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1.
Jacek G. So?nicki 《Monatshefte für Chemie / Chemical Monthly》2000,141(8):475-486
1-Acylmethylene-3,3-dimethyl-1,3-dihydroisobenzofurans were found to be useful precursors for pyrazole synthesis. In the reaction with hydrazine monohydrate they yielded 3-(2-(α-hydroxyisopropyl)-phenyl) substituted NH-pyrazoles, whereas using alkyl- or arylhydrazine gave access to 5-(2-(α-hydroxyisopropyl)-phenyl) substituted NR-pyrazoles with good regioselectivity. Treatment with orthophosphoric acid led to C,N-fused and C,C-fused pyrazoles, respectively. 相似文献
2.
Winfried Wendelin Edith Gößnitzer Dalal Abou El Ella 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):353-374
Summary. The cyclization reactions of trans-3a-hexahydro-2-benzimidazolamine with 2-alkylidene- and 2-benzylidenecyclohexanones and α-tetralones, respectively, yield
mixtures of two isomeric condensates each. Thorough high resolution NMR analyses (1H and 13C NMR, HH-COSY, gs-HSQC, gs-HMBC, 1D TOCSY, and 1D NOE difference spectra) revealed that the corresponding isomers are in all cases linearly fused diastereomeric
12α- and 12β-substituted trans-6aα-dodecahydrobenzimidazo[2,1-b]quinazolines and 7α-substituted trans-8aβ- and trans-8aα-decahydrobenzimidazo[2,1-b]benzo[h]quinazolines, respectively. The formation of corresponding angularly fused regioisomers was not observed so far. The stereochemistry
and the tautomerism of some bases and their hydrochlorides as well as the regiospecific course of the cyclization reactions
are discussed. Biological tests showed that the novel compounds don’t exert remarkable antibacterial and antimycotic effects.
Received November 3, 1999. Accepted November 30, 1999 相似文献
3.
N. P. Tsvetkov V. E. Vakhmistrov A. B. Koldobsky V. N. Kalinin 《Russian Chemical Bulletin》1999,48(9):1685-1687
The method for the preparation of α-substituted acrylonitrile derivatives by the quaternization of the nitrogen atom of both
Me2N groups in the corresponding substituted 3-(dimethylamino)propanal dimethylhydrazones followed by the Hoffman decomposition
of the resulting diiodides was developed.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1707–1709, September, 1999. 相似文献
4.
Syntheses Based on Natural α-Amino Acids. Cyanoethylation of 3-Substituted 5-Methyl-2-thiohydantoins
Starting from α-alanine, the C- and S-cyanoethyl derivatives of 5-methyl-3-phenyl(allyl)-2-thiohydantoins have been synthesized.
It was shown that the products of hydrolysis of C-cyanoethyl derivatives, 5-methyl-3-phenyl(allyl)-(β-carboxyethyl)-2-thiohydantoins,
are formed in addition.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1657–1661, November, 2005. 相似文献
5.
V. S. Reznik Ya. A. Levin V. D. Akamsin I. V. Galyametdinova R. I. Pyrkin 《Russian Chemical Bulletin》2000,49(3):495-498
Primary alkylamines, β-aryloxyethylamines, orN-[β-(2-methoxyphenoxy)ethyl]-α,ω-diaminoalkanes react with alkyl divinyl phosphinates or phenyl(divinyl)phosphine oxide to give the corresponding 4-alkoxy(4-phenyl)-1-alkyl-4-oxo-1,4-azaphosphorinanes. Reactions of the latter with mono- or dihaloalkanes afford 4-phosphapiperidinium halides. 1,4-Azaphosphorinanes containing a β-aryloxyethyl fragment exhibit hypotensive activity. 相似文献
6.
R. K. Rakhmanberdyeva M. R. Mirzaeva D. A. Rakhimov N. D. Abdullaev 《Chemistry of Natural Compounds》1999,35(5):498-501
Galactomannans isolated from the seeds ofGleditsia macracantha (GMM) andGleditsia texana (GMT) have molecular masses (MM) of 750.000 and 795.000 and galactose to mannose ratios of 1.0∶4.9 and 1.0∶3.8, respectively.
GMT and GMM are depolymerized to fragments of MM 25 and 19 kDa with retention of the primary structure and are studied by13C NMR spectroscopy. The principal chains of GMM and GMT are β-1-4-mannopyranose residues in which the hydroxyl groups of C-6
are substituted by single α-D-galactopyranose units.
Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 566–569, September–October, 1999. 相似文献
7.
Mamedov V. A. Saifina D. F. Gubaidullin A. T. Saifina A. F. Rizvanov I. Kh. Ganieva V. R. 《Russian Chemical Bulletin》2009,58(9):1986-1990
A reaction of 3-(α-chlorobenzyl)quinoxalin-2(1 H)-one with α-picoline gives 2-(3-phenyl-indolizin-2-yl)benzimidazole as a result of a ring-contracting rearrangement involving
the fragment C(2)—C(3)—C(Cl)Ph of the quinoxaline system and the fragment N=CH—Me of the α-picoline system. Possible pathways
of this reaction are discussed. 相似文献
8.
A. V. Edunov G. I. Kurochkina M. K. Grachev I. I. Levina T. A. Batalova E. E. Nifant’ev 《Russian Journal of Organic Chemistry》2011,47(7):981-988
Selectively substituted derivatives of α-cyclodextrin and hexa-O-tert-butyldimethylsilyl-α-cyclodextrin containing a definite number of acylated primary or secondary hydroxy groups were synthesized
using benzoic, acetylsalicylic, and 2-(4-isobutylphenyl)propionic acid chlorides in various solvents in the presence of different
bases. The acyl residues were assigned to the C2, C3, or C6 atoms in the carbohydrate fragments on the basis of 13C NMR data. Desilylation of the silyl derivatives with ammonium fluoride in methanol gave the corresponding O-acyl derivatives having free primary hydroxy groups in the α-cyclodextrin skeleton. 相似文献
9.
L. A. Yakovishin V. I. Grishkovets A. S. Shashkov V. Ya. Chirva 《Chemistry of Natural Compounds》1999,35(5):543-546
Two new minor triterpene glycosides L-G1, and L-G2b, the 3-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-gentiobiosyl and 3-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1→4)-O-(6-O-acetyl-β-D-glucopyranosyl)-(1→6)-O-β-D
glucopyranosyl esters of 30-norhederagenin, respectively, are isolated from the leaves of canary ivy (Hedera canariensis Willd.). The structures of the glycosides are found by chemical methods and1H and13C NMR spectroscopy.
Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 623–626, September–October, 1999. 相似文献
10.
Francisc Potmischil Helmut Herzog Joachim Buddrus Mircea D. Gheorghiu 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):345-352
Summary. The stereoselectivities of the quaternization reactions of (4aα,8aβ,9aβ,10aα)- and (4aα,8aα,9aβ,10aα)-tetradecahydro-10-methylacridine
with methyl- and ethyl iodide as well as those of (4aα,8aβ,9aβ,10aα)- and (4aα,8aα,9aβ,10aα)-10-ethyl-tetradecahydroacridine
with methyl iodide were investigated using 13C NMR spectroscopy including 13C-labelling where appropriate. The methylations of both N-methyl amines occur by predominant (60% and 75%, respectively) equatorial
approach, their ethylations occur sterospecifically by equatorial approach, and the methylations of the N-ethyl amines occur
by highly stereoselective (> 90%) axial approach of the quaternizing reagent.
Received October 27, 1999. Accepted November 22, 1999 相似文献
11.
G. Kh. Khisamutdinov V. I. Slovetsky Yu. M. Golub S. A. Shevelev A. A. Fainzilberg 《Russian Chemical Bulletin》1997,46(2):324-327
Methods for the preparation of α-azidopolynitroalkanes by reactions of polynitroalkanes or α-(difluoroamino)polynitroalkanes
with NaN3 were developed. In the case of tetranitromethane, one or two nitro groups can be substituted, depending on the reaction conditions.
The reaction of 1,1,1-trinitroethane with NaN3 affords nitro-1,2,3-triazole, together with 1-azido-1,1-dinitroethane. The IR spectra of α-azidopolynitroalkanes were studied.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 338–341, February, 1997. 相似文献
12.
Marek Burian Ladislav Omelka Silvie Ondrášová Vlasta Brezová 《Monatshefte für Chemie / Chemical Monthly》2003,134(4):501-508
Summary. Several N-phenyl substituted 1,4- and 1,2-phenylenediamines were oxidized using radicals and 3-chloroperbenzoic acid. EPR spectroscopy confirmed the generation of nitroxide radicals originating from the
oxidation of the bridging -NH-group. No radical products suggesting the simultaneous reaction with the NH2-group were observed. Only in the case of 1,4-phenylenediamine, a low concentration of nitroxide radical H–NO–C6H4–NH2 was obtained. In o-aminodiphenylnitroxide the steric effect of the NH2-group causes a partially asymmetrical spin density distribution in both phenyl rings.
Corresponding author. E-mail: omelka@fch.vutbr.cz
Received September 30, 2002; accepted October 4, 2002 相似文献
13.
V. S. Renzik V. D. Akamsin I. V. Galyametdinova S. G. Fattakhov B. E. Ivanov 《Russian Chemical Bulletin》1999,48(5):979-983
Dialkyl β-(2-aroxyethylamino)ethylphosphonates,N-[β-(2-methoxyphenoxy)ethyl]-N′-[β-(diethoxyphosphoryl)ethyl]-α,ω-diaminoalkanes, and diethyl β-(N-arylpiperazino)ethyl-phosphonates were synthesized by the reactions of dialkyl vinylphosphonates with β-aroxyethylamines,N-[β-(2-methoxyphenoxy)ethyl]-α,ω-diaminoalkanes, andN-aryl-piperazines, respectively. The compounds synthesized exhibit hypotensive and α-adrenolytic activities.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 987–991, May 1999. 相似文献
14.
Extraction and characterization of native heteroxylans from delignified corn stover and aspen 总被引:1,自引:0,他引:1
Radnaa Naran Stuart Black Stephen R. Decker Parastoo Azadi 《Cellulose (London, England)》2009,16(4):661-675
Dimethylsulfoxide-solubilized polysaccharides from delignified corn stover and aspen were characterized. The biomass was delignified
by two different techniques; a standard acid chlorite and a pulp and paper QPD technique comprising chelation (Q), peroxide
(P), and acid-chlorite (D). Major polysaccharides in all fractions were diversely substituted xylan. Xylan acetylation was
intact after chlorite delignification and, as expected, xylan from QPD-delignified fraction was de-acetylated by the alkaline
peroxide step. The study of DMSO-extractable xylans from chlorite-delignified biomass revealed major differences in native
acetylation patterns between corn stover and aspen xylan. Xylan from cell walls of corn stover contains 2-O- and 3-O-mono-acetylated xylan and [MeGlcA-α-(1 → 2)][3-OAc]-xylp units. In addition, aspen xylan also contains 2,3-di-O-acetylated xylose. 1,4-β-d-xylp residues substituted with MeGlcA at O-2 position are absent in chlorite-delignified aspen xylan. Sugar composition in accord with NMR-spectroscopic data indicated
that corn stover xylan is arabinosylated while aspen xylan is not. We have shown that corn stover xylan has similar structure
with xylans from other plants of Poales order. No evidence was found to indicate the presence of 1,4-β-d-[MeGlcA-α-(1 → 2)][Ara-α-(1 → 3)]-xylp in corn stover xylan fractions. 相似文献
15.
Edith Gößnitzer Winfried Wendelin Karl Schermanz Karin Frieberger 《Monatshefte für Chemie / Chemical Monthly》2001,132(9):1081-1093
Summary. The reaction of 2-benzylidenecyclohexanone and 1-(4-methoxyphenyl)-2-methyl-1-penten-3-one with guanidine did not yield the
expected 4-phenylhexahydro-2-quinazolinamine and 4-(p-methoxyphenyl)-dihydro-2-pyrimidinamine, respectively, but nitrogen-free products which turned out as [3+3]- and [4+2]-cycloadducts
of two molecules of the applied vinylogous ketone each. According to elemental analyses, mass spectra, and, in particular,
NMR analyses (1H and 13CNMR, HH-COSY, gs-HSQC, gs-HMBC, 1D TOCSY, NOESY, and 1D NOE difference spectra), the prepared dimers were identified as racemic (5E)-5-benzylidene-9β-phenyl-trans-4a-1,2,3,4,4a,5,6,7,8,9a-decahydroxanthen-4aα-ol and 3β,5β-bis-(4-methoxyphenyl)-2α,4β,6α-trimethyl-4α- propionylcyclohexanone, respectively. Structure and stereochemistry of the dimers
are elucidated, and mechanisms for their formation are proposed.
Received April 11, 2001. Accepted (revised) May 18, 2001 相似文献
16.
New dialkyl α-aminophosphonates and α-aminothiophosphonates were synthesized by reactions of dialkyl phosphites orO,O-dialkyl thiophosphites withN-benzylidene 2-(vinyloxy)ethylamine orN-(4-fluorobenzylidene)-2-(vinyloxy)ethylamine.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1815–1817, September, 1999. 相似文献
17.
Christa Grogger Hermann Rautz Harald Stüger 《Monatshefte für Chemie / Chemical Monthly》2001,132(4):453-464
Summary. The dipolar cyclohexasilanes 1-ferrocenyl-4-((2,2-dicyanoethenyl)-phenyl)-decamethylcyclohexasilane (1) and 1-ferrocenyl-3-((2,2-dicyanoethenyl)-phenyl)-decamethylcyclohexasilane (2) were synthesized by conventional methods and fully characterized. Electronic absorption spectroscopic studies suggest increased
σ-π interactions in the cyclohexasilane derivatives when compared to their open-chained analogues. Small but noticeable electron
transmission effects via the cyclohexasilanyl group can be derived from cyclic voltammetric data. Significantly increased values of the quadratic
hyperpolarizabilities β in solution for 1 and 2 are shown by preliminary results of measurements using the EFISH technique.
Received May 30, 2000. Accepted December 20, 2000 相似文献
18.
Antony F. McDonagh Giovanni Agati David A. Lightner 《Monatshefte für Chemie / Chemical Monthly》1998,129(6-7):649-660
Summary. Quantum yields for Z⇄E photoisomerization of the natural bi-chromophore bilirubin IXα in ammoniacal methanol solution were found to vary with excitation
wavelength, whereas no variation (within experimental error) was observed for xanthobilirubic acid and for symmetrically substituted
bilirubins (bilirubin IIIα, bilirubin XIIIα, and mesobilirubin XIIIα) in the same solvent. The quantum yield for Z⇄E photoisomerization of xanthobilirubic acid bound to human serum albumin was also invariant with excitation wavelength. In
contrast, quantum yields for Z⇄E photoisomerization of the symmetrically-substituted bilirubins did show marked excitation wavelength dependency when they
were bound to human serum albumin. These results show that quantum yields for Z⇄E photoisomerization of bilirubins are markedly sensitive to protein binding and to the nature of pyrrole ring β-substituents.
They also demonstrate that wavelength-dependent photochemistry is characteristic of bilirubins with non-identical pyrromethenone
chromophores, as expected from exciton coupling theory, and that complexation with albumin induces wavelength-dependent photochemistry
in symmetrically substituted bilirubins.
Received January 13, 1998. Accepted January 27, 1998 相似文献
19.
Klaus Burger Lothar Hennig Annett Fuchs Dieter Greif Jan Spengler Fernando Albericio 《Monatshefte für Chemie / Chemical Monthly》2005,136(10):1763-1779
Summary. A new approach to trifluoromethyl substituted butenolides and their thioanalogues is described starting from 2-fluoro-3-trifluoromethylfurans
and -thiophenes, respectively. The reaction sequence includes three steps – nucleophilic displacement reaction, Claisen, and finally Cope rearrangement – which can be run as domino reaction. A modification of the domino reaction (transesterification instead of
Cope rearrangement) provides a concise access to α-trifluoromethyl-γ-ketoacids. 相似文献
20.
M. D. Khanova R. M. Sultanova R. R. Rafikov I. P. Baykova R. Z. Biglova V. A. Dokichev Yu. V. Tomilov 《Russian Chemical Bulletin》2008,57(3):617-621
The influence of 1,3-oxazolidine and 1,3-oxathiolane fragments in substituted alkenes on the direction of their catalytic
reaction with diazomethane has been investigated. The olefins bearing an oxazolidine substituent in the α- or γ-position and
an oxathiolane substituent in the γ-position relative to the C=C bond react with diazomethane in the presence of Pd(acac)2 selectively resulting in cyclopropanation products. The use of Cu(OTf)2 does not result in cyclopropanation; however Cu(OTf)2 catalyzes the reaction of diazomethane with 2-(alk-1-enyl)-1,3-oxathiolanes yielding 2,3,5,6-tetrahydro-1,4-oxathiocines
formed through the [2,3]-sigmatropic rearrangement of the intermediate sulfonium ylides.
For Part 15 see Ref. 1.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 604–608, March, 2008. 相似文献