Silica methylated

The wine sample is extracted by ethyl acetate and the organic solution is dried with magnesium sulfate. The GC/MS analysis of the extract can be performed using a fused silica methyl silicone column and the following oven temperature program 60 °C isotherm for 2 min, then raised to 250 °C at 6°C/min. Identification of analyte is based on the library mass spectrum shown in Fig. 8.16 (Chisholm and Samuels, 1992). 

Matsuno et al. [5] studied the interactions of y-crystaUins with silica, methylated silica, and diphenyl silica. They used different techniques to examine the secondary and tertiary structural alterations that took place upon adsorption on these sdica surfaces exhibiting different degrees of hydrophobicity. A comparison was made between conformations of free and surface-bound protein as a function of the electrostatic and hydrophobic character of both the protein and the adsorbent surface. They demonstrated that (1) protein destabdization on hydrophobic surfaces is greater than that on more hydrophilic surfaces, (2) detectable conformational changes tend to increase as the surface hydrophobicity increases, and (3) subtle structural differences among proteins can play an important role in determining differences in protein stability and structure upon adsorption. 

Storage modulus versus volume fraction relation for a flocculated silica-methyl lau-rate system. From Van der Aerschot and Mewis (1992). 

Synonyms Dimethyl silicones and siloxanes, reaction prods, with silica Methylated silica... 

Figure Bl.19.30. Height and friction images of a spin-cast polystyrene-poly(methyl methacrylate) blend obtained with (a) gold and (b) silica probes under perfluorodecalin. Note the reversal of frictional contrast and the high spatial resolution. (Taken from [142], figure 7.)...

A solution of benzyl indole-5-carboxylate(1.0g, 3.98 mmol) and methyl 4-(bro-momethyl)-3-methoxybenzoate (2.06 g, 7.97 mmol) in dry DMF (10 ml) was heated at 80°C for 24 h. The reaction solution was cooled, poured into water (100 ml) and the product extracted with EtOAc (3 x 75 ml). The extract was washed with water and brine and dried over MgSO, . The product was obtained by evaporation of the solvent and purified by chromatography on silica gel using 1 4 EtOAc/hexane for elution. The yield was 1.11 g (32%) and some of the indole (30%) was recovered unreacted. 

Bromo-3-iodo-l-(4-methylphenylsulfonyl)indole (0.476 g, 1.00 mmol), methyl acrylate (0.108 g, 1.25 mmol), EtjN (0.127 g, 1.25 mmol) and Pd(OAc)2 (11 mg, 0.050 mmol) were mixed in a tube, purged with argon and the tube was sealed and heated to 100°C for 1 h. After cooling, it was opened and mixed with CH2CI2 (50 ml). The solution was washed with water and dried (Na SOJ. The residue was purified by chromatography on silica using 1 3 benzene-hexane for elution. The yield was 0.350 g (81%). 

A mixture of 4-bromo-l-(4-methylphenylsulfonyl)indole (88 mg, 0.25 mmol), methyl a-acetamidoacrylate (91 mg, 0.64 mmol), PdCl2(PPh3)2 (16 mg, 0.023 mmol) and NaOAc (82 mg, 0.98 mmol) in EtjN (0.8 ml) and DMF (0.4 ml) was heated to 120°C in a sealed tube for 2 h. The tube was opened and the contents diluted with EtOAc and filtered through Celite. The EtOAc was washed successively with 10% HCl, sat. NaHC03 and brine and then dried (MgS04). The residue was purified by elution through silica gel with 10 1 benzene-EtOAc to give the product as a yellow solid (93 mg, 90%). 

To a stirred ice-cold solution of ethyl 3,6-dihydro-5-hydroxy-8-methyl-6-(phenylsulfonyl)benzo[l,2-b 4,3-b ]dipyrrole-l-carboxylate (368 mg, 0.85 mmol) in TEA (3ml) was added EtjSiH (1.5 ml), After 15 min the solution was allowed to come to room temperature and stirred for an additional 2h. The solution was evaporated in vacuo and the residue dissolved in CH2CI2 (10 ml), washed.with aq. NaHCOj and dried over MgS04. The solution was mixed with AcjO (1ml) and CH2C12 (1ml) and kept at room temperature for 2 h. The reaction mixture was evaporated and the residue purified by chromatography on silica gel using CHjClj-EtOAc (3 1) for elution. The product (271 mg) was obtained in 71 % yield. 

A solution of l-methylpyrano[4,3-b]indol-3-one (1 mmol) and methyl vinyl ketone (5 ml) in toluene (5 ml) containing 5% Pd/C (40 mg) was heated for 48 h in a sealed tube at 110°C. The reaction mixture was evaporated in vacuo and the residue purified by silica gel chromatography to give the product in 80% yield. 

R,5S,6R)-4-(t-Butoxycarbonyl)-5,6-dlphenyl-3>[(sthoxycarbonyt)methyl]-2,3,5,6-tetrahydro-4H-oxazln-2-one (6) To a stirred solution of erode 4 (226 mg 0 48 mmoQ m CH2CI2 (11 mL) was added ketene acetal 5 (450 mg, 2 42 mmol) followed by addition of 2nCl2 (575 mL, 0 44 mmol, 0 76M m THF) Alter 4 min ( was quenched with water Radial chromatography (silica gel EtOAc hexane 1 4) afforded 179 mg of 6 (78%)... 

Magnesium ionophore II (ETH 5214), [A/,A/"-octamethylene-bis(A/ -heptyl-)V"-methyl methylmalonamide)] 1119110-37-1] M 538.8. Reagent ca 700mg) can be purified by flash chromatography on Silica Gel 60 (30g) and eluting with CH2Cl2-Me2CO (4 1). [Anal Chem 61 574 1989.]... 

Coenzyme Q4 (Ubiquinone-4, 2,3-dimethoxy-5-methyl-6-[3,7,ll,15-tetrametbyl-hexadeca-2/,6/,10/,14-tetraenyl]-[l,4]benzoquinone [4370-62-l]M 454.7, m 30 , 33-45 , A (275nm) 185. A red oil purified by TLC chromatography on Si02 and eluted with Et20-hexane. Purity can be checked by HPLC (silica column using 7% Et20-hexane). It has A- ax 270 nm (e 14,800) in pet ether. [NMR and MS Naruta J Org Chem 45 4097 1980 cf Morton Biochemical Spectroscopy (Adam Hilger, London, 1975) p 491]. It has also been dissolved in MeOH/EtOH (1 1 v/v) and kept at 5 until crystals appear [Lester and Crane Biochim Biophys Acta 32 497 1958]. 

Methyl alcohol Charcoal tube method not recom mended. Use silica gel tubes. ... 

Thickeners. Thickeners increase the viscosity of the polychloroprene latex adhesives. Amounts up to 1% of polyacrylates, methyl cellulose, alginates and polyurethane thickeners can be used. Particular attention should be paid to fluctuations in pH when thickener is added in the formulations. For low-pH (7-10) formulations, fumed silica or some silicates can be used. 

Inorganic acids Methyl diacetoacetate Phenyl cellosolve Silica gel Tetradecane... 

PMMA, on the unmodified porous glass and silica gel, and the universal calibration curves for polystyrenes and poly(methyl methacrylates) did not coincide (10,12,19). 

To a solution of m-ethyl cinnamate (44, 352 mg, 85% pure, 1.70 mmol) and 4-phenylpyridine-A-oxide (85.5 mg, 29 mol%) in 1,2-dichloromethane (4.0 mL) was added catalyst 12 (38.0 mg, 3.5 mol%). The resulting brown solution was cooled to 4°C and then combined with 4.0 mL (8.9 mmol) of pre-cooled bleach solution. The two-phase mixture was stirred for 12 h at 4°C. The reaction mixture was diluted with methyl-t-butyl ether (40 mL) and the organic phase separated, washed with water (2 x 40 mL), brine (40 mL), and then dried over Na2S04. The drying agent was removed by filtration the mother liquors concentrated under reduce pressure. The resulting residue was purified by flash chromatography (silica gel, pet ether/ether = 87 13 v/v) to afford a fraction enriched in cis-epoxide (45, cis/trans . 96 4, 215 mg) and a fraction enriched in trans-epoxide cis/trans 13 87, 54 mg). The combined yield of pure epoxides was 83%. ee of the cis-epoxide was determined to be 92% and the trans-epoxide to be 65%. 

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