51170-56-0Relevant academic research and scientific papers
Carbamate Synthesis Using a Shelf-Stable and Renewable C1 Reactant
Dobi, Zoltán,Reddy, B. Narendraprasad,Renders, Evelien,Van Raemdonck, Laurent,Mensch, Carl,De Smet, Gilles,Chen, Chen,Bheeter, Charles,Sergeyev, Sergey,Herrebout, Wouter A.,Maes, Bert U. W.
, p. 3103 - 3114 (2019/06/24)
4-Propylcatechol carbonate is a shelf-stable, renewable C1 reactant. It is easily prepared from renewable 4-propylcatechol (derived from wood) and dimethyl carbonate (derived from CO2) using a reactive distillation system. In this work, the 4-propylcatechol carbonate is used for the two-step synthesis of carbamates under mild reaction conditions. In the first step, 4-propylcatechol carbonate is treated with an alcohol at 50–80 °C in the presence of a Lewis acid catalyst, such as Zn(OAc)2?2 H2O. With liquid alcohols, no solvent is used and with solid alcohols 2-methyltetrahydrofuran is used as solvent. In the second step, the alkyl 2-hydroxy-propylphenyl carbonate intermediates obtained react with amines at room temperature in 2-methyltetrahydrofuran, forming the target carbamates and the byproduct 4-propylcatechol, which can be recycled into a carbonate reactant.
Nucleophilic substitution reaction at the nitrogen of arylsulfonamides with phosphide anion
Yoshida, Suguru,Igawa, Kazunobu,Tomooka, Katsuhiko
supporting information, p. 19358 - 19361 (2013/02/22)
A novel nucleophilic substitution reaction at the nitrogen of arylsulfonamides by means of phosphide anions has been described. This reaction allows for the efficient transformation of arylsulfonamides into synthetically valuable phosphamides, amines, and a variety of protected amines.
The reaction of amines with benzyl halides under CO2 atmosphere
Shi,Shen
, p. 3357 - 3365 (2007/10/03)
To find a useful, practical, and ecologically safer way to synthesize protected amines, the reactions of amines with benzyl halides under CO2 atmosphere were systematically examined. For primary amines, the CO2-inserted products were obtained in higher yields in the presence of DBU as a base, under a high pressure of CO2, and in a low-polarity solvent (toluene/hexane 1:1). Secondary amines gave only low yields of CO2-inserted products.
Carbon Dioxide as a Phosgene Replacement: Synthesis and Mechanistic Studies of Urethanes from Amines, CO2, and Alkyl Chlorides
McGhee, William,Riley, Dennis,Christ, Kevin,Pan, Yi,Parnas, Barry
, p. 2820 - 2830 (2007/10/02)
Several carbamate esters were synthesized from amines, carbon dioxide, and alkyl chlorides.The effect of added base on the yield and selectivity of carbamate ester formation was found to be highly important with the use of sterically hindered guanidine bases giving the best results.Relative rate studies were carried out giving the following order of reactivity between carbamate anions in acetonitrile with benzyl chloride giving carbamate esters: Et2NCO2(-) = Bu2NCO2(-) > t-BuNHCO2(-) = CyNHCO2(-) = s-BuNHCO2(-) > PhNHCO2(-) > CyCH2NHCO2(-) = n-octylNHCO2(-) = n-BuNHCO2(-).Rate studies were carried out with the diethyl, s-butyl, phenyl, and n-butyl carbamates and activation parameters were determined to be Et2NCO2(-), ΔH(excit.) = 11.8 kcal/mol, ΔS(excit.) = -33 eu; s-BuNHCO2(-), ΔH(excit.) = 12.8 kcal/mol, ΔS(excit.) = -33 eu; PhNHCO2(-), ΔH(excit.) = 14.3 kcal/mol, ΔS(excit.) = -28 eu; n-BuNHCO2(-), ΔH(excit.) = 23.4 kcal/mol, ΔS(excit.) = -3 eu.The unusual results obtained from the use of n-BuNHCO2(-) prompted further studies which showed that the rate of the reaction was inversely dependent on carbon dioxide pressure (20 psig CO2, k = 4.84E-4 M-1 s-1; 120 psig CO2, k = 1.83E-4 M-1 s-1).Nitrogen NMR spectroscopy indicated, via a labeling study with 15N amines and 13C enriched carbon dioxide, the formation of doubly inserted product from the addition of two carbon dioxides to ethylamine in acetonitrile.
Highly Selective Generation of Urethanes from Amines, Carbon Dioxide and Alkyl Chlorides
McGhee, William D.,Pan, Yi,Riley, Dennis P.
, p. 699 - 700 (2007/10/02)
Generation of carbamate anions from either a primary or secondary amine, carbon dioxide and a stoichiometric amount of a pentaalkylguanidine followed by the addition of alkyl chlorides gives high yields of urethanes.
Preparation of urethane and carbonate products
-
, (2008/06/13)
The present invention provides a process for preparing urethanes and carbonates from an amine or an alcohol, carbon dioxide and a hydrocarbyl halide. The amine or alcohol is reacted with carbon dioxide in a suitable solvent system and in the presence of a base selected from the group consisting of a phosphazene compound and a mixture of a phosphazene compound and an organic, nitrogenous base, to form the ammonium carbamate or carbonate salt which is then reacted in a polar aprotic solvent with a hydrocarbyl halide. Polymer products can also be prepared utilizing this process or utilizing the resulting urethanes and carbonates under standard polymerization conditions.
Directed Metalation/Snieckus Rearrangement of O-Benzylic Carbamates
Zhang, Pingsheng,Gawley, Robert E.
, p. 3223 - 3224 (2007/10/02)
Benzylic carbamates undergo 1,2- and 1,4-carbamoyl migration reaction after lithiation with s-BuLi or LDA in THF.
Novel Synthesis of Carbamate Ester from Carbon Dioxide, Amines, and Alkyl Halides
Yoshida, Yasuhiko,Ishii, Shigeru,Watanabe, Masayo,Yamashita, Tadataka
, p. 1534 - 1538 (2007/10/02)
A novel synthesis of carbamate ester using carbon dioxide as a direct material is reported in this article.The direct reaction of carbon dioxide, aliphatic amines, and alkyl halides was found to give the corresponding alkyl carbamate esters in good yields.Reactions using secondary alkyl bromides gave carbamate esters in higher yields than those using primary or tertiary alkyl bromides.The carbamate ester yields increased with the addition of N,N-dimethylformamide to the reaction system of carbon dioxide, amines, and alkyl halides.This reaction is considered to prooced by an SN2 displacement reaction of the alkyl halide by the carbamate anion formed from the reaction of carbon dioxide and the amine.
