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1.
I. A. Baidina P. A. Stabnikov N. V. Pervukhina S. A. Gromilov 《Journal of Structural Chemistry》2003,44(5):859-863
A new compound from the series of alkoxyketoiminates, Cu(II) bis-(2-methoxy-2,6-dimethyl-3-imino-5-heptanonate), has been synthesized and studied by X-ray crystallography. Crystal data for CuO4N2C20H36: a=10.154(1), b=9.921(1), c=11.684(2) , =96.17(1)°, space group P21/c, Z=2, dcalc =1.226 g/cm3, R=0.037. The structure is molecular and built from isolated trans-complexes. The copper atom has a plane square environment of two oxygen atoms (Cu–O 1.93 ) and two nitrogen atoms (Cu–N 1.90 ). The O–Cu–N chelate angle is 91.7°. The complex has an intramolecular hydrogen bond, N–H...O 2.16 , involving the alkoxy oxygen atom. The molecular packing in the crystal is close to that of copper(II) dipivaloylmethanate. The calculated van der Waals intermolecular interaction energies and thermogravimetric characteristics of the complexes are compared. 相似文献
2.
K. -H. Frömming V. Wedelich W. Mehnert 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(5):625-629
- and -Cyclodextrin (CD) and heptakis-2,6-di-O-methyl--cyclodextrin (DIMEB) form soluble inclusion compounds with mefenorex (MEF); with -CD a partial inclusion occurs. No solid inclusion compound could be obtained with the four CDs. -, -CD and DIMEB, but not -CD, enhance the nitrosation rate of MEF if the nitrosation assay procedure (NAP test) is applied. During this reaction with - and -CD, solid inclusion compounds of the CDs and nitrosomefenorex (NMEF) precipitate.Part of the Ph.D. thesis of V. Wedelich, Freie Universität Berlin, 1985. 相似文献
3.
According to vibrational spectroscopic data, in the gas phase at 280 °C and in crystals prepared by sublimation, 2-acetylcyclopentane-1,3-dione was established to exist not as trione 1 but as the enol-form 2 with an exo-cyclic C=C bond (v(C=C) = 1593 cm–1) and an intramolecular hydrogen bond. The enol 3 prepared by crystallization from CCl4 is also stabilized by an intramolecular H-bond but has anendo-cyclic C=C bond (v(C=C) = 1545 cm–1). In a trichloroethylene solution, both theexo- andendo-enol forms co-exist, and the percentage of the latter is 11 %. The frequencies in the vibrational spectra have been assigned using the normal coordinate calculation of2, 3, and their OD-analogs. The mechanism of tautomer transfer is discussed in terms of PMO theory.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 57–62, January, 1994.The authors are grateful to professor J. G. Ramos (Madrid Institute of Optics) for making it possible to record the far IR and Raman spectra in his laboratory, to Dr. V. Z. Kurbako for the registration of spectra and its discussion, and to Dr. N. A. Kubasova for recording the Raman spectra with a Coderg Ar-300 instrument. 相似文献
4.
The -ribofuranosylazide1 is transformed after usual derivatization by suitable protecting groups into the P–N-ylid2, which gives the corresponding N-Glykosyl-N-alkylcarbodiimides4 and a small amount of the glykosylisocyanatde-rivative3 by reaction with alkylisocyanates. The carbodiimides4 were reacted with hydrazoic acid to give the alkylaminotetrazolnucleosides5 and finally the free nucleosidanalogs6. In the case of5 c the 5-aziridinyltetrazolnucleosid5 h was formed by an usual neighbouring group reaction. In addition the compound1 is transformed into the 3,5-diprotected anchor derivative7 by reaction withTIPSCl2. The latter could be transformed by usual steps into the alkylaminotetra-zolnucleosides8 with a free 2-OH group. In the next step the 2-p-tolylthiocarbo-nates9 were prepared followed by transformation to the 2-desoxynucleosides10 by means of tributyltinhydride. Finally the free 2-desoxynucleosides11 were prepared. By reacting the carbodiimides4 with phenylisocyanate a mixture of the two possible regiouretidinonnucleosidderivatives12 and13 are formed. In the case of the N-glykosyl-N-allylcarbodiimide4 d only the one isomer13 d arises.
Herrn Prof. Dr.A. Neckel mit den besten Wünschen zum 60. Geburtstag gewidmet. 相似文献
5.
N. Sh. Pal'yants Z. A. Khushbaktova E. A. Pshenichnov V. N. Syrov A. K. Karimov 《Chemistry of Natural Compounds》2000,36(3):299-301
The two hydroxyls of yuccagenin can be glycosylated by Koenigs-Knorr condensation with acetobromorhammose in dichloroethane in the presence of mercuric cyanide. The bisrhamnoside of yuccagenin markedly lowers the cholesterol and triglyceride content in blood serum of healthy animals and animals with experimental hyperlipidemia.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 242–243, May–June, 2000. 相似文献
6.
The 1-[1,8-bis(dimethylamino)-4-naphthyl[ethyl carbocation generated from the corresponding alcohol in benzene in the presence of Al2O3 undergoes elimination according to theE1 mechanism to give previously unknown 1,8-bis(dimethylami no)-4-vinyl naphthalene in a good yield. This compound was also synthesized from 1,8-bis(dimethylamino)-4-formylnaphthalene by the Wittig reaction. Polymerization of the vinylic derivative obtained was studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2297–2300, September, 1996. 相似文献
7.
Reactions of the isopropoxides of some of the lighter lanthanons with bidentate -ketoimines, such asAAH-n-C4H9 andAAH-C6H5 (donor system: N,OH) and tridentate -ketoimines such asAA(CH2CH2)H2 andAA(CH2CHCH3)H2 (donor system: HO,N.OH) have led to products of the typesLn(O-i-C3H7)3n
(AA-R)
n
,Ln(Oi-C3H7) (AAR') andLn
2(AAR')3 [Ln=La(III), Pr(III) or Nd(III);n=1 or 2;R=-n-C4H9 or-C6H5 andR'=-CH2CH2-or-CH2CHCH3-]. Some undergo exchange reactions with an excess oftert-butanol, leading to the corresponding complexesLn(O-tert-C4H9)3n
(AA-n-C4H9)
n
andLn(O-tert-C4H9) (AA-CH2CH2). All these have been characterised by elemental analysis, molecular weight determinations and their ir spectra. A thermogravimetric analysis of the diisopropoxy derivatives has also been carried out.
Schiff-Basen Derivate von Lanthaniden-Synthese von La(III), Pr(III) und Nd(III) chelaten mit -Ketoiminen
Zusammenfassung Reaktionen von Lanthanid-Isopropoxiden mit zweizähnigen -Ketoiminen [AAH-n-C4H9 undAAH-C6H5; Donorsystem: N,OH] und dreizähnigen -Ketoiminen [AA(CH2CH2)H2 undAA(CH2CHCH3)H2; Donorsystem: OH, N,OH] führten zu Produkten vom, TypLn(O-i-C3H7)3-n (AA-R) n ,Ln(O-i-C3H7) (AAR') undLn 2(AAR')3 [Ln=La(III), Pr(III) oder Nd(III);n=1 oder 2;R=n-C4H9 oder C6H5 undR'=CH2CH2 oder CH2CHCH3]. Einige Komplexe unterliegen bei Behandlung mit einem Überschuß vontert-Butanol einer Austauschreaktion, die zu den entsprechenden Butoxid-Komplexen führt [Ln(O-tert-C4H9)3-n , (AA-n-C4H9) n undLn(O-tert-C4H9) (AACH2CH2)]. Alle Derivate wurden mittels Elementaranalyse, Molgewichtsbestimmung und IR-Spektroskopie charakterisiert. Eine thermogravimetrische Analyse der Diisopropoxi-Derivate wurde ebenfalls ausgeführt.相似文献
8.
Limited Configuration Interaction wave functions based on Unrestricted Hartree-Fock natural orbitals are found to be easy to compute and to give much more satisfactory spin densities than are provided by techniques currently in use. 相似文献
9.
A new method for the synthesis of aminovinyl trifluoromethyl ketones was developed. The method is based on the reactions of 4-sulfonyl-1,1,1-trifluorobut-3-ene-2,2-diols with various alkyl-, aryl-, dialkyl-, and alkylarylamines. The stereochemistry of the compounds obtained was studied. 相似文献
10.
Summary. (RS)-2-tert-Butyldimethylsilyl-1,2-thiazetidine-3-acetic acid 1,1-dioxide prepared from (RS)-S-benzyl--homocysteine was condensed via DCC/NHS with various L-amino acid esters or dipeptide esters yielding N-silylated -sultam peptides. A -sultam active ester was isolated as an intermediate. Desilylation with TBAF in THF yielded stable N-unsubstituted products, and deprotection of the benzyl esters was achieved by catalytic hydrogenation. (S)-S-Benzyl--homocysteine was obtained by fractional crystallization of the brucine salt of the racemate and transformed into benzyl (S)-1,2-thiazetidine-3-acetate, which was on the other hand synthesized by an enantiospecific route from -benzyl Boc-L-aspartate. Some -sultam peptides were prepared from the (S)-enantiomer, and finally some -sultam peptides containing D-Ala units were obtained. 相似文献
11.
G. A. Tolstikov A. G. Mustafin R. R. Gataullin L. V. Spirikhin V. S. Sultanova I. B. Abdrakhmanov 《Russian Chemical Bulletin》1993,42(6):1095-1099
-D-Xylofuranosylpyrimidines were obtained by condensation of silyl derivatives of pyrimidines with 1,2-di-O-acetyl-3,5-di-O-benzoyl-D-xylofuranose with subsequent deprotection of the sugar fragment. Refluxing 2-O-tosyl derivatives of nucleosides with NaI results in the formation of 2,2-anhydro-compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1137–1141, June, 1993. 相似文献
12.
Summary Readily available -glycofuranosyl isocyanides1,2,4,5,6,18,19,20 are transformed into the corresponding protected tetrahydrofurans21,22,23,24,25,26 by means of tributyltin hydride andAIBN. The synthesis of18 and19 by dehydration of the formamide15 is described. Starting with 6-deoxy-1,2-O-isopropyliden--D-allofuranose (7) crystalline 1,2-O-diacetyl-3,5-dibenzoyl--D-allofuranose (9) is obtained.9 is first transformed into the anomeric azides11,12 and13,14 and subsequently into the formamide15. 相似文献
13.
V. I. Filyakova Y. G. Ratner N. S. Karpenko K. I. Pashkevich 《Russian Chemical Bulletin》1996,45(9):2163-2168
The composition of products of the interaction of asymmetric fluoroalkyl-containing -diketones with amines was studied. Mixtures of regioisomeric -aminovinylketones and products of cleavage and secondary condensation are formed, depending on the temperature, the solvent, the nature of the fluorinated and nonfluorinated substituents in the -diketone, and the basicity of the amine. The major product is a -aminovinylketone in which the NH2 group is removed from the fluoroalkyl substituent. No -aminovinylimines, products of condensation involving two electrophilic centers, were observed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2278–2284, September, 1996. 相似文献
14.
Gottfried Heinisch Richard Waglechner 《Monatshefte für Chemie / Chemical Monthly》1984,115(10):1171-1183
The preparation of 4-(-chloroalkyl)pyridazines (4, 7b, 7c, 10) is reported. Compounds4, 7a, 7b, and7c were found to be attacked by methoxide ions mainly at the heteroaromatic ring, thus forming 5-methoxy-4-alkylpyridazines.10 on reaction with sodium methanolate yields exclusively 4-benzyl-5-methoxymethyl-pyridazine (12). In addition, starting from4, the amines5a, 5b, 6a, and6b were prepared.
Herrn Univ.-Prof. Dr.Karl Schlögl mit den herzlichsten Wünschen zum 60. Geburtstag gewidmet. 相似文献
15.
Molins Elies Roig Anna Miravitlles Carlos Moreno-Mañas Marcial Vallribera Adelina Gálvez Nicanor Serra Neus 《Structural chemistry》1998,9(3):203-208
The crystal and molecular structure of (BzlMe3N)
2
+
[Fe2OCl6]2- has been determined. The asymmetric unit contains two benzyltrimethylammonium cations and two half -oxo-bis(trichloro-iron(III)) anions. The bridging -oxygen atoms of these anions are located over crystallographic symmetry elements. Therefore, the two anions resulting from the symmetry operations correspond to two different conformers presenting angular and linear dispositions of the Fe-O-Fe bond angle. Mössbauer spectrum consists of two asymmetric lines that are adequately simulated by two equally populated quadrupole doublets associated with the two iron sites. 相似文献
16.
Panayotis Th. Veltsistas Spyros P. Perlepes Miltiadis I. Karayannis John M. Tsangaris 《Monatshefte für Chemie / Chemical Monthly》1990,121(8-9):703-707
Summary The use of ethyl oxamate for the synthesis of inorganic oxamato complexes is reported. A reaction system leading to the preparation of the novel polymeric -oxamato(-2) complexes [M(oxm)(H2O)2]
x
(M=Cu, Zn, Cd), [Co(oxm)(H2O)2]
x
·0.5xH2O and [Ni(oxm)(H2O)2]
x
·xH2O is described (H2
oxm = oxamic acid). Ethyl oxamate can also be used for the preparation of monomeric oxamato(-1) complexes.
Der Einsatz von Ethyloxamat für die Synthese von Oxamato(-1) und neuen -Oxamato(-2)-Komplexen (Kurze Mitt.)
Zusammenfassung Es wird der Einsatz von Ethyloxamat für die Synthese von anorganischen Oxamato-Komplexen beschrieben. Ein Reaktions-System für die Herstellung von neuen -Oxamato(-2)-Komplexpolymeren: [M(oxm)(H2O)2] x ; (M = Cu, Zn, Cd), [Co(oxm)(H2O)2] x ·0.5xH2O und [Ni(oxm)(H2O)2] x ·xH2O, wird vorgestellt. Ethyloxamat kann auch für die Herstellung von monomeren Oxamato(-1)-Komplexen verwendet werden.相似文献
17.
A. Jaumà A. Escuer J.-A. Farrera J. M. Ribó 《Monatshefte für Chemie / Chemical Monthly》1996,127(10):1051-1062
Summary Several Mn, Cu, and Zn chelates of etiobiliverdin-IV-, mesobiliverdin-IX, and its dimethyl ester are studied. The results show that the chemical constitution of the Cu biliverdin chelate corresponds to a formal metal oxidation state of (II) coordinated to a neutral radical of the NH trideprotonated biliverdin. The reactivity of the Cu(II) bilindione chelates in nucleophilic solvents agrees with that expected for a neutral radical structure of the ligand; in CH3OH, they undergo oxidation towards dimethoxybilipurpurins. The magnetic behaviour of Cu(II) etiobiliverdinate-IV- in the solid state shows an intramolecular weak antiferromagnetic coupling d9Cu-to--radical (J=–23 cm–1) and an intermolecular weak antiferromagnetic coupling -radical-to--radical (J=–45 cm–1). The analogy of this magnetic behaviour to that of the cation radical of metalloporphyrins is discussed.
Reaktivität von Pyrrolpigmenten, 21. Mitt.: Struktur und Reaktivität von Cu(II)- und Zn(II)-Chelaten von Bilindionen
Zusammenfassung Einige Mn, Cu and Zn Chelate von Etiobiliverdin-IV-, Mesobiliverdin-IX und seinem Dimethylester werden untersucht. Im Komplex koordiniert ein Metallatom (mit der Formalladung II) mit einem Neutralradikal des dreifach NH-deprotonierten Bilindions. Die Reaktivität des Komplexes gegenüber nukleophilen Lösungmitteln entspricht erwartungsgemäß dem eines neutralen -Radikals; in CH3OH wird er zu Dimethoxybilipurpurin oxidiert. Bei Cu(II)-Etiobiliverdinat-IV beobachtet man im festen Zustand neben schwacher, antiferromagnetischer Kupplung zwischen d9Cu und -Radikal (J=–23 cm–1) auch eine schwache, intermolekulare, antiferromagnetische Wechselwirkung zwischen zwei -Radikalen (J=–45 cm–1). Dieses magnetische Verhalten wird dem des -Kationradikals von Metalloporphyrinen gegenübergestellt.相似文献
18.
A. Lévai 《Monatshefte für Chemie / Chemical Monthly》1995,126(11):1245-1251
Summary 3-Aroyl-4-aryl-2-pyrazolines (21–40) have been synthesized by the reaction of ,-unsaturated ketones (1–20) with diazomethane. These 2-pyrazolines gave -methyl-,-unsaturated ketones (41–46) on thermal denitrogenation.Dedicated to Prof. Dr.F. Sauter on the occasion of his 65th birthday 相似文献
19.
V. I. Saloutin I. T. Bazyl' Z. E. Skryabina O. N. Chupakhin 《Russian Chemical Bulletin》1994,43(5):849-853
The direction of reactions of 2-ethoxycarbonyl-5,6,7,8-tetrafluoro- and 2-carboxy-5,6,7,8-tetrafluorochromones with ammonia, methylamine, hexylamine, and aniline depends on the inductive effect of the substituent at position C-2 of the chromone and on the basicity of the amine. Nucleophilic aromatic substitution of a fluorine atom takes place in the interaction of 2-ethoxycarbonyl-5,6,7,8-tetrafluorochromone with secondary amines (morpholine,N-methylpiperazine) and ethylenediamine.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 904–907, May, 1994. 相似文献
20.
Marcus E. Brewster Roger Vandecruys Geert Verreck Marc Noppe Jef Peeters 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):35-38
We present a novel solid solution/dispersion technology with glass thermoplastic properties that provide good dissolution rates and oral bioavailabilities for poorly water-soluble weak bases. In this process, a thermoplastic gum was prepared by mixing a polyhydroxy acid such as citric acid or tartaric acid with a weakly basic drug, hydroxypropyl--cyclodextrin (HP--CD) and a cellulose polymer such as hydroxypropylmethylcellulose (HPMC) in a protic solvent. Removal of the solvent gave a material which could be loaded into hard gelatin capsules. Several model compounds were processed in this manner including methylene blue and itraconazole. The resulting data indicated that dissolution properties of GTS's based on methylene blue was pH independent and rapid with 80% dissolved within 30 min. Three GTS formulations of itraconazole containing 100 mg of the drug and 500 mg of citric acid as well as various concentrations of HP--CD and HMPC were found to dissolve rapidly (100% in 45 min). One of these formulations was selected for human pharmacokinetic evaluation and demonstrated significant oral bioavailability relative to unmanipulated drug.The studies suggest that the components of the GTS provide for solubilization through complexation and reduced pH and that the cellulose polymer acts to inhibit recrystallization of the supersaturated solution formed. The rationaldevelopment of the GTS dosage form can be useful for generating acceptable formulations for poorly water-soluble drug candidates. 相似文献