Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Superelectrophiles in Synthesis: Preparation of Aromatic Imides.

ABSTRACT: Aromatic carboxylic acids are found to undergo reactions with isocyanates, wherein triflic acid promotes the formation of aromatic imide products in fair to good yields. It is proposed that the carboxylic acid group directs the isocyanate electrophile to the ortho-position. This is thought to occur by the formation of a temporary carbamic acid anhydride group, which cleaves upon ortho-functionalization. A series of imide products are synthesized, and the synthesis of a potential selective inhibitor of tyrosyl DNA phosphodiesterase II is performed.

SUBMITTER: Kennedy SH

PROVIDER: S-EPMC7718718 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Superelectrophiles in Synthesis: Preparation of Aromatic Imides.

Kennedy Sean H SH Schaeff Mark N MN Klumpp Douglas A DA

The Journal of organic chemistry 20191009 21

Aromatic carboxylic acids are found to undergo reactions with isocyanates, wherein triflic acid promotes the formation of aromatic imide products in fair to good yields. It is proposed that the carboxylic acid group directs the isocyanate electrophile to the ortho-position. This is thought to occur by the formation of a temporary carbamic acid anhydride group, which cleaves upon ortho-functionalization. A series of imide products are synthesized, and the synthesis of a potential se ...[more]

PMID: 31571485

Similar Datasets

Radical-mediated dehydrative preparation of cyclic imides using (NH4)2S2O8-DMSO: application to the synthesis of vernakalant.

Project description:Ammonium persulfate-dimethyl sulfoxide (APS-DMSO) has been developed as an efficient and new dehydrating reagent for a convenient one-pot process for the synthesis of miscellaneous cyclic imides in high yields starting from readily available primary amines and cyclic anhydrides. A plausible radical mechanism involving DMSO has been proposed. The application of this facile one-pot imide forming process has been demonstrated for a practical synthesis of vernakalant.

| S-EPMC4505096 | biostudies-literature

Synthesis of alpha-keto-imides via oxidation of ynamides.

Project description:A de novo preparation of alpha-keto-imides via ynamide oxidation is described. With a number of alkyne oxidation conditions screened, a highly efficient RuO2-NaIO4 mediated oxidation and a DMDO oxidation have been identified to tolerate a wide range of ynamide types. In addition to accessing a wide variety of alpha-keto-imides, the RuO2-NaIO4 protocol provides a novel entry to the vicinal tricarbonyl motif via oxidation of push-pull ynamides, and imido acylsilanes from silyl-substituted ynamides. Chemoselective oxidation of ynamides containing olefins can be achieved by using DMDO, while the RuO2-NaIO4 protocol is not effective. These studies provide further support for the synthetic utility of ynamides.

| S-EPMC2720040 | biostudies-literature

Amidine dications as superelectrophiles.

Project description:2-Dimethylalkylammonium pyridinium and 2-dimethylalkylammonium pyrimidinium ditriflate salts are very powerful methylating agents toward phosphorus (triphenylphosphine) and nitrogen (triethylamine) nucleophiles. In competition experiments with triethylamine as nucleophile, these N-methyl disalts are more reactive methylating agents than dimethyl sulfate. Reaction of the pyridinium dications with water as an oxygen nucleophile leads to attack at the 2-position of the heteroaromatic ring and displacement of an ammonium group; 2-hydroxypyridinium compounds are formed in the first instance, which are easily converted to 2-pyridones. Extending the scope of the reactions, a tricationic 2,6-bis(dimethylalkylammonium)pyridinium salt has also been prepared and characterized and its reactivity as a methylating agent assessed in comparison with that of the dications.

| S-EPMC3662401 | biostudies-literature

Preparation of Polyfunctionalized Aromatic Nitriles from Aryl Oxazolines.

Project description:A selective ortho,ortho'-functionalization of readily available aryl oxazolines by two successive magnesiations with sBu2 Mg in toluene followed by trapping reactions with electrophiles, such as (hetero)aryl iodides or bromides, iodine, tosyl cyanide, ethyl cyanoformate or allylic bromides (39 examples, 62-99 % yield) is reported. Treatment of these aryl oxazolines with excess oxalyl chloride and catalytic amounts of DMF (50 °C, 4 h) provided the corresponding nitriles (36 examples, 73-99 % yield). Conversions of these nitriles to valuable heterocycles are reported, and a tentative mechanism is proposed.

| S-EPMC9300023 | biostudies-literature

Superelectrophiles and the effects of trifluoromethyl substituents.

Project description:Trifluoromethyl-substituted superelectrophiles were generated in superacid (CF(3)SO(3)H), and their chemistry was examined. The strong electron-withdrawing properties of the trifluoromethyl group are found to enhance the electrophilic character at cationic sites in superelectrophiles. This leads to greater positive-charge delocalization in the superelectrophiles. These effects are manifested by the unusual chemo-, regio-, and stereoselectivities shown by the superelectrophiles in chemical reactions.

| S-EPMC2883283 | biostudies-literature

A highly regio- and stereoselective synthesis of ?-fluorinated imides via fluorination of chiral enamides.

Project description:A highly ?-facial selective and regioselective fluorination of chiral enamides is described. The reaction involves an enantioselective fluorination exclusively at the electron-rich enamide olefin with N-F reagents such as Selectfluor and N-fluoro-benzenesulfonimide [NFSI] accompanied by trapping of the ?-fluoro-iminium cationic intermediate with water. The resulting N,O-hemiacetal could be oxidized using Dess-Martin periodinane, leading to an asymmetric sequence for syntheses of chiral ?-fluoro-imides and optically enriched ?-fluoro-ketones.

| S-EPMC4540344 | biostudies-literature

Charge delocalization and enhanced acidity in tricationic superelectrophiles.

Project description:This Article presents the results from studies related to the chemistry of tricationic superelectrophiles. A series of triaryl methanols were ionized in Brønsted superacids, and the corresponding tricationic intermediates were formed. The trications are found to participate in two types of reactions; both are characteristic of highly charged organic cations. One set of reactions occurs through charge migration. A second set of reactions occurs through deprotonation of an unusually acidic site on the tricationic species. One of the tricationic intermediates has been directly observed by low temperature NMR spectroscopy. These highly charged ions and their reactions have also been studied using density functional theory calculations. As a result of charge migration, electron density at a carbocation site is found to increase with progression from monocationic to pentacationic structures.

| S-EPMC3269261 | biostudies-literature

Synthesis of N-Protected 1-Aminoalkylphosphonium Salts from Amides, Carbamates, Lactams, or Imides.

Project description:This report describes the development and optimization of the one-pot method for the synthesis of N-protected 1-aminoalkylphosphonium salts based on the three-component coupling of aldehydes and either amides, carbamates, lactams, imides, or urea in the presence of triarylphosphonium salts. The proposed strategy is very efficient and easy to carry out even on a larger scale (20 g) in any typical laboratory. Most reactions occur at temperatures between 50 and 100 °C in a short time (1-2 h) without requiring any catalyst, and simple workup procedures afford good to excellent yields. The exceptions are condensations with imides, which require much higher temperatures (150-170 °C) and longer reaction times (even 30 h). The possibility of carrying out the synthesis under solvent-free conditions (neat reactions) is also demonstrated. It is especially important for less reactive substrates (imides), and reactions required high temperature (or generally harsher conditions). Finally, we prove the developed one-pot methodology can be successfully applied for the synthesis of structurally diverse N-protected 1-aminoalkylphosphonium salts. Mechanistic studies showed the intermediate products of described couplings are 1-hydroxyalkylphosphonium salts, not N-hydroxyalkylamides, -imides, etc., as initially expected.

| S-EPMC8154577 | biostudies-literature

Direct Synthesis of ?-Thio Aromatic Acids from Aromatic Amino Acids.

Project description:Modified amino acids are useful synthetic components in both chemistry and biology. Here we describe a simple, scalable two-step procedure to generate ?-thio aromatic acids from aromatic amino acids with yields of up to 96%. Diazotization and ?-lactone mediated bromination efficiently form the ?-bromo acid with retention of configuration. Thiol substitution with mild reagents such as sodium hydrosulfide or sodium trithiocarbonate provides the inverted, free ?-thio acid. The mildly acidic soft nucleophile can then be utilized in many synthetic applications.

| S-EPMC6101259 | biostudies-literature

Preparation and Properties of Hydrophilic Rosin-Based Aromatic Polyurethane Microspheres.

Project description:Hydrophilic aromatic polyurethane (HAPU) microspheres were prepared through dispersion polymerization of a rosin-based polyurethane dispersion with C=C and styrene (St). The effects of the monomer ratio (i.e., waterborne rosin-based aromatic polyurethane (WRPU) to St), dispersant level, and reaction temperature on the properties of the microspheres were investigated; the effects of pH and adsorption temperature on the adsorption capacity of Orange II were also studied. The microspheres were characterized using Fourier transform infrared spectroscopy, energy-dispersive spectrometry, thermogravimetric analysis, laser particle size analysis, and scanning electron microscopy. The results showed that HAPU microspheres have been successfully synthesized and the produced microspheres exhibited good thermal stability and monodispersion. The optimum reaction conditions for the preparation of the microspheres were determined as a monomer ratio (m WRPU/m St) of 6:4 with 8 wt % poly(vinyl pyrrolidine) (on the basis of the mixed monomer) at 80 °C for 8 h. Under these conditions, the average particle size of the synthetic microspheres was 120 nm and the particle size distribution index was 0.442. The microspheres' adsorption capacity for Orange II reached 17.53 mg·g-1 when the solid-liquid ratio was 1 g·L-1, with an initial concentration of 100 mg·L-1 at pH 5, and the adsorption was conducted at 313 K for 3 h.

| S-EPMC6648592 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data