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1.
1-Dephospho E. coli lipid A () was synthesized and shown to be identical with the corresponding derivative isolated from bacterial cells. This provides the unequivocal evidence supporting the structure of E. coli lipid A () recently proposed by us. 相似文献
2.
A synthesis of (2S,3S,7S)-3,7-dimethylpentadecan-2-yl acetate () and propionate () is described. (2S)-2-Methyldecan-1-yl lithium () was reacted with (3S,4S)-3,4-dimethyl-γ-butyrolactone () to yield the ketoalcohol which upon Huang-Minlon reduction furnished (2S,3S,7S)-3,7-dimethylpentadecan-2-ol (). Acylations gave the esters and . The (2S)-2-methyldecan-1-yl lithium was obtained via asymmetric synthesis. The chiral lactone was obtained from (2S,3S)-trans-2,3-epoxybutane and dimethyl malonate. 相似文献
3.
Martine Bonin José R Romero David S Grierson Henri-Philippe Husson 《Tetrahedron letters》1982,23(33):3369-3372
The cis 2,6-dialkylpiperidine alkaloid (±) dihydro-pinidine and the trans alkaloid (±) solenopsin A were synthesized from a common α-aminonitrile synthon . The key step in this synthesis was the stereoselective reductive decyanation of the 1-benzyl-2cyano-2′, 6-dialkylpiperidines and . 相似文献
4.
M. Imoto S. Kusumoto T. Shiba E.Th. Rietschel C. Galanos O. Lüderitz 《Tetrahedron letters》1985,26(7):907-908
The chemical structure of E. coli lipid A was elucidated to be by determination of the nature of the individual acyl groups bound to the two hydroxyl groups in positions 3,3′ and the two amino groups of the D-glucosamine disaccharide phosphate backbone. 相似文献
5.
Masaru Inage Haruyuki Chaki Shoichi Kusumoto Tetsuo Shiba 《Tetrahedron letters》1980,21(40):3889-3892
6-O-(2-Deoxy-2-myristoylamino-6-O-myristoyl-β-D-glucopyranosyl)-2-deoxy-2-myristoylamino-3,4-di-O-myristoyl-D-glucopyranose () was prepared in a synthetic approach to lipid A which is the active center of bacterial endotoxin. 相似文献
6.
Biogenetic-type synthesis of (±)-dictyopterene A () was achieved employing 1,-5-undecadien-3-ol () postulated to be a biosynthetic intermediate of : this synthesis means that transformation of dictyoprolene () into dictyopterene A () was formally made. 相似文献
7.
A tritriacontanucleotide which has the sequence of the 5half molecule of E.coli glycine tRNA2, was synthesized by the phosphotriester method involving p-anisidate protection for the 3phosphate ends. Di- and trinucleotide units were prepared from 5dimethoxytrityl-2O-tetrahydrofuranyl-3?-O-(o-chlorophenyl)phosphoryl derivatives of uridine, N-benzoylcytidine, N-benzolyadenosine and N-iso-butyrylguanosine by condensation with 35unprotected nucleosides followed by phosphorylation to give 3phosphodiester blocks. The 3terminal dimers and trimers were synthesized by using 3(o- chlorophenyl)phosphoro-p-anisidates instead of 3?,5?-unprotected nucleosides. The 3?-phosphodiesters of oligonucleotides with a chain length of larger than 5 were obtained by removal of the 3?-phosphoro-p-anisidate with isoamyl nitrite. The 5dimethoxytrityl group was removed by treatment with zinc bromide under anhydrous conditions. Fragments were designed to use common dimer blocks and to reduce the step for 5deblocking of larger fragments. Finally a 3phosphodiester block with a chain length of 20 was condensed with a 5OH component (tridecanucleotide). The fully protected 33 mer was deblocked and purified by chromatography. The structural integrity of the product was confirmed by mobility shift analysis and complete digestion with RNase T2. 相似文献
8.
A new synthesis of (±), (+)- and (-)-lineatin (3,3,7-trimethyl-2, 9-dioxatricyclo [3.3.1.04,7] nonane, ) was achieved. The stereochemistry of (+)-lineatin was established as 1, 4, 5, 7 by an X-ray crystallographic analysis of an intermediate . 相似文献
9.
Methyl 5(S), 6(S)-oxido-11-oxo-7-cis-9-trans-undecadienoate was prepared and used for the synthesis of the novel 7-cis-LTD4 () as well as, after isomerization to the all-trans dienal ester , for that of the natural leukotrienes. 相似文献
10.
A general route for synthesis of 6--alkyl-2∝deoxyguanosine nucleosides is described. The key step is conversion of the 6--TPS derivative to the 6-trimethylamino compound . The trimethylamino group is readily displaced by alcohols in the presence of DBU. Using this route the 6--methyl, ethyl and n-butyl 2∝-deoxyguanosine derivatives have been prepared in excellent overall yields. 相似文献
11.
A total synthesis of the novel steroids DL-14α-methylestradiol () and DL-14α-methyl-19-nortestosterone () via cationic cyclization is described. Advantage was taken of the unusual stereoselectivity of Mo(CO)6/-BuOOH epoxidations. 相似文献
12.
G. Eulenberger 《Journal of solid state chemistry》1984,55(3):306-313
The new compound Tl6[Ge2Te6] was prepared by thermal synthesis from the elements. The material is triclinic, space group , with a = 9.471(2), b = 9.714(2), c = 10.389(2) Å, α = 89.39(1), β = 97.27(1), γ = 100.79(1)°, and Z = 2. The crystal structure was determined from single-crystal intensity data measured by means of an automated four-circle diffractometer and refined to an R value of 0.053 for 1831 observed reflections. Tl6[Ge2Te6] is characterized by Ge2Te6 units with GeGe bonds which are linked into a three-dimensional structure by Tl atoms coordinated to essentially six Te atoms. The most important mean distances are Å, Å, and Å. The lone 6s electron pairs of the thallium(I) atoms exhibit significant stereochemical activity. Tl6[Ge2Te6] represents a new structure type. 相似文献
13.
Matsuhiko Aratani Hideo Hirai Kozo Sawada Akira Yamada Masashi Hashimoto 《Tetrahedron letters》1985,26(2):223-226
A new, efficient synthesis of the optically active carpetimycins from penicillins has been achieved via, as key steps, aldol reaction of isonitrile , followed by n-Bu3SnH reduction. 相似文献
14.
A shorter synthesis of 5-thio--glucose is described in 8 steps from commercially available -glucofurano-3,6-lactone. 相似文献
15.
A total synthesis of the natural enantiomer of the title compound was accomplished, which confirmed the structure proposed for the fruiting-inducing cerebroside of . 相似文献
16.
An efficient, highly stereoselective synthesis of (1,3)--chrysanthemic acid 6 is described. The crucial step of this synthesis was the microbiological reduction of dione 1 into ()-ketol 2. 相似文献
17.
A stereospecific, highly efficient, generally applicable synthesis of - and -1-alkoxy-1,3-butadienes involving dehydrative decarboxylations of 4,5-unsaturated-2-alkoxy-3-hydroxy-carboxylic acids is described. 相似文献
18.
Jiro Tsuji Hiroshi Okumoto Yuichi Kobayashi Takashi Takahashi 《Tetrahedron letters》1981,22(14):1357-1358
A simple total synthesis of 18-hydroxyestrone () was carried out by the cycloaddition of o-quinodimethane intermediate. 2-Methoxycarbonyl-3-vinyl-cyclopentanone () was used as the D ring component. 相似文献
19.
The acid catalysed rearrangement of 8-methyl-pentacyclo(5.4.0.02,6.03,10.05,9)undecan-8-endo-o1 () to 3-methyl-(D3)-trishomocuban-4-o1 () provided the key step to the synthesis of the title compound (). 相似文献
20.
A range of conjugated ,-dienes have been prepared in a stereo-specific manner acetylene carbocupration: the value of this procedure has been illustrated by an extremely short synthesis of hexadeca-11, 13-dienal a principle component of Navel Orangeworm Pheromone. 相似文献