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1.
Chloromethyl phenyl sulfides underwent [4+ +2] type polar cyclo-additions with styrene, trans-stilbene, and phenylacetylene in the presence of stannic chloride to afford the thiochroman , and thiochromen derivatives . Under the same reaction conditions, N-allyl-α-chloro-α-(phenylthio)acetamide () gave the intramolecular cycloaddition product . 相似文献
2.
-2-Chlorostilbene undergoes uncatalyzed LiAlH4 reduction giving phenanthrene and -stilbene. An electron transfer radical mechanism is proposed. LiAlH4 induced isomerization of -stilbene produces -stilbene. 相似文献
3.
We have shown that low valent titanium reagents reductively couple α,α′ -bis-(trimethylsiloxy) sulfidees giving olefins in good yield. With unsymmetrical , mixed olefins are obtained suggesting an intermolecular pathway. Finally, we have demonstrated that -episulfide is quantitatively converted to -stilbene. 相似文献
4.
Condensation of 3-fluoro-2-butanone () with alkyl diethylphosphonoacetates () gave alkyl 4-fluoro-3-methyl-2-pentenoates (). Addition of bromine yielded alkyl-2,3-dibromo-4-fluoro-3-methylpentanoates () which were dehydrobrominated to alkyl 2-bromo-4-fluoro-3-methyl-2- pentenoates (). Since these compounds could not be hydrogenated to the desired alkyl 2-bromo-4-fluoro-3-methylpentanoates (), another route was taken. The esters were hydrogenated to alkyl 4-fluoro-3- methylpentanoates () which were converted to their carbanions. Treatment with bromine gave esters , and iodine gave alkyl 4-fluoro-2-iodo- 3-methylpentanoates (). Esters and were converted to alkyl 2-azido-4-fluoro-3-methylpentanoates () whose hydrogenation gave alkyl 2-amino-4-fluoro-3-methylpentanoates (). Hydrolysis afforded γ-fluoroisoleucine (). 相似文献
5.
Regio- and stereoselective methods are described for the synthesis of compounds possessing the stereochemistry of type , , , and from the aldehyde . 相似文献
6.
Treatment of , , and with methyllithium affords , ; , ; and respectively in serviceable yields carbenoid cyclization. 相似文献
7.
The synthesis of the 2,4,6-cycloheptatrienyl ketones – by two alternative routes is reported: Route 1): The adducts from the phenyl(trimethylsiloxy)-acetonitriles , known as “umpolung” reagents, and tropylium tetrafluoroborate are cleaved by triethylammonium fluoride to form the aromatic cycloheptatrienyl ketones –. Route 2): the phenyl, methyl, and cyclopropyl ketone (, , ) are prepared by treatment of the acid chloride with the corresponding organomanganese iodides RMnI (, , ). The Fe-catalyzed coupling reaction of the acid chloride with a Grignard reagent was also used for the preparation of ketone . 相似文献
8.
Reaction of ,,,-[9]annulene anion () with electrophiles (-) leads to substituted ,,,-1,3,5,7-cyclononatetraenes (-) which are precursors for the preparation of 10- and 10,10′-donor-substituted nonafulvenes (e.g. ). The influence of solvent and temperature on the 1H-nmr spectra of the nonafulvenes - has been investigated. 相似文献
9.
Warō Nakanishi Satoru Murata Yoshitsugu Ikeda Tadashi Sugawara Yuzo Kawada Hiizu Iwamura 《Tetrahedron letters》1981,22(42):4241-4244
The reaction of 2-methylselenobenzoic acid with 1,1′-carbonyldiimidazole followed by addition of t-butyl hydroperoxide gave cyclic selenuranes and , suggesting the intramolecular insertion of the neighboring selenium atom into the OO bond of t-butyl 2-methylselenoperoxybenzoate. In the reaction of 2-phenylselenobenzoyl chloride with t-butyl hydroperoxide, cyclic selenurane and the oxide were obtained. 相似文献
10.
Reaction of nerol () with thallium(III) perchlorate gave 6-oxabicyclo[3.2.1]octane derivatives () and (), and 6,9-dioxabicyclo[3.3.1]nonane derivatives () as the cyclization products. 相似文献
11.
The readily-obtained carbohydrate α-enones , and are converted into the four diastereomeric 2,4-di-C-methyl glycopyranosides ,,, which are chiral synthons for the four multistriatins -. 相似文献
12.
Condensation of 1,3-bis(trimethylsiloxy)-1-methoxybutadiene with the acid chloride 12 gave methyl olivetolate (). Condensation of with (+)-p-mentha-2,8-dien-1-ol gave methyl Δ1-tetrahydrocannabinolate () in 55% isolated yield. Alkaline hydrolysis of gave Δ-tetrahydrocannabinol (, Δ1-THC). The synthesis is patterned after the biogenesis of . 相似文献
13.
Reaction of azetidinone phosphoranes with aldehyde gave the olefins , which were converted into carbapenem esters 6 in 4 steps. Hydrogenation of gave the title compounds. 相似文献
14.
Roshantha A.S. Chandraratna Robert R. Birge William H. Okamura 《Tetrahedron letters》1984,25(10):1007-1010
The electronic absorption spectra of the four new 12---locked retinals (1a–1d) bearing 7-, 11- double bond geometries are described and compared with those of analogous 7-, 11--geometries (1e–1h) and parent retinals (2a-h). 相似文献
15.
Flash vacuum pyrolysis of -methylbenzyl chloride-,-2 gives benzocyclobutene-,-2. This finding indicates that the reaction involves net δ-elimination of hydrochloric acid. 相似文献
16.
A short and convenient synthesis of phosphatidyl-α-diglucosyldiglyceride (i.e. compound ) and two related Streptococci glycolipids (i.e. compounds and ) will be presented. 4',6'-Tetraisopropyl-disiloxane-1,3-diyl (TIPS) protected α-glucosyl diglyceride (i.e. compound ) turned out to be a suitable protected precursor. Thus, compound was selectively condensed with glucosyl bromide to afford . Removal of the protecting groups from gave glycolipid . The “dynamic” properties of the TIPS pro- tecting group were utilized to convert 4',6'-TIPS protected into 3',4'- TIPS protected derivative . Compound could then be condensed with either a stearoyl fatty acid or a phosphatidyl moiety to give the fully protected derivatives and , respectively. Finally, removal of all the protecting groups from and afforded the glycolipid and glycophospholipid , respectively. 相似文献
17.
- and -2-Methylamino and 2-benzylamino-3-hydroxymethylbicyclo [2.2.1]heptanes and the corresponding bicycio [2.2.1] heptenes ( -, -) were synthesized from β-amino acid esters containing the norbornane or norbornene skeleton (-). The aminoalcohols were converted to 5,8- methano -3,1-benzoxazines by reaction with formaldehyde. As established by 1H and 13C NMR spectroscopy, the predominant conformation is () for the , and () for the derivatives. 相似文献
18.
Treatment of cyclic sulfates of vic-diois with triphenylphosphine and iodine offers the corresponding olefins in high yields at room temperature. Both cyclic sulfates of d,l-hydrobenzoin and meso-hydrobenzoin give trans-stilbene. 相似文献
19.
Anguidine, , is readily converted into verrucarol diacetate, , in 85 percent yield by application of the Barton-McCombie deoxygenation procedure. To enable conversion into trichodermol, , the primary hydroxyl group of verrucarol, , is selectively acetylated or is selectively acetylated or preferably silylated, thereby paving the way for its deoxygenation in three simple, high-yield reactions. 相似文献
20.
Oxidation of the antibiotic kiriothricin with sodium metaperiodate gave several main degredation products (, , ). Interpretation of the spectral data of these compounds will lead to the constitution of kirrothricin (). 相似文献