- Method for synthesizing trans-cyclohexyldiamine
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The invention discloses a method for synthesizing trans-cyclohexyldiamine. The method comprises the following steps: by using epoxy cyclohexane as the raw material, carrying out ring opening with ammonia water, adding sulfuric acid for dewatering and salification, adding free alkali, carrying out ring opening with ammonia water, and distilling to obtain the trans-cyclohexyldiamine. The method has the advantages of high repetitiveness of the synthesis route, and simple and accessible raw materials, and provides an alternative scheme for obtaining the trans-cyclohexyldiamine pure product.
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- The stereospecific addition of hydroxylamines to α,β-unsaturated sulfones, nitriles and nitro compounds
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N-Alkyl hydroxylamines have been shown to undergo a highly stereospecific cis addition to α,β-unsaturated sulfones, nitriles and nitro compounds.
- O'Neil, Ian A.,Cleator, Ed,Southern, J. Mike,Bickley, Jamie F.,Tapolczay, David J.
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p. 8251 - 8254
(2007/10/03)
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- A diamine-exchange reaction of dihydropyrazines
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Dihydropyrazines reacted with 1,2-diamines to form tetraazadecalins as intermediates, and then the reaction proceeded forward to dissociate into alternate dihydropyrazine and diamine, or backward to dissociate into the starting materials in certain equilibrium. The product distribution is controlled by diamine-exchange equilibrium reaction. The various equilibrium reactions were analyzed by NMR spectroscopy.
- Yamaguchi, Tadatoshi,Ito, Shigeru,Iwase, Yukiko,Watanabe, Kenji,Harano, Kazunobu
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p. 1677 - 1680
(2007/10/03)
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- Lithium diisopropylamide solvated by monodentate and bidentate ligands: Solution structures and ligand binding constants
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6Li and 15N NMR spectroscopic studies of lithium diisopropylamide ([6Li]LDA and [6Li,15N]LDA) in toluene/pentane solutions containing a variety of mono- and polydentate ligands are reported. LDA forms exclusively dimers in the presence of n-BuOMe, Et2O, t-BuOMe, THF, 2- methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, dimethoxyethane, N,N,N',N'-tetramethylethylenediamine, and MeOCH2CH2NR2 (NR2 = NMe2, NEt2, pyrrolidino). Addition of 1,2-dipyrrolidinoethane and (2-pyrrolidinoethyl)dimethylamine provides monomer-dimer mixtures. Treatment of LDA with trans-N,N,N',N'-tetramethylcyclohexanediamine (TMCDA) or trans- 1-(dimethyl-amino)-2-isopropoxycyclohexane in hydrocarbons afford exclusively monomers. Sparteine binds only reluctantly, giving a mixture of unsolvated oligomers and monomer. Competitions of the ethereal ligands vs TMCDA afford binding constants and associated free energies for dimer solvation which are correlated with those obtained previously for lithium hexamethyldisilazide.
- Remenar, Julius F.,Lucht, Brett L.,Collum, David B.
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p. 5567 - 5572
(2007/10/03)
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- Diastereo- and enantioselective synthesis of vicinal diamines via aza-Michael addition to nitroalkenes
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The asymmetric synthesis of protected 1,2-diamines 4 by aza-analogous Michael addition of (-)-(2S,3R,4R,5S)-1-amino-3,4-dimethoxy-2,5-bis(methoxymethyl)pyrrolid ine (ADMP) to nitroalkenes 1 in good overall yields and high enantiomeric excesses (ee = 93-96%) is described. The auxiliary constitutes a novel chiral equivalent of ammonia and is removed under reductive N-N bond cleavage with Raney nickel, which also reduces the nitro group. The absolute configuration was determined by NMR-spectroscopic methods and polarimetry.
- Enders, Dieter,Wiedemann, Juergen
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p. 1443 - 1450
(2007/10/03)
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- THE REACTIONS OF N,N-DIMETHYLPHOSPHORAMIDIC DIFLUORIDE WITH TRANS-2-SUBSTITUTED CYCLOALKANOLS
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An interaction between N,N-dimethylphosphoramidic difluoride and cyclic alcohols containing hydroxyl, alkylamine and methylthiol groups in the trans-β-position was performed. Trans-1-ethylcyclopentane-1,2-diol and trans-2-(N-alkylamino)cyclopentanols react with N,N-dimethylphosphoramidic difluoride to yield 1-ethyl-6-oxabicyclo(3.1.0)hexane and 6-alkyl-6-azabicyclo(3.1.0)hexane, respectively. In the case of trans-2-(N,N-dialkylamino)cyclopentanols and cyclohexanols, such reaction gives a salt of phosphorodifluoridic acid and the corresponding cyclic N,N,N',N'-tetraalkyl-1,2-diamine whereas trans-2-methylthiocyclopentanol is converted to a salt of phosphorodifluoridic acid and N,N-dimethyl-N-(2-methylthiocyclopentyl)amine. Some of described reactions appear to be applicable for the synthesis of various organic compounds, e.g. phosphorylated 2-N,N-dialkylaminocyclopentanethiols. Key words: N,N-dimethylphosphoramidic difluoride, N,N-dimethylphosphoramidothioic difluoride, phosphorodifluoridic acid, phosphorylated dialkylaminocyclopentanethiol, N,N-dialkylaminocycloalkanol, N,N,N',N'-tetraalkyl-1,2-diamine.
- Fokin, E. A.,Sadovnikov, S. V.,Sosnov, A. V.
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- Use of Carboxylic Acids as Chiral Solvating Agents for the Determination of Optical Purity of Chiral Amines by NMR Spectroscopy
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Optically pure mandelic acid, Mosher's acid, and N-(3,5-dinitrobenzoyl)phenylglycine have been used as chiral solvating agents to induce nonequivalence in the 1H NMR spectra of several diamines, amino acid esters, amino alcohols, and other amines.The identity of the chiral solvating agent and the stoichiometry of the solvation complexes that yield the greatest nonequivalence varies with the nature of the substrate.
- Benson, Scott C.,Cai, Ping,Colon, Marcelo,Haiza, Mohammed A.,Tokles, Maritherese,Snyder, John K.
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p. 5335 - 5341
(2007/10/02)
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