21703-06-0Relevant articles and documents
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
Cleavage of carbon-carbon triple bond: Direct transformation of alkynes to nitriles
Okamoto, Noriko,Ishikura, Minoru,Yanada, Reiko
supporting information, p. 2571 - 2573 (2013/07/11)
A new cleavage reaction of carbon-carbon triple bonds proceeds efficiently with NIS and TMSN3, giving the corresponding nitriles in moderate to good yields.
Mild approach to the deprotection of Troc from protected amines using mischmetal and TMSCl
Vellemaee, Eerold,Stepanov, Vladimir,Maeorg, Uno
experimental part, p. 3397 - 3404 (2011/01/04)
The 2,2,2-trichloroethoxycarbonyl (Troc) protecting group was efficiently removed from Troc-protected aliphatic and aromatic amines and also some Troc, Tos- and Troc, Ac-protected amines using activated mischmetal (MM). All reactions were performed by ref
Electrogenerated Superoxide-Activated Carbon Dioxide. A New Mild and Safe Approach to Organic Carbamates
Casadei, Maria Antonietta,Moracci, Franco Micheletti,Zappia, Giovanni,Inesi, Achille,Rossi, Leucio
, p. 6754 - 6759 (2007/10/03)
The electrochemical reduction of O2 (E = -1.0 V vs SCE) in dipolar aprotic solvents in the presence of CO2 gave a carboxylating reagent (O2·-/CO2) able to convert amines and different types of their derivatives into carbamates. Primary and secondary aliphatic and aromatic amines were converted into the corresponding ethyl carbamates by the addition of EtI to the carbamate anions generated in the first step of the reactions. The yields were dependent on the nucleophilicity of the nitrogen atom ω-Bromoethyl- and propylamine gave 2-oxazolidinone and tetrahydro-l,3-oxazm-2-one in moderate yields. N-Acyl or N-(alkoxycarbonyl)alkylamines bearing a leaving group at the β position of the alkyl substituent were converted into 3-substituted-2-oxazolidinones in high yields. By using chiral substrates, enantiopure 3-alkoxycarbonyl(or acyl)-4-substituted oxazolidin-2-ones (70-85% isolated yields) were obtained. This represents a new mild and safe route to these important auxiliaries for asymmetric synthesis. Some limitations of the process are also evidenced and accounted for.
Kinetics and Mechanisms of Oxygen Transfer in the Reaction of p-Cyano-N,N-dimethylaniline N-Oxide with Metalloporphyrin Salts. 2. Amine Oxidation and Oxygen Transfer to Hydrocarbon Substrates Accompanying the Reaction of p-Cyano-N,N-dimethylaniline N-Oxide with meso-(Tetraphenylporphi...
Dicken, C. Michael,Lu, Fu-Lung,Nee, Michael W.,Bruice, Thomas C.
, p. 5776 - 5789 (2007/10/02)
The catalysis of the decomposition of p-cyano-N,N-dimethylaniline N-oxide (NO) with meso-(tetraphenylporphinato)iron(III) chloride IIICl> has been studied at 25 deg C in CH2Cl2 with i = 5.0E-4 to 8.0E-3 M > IIICl>i = 3.0E-5 to 5.0E-4 M.The iron(III) porphyrin catalyst was shown to be unaltered in catalytic efficiency to 120 turnovers (the highest examined).The influence of O2 and the purity of solvent upon the kinetics of the reactions and products obtained have been assessed.In the absence of an oxidizable substrate, NO gives way to the following products: p-cyano-N,N-dimethylaniline (DA), 52percent yield; p-cyano-N-methylaniline (MA), 25percent yield; N-formyl-p-cyano-N-methylaniline (FA), 4percent yield; p-cyanoaniline (A), 2percent yield; N,N'-dimethyl-N,N'-bis(p-cyanophenyl)hydrazine (H), 12percent yield; N,N'-bis(p-cyanophenyl-N-methylmethylenediamine (MD), 6percent yield; and CH2O, 11percent yield.The major portion of the products (i.e., DA, MA, H and MD) absorb appreciably at 320 nm where absorbance by (TPP)FeIIICl is minimal.The formation of products was followed spectrophotometrically at 320 nm and by HPLC at 280 and 320 nm.Both means were found to be in quantitative agreement.Spectral monitoring of the increase in A320 showed that the first-order decomposition of the N-oxide was independent of i but increases with an increase in IIICl>i.The appearance of DA, MA, FA, MD, and CH2O also followed the first-order rate law, while the formation of the products H and A are characterized by a lag period followed by a constantly accelerated formation ending abruptly with the consumption of the N-oxide.Of the various products, only A exhibited inhibition of the kinetics for decomposition of N-oxide by (TPP)FeIIICl.At the concentration formed in the kinetic experiment, however, A is not inhibiting.The rate constant for "oxygen" transfer from NO to (TPP)FeIIICl to form IV=O>+. was determined by trapping this species with 2,4,6-tri-tert-butylphenol (TBPH).In the presence of TBPH trap, DA is formed in 100percent yield, showing that the other decomposition products of the N-oxide arise via stepwise oxidation of DA by IV=O>+..An intermolecular deuterium kinetic isotope effect of unity was obtained by comparison of the initial rate contants for the reactions of p-NCC6H4N+(CH3)2O-/p-NCC6H4N+(CD3)2O-.A discriminatory intramolecular deuterium isotope effect of 4.5 was observed when p-NCC6H4N+(CH3)(CD3)O- was used and the formation of p-NCC6H4NH(CD3)/p-NCC6H4NH(CH3) was monitored.The isotope effects are in agreement with the finding that rate-determining oxygen transfer from NO to (TPP)FeIIICl is followed by demethylation of DA.A variety of alkenes and cyclohexane are shown to compete with DA as substrates.With these, the yields of epoxidation and/or hydroxylation products are comparable to those reported previously when iodosylbenzene was used as the oxygen source under similar conditions.The stereospecifity seen with iodosylbenzene is also evidenced with NO.At 1.0 M 2,3-dimeth...
