Thin layer chromatography silica gel

The bacteriochlorin 10 (65 mg, 0.11 mmol) was dissolved in coned H2S04 (18 mL) and allowed lo react at 20 C for 5 min. The mixture was poured into ice, diluted with H20 and NaOAc (7.5 g, 91 mmol) was added. The mixture was extracted several times with CHC13, the organic extractions were washed with H20 (2 x), dried (Na2S04) and evaporated. Preparative thin-layer chromatography (silica gel) gave 11 and 12 yields 10.7 mg (17%) and 44 mg (70%), respectively. 

The dinitrophenylhydrazones were separated from the reaction mixture by thin-layer chromatography (silica gel G developed with benzene) and further purified by thin-layer chromatography on aluminum oxide G (petroleum ether-diethyl ether (96 to 4), silica gel G (chloroform), and silica gel G (diethyl ether)). In all cases, the specific activities of the dinitrophenylhydrazones remained constant over the course of the last two purifications. 

Tezuka s group (Tezuka and Ando, 1985 Tezuka et al., 1986) was able to isolate and characterize the benzenediazo ether of 1-naphthol (6.10). They stirred a solid mixture of the molecular complex 6.9 formed between an a-azohydroperoxide acid and benzene with an excess of 1-naphthol at room temperature in the dark for several hours. The separation of this solid by thin layer chromatography (silica gel, with a benzene-ethyl acetate mixture [9 1] as eluent) afforded the diazo ether 6.10 as a yellow oil in 17 % yield, together with 4- and 2-phenylazo-l-naphthol (6.11 and 6.12, 4% and 42%, respectively), 4-phenylbenzaldehyde (32%), benzoic acid (23%), and traces of other compounds (Scheme 6-6). Higher yields of the diazo ether (up... 

Values for Vitamin Bg Thin-Layer Chromatography, Silica Gel H... 

Progress of the reaction is followed by either gas chromatography or thin layer chromatography (silica gel, hexane) since the time required for completion of the reaction can vary up to 16 hr. An additional 500 mg of AIBN Is added to the reaction mixture after 3 hr if starting material is still present. 

Progress of the reaction is followed by either gas chromatography or thin layer chromatography (silica gel, hexane). 

Yields sometimes drop when an old bottle of borane-dimethyl sulfide is used. Reaction progress can be monitored by thin layer chromatography (silica gel, eluting with 10 10 1 chloroform-methanol-concentrated ammonium hydroxide). Any remaining phenylalanine stains heavily when exposed to ninhydrin (Rf 0.35). If phenylalanine is detected after 5 hr of reflux, an additional 10 ml (0.10 mol) of borane-dimethyl sulfide is added via syringe, and the solution is heated at reflux for 1 additional hr. 

The chemical purity of the compound is checked by NMR (250 MHz) and thin layer chromatography (silica gel, eluent ethyl acetate) which show the complete absence of the corresponding sulfide and sulfone (Note 8). 

The amount of Na[Ph2CO] solution required depends on how dry the reaction mixture is. When the reaction appears visually to be complete, a small aliquot should be examined (solution IR spectrum) to ensure that the precursor cluster complex has reacted completely [using the 2096 cm-1 v(CO) band of Ru3(CO)j j(PMe2Ph)]. Alternatively, the progress of the reaction may be monitored by TLC (thin layer chromatography) (silica gel, petroleum ether eluant). 

The submitters indicate that the reaction can be monitored for the formation of 5 by thin layer chromatography (silica gel 50% EtOAc/ hexanes). 

An ethanediyl 5,5-acetal (lmmol) was added to a solution of t-butyl bromide (3.05 g) and DMSO (1.5 g). The mixture was heated to 70-75°C under a nitrogen atmosphere. The reaction was followed by thin layer chromatography (silica gel/hexane) and GLC (capillary OV-101 column). Upon completion of the reaction the mixture was poured into water (15 ml) and extracted with hexane (3 X 20 ml). The combined hexane extracts were washed successively with aqueous sodium thiosulfate (10 ml) and water (2 X 10 ml), dried with anhydrous sodium sulfate, and the solvent evaporated. The residue was purified by column chromatography on silica gel using hexane as an eluent, followed by distillation or crystallization to give the corresponding carbonyl compound. 

To the solution of 5.35 g (28 mmol) [3-(lH-benzimidazol-2-yl)propyl]methylamine in 12.5 mL toluene was added by syringe 12.5 mL (11.42 g, 114 mmol) isopropenyl acetate. The reaction mixture was heated to reflux temperature, and stirred at that temperature for 1.75 hours, with reaction completion monitored by thin-layer chromatography (silica gel, eluting with 70% ethyl acetate/30% methanol). The product, N-[3-(lH-benzimidazol-2-yl)propyl]-N-methylacetamide, was obtained in quantitative yield. 

Thin-layer chromatography silica gel 60 F254 (Whatman) plates were obtained from Fisher Scientific. 

Thin-layer chromatography silica gel, HCCIj-MeOH (9 1, v/v). 

Alternatively, the solution composition can be estimated using thin layer chromatography silica gel eluted with 1 4 ethyl acetate/cyclohexane 1,1 -bi-2-naphthol, Rf 0.39 monopentanoate, Rf 0.56 dipentanoate, Rf 0.71. 

DVF was prepared from ferrocene by established procedures (2, 2 4, TJ, 12, 13), recrystallised from methanol (m.p. 39.5-4T.0 °cy, and sFTown to be pure by thin layer chromatography (silica gel with toluene as eluent). 

To ensure high enantiomeric purity of the product there should be <0.5% 1,1 -bi-2-naphthol or its monoester in this solution. The relative amounts of binaphthol species can be accurately determined by HPLC on a reverse-phase column eluted with a water-acetonitrile gradient (50-100% over 10 min). Both 1,1 -bi-2-naphthol and its dipentanoate have equal (within 2%) extinction coefficients at 254 nm. The monopentanoate absorbs more strongly the relative extinction coefficient at 254 nm is 1.13. Alternatively, the solution composition can be estimated using thin layer chromatography silica gel eluted with 1 4 ethyl acetate/cyclohexane 1,T-bi-2-naphthol, Rf 0.39 monopentanoate, Rf 0.56 dipentanoate, Rf 0.71. 

To a solution of [Rh(CO)2Cl]2 (3.9 mg, 0.01 mmol) in dibutyl ether (4 mL) was added a solution of diethyl 6-nonen-3-yn-6,6-dicarboxylate (338b, 266.7 mg, 1.00 nunol) in dibutyl ether (6 mL) under an atmospheric pressure of CO, and the mixture was heated at 130 °C (the oil bath temperature) for 18 h. After evaporation of the solvent in vacuo, the crude products were purified by preparative thin-layer chromatography (silica gel, hexane ethyl acetate = 4 1, t e times) to afford diethyl 8-ethyl-7-oxobicyclo[3.3.0]oct-l-(8)-ene-3,3-dicarboxylate (339b, 268.7 mg 91% yield). ... 

Thin Layer Chromatography.—Silica gel compacted to a density comparable with that of h.p.l.c. columns allowed good separations of a range of malto-... 

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