2621-73-0Relevant articles and documents
Preparation of a novel bromine complex and its application in organic synthesis
Nishio, Yuya,Yubata, Kotaro,Wakai, Yutaro,Notsu, Kotaro,Yamamoto, Katsumi,Fujiwara, Hideki,Matsubara, Hiroshi
, p. 1398 - 1405 (2019/02/07)
Although molecular bromine (Br2) is a useful brominating reagent, it is not easy to handle. Herein, we describe the preparation of a novel air-stable bromine complex prepared from 1,3-dimethyl-2-imidazolidinone (DMI) and Br2, which was identified to be (DMI)2HBr3 by spectral and X-ray techniques. This complex was then used to brominate olefins, carbonyl compounds, and aromatics, as well as in the Hofmann rearrangement. Yields of reaction products using this complex were almost the same or superior to those using other bromine alternatives.
Chemoselective synthesis of carbamates using CO2 as carbon source
Riemer, Daniel,Hirapara, Pradipbhai,Das, Shoubhik
, p. 1916 - 1920 (2018/08/17)
Synthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmosp
Cu(II)-ion-catalyzed solvolysis of N,N- bis(2-picolyl)ureas in alcohol solvents: Evidence for cleavage involving nucleophilic addition and strong assistance of bis(2-picolyl)amine leaving group departure
Belzile, Mei-Ni,Neverov, Alexei. A.,Brown, R. Stan
supporting information, p. 7916 - 7925 (2014/08/18)
The kinetics and products for solvolysis of N-p-nitrophenyl-N′, N′-bis(pyridin-2-ylmethyl) urea (7a), N-methyl-N-p-nitrophenyl-N′, N′-bis(pyridin-2-yl methyl) urea (7b), and N-phenyl-N′,N′- bis(pyridin-2-yl-methyl) urea (DPPU) (7c) promoted by Cu(II) ion in methanol and ethanol were studied under sspH-controlled conditions at 25 °C. Methanolysis and ethanolysis of these substrates proceeds rapidly at a 1:1 ratio of substrate:metal ion, the half-times for decomposition of the Cu(II):7a complexes being ～150 min in methanol and 15 min in ethanol. In all cases, the reaction products are the Cu(II) complex of bis(2-picolyl)amine and the O-methyl or O-ethyl carbamate of the parent aniline, signifying that the point of cleavage is the bis(2-picolyl) - N - C - O bond. Reactions of the Cu(II):7b complexes in each solvent proceed about 3-5 times slower than their respective Cu(II):7a complexes, excluding an elimination mechanism that proceeds through an isocyanate which subsequently adds alcohol to give the observed products. The reactions also proceed in other solvents, with the order of reactivity ethanol > methanol >1-propanol >2-propanol > acetonitrile (with 0.2% methanol) > water spanning a range of 150-fold. The mechanism of the reactions is discussed, and the reactivity and mode of cleavage are compared with that of the M(II)-promoted ethanolytic cleavage of a mono-2-picolyl derivative, N-p-nitrophenyl-N′-(pyridin-2-yl-methyl) urea (4a), which had previously been shown to cleave at the aniline N-C - O bond. The large estimated acceleration of the rate of attack of ethoxide on 7b of at least 2 × 1016 provided by associating Cu(II) with the departing group in this urea is discussed in terms of a trifunctional role for the metal ion involving Lewis acid activation of the substrate, intramolecular delivery of a Cu(II)-coordinated ethoxide, and metal-ion-assisted leaving group departure.
Novel and efficient one-pot synthesis of (aminophenyl)carbamic acid esters
Garofalo, Antonio,Goossens, Laurence,Six, Perrine,Lebegue, Nicolas,Depreux, Patrick
body text, p. 2007 - 2016 (2011/06/24)
A novel and efficient protocol is developed for the synthesis of various (aminophenyl) carbamic acid esters from the reduction and condensation of nitrophenyl isocyanate derivatives. The reaction takes place in various hydroxy derivatives such as alcohols or phenols under a hydrogen atmosphere using Raney nickel as catalyst. Products are obtained by a convenient one-pot synthesis with excellent yields and short reaction times.
Effect of successive increase in alcohol chains on reaction with isocyanates and isothiocyanates
Perveen, Shahnaz,Yasmin, Arfa,Khan, Khalid Mohammed
experimental part, p. 18 - 23 (2010/04/23)
The reaction of isocyanates and isothiocyanates with long-chain alcohols, e.g. n-hexanol, n-heptanol and n-octanol, exclusively gave N-aryl-O-alkyl carbamates, while N-aryl-O-alkyl carbamates were formed along with symmetrical 1,3-disubstituted ureas and thioureas when the same reactions were carried out with small-chain alcohols at room temperature without using any solvent.
New and simple synthesis of acid azides, ureas and carbamates from carboxylic acids: Application of peptide coupling agents EDC and HBTU
Sureshbabu, Vommina V.,Lalithamba,Narendra,Hemantha
experimental part, p. 835 - 840 (2010/06/20)
Conversion of carboxylic acids into acid azides using peptide coupling agents, EDC and HBTU is described. The procedure is efficient, practical and applicable to a diverse range of carboxylic acids including N-protected amino acids. Using the same reagents, one-pot synthesis of ureas, dipeptidyl urea esters and carbamates from acids has also been achieved. The Royal Society of Chemistry 2010.
1-propanephosphonic acid cyclic anhydride (T3P) as an efficient promoter for the Lossen rearrangement: Application to the synthesis of urea and carbamate derivatives
Vasantha, Basavalingappa,Hemantha, Hosahalli P.,Sureshbabu, Vommina V.
experimental part, p. 2990 - 2996 (2010/10/21)
The synthesis of hydroxamic acids starting from carboxylic acids employing 1-propanephosphonic acid cyclic anhydride (T3P) activation is described. Application of ultrasonication accelerates this conversion. Further, the T3P has also been employed to activate the hydroxamates, leading to isocyanates via the Lossen rearrangement. The isocyanates were trapped with suitable nucleophiles to afford the corresponding ureas and carbamates. Georg Thieme Verlag Stuttgart New York.
Synthesis of some heterocycle containing urea derivatives and their anti-viral activity
Verma, Majusha,Singh, Krishna N.,Clercq, Erik D.
, p. 11 - 22 (2007/10/03)
Some new isoindol heterocyclic ureas (6a-6i) have been synthesized using N-aminophthalimide (2) and ethyl N-monosubstituted/ethyl N,N-disubstituted carbamate (5a-5i). All the newly synthesized final compounds have been evaluated for their anti-viral activities against a variety of viruses. The compound (6f) with the methoxy substituent showed reasonably better activity as compared to the standard drugs against all the viruses (cf. Tables 1, 2 and 3). Further, all the products (6a-6i) were found to be active against Vesicular stomatitis virus, Coxsackie virus B4 and Respiratory syncytical virus (cf. Table 2) and the compounds (6h) and (6i) displayed better antiviral activity in comparison to Brivudin and (S)-DHPA (cf. Table 3).
A new access to quinazolines from simple anilines
Chilin, Adriana,Marzaro, Giovanni,Zanatta, Samuele,Barbieri, Vera,Pastorini, Giovanni,Manzini, Paolo,Guiotto, Adriano
, p. 12351 - 12356 (2007/10/03)
A new synthetic pathway to quinazolines is described. This new method uses hexamethylenetetramine in TFA and potassium ferricyanide in aqueous ethanolic KOH, starting from simple N-protected anilines. The method affords substituted quinazolines with high
Synthesis and fungicidal activity of some sulphide derivatives of O-ethyl-N-substituted phenylcarbamates
Adelowo-Imeokparia,Ojo
, p. 324 - 329 (2007/10/03)
Monosulphides of O-ethyl-N-substituted phenylcarbamates were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur dichloride, while the corresponding disulphides were prepared by the reaction between O-ethyl-N-substituted ph
