Methyl ethers separation

Naphthyl methyl ether.—Dissolve 3-6grams(3-naphthnl in I3 5 c.c. 10 per cent, caustic soda solution, add 3 c.c. meth l sulphate, warm the liquid gently and shake vigorously. In. i short time the naphthyl methyl ether separates as a solid mass. The product is heated for ten minutes on the water-bath, a little water is added, and the naphthyl ether filtered and washed with water. It is crystallised from alcohol and deposits in lustrous plates m. p. 70—72°. The yield is theoretical. It may be used for analysis by Zeisel s method. 

Recrystallise from methylated spirit, from which the methyl 2-naphthyl ether separates readily as colourless crystals, m.p. 72° yield, 9 g. 

The general reaction procedure and apparatus used are exactly as described in Procedure 2. Ammonia (465 ml) is distilled into a 2-liter reaction flask and to this is added 165mlofisopropylalcoholandasolutionof30g(0.195 mole) of 17/ -estradiol 3-methyl ether (mp 118.5-120°) in 180 ml of tetrahydrofuran. The steroid is only partially soluble in the mixture. A 5 g portion of sodium (26 g, 1.13 g-atoms total) is added to the stirred mixture and the solid dissolves in the light blue solution within several min. As additional metal is added, the mixture becomes dark blue and a solid (matted needles) separates. Stirring is inefficient for a few minutes until the mass of crystals breaks down. All of the sodium is consumed after 1 hr and 120 ml of methanol is then added to the mixture with care. The product is isolated as in Procedure 4h 2. After being air-dried, the solid weighs 32.5 g (ca. 100% for a monohydrate). A sample of the material is dried for analysis and analyzed as described in Procedure 2 enol ether, 91% unreduced aromatics, 0.3%. The crude product may be crystallized from acetone-water or preferably from hexane. 

Examples shown in this chapter are for PMMA. Other polymers can be separated as well. The polymers separated so far (1,2) include polystyrene, poly(a-methylstyrene), polycaprolactone, polycarbonate, poly(hexyl isocyanate), polytetrahydrofuran, poly (vinyl methyl ether), and polyvinylpyrrolidone. 

The homolog of epinephrine in this series is a potent vasoconstrictor. Reaction of 3,4-dimethoxypropiophenone with butyl nitrite leads to nitrosation at the a position (36). Stepwise reduction of the nitrosoketone leads to the amino alcohol (37). Removal of the methyl ether affords racemic 38. Resolution of this last followed by separation of the (-) isomer gives levonor-defrine (38). ... 

Methyl-substituted primary alcohols can be separated after derivatization with [6-methoxy-2,5,7,8-tetramethylchromane-2-carboxylic acid] (Trolox M methyl ether) [13] while sec.- and tert.-alcohols are derivatized with 2-dimethylamino-l,3-dimethyl-octahydro-lf/-l,3,2-benzodiazaphosphole [14] (Eig. 7-5). 

Likewise, synthetic 2//-azepines isomerize to 3//-azepines in refluxing chloroform (2-3 h) or in tert-butyl methyl ether at room temperature.291 The isomers can be readily separated by chromatography on silica gel, as the more basic 2//-azepines30 have lower Rf values. In contrast, 7-butyl-2//-azepin-2-acetic acid (11), obtained by heating the tert-butyl ester 10 with iodotrimethylsilane, is stabilized by intramolecular hydrogen bonding and shows no tendency to rearrange to the 3//-isomer.291... 

C. (E)- -Iodo-4 -phenyl-2-butene. In a 20-ml., round-bottomed flask are placed 2.0 g. (0.008 mole) of 2-(4/-phenyl-l -buten-3 -yl)thio-2-thiazoline, 5 ml. of methyl iodide [Methane, iodo-], and 2 ml. of di-methylformamidc. The resulting solution is heated at 75-80° for 2.5 hours under a nitrogen atmosphere (Note 13), cooled, and poured into 10 ml. of water. Extraction with three 12-ml. portions of ether separates the product from water-soluble by-products. The extracts are combined, washed with 8 ml. of 1% aqueous sodium thiosulfate and two 8-ml. portions of water, dried over anhydrous magnesium sulfate, and filtered to remove the drying agent. Removal of ether by distillation at 30° (100 mm.) leaves 1.5-1.7g. (74-82%) of ( )-l-iodo-4-phenyl-2-butene (Notes 14 and 15). 

Fia. 1.—Scheme for the Degradation of the Ethyl Methyl Ether of Kojic Acid, and the Separation and C14-Assay of the Fragments ( = Assayed for C14). 

The mixture was transferred into a separating funnel. The aqueous phase was separated and extracted with tert-butyl methyl ether (2 x 20 mL). The brown combined organic layers were filtered through a pad of Celite , and then washed with water (2 x 40 mL) and with brine (2 x 40 mL), dried over sodium sulfate, filtered and concentrated under reduced pressure, giving a brown oil (700 mg). 

Isopropanolamines, 20 795, 812 2-Isopropanol-water system, evolving separation strategies for, 22 322-325. See also Water- IPA-hexane system Isopropenyl acetate, 7 148 74 596 m-Isopropenyl-a,a-dimethylbenzyl isocyanate (TMI), 25 463 Isopropenyl methyl ether, production from acetone, 7 163... 

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