- Deuterated arglabin dimethylamine fumarate and preparation method thereof, and application of deuterated dimethylamine fumarate to drug preparation
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The invention relates to deuterated arglabin dimethylamine fumarate with a structure as shown in a formula (I) which is described in the specification and a preparation method thereof, and applicationof deuterated arglabin dimethylamine fumarate to drug preparation.
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Paragraph 0005
(2018/07/30)
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- Tetra(amino)methanes: Implications of their structure and reactivity pattern for hypothetical carbon nitride frameworks
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Because of their possible role as model compounds for the structural units of carbon nitride C3N4, the preparation, structural chemistry, and some representative reactions of tetra(amino)methanes have been (re)investigated. In the crystal, C(NMe2)4 (1) has a molecular geometry close to D2d symmetry as proposed by theoretical calculations using state-of-the-art density functional methods. The coordination of the central carbon atom is distorted tetrahedral and the configuration of the nitrogen atoms is strongly pyramidal, as opposed to almost planar in the tetra(amino)silanes. Tetra(pyrrolidinyljmethane has a similar core structure, with all heterocyclic substituents in an envelop conformation flexible in solution. Tetra(piperidinyl)methane is more rigid in solution, owing to a more congested structure, with much higher inversion barriers for the six-membered rings. Hydrolysis of 1 leads to Me2NH and hexamethylguanidinium hydroxide, and treatment of 1 with HAuCl4(aq) affords crystalline [C(NMe2)3]+ AuCl4-, the structure of which has also been determined. Compound 1 is a strong nucleophile and can be used as an aminating agent, converting e.g. halosilanes into dimethylaminosilanes, with the guanidinium cation as the leaving group. The experimental results are discussed in the light of recent predictions regarding bulk carbon nitrides. WILEY-VCH Verlag GmbH, 1997.
- Jockisch, Alexander,Schier, Annette,Schmidbaur, Hubert
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p. 1739 - 1744
(2007/10/03)
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- Thermolysis, Photolysis, and Acid Catalysis of an α-(Dimethylamino)azoalkane. Amino Stabilization of a Carbon Radical Center
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The unsymmetrical azoalkane 2-(tert-butylazo)-2-(dimethylamino)propane (7) has been synthesized cleanly by nucleophilic displacement of chloride from the corresponding α-chloroazoalkane 5 with dimethylamine.Thermolysis of 7 in hydrocarbon solvents affords typical radical-derived products and exhibits activation parameters ΔH(excit.) = 26.6 +/- 0.4 kcal/mol and ΔS(excit.) = -6.6 +/- 1.1 eu.Since the thermolysis rate of 7 is 104 faster than that of 1,2-di-tert-butyldiazene, the large stabilization of α-amino radicals is supported.Unusual products were obtained in acetonitrile, suggesting reduction of the azo linkage by 2-(dimethylamino)-2-propyl radicals and cleavage of the resulting hydrazyl radicals.In protic solvents, 7 undergoes acid catalyzed decomposition via tert-butyldiazene as a postulated intermediate.
- Engel, Paul S.,Wu, Wen-Xue
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p. 2720 - 2725
(2007/10/02)
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- A New Method for Obtaining Isotopic Fractionation Data at Multiple Sites in Rapidly Exchanging Systems
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A new method for rapidly and conveniently obtaining isotopic fractionation factors in dilute aqueous solutions of compounds containing rapidly exchanging OH, NH, and SH groups is described.Shifts in the positions of NMR peaks for spectroscopically observable nuclei induced by isotopic substitution are the basis of this procedure which has the unique capability of separately measuring the isotopic exchange constants simultaneously for several different groups in the same molecule.The results for a series of alcohols, amines, thiols, phenols, acids, and amides with use of 13C NMR spectroscopy are reported.Atypically low values of Kfrac are observed in several cases, indicating that there are strong internal hydrogen bonds in competition with those to water, yielding conformational information.
- Jarret, Ronald M.,Saunders, Martin
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p. 2648 - 2654
(2007/10/02)
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- Calculation of the Vibrational Spectrum of Dimethylamine and of Its Deuterium Derivatives
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We have calculated the fundamental vibration frequencies and forms for four isotopic analogues of dimethylamine: (CH3)2NH(D) and CH3CD3NH(D).The results are consistent with experimental i.r. and Raman spectral data for different states of aggregation.The interpretation of some of the bands is specified.
- Muldagaliev, Kh. Kh.,Pesterev, V. I.,Agashkin, O. V.
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p. 1757 - 1758
(2007/10/02)
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