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1.
Benzaldehyde and substituted benzaldehydes react with styrene ( 1), -methylstyrene, ( E)-1-propenylbenzene and anethole in presence of sulfuric acid to give 2,4,6-triaryl-1,3-dioxanes. In acetic acid from 1 and benzaldehyde (1 R,3 S)-and (1 RS,3 RS)-1,3-diacetoxy-1,3-diphenylpropane is formed. The relative configuration of the products is determined by means of 1H-NMR spectroscopy.
Herrn Prof. Dr. Anton v. Wacek, emerit. Vorstand des Instituts für Organische Chemie und Organisch-chemische Technologie der Technischen Universität Graz, in Verbundenheit zum 80. Geburtstag gewidmet. 相似文献
2.
By reaction of 2-[(1 RS, 2 RS)-2-hydroxy-1-methyl-propyl]-2-phenyl-1,3-dithiane ( 1 a) with cis-2-butene oxide, subsequent reduction and acetalization c-4, t-5-dimethyl- r-2, c-6-diphenyl-1,3-dioxane ( 3 a) and t-4, c-5-dimethyl- r-2, c-6-diphenyl-1,3-dioxane ( 3 b) were synthesized as model compounds. For the same purpose by aldol reaction of cyclohexanone and reduction (1 RS, 2 SR)-2[( RS)-hydroxy-(4-methoxyphenyl)methyl]cyclohexanol ( 7 a), (1 RS, 2 RS)-2[( SR)-hydroxy-(4-methoxyphenyl)methyl]cyclohexanol ( 8 a), and (1 RS, 2 RS)-2[( RS)-hydroxy-(4-nitrophenyl)methyl]cyclohexanol ( 8 b) and by acetalization (2 , 4 , 4 a, 8 a)-2,4-bis(4-methoxyphenyl)hexahydro-4 H-1,3-benzodioxin ( 9 a) and (2 , 4 , 4 a, 8 a)-2,4-bis(4-nitrophenyl)hexahydro-4 H-1,3-benzodioxin ( 10 b) were obtained. From Prins reactions, starting with 2-butene 3 a, c-4, c-5-dimethyl- r-2, c-6-diphenyl-1,3-dioxane ( 3 c), r-4, t-5-dimethyl- c-6-phenyl-1,3,2-dioxathiane-2,2-dioxide ( 4), and (2 Z, 4 E)-1,5-diphenyl-4-methyl-2,4-pentadien-1-on ( 5), and starting with cyclohexene ( E)-3-(4-methoxybenzylidene)cyclohexenyl-4-methoxyphenyl ketone ( 11) have been isolated in low yields. 4. Mitt.:Griengl, H., Nowak, P., Mh. Chem.109, 11 (1978). 相似文献
3.
The four diastereomeric 2-(hydroxyphenylmethyl)cyclohexanols 2a-2d are prepared. By reaction with benzaldehyde each 2a-2c gives stereospecifically only one of the two possible configurationally correlated 2,4-diphenylhexahydro-4 H-1,3-benzodioxins 3a-3c. However, from (1 RS, 2 SR)-2 [( SR)-hydroxyphenylmethyl]cyclohexanol ( 2d) both dioxins 3d and 3e are obtained. The configurational assignments are based on 1H-NMR spectroscopy and synthetic correlations. Conformational aspects are discussed. As is shown by chromatography, in Prins reactions of cyclohexene with benzaldehyde only one dioxin 3c is formed. 相似文献
4.
Heating of 2-benzylidene-1-indanone ( 1) either in dimethylformamide in the presence of guanidine carbonate or in n-propanol in the presence of thiourea and sodium propylate yields a dimer P with the structure of 1,3-diphenyl-3a,8a-dihydrospiro{cyclopenta[a]indene-2,2(1 H,3 H)-indene}-1,8(3H)-dione ( 7); this was deduced from the 400 MHz- 1H- and 100MHz- 13C-nmr-spectra and the corresponding two-dimensional HH- and CH-correlations. A possible mechanism for the formation of the spirocompound 7 is proposed; the stereo formula of the dimer 7 K was established on the basis of a 400 MHz-HH-NOESY experiment. 相似文献
5.
The Diels-Alder adduct (±)- 3 of 2,4-dimethylfuran and 1-cyanovinyl acetate was converted stereoselectively into benzyl 6-(4-chlorophenylsulfonyl)-1,3- exo,5-trimethyl-7-oxabicyclo[2.2.1]hept-5-en-2- exo-yl ( 26 ) and -2- endo-yl ether ( 36 ). Addition of LiAlH 4 to the latter led to the 3- O-benzyl derivatives 28 and 37 of (1 RS,2 SR,3 SR,6 SR)- and (1 RS,2 SR,3 RS,6 SR)-5-(4-chlorophenylsulfonyl)-2,4,6-trimethylcyclohex-4-ene-1,3-diol, respectively. Methylenation of 6- exo-(4-chlorophenylthio)-1-methyl-5-methylidene-7-oxabicyclo[2.2.1]heptan-2-one ( 16 ), obtained by reaction of (±)- 3 with 4-Cl-C 6H 4SCl and saponification gave, 6- exo-(4-chlorophenylthio)-1-methyl-3,5-dimethylidene-7-oxabicyclo [2.2.1]heptan-2-one ( 43 ), the reduction of which with K-Selectride afforded 6- exo-(4-chlorophenylthio)-1,3- endo-dimethyl-5-methylidene-7-oxabicyclo[2.2.1]heptan-2- endo-ol ( 44 ). The 3- O-benzyl derivative 48 of (1 RS,2 RS,3 RS,6 SR)-5-(4-chlorophenylsulfonyl)- 2,4,6-trimethylcyclohex-4-ene-1,3-diol was derived from 44 via based-induced oxa-ring opening of benzyl 6- endo-(4-chlorophenylsulfonyl)-1,3- endo-5- endo-trimethyl-7-oxabicyclo[2.2.1]hept-2- endo-yl ether ( 49 ). Benzylation of 28 , followed by reductive desulfonylation and oxidative cleavage of the cyclohexene moiety afforded (2 RS,3 SR,4 RS,5 RS)-3,5-bis(benzyloxy)-2,4-dimethyl-6-oxoheptanal ( 32 ). 相似文献
6.
Abstract Two kinds of ganglioside GM 4 thioanalogs having different fatty acyl groups at the ceramide moiety, (2 S, 3 R, 4 E)-1- O-[3- S-(5-acetamido-3,5-di-deoxy- D- glycero-α- D- galacto-2-nonulopyranosylonic acid)-3-thio-β- D-galacto-pyranosyl]-2-octadecanamido (or -tetracosanamido)-4-octadecene-1,3-diol ( 12, 13), have been synthesized. Condensation of the trichloroacetimidate 7, derived from 1,2,4,6-tetra- O-acetyl-3- S-(methyl 5-acetamido-4,7,8,9-tetra- O-acetyl-3,5-dideoxy- D- glycero-α- D- galacto-2-nonulopyranosylonate)-3-thio-β- D-galactopyranose ( 6) by selective 1- O-deacetylation and subsequent trichloroacetimidation, with (2 S, 3 R, 4 E)-2-azido-3- O-benzoyl-4-octadecene-1,3-diol ( 4), gave the coupling product ( 8), which was converted into the title compounds via selective reduction of the azide group, condensation with fatty acids, and removal of the protecting groups. 相似文献
7.
( Z)-1,6-Anhydro-3-deoxy-4-methylsulfanyl-3-[(methylsulfanyl)methylene]-β- D- erythro-hexopyranos-2-ulose ( 1) reacted with diethyl malonate, 1,3-diketones, N-aryl-3-oxobutyramides and dialkyl 3-oxoglutarate, respectively, in the presence of potassium carbonate and crown ether to yield diethyl 2-(1,6-anhydro-4-methylsulfanyl— D- arabino-hex-2-ulopyranos-3-ylmethylene) malonate ( 2), 1-{(1 R,2 S,8 S,9 R)-2-hydroxy-4-methyl-8-methylthio-3,11,12- trioxatricyclo7.2.1.0 2,7dodeca-4,6-dien-5-yl} ethanone ( 3), (1 R,2 S,12 S,13 R)-2-hydroxy-12-methylthio-3,15,16-trioxatetracyclo[11.2.1. 0 2,11. 0 4,9] hexadeca- 4(9),10-dien-8-one ( 4), (1 R,8 S,9 R)-5-acetyl-3-aryl-8-methylthio-11,12-dioxa- 3-azatricyclo-[7.2.1.0 2,7]dodeca-2(7),5-dien-4-ones ( 5, 6) and dialkyl (1 R,8 S,-9 R)-4-hydroxy-8-methylthio-11,12-dioxatricyclo[7.2.1.0 2,7]dodeca-2(7),3,5-triene-3,5-dicarboxylates ( 7, 8), respectively. 相似文献
8.
Preparations of dimethyl (1 RS,2 SR,4 RS,5 SR,6 SR,7 RS)- and dimethyl (1 RS,2 SR,4 RS,5 SR,6 RS,7 SR)-8-oxa-3-azatricyclo[3;2.1.0 24] octane-6,7-dicarboxylate 15 and 18 , resp.) and of their N-(tert-butyloxy)carbonyl ( 14 , 17 ) and V-benzoyl ( 16 , 19 ) derivatives are described. While treatment with nucleophilic acids (HCl, HBr. A cOH) of the exo, exo-diesters 14 and 16 gave the corresponding products 23–27 of aziridine trans -addition, the exo, endo -diesters 17 and 19 led to the corresponding amino-lactones 63 (methyl (1 RS,2 RS,3 SR,6 RS,7 SR,9 RS)-2-{[(tert-butyloxy)carbonyl] amino}-5-oxo-4,8-dioxatricyclo[4.2.1.0 37] nonane-9-carboxylate) and 64 (methyl (1 RS,2 RS,3 SR,6 RS,7 SR,9 SR)-2-(benzoylamino)-5-oxo-4,8-dioxatricyclo[4.2.1.0 3′7] (nonane-9-carboxylate). Under non-nucleophilic acidic conditions, the N-benzoylaziridine 16 was rearranged quantitatively into dimethyl (1 RS,2 SR,26 SR,67 SR,7 SR,8 SR,9 SR)-4-phenyl-5,10-dioxa-3-azatricyclo[4.3.1.0 2′7] dec-3-ene-8,9-dicarboxylate( 31 ), and 19 into dimethyl (1 RS,2 SR,26 SR,67 SR,7 SR,8 SR,9 SR)-4-phenyl-3,10-dioxa-5-azatricyclo [5.2.1.0 2′6] dec-4-ene-8,9-di-carboxylate ( 65 ). Possible mechanisms of these highly selective reactions and rearrangements are discussed. 相似文献
9.
Summary Different functionalized alkyl 3-oxo-butyrates ( 2) were reacted with 5-amino-3- Q-1 H-1,2,4-triazoles ( 1) to yield 3 and 4 type 1,2,4-triazolo[1,5-a]pyrimidinones. In case of 2 ( R
1=methyl, R
2=1-ethoxycarbonylethyl, R
3=ethyl) beside the corresponding derivative 4 the unexpected 5,6-dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-methylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9 H)-one ( 7) was isolated, representing a novel ring system.
Über Triazole, 19. Mitt.: Die Reaktion von 5-Amino-1,2,4-triazolen mit funktionalisierten Acetoessigestern Zusammenfassung Verschiedene funktionalisierte 3-Oxo-buttersäurealkylester (2) wurden mit 5-Amino-3-Q-1H-1,2,4-triazolen (1) umgesetzt, wobei 1,2,4-Triazolo[1,5-a]pyrimidinone der Typen3 und4 erhalten wurden. Im Fall von2 (R
1=Methyl,R
2=1-Ethoxycarbonylethyl,R
3=Ethyl) wurde neben dem erwarteten Derivat4 das unerwartete 5,6-Dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-me-thylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-on (7) isoliert, welches ein neues Ringsystem darstellt. 相似文献
10.
1,3-Skeletal rearrangement of N-substituted ketimines via a possible intimate ion pair is discussed. (CH 3) 3SiCH=C=O ( 1) reacts with N-(aziridinyl)-triphenylphosphinimine ( 2) to give N-(1-aziridinyl)-2-trimethylsilylketen-1-imines ( 3). The compounds 3 b, c are thermally labile and do not undergo 1,3-rearrangement but a retro-ene type reaction to yield (CH 3) 3SiCH 2CN and 2,3-diphenyl-2 H-azirine ( 4). Diphenylketene ( 5) reacts with N-(N, N-dialkylamino)-triphenylphosphinimines ( 6) to yield -(N-disubstituted-amino)-nitriles ( 7). , -Dimethyl--(triphenylphosphinimino)-acetonitrile ( 9) reacts with ( 5) at room temperature to form , -dimethyl--(2, 2-diphenylketen-1-imino)-acetonitrile ( 10) which rearranges at 80° to dimethyl diphenylsuccinonitrile ( 11). The reaction of 5 with 7-(triphenylphosphinimino)-7-azabicyclo[4.1.0]heptane ( 12) gives tetraphenylsuccinonitrile 13 and 7-(7-azabicyclo[4.1.0]heptane)-, -diphenylacetonitrile ( 14). Finally the synthesis of N-acylketenimines ( 16) from ( 5) and acyltriphenylphosphinimines ( 15) is reported.
38. Mitt.: Chr. Ivancsics und E. Zbiral, Mh. Chem. 106, 839 (1975). 相似文献
11.
Stereoselective Synthesis of 5a-Ethyl-1,2,3,3a,4,5,5a,6,9a,9b-decahydro- 1,3,4-trihydroxy-3a-(hydroxymethyl)-7H-benz[e]inden-7-one Derivatives
Homochiral Diels-Alder cyclodimerization of (±)-6-ethenyl-7-oxabicyclo[2.2.1]hept-5-en-2- endo-ol ( 1 ) followed by oxidation gives (1 RS,4 RS,4a SR,4b SR,5 RS,8 RS,8a RS)-8a-ethenyl-1,3,4,4a,4b,5,6,8,8a,9-decahydro-1,4:5,8-diepoxyphenanthrene-2,7-dione ( 18 ). Selective hydrogenation followed by epoxidation produced (1 RS,4 RS,4a RS,5a RS,6a RS,7 RS,10 RS,10a SR,10b RS)-6a-ethyl-1,4,5a,6,6a,7,9,10,10a,10b-decahydro-1,4:7,10-diepoxyphenanthro[8a,9- b]oxirene-3,8-dione ( 21 ), which was solvolyzed (Me 3SiOSO 2CF 3, Piv 2O) with concomitant pinacol rearrangement involving an acyl-group migration to give a 6-oxo-7-oxabicyclo[2.2.1]hept-2-yl cation intermediate, which finally generated (1 RS,3 SR,3a RS,4 SR,5a RS,6 RS,9 RS,9a SR,9b SR)-5a-ethyl-1,4,5,5a,6,7,8,9,9a,9b-decahydro-7,10-dioxo-3 H-6,9-epoxy-1,3a-ethanonaphtho[1,2- c]furan-3,4-diyl bis(2,2-dimethylpropanoate) ( 24 ). Photo-reductive 7-oxa bridge opening of 24 , followed by water elimination and silylation, provided (1 RS,3 SR,3a RS,4 SR,5a SR,9a SR,9b SR)-7-{[( tert-butyl)dimethylsilyl]oxy}-5a-ethyl-1,4,5,5a,9a,9b-hexahydro-10-oxo-3 H-1,3-ethanonaphtho[1,2- c]furan-3,4-diyl bis(2,2-dimethylpropanoate) ( 34 ). Reduction of 34 with NaBH 4 in MeOH followed by desilylation and alcohol protection produced (1 RS,3 RS,3a RS,4 SR,5a SR,9a SR,9b SR)-5a-ethyl-2,3,3a,4,5,5a,6,7,9a,9b-decahydro-1,3-bis(methoxymethoxy)-3a-[(methoxymethoxy)methyl]-7-oxo-1 H-benz[ e]inden-4-yl 2,2-dimethylpropanoate ( 5 ), a polyoxy-substituted decahydro-1 H-benz[ e]indene derivative with cis-transoid- trans junction for the two cyclohexane and the cyclopentane rings bearing an angular 3a-(oxymethyl) substituent. 相似文献
12.
The enantiomers of the title compound, the important photochromic material ( RS)- 1b, have been enriched semipreparatively by liquid chromatography. As a consequence, we were able to determine the barrier of the thermal interconversion ( R)- 1b( S)- 1b via time-dependent polarimetry, amounting to ΔG ≠=85.9 kJ/mol at 22.0°C in d 6-DMSO (Table 2). The thermal equilibration of the corresponding merocyanine 2b was monitored in d 6-DMSO by time-dependent 1H NMR, resulting in ΔG 1≠=102.8 and ΔG 2≠=92.0 kJ/mol at 22°C (Table 1). This means that, starting from ( RS)- 1b, the opened isomer 2b is attained by a slow reaction (ΔG 1≠=102.8 kJ/mol, Fig. 4). Therefore, the merocyanine 2b cannot be identified with the intermediate required for the fast process of C( sp3)–O bond cleavage (ΔG ≠=85.9 kJ/mol) upon the above enantiomerization of ( RS)- 1b. Apparently, these two thermal isomerizations (Fig. 4) are independent of each other. The structure of the unknown intermediate of the interconversion ( R)- 1b( S)- 1b must therefore differ from the known one of merocyanine 2b. Table 1. Equilibration between spiro compounds ( RS)- 1 and merocyanines 2 at 22°C, measured by time-dependent UV absorptions[3] for ( RS)- 1a2a and by time-dependent 1H NMR intensities for the other compounds
Article Outline- 1. Introduction
- 2. Equilibration of the merocyanine 2b with the spiro compound (RS)-1b
- 3. Preparative separation and characterization of the enantiomers of the spiro compound (RS)-1b
- 4. Enantiomerization of the spiro compounds (R)- and (S)-1b
- 5. Discussion of the two different isomerizations investigated
- 6. Experimental
- 6.1. General methods
- 6.2. (±)-6-Nitro-1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline] 1b[43]
- 6.3. (+)436-6-Nitro-1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline] 1b
- 6.4. (−)436-6-Nitro-1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline] 1b
- 6.5. 4-Nitro-2-[(E)-2′-(1′′,3′′,3′′-trimethyl-3H′′′-2′′-indoliumyl)-1′-ethenyl]-1-phenolate 2b[19]
- Acknowledgements
- References
1. IntroductionMany derivatives of 1′,3′,3′-trimethylspiro[2 H-1-benzopyran-2,2′-indoline] 1a (Scheme 1) are of interest because of their photochromism.[2] The parent molecule 1a can be transformed photochemically into the merocyanine 2a which isomerizes thermally with a very high rate back to 1a.[3] Therefore, unsubstituted 1a has no practical value with respect to photochromism. This situation changes upon the introduction of a nitro group into the 6-position: the title compound 1b has probably been cited in the literature most often among all photochromic materials. The corresponding merocyanine 2b is obtained by irradiation and reverts to the equilibrium mixture (Scheme 1) consisting predominantly of the spiro compound 1b. The rate of isomerization of 2b is much lower than that of the 2a→ 1a reversal.[3, 4, 5, 6, 7 and 8] Although analogs have now been found which are more stable to light than 1b, the latter has been significant for the development of practical applications of photochromism and continues to be significant for basic research,[2, 9 and 10] e.g. with respect to 1b chemically bonded to another molecule. A further nitro group in the 8-position again changes the properties: only a very small amount of the spiro compound 1c appears in the thermal equilibrium[11 and 12] ( Scheme 1) in dipolar aprotic solvents, which means that the observed photochromism is a reversible one with limited applicability. 相似文献
13.
Two d 10 transition-metal complexes having racemic and enantiomeric 1,2,2-trimethylcyclopentane-1,3-diamine ligands, [Zn(L a) 2](NO 3) 2 · CH 3CH 2OH ( 1) and [Cd(L b) 2Cl](ClO 4) ( 2) (L a = D,L-1,2,2-trimethylcyclopentane-1,3-diamine, L b = D-(+)-1,2,2-trimethylcyclopentane-1,3-diamine or ( 1R, 3S)-1,2,2-trimethylcyclopentane-1,3-diamine), were synthesized and characterized by X-ray single-crystal diffraction. They crystallize in the Pbca and P2 12 12 1 space groups, respectively, and have different coordination numbers and coordination geometry (four-coordinate tetrahedron for Zn(II) in 1 and five-coordinate square-based pyramid for Cd(II) in 2) mainly due to their different ionic radii. 相似文献
14.
Summary 2-(1-Acetoxyalkylidene)- and 2-(1-acetoxybenzylidene)-1,3-indanediones ( 1a–1e) were proven to be the products of acetylation of 2-acyl-1,3-indanediones ( 2a–2e) by ketene using a detailed investigation and correlation analysis of infrared spectral data as well as 1H-NMR and 13C-NMR spectra. Study by means of CNDO/2 and MMPI methods also demonstrates that the structure 1 is more stable as the alternative one of 2-acyl-3-acetoxy-2-indene-1-ones ( 5). It was shown that the recently proposed general correlations v(C=O) s vs. v(C=O) as and v(C=O) vs. X +(R) as well as the mechanical anharmonicities of asymmetric C=O stretching vibration can be successfully used as a tool of structural diagnostics of cyclic 1,3-dicarbonyl compounds.
Strukturaufklärung von Acetylierungsprodukten von 2-Acyl-1,3-indandionen mittels Korrelation von Infrarot-Daten Zusammenfassung 2-(1-Acetoxyalkyliden)- und 2-(1-Acetoxybenzyliden)-1,3-indandione (1a–1e) wurden mittels einer detaillierten infrarot-spektroskopischen Untersuchung (IR-Korrelation) und1H-NMR und13C-NMR Spektroskopie als Acetylierungsprodukte von 2-Acyl-1,3-indandionen (2a–2e) mit Keten nachgewiesen. CNDO/2- und MMPI-Rechnungen zeigten auch, daß Struktur1 stabiler ist, als die der alternativen 2-Acyl-3-acetoxy-2-inden-1-one5. Es wird gezeigt, daß die kürzlich vorgeschlagenen allgemeinen Korrelationen v(C=O)s gengen v(C=O)as und v(C=O) gegen X
+(R) und auch die mechanischen Anharmonizitäten der asymmetrischen C=O Streckschwingung erfolgreich als Werkzeug zur Strukturaufklärung cyclischer 1,3-Dicarbonyl-Verbindungen eingesetzt werden können. 相似文献
15.
Three polyether complexing agents were prepared whose shapes could be photochemically altered by means of an azobenzene fragment incorporated into the middle of the polyether chain. The compounds are 1, bis-4,4-[2-(methoxyethoxy)acetamido]azobenzene, 2, bis-4,4-[2-(1,3-dimethoxy-2-propoxy)acetamido]azobenzene and 3,bis-4,4-{2-[2-(2-methoxyethoxy)ethoxy]acetamido}azobenzene. Extraction equilibrium constants, K
EXT, for the extraction of Li +, Na + K +, and Cs + ions from water into an organic solvent were measured for these three agents under irradiation and in the dark. Compounds 1 and 2 were found to give substantially larger KExT values on irradiation than in the dark. The K(light)/ K(dark) ratios for the three compounds ranged from 0.47 to 16.6.For part 2 see ref. [1] 相似文献
16.
Starting from (±)-7-oxanorbornenone ((±)- 14), (±)-(1 RS,2 RS,3 SR,6 SR)-6-azidocyclohex-4-en-1,2,3-triol ((±)- 24) and (±)-(1 RS,2 RS,3 SR,6 RS)-6-azidocyclohex-4-en-1,2,3-triol ((±)- 26) were obtained. Epoxidation of the latter cyclohexene derivative gave two epoxides (±)- 30 and (±)- 31 that were converted into (±)-conduramine F-1 epoxides (±)- 10 and (±)- 11 and N-substituted derivatives (±)- 12 and (±)- 13. Compound (±)-(1 RS,2 SR,3 RS,4 SR,5 RS,6 SR)-5-({[4-(trifluoromethyl)phenyl]methyl}amino)-7-oxabicyclo[4.1.0]heptane-2,3,4-triol ((±)- 12c) is a good, non-competitive inhibitor of β-xylosidase from Aspergillus niger ( Ki=2.2 μM), and (±)-(1 RS,2 RS,3 SR,4 RS,5 SR,6 SR)-5-{[(biphenyl-4-yl)methyl]amino}-7-oxabicyclo[4.1.0]heptane-2,3,4-triol ((±)- 13d) is a good inhibitor of α-glucosidase from brewer's yeast ( Ki=2.8 μM, non-competitive). 相似文献
17.
The crystal structures of two binuclear complexes between caesium and 1,3-calix[4]- bis-crowns have been determined. Cs 2
Bis-benzoC6(NO 3) 2. 3CHCl 3 ( 1) in which Bis-benzoC6 is 1,3-calix[4]- bis-benzo-crown-6, crystallizes in the orthorhombic system: space group Pca2
1 a=19.513(10), b=15.382(5), c=23.708(9) Å, V=7116(5) Å 3, Z=4. Refinement led to a final conventional R value of 0.065 for 2321 reflections. The structure of ( 1) is analogous to those already reported with Bis-C6, (in which Bis-C6 is, 1,3-calix[4]- bis-crown-6) and NO
3
–
as a counter-ion. Cs 2
Bis-C6(NCS) 2 ( 2) crystallizes in the monoclinic system: space, group C2 a=36.57(2), b=11.47(1), c=13.65(1) Å, =109.03(5)°., V=5415(6) Å 3, Z=4. Refinement led to a final conventional R value of 0.063 for 2227 reflections. Compound ( 2) is made of dimers bridged by a disordered NCS – ion. The crown ether chain conformations are discussed.
Supplementary data relating to this article (atomic coordinates, anisotropic displacement parameters, bond distances and angles and observed and calculated structure factors) are deposited with the British Library as Supplementary Publication No. SUP 82199 (52 pages). 相似文献
18.
Summary The reactivity of cyanomethylene-indolones ( 1 a–e) and 2-(dicyanomethylene)-indan-1,3-dione ( 4) towards 1,5-disubstituted 3-pyrazolones ( 2 a–c) was investigated. The reactions yield spiro[indene- and spiro[indole-4- and 6-pyrano[2,3-c]pyrazoles] ( 3 a–e, 5 a–c). The structures are proven by 13C-NMR-spectroscopy. The mechanisms of the reactions are discussed. 相似文献
19.
3-Oxo-1,3-oxathiane ( 1) and its monomethyl derivatives were prepared by oxidation of the corresponding 1,3-oxathianes. The structural analysis was carried out by 1H and 13C NMR, FTIR, and mass spectrometry. At 298 K compound 1 was a 1 1 (at 173 K a 3 1) mixture of the SO(ax) and SO(eq) chair forms. The major oxidation products of methyl 1,3-oxathianes attained exclusively the SO(ax), Me(eq) chair forms except that of the 5-methyl derivative, which consisted of 7% of the SO(eq), Me(ax) chair conformation in CDCl 3 solution. The minor products of oxidation existed in anancomeric SO(eq), Me(eq) chair conformations. The oxidation of 2-methyl- 1,3-oxathiane, however, led to 3,3-dioxo derivative ( 6) in addition to the trans [SO(eq)] monoxide. The crystal structures of 6 and trans-3-oxo-5-methyl-1,3-oxathiane were solved by X-ray diffractometry. 相似文献
20.
Mono and bis tricarbonylchromium complexes of diphenic acid and its monomethylester ( 3, 4, 15, 16) were prepared by treating the corresponding methyl and trimethylsilylesters (e.g. 12) with Cr(CO) 6 and subsequent hydrolysis of the complexes 1, 2, 13, and 14. Diborane reduction of the carboxylic acids gave hydroxymethyl derivatives, amongst which the diol 8 a is a key substance for configurational analyses by 1H-nmr and ir spectroscopy. In this context monosubstituted biphenyl complexes ( 9–11) were prepared as reference substances. Complexation of the lactone 23 of 2-hydroxymethyl biphenyl-2-carboxylic acid afforded (besides two isomeric monocomplexes) mainly the trans-biscomplex 26 b, a key intermediate for ring opening and cyclization reactions.The stereochemical possibilities of the biscomplexes are discussed. The racemate configuration is preliminarily assigned to diphenic acid bistricarbonylchromium and its derivatives. 2. Mitt.; 1. Mitt.:K. Schlögl undR. Schölm, Mh. Chem.109, 1227 (1978). 相似文献
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