Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Tetrahydro furane

Examples of mono-layer adsorption isotherms obtained for chloroform and butyl chloride are shown in Figure 5. The adsorption isotherms of the more polar solvents, ethyl acetate, isopropanol and tetrahydro-furan from -heptane solutions on silica gel were examined by Scott and Kucera [4]. Somewhat surprisingly, it was found that the experimental results for the more polar solvents did not fit the simple mono-layer... [Pg.94]

Birch reductions in ammonia-tetrahydro-furan-/-butyl alcohol, 49... [Pg.495]

Reductions in ammonia-toluene-tetrahydro-furan solution, 54... [Pg.497]

The 17a-ethynyl compound (59) has been prepared in 88% yield from estr-4-ene-3,17-dione (58) and acetylene, at 2-3 atm pressure in tetrahydro-furan in the presence of potassium t-butoxide. Presumably the A-ring enone system is protected as the enolate anion during the course of the reaction. [Pg.66]

The phosphorodichloridate was hydrolyzed by adding to a stirred solution of sodium carbonate (253 grams) in water (2.9 liters). After 1 hour the solution was cooled and acidified with a solution of concentrated sulfuric acid (30 ml) in water (150 ml) and then extracted with a mixture of tetrahydrofuran and chloroform (2.3/1 3 x 1 liter). The tetrahydro-furan/chloroform liquors were bulked and evaporated to dryness to give a light brown oil. This was dissolved in water (1 liter) and titrated with 2N sodium hydroxide solution to a pH of 4.05 (volume required 930 ml). The aqueous solution was clarified by filtration through kieselguhr and then evaporated under reduced pressure to a syrup (737 grams). [Pg.1536]

Detailed mechanistic studies101 indicate that benzazepines arc formed by 1,7-electrocyclization of a nitrile ylidc intermediate followed by a [l,5]-sigmatropic hydrogen shift in the initially formed 9a//-2-benzazepine. Similar products, e.g. 9, have been obtained by generating the nitrile ylide 8 from the imidoylchloride, e.g. 7. with potassium /ert-butoxide in tetrahydro-furan.101... [Pg.224]

N. A-Diethyl-2.3-dihydro-8//-thieno[2,3-r/]azcpin-7-amine (20), which is obtained in 49 % yield by photolysis of 6-azido-2,3-dihydrothiophene in a mixture of diethylamine and tetrahydro-furan. on treatment with bromine yields the fully unsaturated derivative 21.1,4... [Pg.231]

Iodination of 4 with molecular iodine in the presence of mercuric oxide formed the 3-iodo derivative (52JA4951 66CJC2283). Iodine in tetrahydro-furan oxidatively cyclized /3-(3-benzo[b]thienyl)-a-mercaptoacrylic acids rather than iodinating the thiophene ring [70JCS(C)2431]. [Pg.254]

Reaction of alkyl phenylmethanesulphinates 100 with n-butyllithium in tetrahydro-furan at — 80 °C afforded the corresponding benzyl n-butyl sulphoxide160 (equation 53). Preparation of optically active sulphoxides by this reaction will be discussed later in this chapter. [Pg.259]

An interesting finding is a slow increase (f 1/2 0.5 ms), observed in PBS in tetrahydro-furan solution, after the faster decrease (t1/2 30/rs). This indicates that some of the fragments diffuse while still carrying reactive sites and can combine in the bulk. [Pg.922]

Analysis and purification of the product solution is best accomplished by gas chromatography. The submitters used a 500 cm. by 0.6 cm. aluminum or polyethylene column packed with 21% oxydipropionitrile on Chromosorb P with column, injector and detector operated at 25° and a flow rate of 50 ml./minute. Under these conditions the retention times of bicyclopentene and cyclopentadiene were 3 and 5 minutes, respectively, beyond that of the coinjected air. Since bioyclo-pentene is extremely labile with respect to acid catalysis any contact with water, hydroxylic solvents, and nonprotic acids should be avoided (Note 11). Bicyclopentene stored at —78° in anhydrous tetrahydro-furan is stable indefinitely. [Pg.18]

Solutions containing approximately 1.6JH butyllithium in hexane were purchased either from Alfa Inorganics, Inc., or from Foote Mineral Company, The concentration of butyllithium in these solutions can be determined either by a double titration procedure2 or by dilution with anhydrous tetrahydro furan followed by titration with 2-butanol in the presence of a 2,2 -bipyridyl indicator.3 In either ease the total base concentration in the reagent is determined by titration with standard aqueous acid. [Pg.124]

Zucker-(tosyl-hydrazone) werden mit Natrium-cyano-trihydrido-borat in Tetrahydro-furan/Methanol in Desoxyzucker iibergefiihrt5. [Pg.370]

Similarly, triphenyltin hydride reacts with diethylzinc or diethyl-cadmium in a strongly solvating solvent, such as oxolane (tetrahydro-furan) or 1,2-dimethoxyethane, to give the solvated, metal-metal-bonded products (272). [Pg.23]

The high chemoselectivity for the Baeyer-Villiger process was utilized in the synthetic elaboration of another hetero-bicyclic substrate. The biooxidation only provides the expected unsaturated lactone in a desymmetrization reaction without compromising the olefin functionality. The biotransformation product was then converted to pivotal intermediates for C-nucleosides like showdomycin, tetrahydro-furan natural products like kumausyne, and goniofufurone analogs in subsequent chemical operations (Scheme 9.17) [161]. [Pg.245]

Shat general strategies can you suggest for the synthesis of Symmetrical 2,3-di substituted tetrahydro-furans (48) ... [Pg.349]

In order to estimate the branching factor e for polyvinyl acetate we have analyzed the SEC data obtained on sample PVAc-E4 using the MWBD method with various e values. This sample was synthesized under kinetically controlled conditions (isothermal, T = 60°C, [AIBN] = 10"5 g-mole/1, conversion level of 48.5 percent). The SEC measurements were made at 25°C in tetrahydro-furan. The Mark-Houwink coefficients used for linear polyvinyl acetate are those suggested by Graessley (21), namely K = 5.1 x 10"5 dl/gm and a = 0.791. The whole polymer M, Mj, and B j values obtained are listed in Table II. [Pg.137]


See other pages where Tetrahydro furane is mentioned: [Pg.323]    [Pg.91]    [Pg.38]    [Pg.44]    [Pg.55]    [Pg.232]    [Pg.74]    [Pg.82]    [Pg.211]    [Pg.311]    [Pg.367]    [Pg.568]    [Pg.41]    [Pg.200]    [Pg.669]    [Pg.471]    [Pg.21]    [Pg.652]    [Pg.97]    [Pg.490]    [Pg.471]    [Pg.831]    [Pg.409]    [Pg.56]    [Pg.168]    [Pg.828]    [Pg.186]    [Pg.68]    [Pg.831]    [Pg.20]   
See also in sourсe #XX -- [ Pg.142 ]




SEARCH



1.4- Dihalides furans, tetrahydro

Furan ring tetrahydro

Furan ring tetrahydro— from

Furan tetrahydro- from

Furan tetrahydro-, chlorination

Furan, 2- tetrahydro

Furan, 3-hydroxy-1,2,3,4-tetraHYDRO

Furan, 3-hydroxy-1,2,3,4-tetraHYDRO 3-methyl

Furan, tetrahydro hafnium, niobium, scandium, titanium

Furan, tetrahydro iron-magnesium complexes

Furan, tetrahydro molybdenum complexes

Furan, tetrahydro vanadium, and zirconium complexes

Furan, tetrahydro-, actinide and

Furan, tetrahydro-, actinide and lanthanide complexes

Furan, tetrahydro-, compound with

Furan, tetrahydro-, compound with borane

Furan, tetrahydro-, compound with warning and purification

Furan, tetrahydro-, iron complex

Furan, tetrahydro-, lanthanide complexes

Furan, tetrahydro-, lanthanide complexes iron complex

Furan, tetrahydro-, lanthanide complexes lutetium complex

Furan, tetrahydro-, lanthanide complexes magnesium complex

Furan, tetrahydro-, lanthanide complexes neodymium complex

Furan, tetrahydro-, lanthanide complexes samarium complex

Furan-3,4-diones, tetrahydro

Tetrahydro furan synthesis

Tetrahydro-2,2-dimethyl-5- furan

Tetrahydro-furan calculation

Tetrahydrofuran (s. a. Furans tetrahydro

© 2024 chempedia.info