Solvolysis of endo-norbornyl arylsulfonates proceeds in glacial acetic acid, aqueous acetone and aqueous dioxane to give completely the corresponding exo-derivative. That this endo to exo change involves rearrangement is clear from the complete resolution of endo-norbornyl alcohol and the solvolysis of optically active endo-norbornyl />-bromobenzenesulfonate in glacial acetic acid, ethanol and 75% aqueous acetone. Nearly complete loss of activity attends the formation of exo-products, first-order polarimetric rate constants agreeing with titrimetric rate constants within experimental error.The facts are most simply explained with carbon migration in the norbornyl cation. While the geometry in the ewdo-norbornyl pbromobenzenesulfonate is unfavorable to participation of the Ci-Ce bonding electron cloud in the ionization process, ionization is, for the most part, followed by rearrangement to the presumably more stable bridged structure.Solvent intervention, with 7-8% inversion, competes with carbon migration in acetolysis.
Communications to the Editor 2953 One cubic centimeter of hot 0.3 M trichloroacetic acid was added to each sample and the insoluble protein which formed was collected by centrifuging. It was washed three times with 2.5 cc. of 0.1 M trichloroacetic acid. Fifty gamma of chymotrypsin produced an insoluble protein containing 3.6 mg. of nitrogen per 0.66 g. of Witte peptone in forty hours. One milligram of chymotrypsin produced insoluble protein containing 9.84 mg. of nitrogen under similar conditions.The protein synthesizing property of chymotrypsin is of biological importance because under optimum conditions this enzyme displays only weak proteolytic action.
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