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1.
The synthesis of N-benzoyl-L-daunosamine (14) from the C4threo aldehyde (2b), prepared from D-threonine, through the intermediacy of the C7 adduct (7a) is reported  相似文献   

2.
Contrary to the precedents, 1,3-anti stereoselection was found in the intramolecular Michael addition of ethyl threo,5-carbamoyloxy-4-trialkylsilyloxy-2-hexenoate to culminate in a synthesis of N-benzoyl-D,L-daunosomine. The antiperiplanar effect due to the group at 4-position was revealed to play a major role in the stereoselection in this type of reactions. N-benzoyl-D,L-3-epidaunosamine was also synthesized by 1,2-syn asymmetric induction.  相似文献   

3.
The enantiomeric alcohols (2) and (11), obtained from (2R,3R) tartaric acid and, respectively, L-threonine, have been used to construct the C6, enantiomeric deoxy amino sugar derivatives (7) and (12)  相似文献   

4.
2-0-(α-D-Mannopyranosyl)-L-gulopyranose, the sugar portion of bleomycin has been synthesized.  相似文献   

5.
The 1H and 13C nmr spectra of exo, exo-9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d6 or alkaline D2O, clearly show that it exists in a boat-chair-conformation with equatorial carboxyl groups, thus being the first case of boat-chair preference of a bicyclo[3.3.1] nonan-9-one due to the presence of exo,exo-2,4- substituents.  相似文献   

6.
J Leitich 《Tetrahedron letters》1980,21(32):3025-3028
The relative rates of formation of cis and trans [2+2]cycloadducts of benzyne to cis, trans- and cis, cis-1,5-cyclooctadiene, trans- and cis-cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described.  相似文献   

7.
1,3,7,9,11,12,14-Heptazapentacene-2,4,8,10 (14H,3H,9H,12H)-tetraones (mixed flavins) were prepared by the cyclization of 1,5-dihydro-8-[N-alkyl-N-(5-nitrouracil-6-yl)-amino-5-deazaflavins with Vilsmeier reagent. The mixed flavins oxidized alcohol under neutral condition in sunlight and a remarkable autorecycling was observed.  相似文献   

8.
13C-NMR spectral data on 6-aminohexyl glycosides of O-β-D-galactopyranosyl-2-acetamido-2-deoxy-β-D-glucopyranose are pr  相似文献   

9.
The synthesis of N-benzoyl-L-ristosamine (7) from natural tartaric acid through the intermediacy of the δ-xylo and γ-ribo lactones (4) and (6) is reported.  相似文献   

10.
Kenji Mori  Hideto Mori 《Tetrahedron》1985,41(23):5487-5493
(1S,5R)-(-)-Karahana ether (8,8-dimethyl-2-methylene-6-oxabi-cyclo[ 3.2.1]octane) and (1S,5R)-(-)-karahana lactone (8,8-dimethyl-2-methylene-6-oxabicyclo [3.2.1]octan-7-one) were synthesized from (S)-3-hydroxy-2,2-dimethylcyclo-hexanone. The natural karahana lactone was shown to be almost racemic (ca. 1.3 % e.e.).  相似文献   

11.
(1R,3R,5S)-1,3-Dimethyl]-2,9-dioxabicyclo[3.3.1]nonane 1 has been stereoselectively synthesized based on a highly stereoselective method for the synthesis of 1,3-syn-polyol.  相似文献   

12.
Two steroids, 3-oxo-chol-4-ene-24-oic acid (2) andi ts unsaturated analog 4 have been isolated from the dorid nudibranch Aldisasanguineacooperi, and the acid 2 has been shown to have antifeedant properties.  相似文献   

13.
We describe a short synthesis of (S)-5-hydroxymethyl-(5H-furan-2-one and some 5-O-derivatives, which are being used as key starting products for the synthesis of several antileukaemic lignan lactones, from D-ribonolactone.  相似文献   

14.
A shorter synthesis of 5-thio-D-glucose is described in 8 steps from commercially available D-glucofurano-3,6-lactone.  相似文献   

15.
Sterepolide and dihydrosterepolide, new sesquiterpenes isolated from the fungus Stereumpurpureum, are assigned structures 4 and 7, respectively. The assignments are based mainly on spectroscopic studies and similarities to isolactarorufin (5). A possible mode of biogenesis of these isolactarane type sesquiterpenes is discussed.  相似文献   

16.
A novel olefin metathesis sequence permits ready access to functionalised cis, syn, cis-tricyclo [6.3.0.02,6] undecane based bis-enones. These bis-enones have been shown to undergo cage cyclisation in sunlight with remarkable ease and efficiency.  相似文献   

17.
A range of conjugated Z,Z-dienes have been prepared in a stereo-specific manner via acetylene carbocupration: the value of this procedure has been illustrated by an extremely short synthesis of hexadeca-11Z, 13Z-dienal a principle component of Navel Orangeworm Pheromone.  相似文献   

18.
The C4erythro and threo diols (7) and (8) are converted either into the chiral epoxides (13) and (15) or into the enantiomers (14) and (16); the epoxide (13) is used as chiral synthon for the preparation of (3S,4S) 4-methyl-3-heptanol (21).  相似文献   

19.
Alkylation of dibutylstannylene complexes of 3,4,6-tri-O-benzyl-D-mannopyranose, methyl 6-O-trityl-α-D-mannopyranoside and methyl α-D-mannopyranoside gives respectively β-D-mannopyranoside and 3-O-alkyl derivatives with high selectivity.  相似文献   

20.
Treatment of halo-F-methylphosphonium salts with potassium fluoride and halogen (I2, Br2, ICl, IBr) gives modest yields of halo-F-methanes. This method of preparation augments the classical Hunsdiecker approach to these materials.  相似文献   

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