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Hepta dimethyl ether

A disaccharide, G, CiiHaoOio/ is hydrolyzable by a-glucosidase, yielding D-glucose and a D-pentose. The disaccharide does not reduce Fehling s solution. Methylation of G with dimethyl sulfate in NaOH yields a hepta-methyl ether, H, which upon acid hydrolysis yields 2,3,4,6-tetra-O-methyl-D-glucose and a pentose tri-0-... [Pg.1189]

The value of methylation studies in structural determination of carbohydrates is well known. Methylation of sucrose has generally been achieved by the use of dimethyl sulfate-sodium hydroxide,34,35 methyl iodide-silver oxide-acetone,20 sodium hydride-methyl io-dide-N,N-dimethylformamide,35 or diazomethane-boron trifluoride etherate.36,37 The last method (already applied to monosaccharides38,39) has been found particularly useful for sucrose, because it proceeds without concomitant migration of acyl groups. The reaction of 2,3,6,T,3, 4, 6 -hepta-0-acetylsucrose (21) and 2,3,4,6,1, 3, 4 -hepta-O-acetylsucrose (22) with diazomethane in dichloromethane in the presence of a catalytic proportion of boron trifluoride etherate for 0.5 h at —5° gave the corresponding 4-methyl (23) and 6 -methyl (24)... [Pg.243]

Propa, Propanoic acid Buta, butanoic acid Penta, pentanoic acid Hexa, hexanoic acid Hepta, heptanoic acid Octa, octanoic acid Nona, nonanoic acid Deca, decanoic acid Pal, palmitic acid St, stearic acid Piva, trimethylacetic acid Vers, Versatic acid a-BrHexa, a-bromohexanoic acid x-BrSt, a-bromostearic acid Me2(OH)Hexa, 2,5-dimethyl-2-hydroxyhexanoic acid a,a -DAC, a,a -dialkylcarboxylic acid Naph, naphthenic acid cy-PA, cyclopentylacetic acid cy-Hexa, cyclohexanecarhoxylic acid C7-C mix, C7-C9 mixture CB, chlorobenzene cy-Hexn, cyclohexane 1,2-DCE, 1,2-dichloro-ethane (i-Pr)2CO, diisopropyl ketone i-amOAc, isoamyl acetate i-amOH, isoamyl alcohol MIBK, 4-methyl-2-pentanone NB, nitrobenzene n-Hexn, n-hexane PE, petroleum ether TCB, 1,2,4-trichlorobenzene. [Pg.154]

Diazopropane (10 mmol) in 12 was added in small portions to a solution of bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarbonitrile (1.1 g, 8 mmol) in EtjO at between — 40"C and - 50°C. The temperature of the mixture was allowed to rise to 25 °C and the progress of the reaction was followed by chromatography. The 5,5-dimethyl-3,4-diaza-exo-tricyclo[5.2.1.0 ]deca-3,8-diene-2,6-dicarbonitrile (6b) produced was purified by chromatography [silica gel, 30% EtjO in petroleum ether (bp 40-60°C)] yield 441 mg (26%) ... [Pg.1105]

Full details have been published on the hydroboration of acyclic oteo-dienes, using monochloroborane etherate, and on the conversion of the cyclic boranes so obtained into carbocycles. Thus hexa-1,5-diene was treated with monochloroborane to give a mixture of chlorodialkylboranes which were thermally depolymerized and treated with methanol (Cl - OMe) and dichloromethyl methyl ether to give a mixture of cycloheptanone and 2-methylcyclohexanone (74% total yield) in a 90.5 9.5 ratio, respectively. 2,5-Dimethylhexa-1,5-diene was similarly converted into 3,6-dimethyl-cycloheptanone. ° Hepta-1,6-diene has been converted into cycloheptane (67%) by treatment with diborane and then alkaline AgNOj in a new cyclization procedure. Diketones (35 n = 1, 2, or 3) cyclize to give acylcyclopentenes rather than cyclo-heptenones. ... [Pg.187]

Typical procedure. l,4-Dimethyl-5,6-diphenyl-3-propionylbicYclo[2.2. l]hepta-2,5-diene-2-carbonitrile 1474 [1119] A solution of the amide 1473 (104.8 mg, 0.28 mmol) and p-tosyl chloride (119.8 mg, 0.63 mmol) in absolute pyridine (2 mL) was refluxed for 2.5 h. The mixture was then poured onto ice, acidified with 10% aq. HCl, and extracted with diethyl ether. The combined extracts were washed with 10% HCl and brine, dried, and concentrated to dryness. Chromatography on silica gel eluting... [Pg.382]


See other pages where Hepta dimethyl ether is mentioned: [Pg.81]    [Pg.59]    [Pg.414]    [Pg.44]   


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