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1.
The synthesis of trans-1-amino-4-benzyl-2,6-dimethylpiperazine (1b), trans-4-benzyl-2,6-dimethylpiperazine (VIIb) and trans-2,6-dimethylpiperazine (IIb) are described, by condensation of N-benzyl-1,2-propanediamine with α-bromopropionate and successive thermal cyclization and reduction with lithium aluminum hydride. The assignment of the cis, trans configuration to the isomers was based on a thorough examination of the ring proton nmr signals of the two isomers of 4-benzyl-2,6-dimethylpiperazine (VIIa and VIIb) interpreted in terms of conformational considerations. 相似文献
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Baldev Singh Manhas Narinder Kaur Ajaib Singh Dhindsa 《Transition Metal Chemistry》1992,17(4):287-291
New copper(II) acetate complexes with the saturated diheterocyclic bases (L-L): piperazine, 1-methylpiperazine, and 1,4-dimethylpiperazine
and their monohydrochlorides, have been prepared and characterised by physico-chemical and spectroscopic methods. They are
magnetically dilute and antiferromagnetic, with stoichiometries of the type Cu(OAc)2(B)n(B=L-L or L-LHCl and n=2, 1 or 0.5). 相似文献
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P Liuni A Jeganathan DJ Wilson 《Angewandte Chemie (International ed. in English)》2012,51(38):9666-9669
Intensified searching: In enzymes, conformational dynamics are linked to the catalytic reaction coordinate. A novel analytical approach was used to monitor catalysis-linked dynamics in chymotrypsin, revealing that in some enzymes, catalysis is promoted by intensified, but undirected conformational sampling after substrate binding. 相似文献
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The IR absorption spectra of 1,1,4,4-tetramethyl- and 1,1,4,4-tetraphenyl-1,4-disilacyclohexanes have been studied. The group spectral analysis of these compounds shows that the silicon atoms have barene properties. The presence at about 980 cm–1 of one strong band (and not two) of C-C stretching vibrations in agreement with the selection rules confirms the chair form of the heterocycle. 相似文献
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One unusual dimeric tropane alkaloid, bishyoscyamine, was isolated from the roots of Anisodus acutangulus, whose structure including the absolute stereochemistry was unambiguously determined based on extensive 1D NMR and 2D NMR, HR-ESI-MS [α]D and CD spectroscopic analyses. To our knowledge, bishyoscyamine is the first example of tropane alkaloid dimer condensed by a C-N bond. 相似文献
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The syntheses of 1, 2-annelated 1, 4-benzodiazepines (IV, Y = N) and 4, 1-benzoxazepines (IV, Y = 0) are described (Scheme 1). The key step is a nucleophilic aromatic substitution of 2-substituted piperazines (II, Z = N? CH3), piperidines (II, Z = CH2) or pyrrolidines (II, Z= (CH2)0) with activated aryl halides (I). 相似文献
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Janetka JW Furness MS Zhang X Coop A Folk JE Mattson MV Jacobson AE Rice KC 《The Journal of organic chemistry》2003,68(10):3976-3980
A convenient, high-yield enantioconvergent synthesis of (-)-1-allyl-(2S,5R)-dimethylpiperazine from trans-2,5-dimethylpiperazine has been developed. This compound is an important intermediate in the synthesis of delta-opioid receptor ligands. The process allows for the laboratory preparation of 100 g quantities of this enantiomerically pure diamine without chromatography. The key steps in the sequence were an efficient optical resolution using relatively inexpensive resolving agents, followed by interconversion of the unwanted (+)-enantiomer into the desired (-)-enantiomer. 相似文献
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The preferred solute conformation of ethyl 3α-phenyltropane-3β-carboxylate hydrochloride, the tropane analogue of pethidine, is shown to be a piperidine chair with an axial 3-phenyl substituent by analysis of its 1H NMR characteristics and spectral comparisons with model compounds. Conformational studies of synthetic intermediates are also reported and favoured boat forms identified for 3α-diphenylhydroxymethyl-3β-tropanol and 3α-phenyl-3β-tropanyl phenyl ketone. In the hot-plate test for analgesia performed on mice, ethyl 3α-phenyltropane-3β-carboxylate is about 1·5 times as effective as pethidine. 相似文献
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The chemical properties of 1,4- and 1,5-diazabicyclo[4, 4, 0]decanes and their 5- and 4-oxo derivatives, respectively, have been studied. 相似文献
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D. K. Rohrbaugh H. D. Durst F. R. Longo S. Munavalli 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2639-2650
Treatment of 1, 3-cyclohexadiene with CF 3 SCl at m 80°; furnishes 15 compounds. All but the two dimerized adducts arise from the free radical catalyzed addition of CF 3 S and Cl radicals to carbon-carbon double bonds. One dimerized product arises via dimerization of the substrate itself, while the other results from the cross-coupling of the substrate with the reaction product. The same reaction with 1, 4-cyclohexadiene gives 14 compounds. The mass spectral characterization of various compounds and their probable mechanism of formation are presented in this article. 相似文献
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1, 2, 5-Trimethyl-4-phenylethynylpiperidol-4 and 1 2, 5-trirnethyl-4-ß-phenylethynylpiperidol-4 are prepared by various methods. Their interconversion is studied, and individual stereoisomeric forms of these piperidols isolated. 1, 2, 5-Trimethyl-4-phenylethynylpiperidol-4 is hydrated, and the resultant -(1, 2, 5-trimethyldidehydropiperidyl-4) acetophenone used to effect synthesis of a number of secondary and tertiary carbinols. 2, 5-Dimethyl-4-ß-phenylethylpyridine is prepared from 1, 2, 5-trimethyl-4-ß-phenylethylpiperidol-4. 相似文献
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In this work, the experimental vapor pressures of four amines 1,2-bis(dimethylamino)ethane, 1-methylmorpholine, 1,2-bis(2-aminoethoxy)ethane and N-benzylethanolamine using a static apparatus are reported. The temperature range is comprised between 273.18 and 364.97 K and the pressure range between 0.782 Pa and 333 kPa. The molar enthalpies of vaporization at 298.15 K were calculated from Clausius–Clapeyron equation fitted on the experimental results. 相似文献
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Condensation of aryl- and aroylhydrazines and thiosemicarbazide with 2-diphenylphosphinoyloxybenzaldehyde results in formation of the corresponding hydrazones and thiosemicarbazone. The products give rise to conformational equilibrium between rotational and Z,E isomers, which is strongly displaced toward the E,E',Z' isomer and is determined by the nature of substituent in the hydrazine fragment. 相似文献