Reaction Of Carbamates Research Articles

ChemInform Abstract: Synthesis of 4,4‐Dialkyl‐1‐iodo‐3‐buten‐2‐ones (IV) by the Reaction of Tertiary α‐Allenic Alcohol Carbamates (III) with N‐ Iodosuccinimide and Aqueous Sodium Bicarbonate.

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Gas chromatographic—mass spectrometric determination of ethyl carbamate as the xanthylamide derivative in Italian aqua vitae (grappa) samples

A selective reaction of ethyl carbamate (urethane) and methyl urethane (urethylane), as internal standard, with xanthydrol was effected to detect urethane after extraction from Italian aqua vitae (grappa) samples. The xanthylamides formed were determined by gas chromatography—mass spectrometry in the selected ion monitoring mode on an apolar DB 5 silica column. The linearity of the method was tested from 10 to 1000 μg/1, with a detection limit of 1 μg/1.

3-Hydroxy-4-methylthiazole-2(3H)-thione carbamates (TTOC carbamates). Useful precursors for monoalkylaminium cation radicals

TTOC carbamates containing a primary amine group would appear to be the most useful precursors for monoalkylaminium cation radicals now available. The corresponding PTOC carbamates are not stable, and the reaction conditions necessary for the production of chloramines from amines and for the generation of monoalkylaminium cation radicals from chloramines are substantially more severe than those required for production and reactions of TTOC carbamates

Studies on Organophosphorus Compounds XLVII: Acetyl Chloride - A Versatile Reagent for the Synthesis of 1-Aminoalkyl- and Amino(aryl)methylphosphonic Acid Derivatives

Acetyl chloride is used successfully in the synthesis of 1-aminoalkyl- and amino(aryl)methylphosphonic acid derivatives by a three-component condensation reaction involving diethyl phosphoramidate, aldehydes and diphenyl phosphite. Furthermore, in the reaction of benzyl carbamate, aldehydes and phosphorus(III) chloride, acetyl chloride facilates the formation of alkyl hydrogen 1-(benzyloxycarbonylamino)alkylphosphonates or aryl(benzyloxycarbonylamino) methylphosphonates, key intermediates in the synthesis of phosphonopeptide with a P-N bond. In comparison with other methods, the present variation affords wider scope of application including the use of some aliphatic aldehydes, fair yields and mild reaction conditions.

ChemInform Abstract: Studies on Organophosphorus Compounds. Part 46. A Facile and Direct Route to Dialkyl 1‐(Benzyloxycarbonylamino)alkylphosphonates and Dialkyl or Diphenyl α‐(Benzyloxycarbonylamino)benzylphosphonates.

AbstractThe three component reaction of benzyl carbamate (I), aromatic aldehydes such as (II), and the dialkyl phosphite (III) yields the corresponding phosphonates, e.g. (IV).

ChemInform Abstract: The Lewis Acid‐Mediated Reaction of Carbamates with γ‐Oxygenated Allyltin and Its Application to (.+‐.)‐Statine Synthesis.

AbstractThe reaction of the carbamate (I) with the allylstannyl compound (II) gives only the anti‐alcohol (III).

Syntheses and reactions of silyl carbamates. 1. Chemoselective transformation of amino protecting groups via tert-butyldimethylsilyl carbamates

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSyntheses and reactions of silyl carbamates. 1. Chemoselective transformation of amino protecting groups via tert-butyldimethylsilyl carbamatesMasahiro Sakaitani and Yasufumi OhfuneCite this: J. Org. Chem. 1990, 55, 3, 870–876Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February 1990https://doi.org/10.1021/jo00290a015RIGHTS & PERMISSIONSArticle Views6110Altmetric-Citations238LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (955 KB) Get e-Alerts Get e-Alerts

Syntheses and reactions of silyl carbamates. 2. A new mode of cyclic carbamate formation from tert-butyldimethylsilyl carbamate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSyntheses and reactions of silyl carbamates. 2. A new mode of cyclic carbamate formation from tert-butyldimethylsilyl carbamateMasahiro Sakaitani and Yasufumi OhfuneCite this: J. Am. Chem. Soc. 1990, 112, 3, 1150–1158Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://doi.org/10.1021/ja00159a040RIGHTS & PERMISSIONSArticle Views1407Altmetric-Citations59LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Studies on Organophosphorus Compounds; XLVI. A Facile and Direct Route to Dialkyl 1-(Benzyloxycarbonylamino)alkylphosphonates and Dialkyl or Diphenyl α-(Benzyloxycarbonylamino)benzylphosphonates

A simple and direct method for the preparation of dialkyl 1-(benzyloxycarbonylamino) alkylphosphonates and dialkyl or diphenyl α-(benzyloxycarbonylamino)benzylphosphonates in high yields consists of the three-component reaction of benzyl carbamate, an alkanal or a benzaldehyde, and a dialkyl (or dipbenyl)-phosphite in acetyl chloride at 0°C (for alkanals) or in acetic acid containing thionyl chloride at 20-70°C (for benzaldehydes). Removal of the benzyloxycarbonyl group by standard methods or selective hydrolysis of the dialkyl phosphonate moiety leads to the formation of derivatives of aminoalkylphosphonic acids bearing free amino or acidic functions, which are useful intermediates in phosphonopeptide synthesis.

Basic media behavior of N-[2-(1-hydroxy-2-Y-ethyl)phenyl] ethyl carbamates (Y = SMe, SOMe, SO 2Me, H, Br, CN)

From the results obtained in the hydrolysis reaction of the carbamate group of some thioderivatives compounds whose common structure is (2 → tOOCNH-C6H4)-CHOH-CH2Y a mechanism is suggested to explain the products, as well as the relationship between the relative configuration of diastereoisomeric sulfoxides (Y = SOMe) with the reaction rate and with the stereochemical outcome. Other interesting and unexpected products are yielded when the hydrolysis reaction of others carbamates (Y = H, Br, CN) is carried out In the present cases, the carbamate functioh seems to behave as a very versatile group capable of readily undergoing conversions to several Kinds of heterocycles.

The Lewis acid mediated reaction of carbamates with γ-oxygenated allyltin and its application to (±)-statine synthesis

The Lewis acid mediated reaction of acyliminium ions (6) with γ-oxygen substituted allyltin (1c) gave the amino alcohol derivatives (7) and/or (8) in good yields; in certain cases very high diastereoselectivity was achieved and the procedure was applied to the synthesis of (±)-statine.

鎖状系における高ジアステレオ選択的アミノ化法とアミノ糖合成

We have found prominent 1, 2- and 1, 3-asymmetric induction in the intramolecular conjugate additions of γ- and δ-carbamoyloxy- α, β-unsaturated esters. They provide a good way to achieve diastereoselective amination of acyclic olefinic systems, since complementary diastereoface-selection is accomplished by changing the site of carbamoyloxy group between γ- and δ-positions, as summarized in Fig. 15; almost complete stereocontrol is achieved by using Z-olefins. We demonstrated the synthetic utility of this method by the stereoselective syntheses of all four possible diastereomers of racemic N- acyl 3-amino-2, 3, 6-trideoxyhexose. Furthermore, N-acyl derivatives, 5, 7 and 8, of three naturally occurring sugars were synthesized in a stereodivergent manner starting from L-lactate. The antiperiplanar effect was revealed to play a major role in the reactions of homoallyic carbamates with allylic chiral center.

A 19F nuclear magnetic resonance study of the interaction of carbon dioxide with fluoro-amino acids

The 19F nuclear magnetic resonance (NMR) spectra of 3-fiuorophenylalanine and 3-fluorotyrosine in bicarbonate buffer are characterized by a main resonance band and a well-resolved upfield resonance. We show that the upfield resonance is due to the formation of a carbamate between the amino group of the amino acid and bicarbonate. The intensity of the upfield resonance is dependent on the pH (pD) of the solution and reflects changes in the concentration of the free amino acid and carbamate. Thus the normalized spectral peaks can be used to quantitate the free amino acid and carbamate concentrations and these concentrations have been used to determine the equilibrium constant of the carbamate reaction. The value of the equilibrium constant obtained, using an equation which considered the various ionic states of the reactants, was 8.52 × 10−6 ± 0.27 × 10−6 for 3-fiuorophenylalanine and 8.84 × 10−6 ± 0.72 × 10−6 for 3-fluorotyrosine. These values are within the range expected for amino acids and indicate that the fluorine nucleus does not perturb the reaction significantly and that the 19F NMR can be used to quantitate the formation of carbamates in solutions of fluorine-labelled amino acids.

Palladium-catalyzed reaction of allyl carbamates; allylation of carbonucleophiles, and protection-deprotection of amines

Allylation of carbonucleophiles with allylic carbamates under neutral conditions has been studied. The C-allylation of carbonucleophile is competitive with the N-allylation of amines, and the structure of amines is crucial for the selectivity. Bulky secondary amines gave the best results. Also a new method of protection-deprotection of amines as carbamates has been developed. Smooth deprotection is possible by the palladium-catalyzed reaction of allyl carbamates with formic acid. This method is particulary useful for primary amines, including optically active amino acids.

Trimethylsilylated N- alkyl-substituted carbamates I.preparation and some reactions

Trimethylsilyl N-monoalkyl- and N, N-dialkyl-carbamates have been made in 85–95% yields by silylation of the corresponding ammonium carbamates with trimethylchlorosilane. Trimethylsilyl N N-dimethylcarbamate can be used for silylation of alcohols,phenols, and carboxylic acids. The silycarbamates react with carboxylic acid halides to give the corresponding acide amides. The reaction of trimethylsilyl carbamates with carboxylic anhydrides give the corresponding silyl carboxylate and acid amide, while the reaction with dicarboxylic anhydrides give the trimethylsilyl monoamide of the corresponding dicarboxylic acid, i.e. Me 3SiO 2-C ▪CONR 1R 2.

Regio and stereospecific synthesis of [formula omitted] and [formula omitted] 3-methyl-6-methylethyl cyclohexenes and 3-methyl-4-methylethylcyclohexenes. Reactions of allylic acetates and carbamates with Li 2Cu 3Me 5 and LiCuMe 2

The isomeric alkenes 1 – 4 have been obtained by syn , γ substitution of the appropriate allylic carbamates with Li 2Cu 3Me 5. The behaviour of carbamates is deeply affected by the nature of the copper reagent.

Partially carbamate reaction of cellulose with urea

Partially carbamate reaction of cellulose with urea

Stereospecific 2H-azirine formation from the modified Neber reaction of oxime carbamates

Stereospecific 2H-azirine formation from the modified Neber reaction of oxime carbamates

ChemInform Abstract: THE CHEMISTRY OF ISOCYANIC ACID AND ITS DERIVATIVES. PART V. THE OXIDATIVE COUPLING OF ETHYL CARBAMATE AND UREA WITH CYCLOHEXENE, TETRAHYDROFURAN, AND CYCLOOCTADIENE EFFECTED BY PALLADIUM(II) CHLORIDE

AbstractCyclohexen (I) und Ethylcarbamat geben in Gegenwart von PdCl2 die Kupplungsprodukte (II) und (offenbar über eine Wasserstofftransfer‐Reaktion) (III).

The Chemistry of Isocyanic Acid and Its Derivatives. Part V. The Oxidative Coupling of Ethyl Carbamate and Urea with Cyclohexene, Tetrahydrofuran, and Cyclooctadiene Effected by Palladium(II) Chloride

Abstract The reaction of ethyl carbamate with cyclohexene promoted by PdCl2 gave ethyl 1-cyclohexenylcarbamate. The reaction of ethyl carbamate and tetrahydrofuran gave ethyl 2-tetrahydrofurylcarbamate. Ethyl carbamate and 1,5-cyclooctadiene–PdCl2 complex (4) reacted to give ethyl 4-cyclooctenylcarbamate. The reaction of urea and 4 afforded cyclooctylurea and 4-cyclooctenylurea.