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1.
Nitrogen inversion barriers have been measured for 7-chloro-1,7-diazabicyclo-[2.2.1] heptane and [2.2.2]octane; the unusual nature of the bridging nitrogen in bicyclo [2.2.11 systems is discussed. 相似文献
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1,2-cis-Fused bicyclic sugar thiocarbamates of gluco and manno configurations have been prepared by treatment of the corresponding O-unprotected amino sugars and glycopyranosyl amines with thiophosgene. The reactivity of these compounds towards amines has been studied in order to determine whether these compounds could act as latent isothiocyanates; it is shown that 1,2-cis-fused bicyclic sugar thiocarbamates are more stable than their trans analogues, and are not transformed into thioureas upon treatment with amines. An unprecedented isomerization of a peracetylated glucopyranoso[2,1-d]oxazolidine-2-thione into a glucopyranoso[2,1-d]thiazolidin-2-one in DMF is also reported. The structure of this thiazolidin-2-one was confirmed by X-ray crystallography. 相似文献
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Giancarlo Bettoni Flaviano Morlacchi Roberto Perrone Vicenzo Tortorella Claudio Vetuschi 《Journal of heterocyclic chemistry》1979,16(3):591-594
Chiroptical properties of several 2 or 3 monosubstituted azetidines, pyrrolidines and piperidines as free bases and N-[2-pyridyl N-oxide] derivatives has been examined. The absolute configuration can be unambiguously established, independently on the nature of the substituent and the size of the ring, only for 2-substituted N-[2-pyridyl N-oxide]amine derivatives. This behaviour is explained in terms of limited rotational freedom in these compounds. 相似文献
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The bridging nitrogen in 7-aza- and 1,7-diazabicyclo[2 2.1]heptanes and unsaturated derivatives shows unusually large deshielding in the 15N NMR. 相似文献
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1,6-Diazabicyclo[4.3.3]dodecane (7), 1,6-diazabicyclo[4.3.2]undecane (8) and 1,8-diazabicyclo[6.3.3]tridecane (9) have been made by reduction of tricyclic α-aminoammonium salts with LiAlH4; the protonation and oxidation of 8 and 9 are discussed. 相似文献
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The nitrogen inversion barriers of nine 3,6-dihydro-1,2-oxazines are discussed. Polar solvents were found to increase the nitrogen inversion barriers which, in turn, decrease with increasing size of the N-substituent. 相似文献
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The scope of an unexpected Mitsunobu cyclisation to prepare N-arylated Fsp3-enriched azacycles was investigated. In the current study, we have identified whether a pKa-dependent Mitsunobu cyclodehydration or a pKa-independent Mitsunobu intramolecular reaction was in operation. A Mitsunobu reaction, creating a leaving group, followed by intramolecular nucleophilic displacement was determined to be the dominant pathway. 相似文献
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《Journal of fluorine chemistry》1986,34(2):183-189
Electrochemical fluorination of N,N-diethylcyclohexylamine and N-ethyldicyclohexylamine gave the corresponding F-amines together with several other compounds arising from incomplete fluorination and fragmentation reactions. In the case of N,N-diethylcyclohexylamine yields of 51–52% were obtained and most of the reaction products were isolated and identified. With N-ethyldicyclohexylamine a lower yield (16%) was observed; the resultant reaction mixture was too complex to allow the identification of its components. Comments are made about the reaction mechanism, and NMR and IR data are reported for identified compounds. 相似文献
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《Tetrahedron letters》2014,55(52):7219-7221
Cyanomethylenetributylphosphorane-mediated ring closure for the asymmetric synthesis of 2-substituted cyclic amines such as azetidines, pyrrolidines and a piperidine is reported. The desired stereochemistry at the 2-position was fixed using (S)-tert-butyl sulfinamide as a chiral auxiliary. 相似文献
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The catalytic resolution of racemic cyclic amines has been achieved by an enantioselective amidation reaction featuring an achiral N-heterocyclic carbene catalyst and a new chiral hydroxamic acid cocatalyst working in concert. The reactions proceed at room temperature, do not generate nonvolatile byproducts, and provide enantioenriched amines by aqueous extraction. 相似文献
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Condensation of fluorine-containing benzaldehydes with naphthalen-2-amine or quinolin-6-amine and cyclic ketones (cyclopentanone, cyclohexanone, and 4-methylcyclohexanone) gave new fluorine-containing derivatives of cyclopenta[c]benzo[f]quinoline, benzo[a]phenanthridine, and cyclopenta[a]- and benzo[a]-[4,7]phenanthroline. Intermediate products, 2-[(fluorophenyl)(2-naphthylamino or quinolin-6-ylamino)methylidene] cyclohexanones, dihydrobenzo[f]quinolines, and dihydro-4,7-phenanthrolines, were isolated. 相似文献
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Masahito Ochiai Minako Inenaga Yoshimitsu Nagao
Robert M. Moriarty
Radhe K Vaid Michael P. Duncan 《Tetrahedron letters》1988,29(52):6917-6920Cyclic amino acids L-proline, pipecolinic acid and L-2-pyrrolidinone-5-carboxylic acid undergo oxidative decarboxylation with iodosobenzene in various solvents (including water) to yield the lactam and imide in the latter case. The reaction proceeds via initial imine formation. 相似文献
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The surface tension of aqueous solutions of simple cyclic, heterocyclic and aromatic amines was measured with a Du N?uy tensiometer at 25 degrees C and the results discussed in terms of structure-aggregation relationships. The simple compounds used in this study were piperazine, piperidine, morpholine, 3-methylpyridine, cyclohexylamine and benzylamine, with carbon numbers ranging from four to seven. Piperazine, piperidine and morpholine did not form micellar associations but cyclohexylamine, benzylamine and 3-methylpyridine did, indicating that more than six carbons are necessary to form micellar associations, at least for compounds having a six-membered ring. 相似文献
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Markov J Fischer R Wagner H Noormofidi N Baumgartner J Marschner C 《Dalton transactions (Cambridge, England : 2003)》2004,(14):2166-2169
Salt elimination reactions of tris(trimethylsilyl)silyl potassium (1), and two 1,4-dipotassiooligosilanes (3, 5) with 2,2,6,6-tetramethylpiperidinodichloroborane and diethylaminodichlorophosphane have generated open (2), cyclic (4) and bicyclic (6) bora- and phosphaoligosilanes. A monosilylated phosphane and the two five-membered cyclosilanes have been subjected to single crystal X-ray diffraction analysis. 相似文献