhi,Seppelt, Konrad
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p. 261 - 265
(2007/10/02)
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- A Novel Series of N-(1-Aminoalkylidene)carboximidamides as Potential Hypoglycemic Agents
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Nitrogen heterocyclic carboximidamides, such as linogliride, 1a, have been shown to possess significant hypoglycemic activity and have shown clinical efficacy as potential antidiabetic agents.We evaluated the biological significance of the heterocyclic ring A of general structure 1, which has always been maintained in this class of compounds, by preparing acyclic compounds of general structure 2.Preliminary in vivo biological testing, i.e., the glucose tolerance test in rats, indicates that a number of the specific acyclic carboximidamides prepared, 6a-6kk, possessed significant hypoglycemic activity often comparable to, and in some cases better than, the activity noted for our model compound, 1a.These results suggest that the heterocyclic ring A of 1 is not essential for hypoglycemic activity for this class of compounds.
- Breslin, Henry J.,Kukla, Michael J.,Tuman, Robert W.,Rebarchak, Mary C.,Bowden, Charles R.
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p. 1597 - 1603
(2007/10/02)
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- THIONO COMPOUNDS. 7. OXIDATION OF THIOAMIDES IN RELATION TO ADVERSE BIOLOGICAL EFFECTS
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Thioacetamide, thioacetamide S-oxide (1), and thiopivalamide S-oxide (8) were oxidized with H2O2 in H2(18)O to generate the corresponding amides with at least 50percent 18O incorporation; hydrolysis of the S-oxides to the amides or 18O exchange with the amides occurs much more slowly.When 1 and trifluorothioacetamide (6) were oxidized with three and four equivalents of H2O2, respectively, in the presence of benzylamine, N-acetylbenzylamine (5) and N-benzyltrifluoroacetamide (7) were isolated in respective yields of 17percent and 37percent.These results are interpreted as evidence for an oxidative desulfurization mechanism involving nucleophilic attack at the carbon atom of an S,S-dioxide or trioxide intermediate as the major pathway; a minor pathway may involve the intermediacy of an oxathiirane S-oxide (3) or dioxide (4) species.Understanding is added to the behavior of S-oxides in aqueous solution, as well as to thermal stability in deuterochloroform.Also reported are studies of the preparation and properties of some N,N-dialkyl derivatives of 8, of reduction of 1 with NADH or NADPH, and of generation and trapping of species related to sulfoxylate ion.
- Hillhouse, John H.,Blair, Ian A.,Field, Lamar
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p. 169 - 184
(2007/10/02)
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- SOME OXYGEN-DONOR COMPLEXES OF CYCLOPENTADIENYL THORIUM(IV) HALIDES.
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The complexes left bracket Th(cp)X//3L//y right bracket (cp equals eta **5-C//5H//5; when y equals 2, X equals Br, L equals thf and X equals Cl, L equals tppo; when y equals 2. 5, X equals Cl, L equals thf, dma and X equals Cl, Br, L equals dmpva; when y
- Bagnall,Beheshti,Heatley
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