- Smooth isoindolinone formation from isopropyl carbamates via bischler-napieralski-type cyclization
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Isopropyl carbamates derived from benzylamines provide isoindolinones by treatment with phosphorus pentoxide at room temperature. Utility of this Bischler-Napieralski-type cyclization and a new mechanism involving a carbamoyl cation for rationalization of this smooth conversion are discussed.
- Adachi, Satoshi,Onozuka, Masao,Yoshida, Yuko,Ide, Mitsuaki,Saikawa, Yoko,Nakata, Masaya
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supporting information
p. 358 - 361
(2014/04/03)
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- Heterogeneous CeO2 catalyst for the one-pot synthesis of organic carbamates from amines, CO2 and alcohols
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Heterogeneous CeO2 catalyst can catalyze the one-pot synthesis of methyl benzylcarbamate from benzylamine, CO2 and methanol. The yield of methyl benzylcarbamate reached 92% at >99% benzylamine conversion and 92% benzylamine-based selectivity even in the absence of the dehydrating agents. The catalyst is reusable after the calcination at 873 K for 3 h. Various carbamates can be synthesized with good yield and high selectivity by the reaction of amines + CO2 + alcohols over CeO2. The main formation route of methyl benzylcarbamate is suggested to be the reaction of dimethyl carbonate or the precursor of dimethyl carbonate formation with benzylamine.
- Honda, Masayoshi,Sonehara, Satoru,Yasuda, Hiroshi,Nakagawa, Yoshinao,Tomishige, Keiichi
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scheme or table
p. 3406 - 3413
(2012/01/15)
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- Effect of successive increase in alcohol chains on reaction with isocyanates and isothiocyanates
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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.
- Perveen, Shahnaz,Yasmin, Arfa,Khan, Khalid Mohammed
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experimental part
p. 18 - 23
(2010/04/23)
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- Pd-catalyzed N-arylation of secondary acyclic amides: Catalyst development, scope, and computational study
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We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ligand were explored through synthetic, mechanistic, and computational studies. Systematic variation of the ligand revealed the importance of (1) a methoxy group on the aromatic carbon of the "top ring" ortho to the phosphorus and (2) two highly electron-withdrawing P-bound 3,5-(bis)trifluoromethylphenyl groups. Computational studies suggest the electron-deficient nature of the ligand is important in facilitating amide binding to the LPd(II)(Ph)(X) intermediate.
- Hicks, Jacqueline D.,Hyde, Alan M.,Cuezva, Alberto Martinez,Buchwald, Stephen L.
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supporting information; experimental part
p. 16720 - 16734
(2010/04/04)
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- Study of the stability of carbocations by chlorosulfonyl isocyanate reaction with ethers
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The stability order of various alkyl, allyl, and benzyl carbocations was investigated using the novel technique for comparing the stability of carbocations in solution developed by using a simple CSI reaction with various ethers. The p-methoxycinnamyl carbocation was the most stable in our reaction system and the next stable carbocation was the p-methoxybenzyl carbocation. The stability of the other carbocations decreased with methacryl, t-butyl, cinnamyl, acryl, benzyl, 2° and allyl carbocations in that order.
- Kim, Ji Duck,Han, Gyoonhee,Jeong, Lak Shin,Park, Hyun-Ju,Zee, Ok Pyo,Jung, Young Hoon
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p. 4395 - 4402
(2007/10/03)
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- α-Haloalkyl Haloformates and Related Compounds 1. A Convenient Synthesis of Carbamates via Chloromethyl Carbamates
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The preparation of carbamates under mild conditions utilizing a new class of activated carbonates (containing chloromethyl function) is described.
- Patonay, Tamas,Patonay-Peli, Erzsebet,Mogyorodi, Ferenc
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p. 2865 - 2885
(2007/10/02)
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- New Agents for Alkoxycarbonylation of Amines
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Alkoxycarbonylated pyrazinols and pyrazinethiols were prepared.These compounds were shown to be convenient agents for alkoxycarbonylation of aliphatic amines.
- Ohta, Akihiro,Inagawa, Yukiko,Inoue, Masami,Shimazaki, Makoto,Mamiya, Yukari
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p. 1173 - 1177
(2007/10/02)
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- Reactions of Primary and Secondary Amines with Fluoronitrene Generated from Isopropyl N,N-Difluorocarbamate
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Isopropyl N,N-difluorocarbamate deaminates primary amines, RNH2, affording RH, N2, RNHCO2-i-C3H7, and RNH2*HF.With secondary amines, dibenzylamine gives bibenzyl, whereas pyrrolidine yields a ring-expansion product, 2,3,4,5-tetrahydropyridazine.The reactions are consistent with the generation of fluoronitrene and subsequent production of the intermediates RN=NH from RNH2 and R2N=N from R2NH.The advantages of using isopropyl N,N-difluorocarbamate as a source of fluoronitrene are discussed.
- Klopotek, David L.,Hobrock, Brice G.,Kovacic, Peter,Jones, Martin B.
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p. 1665 - 1667
(2007/10/02)
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