نتایج جستجو برای: methylene chloride
تعداد نتایج: 101320 فیلتر نتایج به سال:
1-(2-Alkynylphenyl)ketoximes react with Lawesson's reagent catalyzed by InCl(3) and cyanuric chloride leading to 4-methylene-4H-benzo[d][1,3]thiazines in good yields. This tandem reaction proceeds with high efficiency through Beckmann rearrangement, thioamide formation, and intramolecular nucleophilic cyclization.
An efficient and selective method was developed for the deprotection of triethylsilyl (TES) ethers using formic acid in methanol (5-10%) or in methylene chloride 2-5%) with excellent yields. TES ethers are selectively deprotected to the corresponding alcohols in high yields using formic acid in methanol under mild reaction conditions. Other hydroxyl protecting groups like t-butyldimethylsilyl (...
Chromatographic investigation of the methylene chloride/methanol extract of the aerial parts of Artemisia herba-alba afforded a new monoterpene dimer, in addition to a known monoterpene and three known sesquiterpene lactones. The structures of the compounds were determined by comprehensive NMR analyses, including DEPT, COSY, HMQC, HMBC, and HRMS.
Basic hydrolysis of a dichloromethane extract of Stevia lucida yielded (4R,5S,7R,9R,10R,11R)-7,9-dihydroxylongipin-2-en-1-one (1), which was oxidized and subjected to acidic conditions to generate the new seco-moreliane derivative 3. The structure of 3 was established based on NMR data interpretation and confirmed computationally. A plausible mechanism for the carbocationic rearrangement of the...
A luminescence supramolecular hyperbranched polymer is reversibly fabricated by successively adding acid and base to a solution of an AB2 platinum(II) monomer in dichloromethane on the basis of acid-base controllable host-guest recognition of dibenzo[24]crown-8 moieties with dialkylammonium ion centers.
A simple, efficient and highly functional group compatible method for the synthesis of propargylamines from terminal alkynes, dichloromethane and tertiary amines using silver catalysts has been developed.
Eight glucosylceramides (1-8) were isolated from the water-insoluble lipid fraction of a methylene chloride/methanol/water extract of the Patagonian starfish Anasterias minuta. One of the constituents was identified as a new glucosylceramide, anasterocerebroside A (1), while the known glucosylceramide 7 was isolated and characterized for the first time as a pure compound. The structures of 1 an...
High-pressure anion-exchange chromatography with gradient elution has been used to resolve ultraviolet-absorbing constituents from normal and pathologic specimens of human urine. We have identified 50 of these constituents by using multiple-analytical techniques. Ultraviolet spectral maxima, gas chromatographic methylene unit (MU) retention values (for trimethylsilyl derivatives), and the major...
Doping of zinc with silver, palladium, and gold was found to increase reactivity towards carbon tetrachloride in water. Commercial zinc dust, cryochemically prepared zinc metal particles (SMAD nanoparticles), and zinc dust pressed into pellets (mechanically activated zinc) were employed. Reduction products detected were methane, ethylene, acetylene, and other hydrocarbons along with products of...
This patient had clear evidence of ectopic adrenocorticotrophic hormone syndrome secondary to oat-cell carcinoma of lung. In association with this and as an initial feature she had a spontaneous cure of lifelong psoriasis. We think that these two events were related and can find no other reports of this unusual phenomenon. Just as the onset of certain skin lesions may herald an underlying neopl...
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