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1.
Zusammenfassung Die Untersuchungen über die Reaktion zwischen 2,5-Dihydroxy-1,4-dithianen und Aminen der allgemeinen Formel R–NH2 und R–NHNH2 wurden fortgesetzt. Aus 2,5-Dihydroxy-1,4-dithian (I) und Ammoniak bildet sich das trizyklische System des 2,5-Di-(N-2,5-endimino-1,4-dithianyl)-1,4-dithians. Dagegen reagiert 2,5-dimethyl-2,5-dihydroxy-1,4-dithian mit Ammoniak zu 2,5-Dimethyl-2,5-endimino-1,4-dithian. Weiters gibt I mit Thiosemikarbazid N-Thioureido-2,5-endimino-1,4-dithian. Um zu wasserlöslichen Derivaten des Ringsystems zu gelangen, die einer pharmakologischen und bakteriostatischen Untersuchung unterzogen werden können, wurden die zur Salzbildung fähigen Verbindungen N--Diäthylaminoäthyl-2,5-endimino-1,4-dithian und N-Isonicotinsäureamido-2,5-endimino-1,4-dithian hergestellt.Herrn Prof. Dr.F. Wessely zu seinem 60. Geburtstag in aufrichtiger Verehrung gewidmet. 相似文献
2.
Methyl 2,5-dimethoxy-2,5-dihydrofuran-2-carboxylate is formed in the reaction of HCl-CH3OH with methyl 5-nitro-2-acetoxy-2,5-, 5-nitro-4-acetoxy-4,5-, and 2,5-diacetoxy-2,5-dihydrofuran-2-carboxylates, whereas methyl 2,5-dioxo-3-pentenoate bis(2,4-dinitrophenylhydrazone) and 4-oxo-2-penten-1,5-dioic acid 2,4-dinitrophenylhydrazone are isolated in the presence of 2,4-dinitrophenylhydrazine. Methyl 5-nitrofuran-2-carboxylate is formed by treatment of methyl 5-nitro-2-acetoxy-2,5-dihydrofuran-2-carboxylate with aqueous solutions of acetic or phosphoric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1600–1603, December, 1977. 相似文献
3.
The configurations of 1,4:3,6-dianhydro-2,5-di-O-mesyl-D -mannitol, 1,4:3,6-dianhydro-2,5-di-O-mesyl-D -glucitol, 1,4:3,6-dianhydro-2,5-di-O-mesyl-L -iditol, 1,4:3:6-dianhtydro-2-deoxy-2-iodo-5-O-mesyl-D -mannitol, 1,4:3:6-dianhtydro-2-deoxy-2-iodo-5-O-mesyl-D -glucitol, 1,4:3,6-dianhydro-2-deoxy-2-iodo-5-O-mesyl-L -iditol, 1,4:3,6-dianhydro-2,5-dideoxy-2,5-diiodo-D -glucitol and 1,4:3,6-dianhydro-2,5-dideoxy-2,5-diiodo-L -iditol were determined by 13C NMR spectroscopy, by invoking the field-effect. 相似文献
4.
Filyakova T. I. Kodess M. I. Zapevalov A. Ya. Saloutin V. I. 《Russian Journal of Organic Chemistry》2003,39(7):1010-1015
Perfluorotetrahydrofuran-2-carboxylic acid was converted through a series of transformations into perfluoro-2,3-dihydrofuran and perfluoro-2,5-dihydrofuran; likewise, from (2-perfluorotetrahydrofuryl)difluoroacetic acid 2-trifluoromethylpentafluoro-2,3-dihydrofuran was obtained. Perfluoro-2,3-dihydrofuran and 2-trifluoromethylpentafluoro-2,3-dihydrofuran underwent isomerization into perfluoro-2,5-dihydrofuran and 2-trifluoromethylpentafluoro-2,5-dihydrofuran by the action of cesium fluoride. Treatment of perfluoro-2,5-dihydrofuran with SbF5 resulted in ring opening and formation of cis-perfluoro-2-butenoyl fluoride, while 2-trifluoromethylpentafluoro-2,3-dihydrofuran was converted into 2-trifluoromethylpentafluoro-2,5-dihydrofuran under the same conditions. Perfluoro-3,4-epoxytetrahydrofuran and 2-trifluoromethyl-3,4-epoxypentafluorotetrahydrofuran containing fused oxirane and tetrahydrofuran rings were synthesized by reactions of perfluoro-2,5-dihydrofuran and 2-trifluoromethylpentafluoro-2,5-dihydrofuran, respectively, with sodium hypochlorite. 相似文献
5.
Synthesis of 2,5-diethynyl substituted oxepins from trans-1,4-diethynylcyclohexa-2,5-diene-1,4-diols
Arkasish Bandyopadhyay 《Tetrahedron letters》2005,46(18):3221-3224
Reaction of trans-1,4-bis(trimethylsilylethynyl)cyclohexa-2,5-diene-1,4-diol with n-BuLi followed by methanesulfonyl chloride resulted in the formation of a dark red solid, which was identified as 2,5-bis(trimethylsilylethynyl)oxepin. Deprotection of the silyl groups resulted in the formation of 2,5-diethynyloxepin, a red, shock sensitive solid. Reaction of a differentially substituted cyclohexa-2,5-diene-1,4-diol gave a mixture of 2,5-diethynyl substituted oxepins. 相似文献
6.
Massenspektroskopische Untersuchungen an 2,5-Diaryl-1-(arylimino)-1λ4,2,5-thiadia-zolidin-3,4-dionen
Richard Neidlein Peter Leinberger Alfred Hotzel 《Journal of mass spectrometry : JMS》1977,12(10):628-630
The mass spectra of 2,5-diaryl-1-(arylimino)-1λ4,2,5-thiadiazolidin-3,4-diones have been examined. Some fragmentations are explained by rearrangement of the title compounds to 1,3-(diarylimino)-5-aryl-1λ4,2,5-thioxazolidin-4-ones and 1-oxo-2,5-diaryl-3-(arylimino)-1λ4,2,5-thiadiazolidin-4-ones. 相似文献
7.
A number of new polymeric materials have been prepared by the self-condensation of 2,5-diamino-p-benzoquinonediimide and by its condensation with 2,5-diamino-p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, and 2,5-dichloro-p-benzoquinone. Ladder polymers were expected, but in every case polymers with some open rings were obtained. 2,5-Diaminohydroquinone was condensed with 2,5-diamino-p-benzoquinonediimide and with 2,5-diamino-p-benzoquinone to produce heat stable polymers but the expected ladder structures were not obtained. Thermogravimetric analyses of the polymers in nitrogen all showed a weight loss at 100–150°C of 3–14% which was presumably due to loss of either chemically combined or absorbed water on the polymer and then only a 5% weight loss up to about 600°C with a final weight loss of 19% at 900°C. 相似文献
8.
Akihiro Ohta Fusako Yamamoto Yasuhiko Arimura Tokuhiro Watanabe 《Journal of heterocyclic chemistry》1982,19(4):781-784
Some 3,6-dialkyl-1,4-dihydroxy-2,5-dioxopiperazines were conveniently prepared from the corresponding 3,6-dialkyl-2,5-dichloropyrazines via their 1,4-dioxides and 3,6-dialkyl-2,5-dihydroxypyrazine 1,4-dioxides. On the basis of the examination of pmr, tlc, and glc of the 2,5-dioxopiperazines derived from the products, it was clarified that all the products were cis-diastereomers. 相似文献
9.
10.
Substrate selectivity of Gluconobacter oxydans (ATCC 9937) for 2,5-diketo-d-gluconic acid (2,5-DKG) production was investigated with glucose, gluconic acid, and gluconolactone in different concentrations
using a resting-cell system. The results show that gluconic acid was utilized favorably by G. oxydans as substrate to produce 2,5-DKG. The strain was coupled with glucose dehydrogenase (GDH) and 2,5-DKG reductase for synthesis
of 2-keto-l-gulonic acid (2-KLG), a direct precursor of l-ascorbic acid, from glucose. NADP and NADPH were regenerated between GDH and 2,5-DKG reductase. The mole yield of 2-KLG of
this multienzyme system was 16.8%. There are three advantages for using the resting cells of G. oxydans to connect GDH with 2,5-DKG reductase for production of 2-KLG: gluconate produced by GDH may immediately be transformed into
2,5-DKG so that a series of problems generally caused by the accumulation of gluconate would be avoided; 2,5-DKG is supplied
directly and continuously for 2,5-DKG reductase, so it is unnecessary to take special measures to deal with this unstable
substrate as it was in Sonoyama’s tandem fermentation process; and NADP(H) was regenerated within the system without any other
components or systems. 相似文献
11.
The corresponding diureides of tetrahydrofuran-2,5- and tetrahydrothiophene-2,5-dicarboxylic acids and the dithioureide of tetrahydrothiophene-2,5-dicarboxylic acid were obtained by the acylation of thiourea, urea, and its N-methyl-, N-tert-butyl- and N-phenyl derivatives with the acid dichlorides of tetrahydrofuran-2,5- and tetrahydrothiophene-2,5-dicarboxylic acids.See [1] for communication XLIX.DeceasedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1587–1589, December, 1971. 相似文献
12.
《合成通讯》2012,42(24):3401-3411
AbstractThe base-catalyzed reaction of 1,5-diphenyl-pentane-1,3,5-trione with aromatic/heteroaromatic 1,2-diones leading to the synthesis of 2,5-diaroyl-4-hydroxycyclopent-2-enones and its conversion to 2,5-diaroylcyclopentadienones is reported here. 2,5-Dibenzoyl-4-hydroxycyclopent-2-enone and 2,5-dithenoyl-4-hydroxycyclopent-2-enone are valuable compounds which act as chemosensors for selective detection of Fe3+ and Cu2+, respectively. 相似文献
13.
Summary 1,4-bis-(Dipyrrinone-9-ylidene)-butene-2, a verdinoid system extended at C-10, was synthesized by condensing a dipyrrinone unsubstituted in position 9 with 2,5-dihydro-2,5-dimethoxyfuran or 2,5-dimethoxy-tetrahydrofuran. The chemical and spectroscopic properties of this novel chromophoric system are discussed.
Zur Chemie von Pyrrolpigmenten, 95. Mitt.: 1,4-bis-(Dipyrrinon-9-yliden)-buten-2 — ein neuerb-homo-Verdinchromophor
Zusammenfassung 1,4-bis-(Dipyrrinon-9-yliden)-buten-2, ein verdinoides, in Position 10 extendiertes System, wurde durch Kondensation eines in Position 9 unsubstituierten Dipyrrinons mit 2,5-Dihydro-2,5-dimethoxy-furan oder 2,5-Dimethoxy-tetrahydrofuran synthetisiert. Die chemischen und spektroskopischen Eigenschaften dieses neuen chromophoren Systems werden diskutiert.相似文献
14.
Cyclic Compounds Made of Phosphorus, Carbon, and Sulfur By reaction of P4S10 with excess tri-n-dodecylamine and tribenzylamine bis(didodecylammonium)-3,6-diundecyl-2,5-dithioxo-1,4,2λ5,5λ5-dithiaphosphorinan-2,5-disulfide ( IId ) and bis(tribenzylammonium)-3,6-diphenyl-2,5-dithioxo-1,4,2λ5,5λ5-dithiaphosphorinan-2,5-disulfide ( IIe ), respectively, are formed. Reactions of the ammonium-3,6-dialkyl-2,5-dithioxo-1,4,2λ5,5λ5-dithiaphosphorinan-2,5-disulfides with aqueous alkali solutions and CH3I as well as their therolysis are described. 相似文献
15.
Condensation of 1,4-diacetylpiperazine-2,5-dione with aldehydes has been applied to the synthesis of albonoursin and unsymmetrical 3,6-diarylidenepiperazine-2,5-diones. The reaction has been extended to 1,4-diacetyl-3,6-dimethylpiperazine-2,5-dione, which gives derivatives of 2-methyl-3- phenylserine. The mechanism and stereochemistry are discussed; cis 1-acetyl-3-isobutylidene- piperazine-2,5-dione has been isolated. 相似文献
16.
S. A. Grabovskii E. A. Markov E. G. Galkin N. N. Kabal’nova 《Kinetics and Catalysis》2009,50(2):180-185
The products and kinetics of the thermolysis of 1,2-dioxaspiro[2,5]octane in cyclohexanone and cyclohexanone-CCl4 mixtures are studied. 1,2-Dioxaspiro[2,5]octane is consumed via two parallel routes: isomerization to oxepan-2-one and solvent (cyclohexanone) oxidation with the partial escape of radicals from the cage (17% at 25 °C). Under an inert atmosphere, the alkyl radicals formed by solvent oxidation initiate the chain radical decomposition of 1,2-dioxaspiro[2,5]octane. The mechanism of 1,2-dioxaspiro[2,5]octane thermolysis is discussed on the basis of the results obtained. The activation parameters of 1,2-dioxaspiro[2,5]octane isomerization to oxepan-2-one and reactions of dioxaspiro[2,5]octane with cyclohexanone are discussed. 相似文献
17.
Yeganeh Khaniani Hamid Golchoubian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2817-2823
A convenient method for the preparation of the phenol-based ligands 1,6-bis(2-thiophenyl)-2,5-bis(2-hydroxy-3-hydroxymethyl-5-methylbenzyl)-2,5-diazahexane and 1,6-bis(5-methyl-2-thiophenyl)-2,5-bis(2-hydroxy-3-hydroxymethyl-5-methyl-benzyl)-2,5-diazahexane possessing two dissimilar compartments having multifunctional groups is reported. To synthesize these ligands, an equivalent of 1,6-bis(2-thiophene)-2,5-diazahexane or 1,6-bis(5-methyl-2-thiophene)-2,5-diazahexane and two equivalents of 2,2-dimethyl-6-methyl-8-(chloromethyl)benzo-1,3-dioxin were reacted in the presence of Na2CO3 in 1,4-dioxane, followed by acid hydrolysis of an acetonide-protecting group. Characterization data for the new compounds is reported. 相似文献
18.
19.
Starting from 2,5-dichlorothiophen many new 3,4-disubstituted thiophens have been made including the dialdehyde. Treatment of this with phosphorus pentabromide could be made to give 2,5-dichloro-3- dibromomethylthiophen-4-aldehyde, 2,5-dichloro- or 2-bromo-5-chloro-3,4-bisdibromomethylthiophen. the latter two compounds reacted with sodium iodide to give the corresponding cis- and trans-3,4-dibromo cyclobuteno[c]thiophen derivatives (18–21). Reaction of trans-3,4-dibromo-2,5-dichlorocyclobuteno[c]thiophen with N-bromosuccinimide resulted in fission of the 4-membered ring regenerating 2,5-dichloro-3,4-bisdibromomethylthiophen.When 2,5-dichloro-3,4-di-iodothiophen was treated with butyl-lithium followed by dimethylsulphate it gave 2,5- dichloro-3,4-dimethylthiophen together with a low yield of a red compound which is considered to be a dichloro dimethyl derivative (11) of bisthiophenindigo.Several unsuccessful approaches to the synthesis of dithiophen analogues of biphenylene are outlined. These included heating various 3,4-di-iodothiophens and 4,4′-di-iodo-3,3′-bithienyls with copper as well as the flash vacuum pyrolysis of the latter compounds, of thiophen-3,4-dicar?ylic anhydrides and of 2,5-dichloro-3-iodothiophen-4-car?ylic acid. 相似文献
20.
采用3-烷基噻吩与对硝基苯甲醛和对二甲氨基苯甲醛的聚合反应得到了5种聚(3-烷基)噻吩取代苯甲烯衍生物:聚(3-丁基)噻吩对硝基苯甲烯(PBTNBQ)、聚(3-己基)噻吩对硝基苯甲烯(PHTNBQ)、聚(3-丁基)噻吩对二甲氨基苯甲烯(PBTDMABQ)、聚(3-己基)噻吩对二甲氨基苯甲烯(PHTDMABQ)和聚(3-辛基)噻吩对二甲氨基苯甲烯(POTDMABQ).计算其光学禁带宽度分别为PBTNBQ(1.82eV),PHTNBQ(1.85eV),PBTDMABQ(1.71eV),PHTDMABQ(1.78eV)和POTDMABQ(1.67eV).利用简并四波混频技术测量了5种聚合物薄膜的三阶非线性极化率,分别为1.74×10-8,1.82×10-8,5.62×10-9,8.64×10-9和1.22×10-8esu,均具有较大的三阶非线性光学性能.针对取代基结构对聚(3-烷基)噻吩取代苯甲烯衍生物的三阶非线性光学性能的影响从分子内极化程度和主链电子的离域程度两个方面进行了讨论. 相似文献