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1.
The stereospecific syntheses of the eleven racemic 2,2, exo-3-trimethyl-exo-5-norbornyl-cyclohexanols related to the formula VI have been achieved. Moreover, the fragrant properties of these isomeric and stereomeric cyclohexanols have been carefully estimated by a team of four well-experienced perfumers. In good agreement with our earlier observations [1 ab], it was concluded that the axial 3-(2,2, exo-3-trimethyl-exo-5-norbornyl)-cyclohexanols, threo (XXIV) and erythro (XXIX), are the only isomers which display a very powerful and genuine sandalwood odour. The other cyclohexanols were found to be about 20–100 times less fragrant (4 compounds), or practically odourless (5 compounds).  相似文献   

2.
Partial Synthesis and Oncostatic Properties of Pseudotubulosines, Analogues of Emetine and Tubulosine Pseudotubulosines, structural analogues of emetine and tubulosine, have been synthesized by either Pictet-Spengler or Bischler-Napieralski condensation from dihydrocorynantheal or corynantheidal. Spectral data, cytotoxic and oncostatic properties of these new alkaloids are described.  相似文献   

3.
Diglycosyl Derivatives. Preliminary communication Novel types of diglycosyl compounds, some of them bearing a resemblance to natural di- or tri-saccharides are described: a diglycosyldiyne ( 1 ), a diglycosylthiophene ( 2 ), a diglycosylaziridine ( 3 ), a diglycosyldioxolane ( 4 ), as well as six C,N-diglycosylnitrones, 9b–9f and 14 . These C,N-diglycosylnitrones, on treatment with an acetylenic Grignard reagent, led to the expected acetylenic diglycosyl-hydroxylamine 11 , whereas diglycosylisoxazolines (f. ex. 10 ) were obtained when these nitrones underwent 1,3-dipolar cycloaddition to acetylenic compounds.  相似文献   

4.
The qualitative and quantitative isotopic analysis of mixtures of nuclear isomers of ethanol C2H5–nDnOH is described. The samples are obtained by reduction reactions and in each of them an isomer is markedly predominant. After a mass spectrometric determination of the amount of isotopic species with the same overall deuteration, these species are identified by proton and deuteron NMR, by combining the spectral schemes of all the isomers which can be assumed until agreement is reached with experimental spectra; isotope effect on δ is taken into account. The importance of the isotopic varieties are then determined by integrating some characteristic lines, with variable accuacy. For each sample, the total intensities of methyl and methylene signals are also compared in proton and deuteron resonance. By elevating the temperature of the sample, one can see the fine structure of a methylene signal broadened by the deuteron quadrupole relaxation.  相似文献   

5.
The synthesis of branched-chain sugars of the gem-hydroxy-formyl and the gem-hydroxy-hydroxymethyl types is described. A 5-deoxy-1,2-O-isopropylidene-furanos-3-ulose is treated with cyanomethylene-triphenyl-phosphorane, yielding the two geometrical isomers of the corresponding branched-chain unsaturated sugar. Cis-dihydroxylation(KMnO4) of these cyanomethylenic compounds affords stereoselectively and in high yield the gem-hydroxy-formyl branched chain sugars whose formyl group is on the more hindered face of the furanose ring. The hydroxymethyl analogues of the latter compounds are readily prepared by their borohydride reduction. This method constitutes a new general route to type A branched-chain sugars epimeric at the branching-point with the sugars which would have been obtained by the classical procedure involving Grignard reagents.  相似文献   

6.
A 1H and 13C n.m.r. study of heterocyclic azines is presented and the influence of Z/E isomerism on the 13C chemical shifts is examined. The kinetic study of the formation and Z/E isomerization of these compounds has been carried out and mechanisms of these reactions are discussed.  相似文献   

7.
Synthesis of Terminal Acetylenic Sugars Derivatives and Ynuronic Acids Derivatives by Use of a Wittig Reaction The method described for the preparation of terminal acetylenic sugars presents two advantages over earlier procedures: no new asymmetric center is created and the chain can be extended by one or more C-atoms. The method also allows preparation of ynuronic acids. The aldehydosugars derivatives 1–7 gave in good to excellent yields the corresponding gem-dibromoenoses 8–14 from which either the terminal acetylenic sugars derivatives 15–21 or the ynuronic acids 22–24 were easily prepared. A few examples of 1,3-dipolar cycloadditions (leading to 28–30 ) with these acetylenic sugar derivatives are also described.  相似文献   

8.
Thirty-two sterols are identified in the sponge Hyrtios sp. In addition to fourteen monohydroxylated compounds, the sterol fraction contains eight functionalized sidechain sterols, three of them new: 3 β-hydroxy-24-norchol-5-en-23-al (19) , (22-trans)-3 β-hydroxycholest-5, 22-dien-24-one (20) and (22R, 23R, 24S) or (22S, 23S, 24S)- 22,23-epoxy-24-methylchoest-5-en-3 β-ol (24). The probable biological origin, rather than artifact production, of these undescribed components is discussed.  相似文献   

9.
Deconjugation of sugars enones. Preliminary Communication Branched-chain sugar enones 1 and 2 ( R = Ac) deconjugated toposelectively (only the E isomers reacting) to 3 . The same phenomenon was noted in the case of Z- 4 which gave E- 5 . The kinetic parameters of these reactions favored a concerted mechanism, i.e. a [1, 5]-sigmatropic shift.  相似文献   

10.
Synthesis of Novel Types of C-Glycosyl-derivatives from Acetylenic Sugars or Partial Synthetic Equivalents thereof The concept of synthetic equivalent is not unequivocal and, for example, α-fluoroenamines may behave in some cases as synthetic equivalents of ynamines and, in other situations, quite differently. Some uses of these α-fluoroenamines, ‘partial synthetic equivalents’ of ynamines, for the synthesis of C-glycosyl derivatives of coumarins, chromones, quinolines, quinolones, thietenes and isoxazoles are described. We also report the preparation of a series of mono- and diglycosylthiophenes by reacting HS? with mono- and diglycosylbutadiynes. Acetylenic sugar derivatives have also been used for the synthesis of a diglycosylazaphosphorine and a spirooxolenone.  相似文献   

11.
The sodium salt Na2[Os(CO)4] has been obtained in high yields by the reduction of either OsH2(CO)4 or Os3(CO)12 with sodium sand in the presence of catalytic amounts of 2, 2′-bipyridyle. The reaction of Na2[Os(CO)4] with alkylating agents such as methyl and ethyl iodide produces OsR2(CO)4 (R = CH3, C2H5). NMR. and IR. spectra indicate a cis-octahedral structure of symmetry C2v for these new alkyl compounds. Bromine breaks one osmium-carbon bond in cis-Os(CH3)2(CO)4 to give cis-OsCH3Br(CO)4, whereas in cis-Os(C2H5)2(CO)4 both ethyl groups are easily displaced by bromine to give cis-OsBr2(CO)4. Under CO pressure and at elevated temperature cis-Os(CH3)2(CO)4 is converted to Os(CO)5 and ethane. With cis-Os(C2H5)2(CO)4 two CO are inserted in osmium-carbon bonds to give . NMR. and IR. data suggest a cis-configuration for this derivative and the possibility of the presence of rotational isomers.  相似文献   

12.
Reaction of α-bromoisobutyrophenone on quinoline 1-oxide and isoquinoline 2-oxide in the presence of silver perchlorate leads to N-alkoxyquinolinium and isoquinolinium salts bearing a keto group in their alkoxyl chain. On treatment with secondary amines these salts are quantitatively converted to 2-benzoylquinoline and 1-benzoylisoquinoline. This conversion results from a decomposition analogous to the Katritzky mode A of the intermediate isoxazolo[2,3-a]quinolinium or isoquinolinium salts which are first formed by a Proton Abstraction Ring Closure sequence. These tricyclic intermediates have been isolated when 2,2,6,6-tetramethylpiperidine was used.  相似文献   

13.
Carbohydrate Derivatives Bearing a gem-Dihalogenoethenyl Group Treated with the appropriate Wittig reagent, aldehydosugar derivatives ( 1–13 ) led in good to excellent yields to the expected gem-difluoro, gem-chlorofluoro-and/or gem-dichloroenoses ( 14–29 ). Examples of their dibromo analogues had been previously described (see e.g. [1]) but the diiodo derivatives could not be isolated, The influence of the conditions on the yields is reported as well as spectroscopic properties (particularly the long-range 13C, 19F- and 1H, 19F-coupling constants) of these new enoses.  相似文献   

14.
The condensation of 1,5-diaminoimidazoles with ethyl aceto-acetate gives two types of compounds: imidazo[1,5-b]-1,2,4-triazepinones and imidazo[4,5-b]pyridinones. The structure of these compounds is demonstrated by rmn and mass spectroscopy. The formation of imidazo[4,5-b]pyridinones from imidazo[1,5-b]-triazepinones through a new transposition is also shown.  相似文献   

15.
Derivatives of new polydienic systems have been isolated. Two [2]benzothienophthalazines, nitrogenous analogues of unknown anthra[2,3-c]thiophens are described. A furo[3,4-g]-phtalazine and a thieno[3,4-g]phthalazine are isolated. These different compounds react with philodienes. The first tetraza-2,3,8,9-naphthacenes have been synthesized. Structures of these compounds are proved by chemical and spectrographical methods.  相似文献   

16.
Diamines react with 3-dimercaptomethylenecamphor giving either a bis-oxothioamide or a heterocyclic compound via in oxoaminothioamide intermediate. In this last reaction, there is cleavage of both C? S bonds. Similarly, diamines react with β-oxothioamides to produce the same heterocyclic derivatives. In these reactions, a transamination is involved and the carbonyl group of camphor is preserved. A distinctly different reaction occurs when the same camphor derivatives are treated with hydrazine; thioxo- alcoylamino- or arylaminoindazoles are then obtained. Ring closure occurs on the carbonyl carbon of the camphor molecule.  相似文献   

17.
O-Substituted derivatives of 2-(3,4-dihydroxyphenyl)indole have been synthesized from acetovanillone by various methods using hydroxyl protective groups such as benzene sulfonyl and methylsulfonyl. Thus these groups facilitate Fischer and Bischler indole synthesis. Moreover, selective O-demethylation and O-alkylation reactions are allowed. Finally, the already quoted protective groups may be easily removed to yield back the 2-(4-hydroxy-3-alkyloxyphenyl)indoles.  相似文献   

18.
Substitution reactions of 2-methylsulfonyl thiazolo[5,4-b]-pyridine (3) and 2-methylsulfonyl benzothiazole (10) by nucleophilic anionic reagents were studied. In N,N-dimethylformamide, at 20°, these reactions are fast, particularly with compound 3 . Also studied were the kinetics of the substitution by sodium methylate, and the pKa′s of the acidic compounds. This work allows the comparison of benzothiazole with its “7-aza” analog.  相似文献   

19.
Synthesis of Sugar Derivatives Bearing a Spiro Heterocycle via Nucleophilic Cyclization Treated with the 1,4-binucleophiles 1,2-diaminoethane, 2-aminoethanol, 2-aminoethanethiol, L -cysteine, o-phenylenediamine, o-aminophenol or o-aminothiophenol the ketosugar derivative 1 gave in good yields the corresponding spiro derivatives 2–8 . In each case, the reaction was stereospecific leading to the isomer bearing the N-atom on the endo face of the bicyclic starting material. Starting from the sugar enone 9 , the aromatic 1,4-binucleophiles led stereospecifically to the spirobenzo [b]-diazepine 10 , -oxazepine 11 or -thiazepine 12 . In one case, an imine (13) was isolated. As 13 cyclized to 6 , the intermediate formation of these kind of derivatives could be considered as a common step for all these reactions.  相似文献   

20.
1-Alkyl-2-(N-methylidenealkylamino)aziridines are obtained by the reaction of primary amines with either α-chloroacraldehyde or α-chlorocrotonaldehyde. Structural assignments are made by nmr spectroscopy. The thermal rearrangement of 1-alkyl-2-(N-methylidenealkylamino)-3-methylaziridines to pyrroles is described.  相似文献   

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