Petroleum ether, as solvent

Shoaf and Lium [103] used thin layer chromatography to separate algal chlorophylls from their degradation products. Chlorophyll is extracted from the algae with dimethyl sulphide and chromatographed on commercially available thin layer cellulose sheets, using 2% methanol and 98% petroleum ether as solvents, before determination by either spectrophotometry or fluorometry. 

Sisido, K. Kurozumi, S. Utimoto, K. J. Org. Chem. 1969, 34, 2661. [Biichi, G. and Egger, B. (J. Org. Chem. 1971, 36, 2021) obtained a high yield (93.5%) of methyl jasmonate in the hydrogenation using Lindlar catalyst in petroleum ether as solvent, compared to 60% yield obtained by Sisido et al. in methanol, although on a much larger scale],... 

A mixture of Fmoc-Xaa-OH (2 mmol), HODhbt (2.2 mmol), and SOCl, (20 mmol) in CHjCl, (12 mL) was heated at reflux until the esterification was complete as indicated by TLC as described above. Residual SOClj was removed in vacuo and the products were crystallized by adding EtOAc to the resulting oils or by adding a soln of the products in EtOAc to petroleum ether while stirring. Some products were purified by passing them through a column of silica gel using EtOAc or EtOAc/petroleum ether as solvent. 

Acid-catalyzed reaction of lb with acetone and simultaneous azeotropic removal of water provides diethyl (27 ,3i )-2,3-0-isopropylidenetartrate 3 in 82—83% yield after distillative purification [3]. However, it has been reported that upon application of this method in petroleum ether as solvent, significant racemate formation was observed [4]. The preferred method for the preparation of 3 involves a transketalization reaction of lb with 2,2-dimeth-oxypropane under acidic catalysis. The yield is nearly quantitative with no loss of optical integrity [5]. 

Cyclopropanation reactions were carried out with ethyl diazoacetate as car-bene source and styrene, using petroleum ether as solvent (Scheme 15). After completion of the reaction, the mixture was filtered in order to separate catalyst and products. The heterogeneous system provided slightly higher yields (up to 90%) and similar lower diastereoselectivities compared to the homogeneous system. 

The extraction and cleanup of samples was dealt with earlier. As was indicated, this can be done very simply with excellent results. For example, the PCBs can be extracted by being vigorously shaken mechanically with dichloromethane or petroleum ether as solvent and then placed in an ultrasonic bath for a short while. After decantation, the organic phase is concentrated by selected evaporation. 

Koini et al. [125] reported an efficient and mild method for the chlorination and bromination of oxygenated aromatic compounds (phenols, substituted phenols, methoxyarenes, and 1,4-benzoxazines) (178/180) with good regioselectivity and yields (47-68%), using a combination of HCl or HBr/(30%)H2O2/AcOH in petroleum ether as solvent (Scheme 47). The use of ultrasound irradiation did not confer any additional advantage when compared with conventional heating. 

Peroxypropionic -- - 7, 324 suppl. 21 Persulfate 21, 224 23,156 Peroxytrifluoroacetic acid as reagent 23,152 Petroleum ether as solvent... 

Usually the first step is an extraction of the desired compounds from plant material. This extraction can be done by different solvents, e.g., methanol [85], n-hexane [86], petroleum ether or solvent mixtures such as methanol/chloroform [87]. The use of a second liquid-liquid extraction (LLE) with 0.1 M NaOH after extraction with a non-polar solvent like n-hexane makes a separate analysis of acidic cannabinoids possible, which can be found... 

In a sensitive and specific colorimetric method 1,1,1-trichloro-2,2-bis(p-methoxyphenyl)-ethane is extracted from plant or animal tissue, using benzene or petroleum ether as the solvent. The solvent is evaporated at room temperature by a current of air and the residue dehydroha log ena ted with 2% alcoholic potassium hydroxide. By petroleum ether extraction the resulting 1,1-dichloro-2,2-bis(p-methoxyphenyl)-ethylene is removed from the reaction mixture. After the solvent is removed by air evaporation the dehydroha log ena ted methoxychlor is isolated from the nonsaponifiable portion of the fats and waxes by dissolving the residue in hot acetone, chilling, and filtering. After the acetone is removed by air evaporation, the residue is treated with 85% sulfuric acid. This produces a red solution with an absorption maximum at 555 m/z, the intensity of which can be read on a colorimeter and is a function of the methoxychlor concentration. Beer s law is obeyed over the range of 1 to 50 micrograms. 

A mixture of benzaldehyde (1.06 g, 10 mmol), ethane-1,2-diol (0.62 g, 10 mmol) and commercial grade cadmium iodide (1.85 g, 5 mmol) were thoroughly mixed at room temperature in an Erlenmeyer flask and placed in a commercial micro-wave oven operating at 2450 MHz frequency. After irradiation of the mixture for 1.5 min (monitored vide TLC) it was cooled to room temperature, extracted with dichloromethane, washed with sodium thiosulfate and dried over anhydrous Na2S04- Evaporation of the solvent gave almost pure products and there was no evidence for the formation of any hydroxy ester or iodoester. Further purification was achieved by column chromatography on silica gel using 1 5 chloroform-petroleum ether as eluent. 

A solution of or /zo-hydroxybenzalacetone 2 (1.62 g, 0.01 mol) and ortho-phenylenediamine 1 (1.1 g, 0.011 mol) in methanol (30 ml) containing two drops of concentrated hydrochloric acid was refluxed for 1 h (TLC control Scheme A.29). After evaporation of the solvent, the oil formed was chromatographed on silica gel (CHC13) and then compound 3 was crystallized from diethyl ether-light petroleum ether as colorless prisms (0.35 g, 14%). Melting point 126-127°C (dec.). 

El-Deeb, et al (175) have reported the comparative study of differential adsorption of camphor on both aluminium oxide and silicic acid. The retention volumes were determined by using Petroleum-ether and ether as solvents. 100 mg of material was chromatographed on column of 1 cm diameter and 10 g of either Alumina or silicic acids (mesh No. 30). The results are presented in Table 8. 

The substrate (1 mmol) and IOB (110 mg, 5 mmol) were dissolved in acetonitrile-water (10 ml, 2 1) at 60°C. The mixture was stirred for 10 min and then NBS (218 mg, 1 mmol) was added. After stirring for 30 min at 60°C, the solvents were evaporated. The aqueous phase was washed with ether (3 x 10 ml), dried and concentrated. The residue was separated using flash chromatography with petroleum ether as the eluent. 

By using ether instead of benzene or petroleum ether, as specified in the older methods, the evaporation of the solvent after the reaction is facilitated. 

Phenylbenzoyldiazomethane has been prepared by the oxidation of benzilhydrazone with mercuric oxide,4 using benzene or petroleum ether as the solvent, and without the catalyst here specified. 

Phenyl 4-(Phenyltelluro)phenyl Tellurium2 A 500-ml, three-necked, round-bottom flask is fitted with a cold-finger condenser charged with dry ice/ethanol, a nitrogen inlet, and a magnetic stirrer. 250 ml of liquid ammonia are condensed into the flask, 1.6 g (4 mmol) of diphenyl ditellurium and then pieces of sodium are added until the blue color persists. A very small amount of diphenyl ditellurium is added to discharge the blue color followed by 1.13 g (4 mmol) of 4-bromoiodobenzene, and the mixture is irradiated for 220 min. The reaction is quenched by addition of 10 ml of distilled water, the ammonia is allowed to evaporate, the residue is diluted with 100 ml of water, and the whole is extracted three times with 100 ml of diethyl ether. The extract is dried with anhydrous sodium sulfate, the solvent is distilled off, and the residue is chromatographed on neutral aluminum oxide with petroleum ether as eluent yield 0.58 g (30%) m.p. 88-907... 

Representative procedure,35 To flame-dried LiCI in THF (20 equiv) was added Sml2 in THF (3 equiv) and the solution was stirred for 30 min. The amide (1 equiv) in THF was then added and the reaction mixture stirred for 24 h. The mixture was poured into saturated aqueous Na2S03 and extracted with EtOAc. The combined organic extracts were then washed with saturated aqueous Na2S03 and brine and dried (MgS04) and the solvent was removed in vacuo. The crude product was purified by column chromatography (EtOAc-petroleum ether as eluent). 

In addition to the magnesium compounds, lithium alkyls are versatile reagents that also function as alkyl group transfer agents. Lithium alkyls are prepared by the reaction of lithium with an alkyl halide using benzene or petroleum ether as a solvent ... 

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