- Rediscovering aminal chemistry: Copper(ii) catalysed formation under mild conditions
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Aminals, the N,N analogues of acetals, have been thoroughly explored in organic chemistry, with a particular focus on heteroaromatic aldehyde lithiation. Nevertheless, the existing methodologies for their formation typically employ harsh conditions limiting their usefulness. In this work, we present an efficient and mild methodology for the preparation of aminals from aromatic aldehydes, including furanic platforms. These mild conditions allowed ease of access to a plethora of aminals and as such we set out to explore previously unaccessible potential applications. By studying the stability of various aminals, we were able to develop a simple aldehyde protecting group based on a commercial diamine which is deprotected under mind conditions. We developed a protocol for the scavenging of genotoxic aldehydes by taking advantage of our methodology and a diamine resin, as well as early studies on the development of a stimuli-responsive release system using a salycil aldehyde derived aminal. This journal is
- Afonso, Carlos A. M.,António, Jo?o P. M.,Gomes, Rafael F. A.,Mendon?a, Ricardo,Pereira, Juliana G.
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supporting information
p. 7484 - 7490
(2020/11/18)
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- N-(Hydroxybenzyl)benzamide Derivatives: Aqueous pH-Dependent Kinetics and Mechanistic Implications for the Aqueous Reactivity of Carbinolamides
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The rate constants for the aqueous reaction, between pH 0 and 14, have been determined for a series of amide substituted N-(hydroxybenzyl)benzamide derivatives, in H2O, at 25 °C, I = 1.0 M (KCl). The N-(hydroxybenzyl)benzamide derivatives were found to react via three distinct mechanisms with the kinetically dominant mechanism being dependent on the pH of the reaction solution. It has been shown that the carbinolamides react via a specific-base-catalyzed mechanism (E1cB-like) under basic and pH neutral conditions. At lower pH values, an acid-catalyzed mechanism was kinetically dominant and, last, a water reaction was postulated at pH values where neither the hydroxide-dependent nor the general-acid-catalyzed mechanism was dominant. Contrary to earlier studies with N-(hydroxymethyl)benzamide compounds, no evidence for mechanistic variation based upon the nature of the amidic substituent was observed for any of the N-(hydroxybenzyl)benzamide derivatives studied between pH values of 0-14. The rate for the acid-catalyzed reaction (kH, ρ = -1.17), the apparent second-order hydroxide rate constant (k1′, ρ = 0.87), the hydroxide-independent rate (k1, ρ = 0.65), and the pKa's of the hydroxyl group of the carbinolamide (ρ = 0.23) are reported.
- Koyanagi, Takaoki,Nagorski, Richard W.,Przybyla, David E.,Rafie, Mohammad I.,Siena, Paul M.
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- Copper(I)-catalyzed coupling reaction of aryl boronic acids with N,O-acetals and N,N-aminals under atmosphere leading to α-aryl glycine derivatives and diarylmethylamine derivatives
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We demonstrated a copper(I)-catalyzed coupling reaction of aryl boronic acids with N,O-acetals and N,N-aminals leading to the synthesis of α-aryl glycines and diarylmethylamines. Under an ambient atmosphere, this catalytic system could be applied to the activation of a C(sp3)-O bond of N,O-acetals with an ester and an aryl group, or without a coordinating substituent, as well as to a C(sp3)-N bond of N,N-aminals.
- Sakai, Norio,Hori, Hiroaki,Yoshida, Yoshihiro,Konakahara, Takeo,Ogiwara, Yohei
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p. 4722 - 4729
(2015/07/27)
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- Solvent-free synthesis of monoacylaminals from the reaction of amides and aminals as precursors in carbinolamide synthesis
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A solvent-free method of generating monoacylaminals by heating the amide and aminal starting materials in the presence of one another has been developed. Yields were generally between 45% and 65% with the monoacylaminal being isolated, needing no further purification after drying under high vacuum.
- Sansone, Matthew F.,Koyanagi, Takaoki,Przybyla, David E.,Nagorski, Richard W.
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supporting information; experimental part
p. 6031 - 6033
(2010/11/21)
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- Zinc-mediated allylation and alkylation of aminals in the presence of TMSCl and diisopropylamine
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(Chemical Equation Presented) An alkylation of aminals with organozinc reagents derived from allyl bromide, benzyl bromide, α-bromoacetate, and α-bromonitrile proceeded efficiently in the presence of TMSCl and diisopropylamine. This reaction system was applied to the synthesis of an antispasmodic: butaverine.
- Hatano, Bunpei,Nagahashi, Keita,Kijima, Tatsuro
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supporting information; body text
p. 9188 - 9191
(2009/04/11)
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- A new protocol for the preparation of aminals from aromatic aldehydes and their facile conversion to phosphonates
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A new and fast method for the preparation of aminals is reported from the reaction of aromatic aldehydes and secondary amines in the presence of potassium carbonate in high yields. The aminal can be converted to the corresponding iminum salt in reaction with acetyl chloride very easily and in very short time with high yield. Addition of trialkylphosphite, as one possible nucleophile, to the prepared iminium salt produces the α-amino phosphonate in very high yield.
- Dezfuli, Mohammad Karimi,Saidi, Mohammad Reza
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- A convenient direct synthesis of α-N,N-dialkylaminophosphonates under aprotic conditions
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A general one-pot synthesis of N,N-dialkylaminophosphonates under aprotic conditions is proposed using aromatic, heteroaromatic or aliphatic aldehydes and N,N-dialkyl-aminosilanes under trimethylsilyltriflate catalysis.
- Malhiac, Catherine,Combret, Jean-Claude,Boussad, Kamal,Klein, Jean-Louis
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p. 299 - 301
(2007/10/03)
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- Novel synthesis of α-acetylstyrylphosphonates
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α-Acetylstyrylphosphonates were conveniently synthesized from 2-oxopropylphosphonates and substituted (dimorpholinomethyl)-benzenes (animals). 4-Benzylidenemorpholinium carboxylates, generated from animals by the action of α-halo acids, reacted with the phosphonates to give the products by elimination of the amine. The yields were influenced by the nature of substituents and their position in the phenyl ring and could be improved by adjustment of the acidities of the reacted acids. α-Acetylstyrylphosphonates containing various substituents on every position (at the 2-, 3-, or 4-position) in the phenyl ring were obtained generally in excellent yields using monochloroacetic acid.
- Sakoda,Matsumoto,Seto
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p. 705 - 713
(2007/10/02)
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- Reaction of Thioaldehydes with Amines
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The reaction of phosphonium ylides with elemental sulfur gave thioaldehydes, which changed to the corresponding thioamides in good yields when treated with amines.When thioaldehydes containing α-hydrogens were treated with secondary amines, the corresponding enamines or reduction products were obtained.
- Okuma, Kentaro,Komiya, Yasuo,Ohta, Hiroshi
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p. 2402 - 2406
(2007/10/02)
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- N-(1-Haloalkyl)pyridinium Salts: Preparation and Use for New Syntheses of Other N-(1-Substituted-alkyl)pyridinium Salts, N,N'-(1-Alkylidene)bisamines, and N,N'-(1-Alkylidene)bisbenzazoles
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N-(1-Haloalkyl)pyridinium halides, obtained from an aldehyde, a thionyl halide, and pyridine, react readily with nucleophiles to yield N-(1-substituted -alkyl)pyridinium salts.N-(1-Bromoalkyl)pyridinium bromides rect readily with a wide range of nucleophiles to replace either the halogen ( by 1 mol ) or both halogen and pyridinium ( 2 mol ).They are useful precursors for the preparation of bisbenzazoles and other aminals under neutral and mild conditions.
- Anders, Ernst,Tropsch, Juergen G.,Katrizky, Alan R.,Rasala, Danuta,Eynde Vanden, Jean-Jacques
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p. 4808 - 4812
(2007/10/02)
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- Trimethylsilylamines III: mise en evidence du compose d'addition sur les aldehydes; preparation d'aminals et de β-dialkylamino β-arylesters en milieu aprotique
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Dialkylaminotrimethylsilanes react with aromatic aldehydes using trimethylsilyltriflate and tetrabutylammonium fluoride as catalysts and lead quantitatively to the corresponding aminals in aprotic media.The intermediate silylated hemiaminal can be characterized in many cases, mainly with pyridinecarbaldehydes.Aminals are obtained from aliphatic aldehydes using fluoride ion as catalyst.A one-pot synthesis of some β-dialkylamino β-arylesters from these reagents is described.
- Aube, Philippe,Christot, Isabelle,Combret, Jean-Claude,Klein, Jean-Louis
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p. 1009 - 1014
(2007/10/02)
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- Reactions of Phosphonium Ylides with S8 or Se in the Presence of Amines. Formation of Thioaldehydes or Selenoaldehydes
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The reaction of phosphonium ylides with elemental sulfur gave thioaldehydes which were successfully changed to corresponding thioamides when treated with secondary amines.On the other hand, the reaction of selenoaldehydes with secondary amines afforded bis(dialkylamino)methanes in good yields.
- Okuma, Kentaro,Komiya, Yasuo,Ohta, Hiroshi
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p. 1145 - 1148
(2007/10/02)
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