tra of benzophenone and benzhydrol showed that the aromatic protons of the former absorb further downfield than those of the latter, so that the presence of a small amount of benzophenone in the sample would not interfere with the deuterium analysis.Carbonation of the Remaining Grignard Reagent.-The carbonation was begun 20 min after the reaction of the Grignard reagent with 0.5 equiv of benzophenone. Crushed Dry Ice contained in a 250-ml erlenmeyer flask was slowly added through Gooch tubing to the unconsumed Grignard reagent contained in a round-bottomed flask equipped with condenser and mechanical stirrer. Once all the Dry Ice had been added, the reaction mixture was allowed to attain room temperature overnight.The mixture was then treated with 6 N hydrochloric acid until two clear layers separated. The aqueous layer was extracted several times with ether, and the extracts were combined with the organic layer. The yield of norbornyl acid was 62% of the theoretical amount as determined by titration of an aliquot of the ethereal solution in 65% methanol with standard sodium hydroxide solution to a phenolphthalein end point. The solution of norbornyl acid was then extracted with three 50-ml portions of 2 N sodium hydroxide solution and one 50-ml portion of water. The combined base extracts were held for the methylation step.Reaction of Norbornyl Acid with Diazomethane.-Diazomethane was prepared from Diaz aid (21.5 g, 0.1 mol).' 9Just prior to the reaction with diazomethane, the norbornyl acid was liberated from the sodium salt by acidification and extraction with ether. Esterification was accomplished by the dropwise addition of the dried norbornyl acid solution to diazomethane at 0°. The mixture was allowed to stand until nitrogen was no longer evolved and was then treated with 3 M sulfuric acid until the disappearance of the yellow color. The two layers were separated, and the aqueous layer was extracted several times with ether. The extracts were combined with the organic layer, washed with two 50-ml portions of 0.05 M sodium carbonate solution, and then dried (MgSCh). The ethereal solution was then filtered, combined with an ether wash of the magnesium sulfate, and concentrated by distillation at atmospheric pressure. Analysis of the residual oil by glpc gave (19) Th.
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