odically, quenched as in the preceding experiment, and analyzed. The solvolysis of the acidified K salt suspension was complete inless than 1 hr ( Figure 3). Solvolysis at High Temperature (in Glass Vessels).-I (50 mg), 6 ml of dioxane, and 18 11 of HzO were mixed in a 10-ml Bantam wale flask fitted with a condenser. The mixture desulfated before it had reached maximum temperature on top of a steam bath. In many such experiments solvolysis occurred within 2-4 min. The solvolysis in glass could be prevented for many hours by 10-20 pl of KOH (8-1 M ) , but only if the ieaction mixture was not disturbed (vide supra). The aqueous alkali does not dissolve in the dioxane, but merely coats the walls of the flask. C. Stability at High Temperature in Teflon. 1.-A reaction mixture of 50 mg of I, 5 ml of dioxane, and 20 pl of 8 X d l KOH (<0.001 mol/mol sulfate ester) was heated in a Teflon bottle for intermittent brief periods until the sulfate had dissolved, and thence continuously in a steam cone (96'). This concentration of KOH did not prevent desulfation in glass. After 2 hr, the solution was chilled, sampled, and found not acidic to methyl red; ncr was octanol-2 detectable by glc. The solution was transferred to a clean, glass round-bottom flask with condenser and heated on the steam bath. Desulfation occurred in about 3 min.2.--Experiment C-1 was repeated except that 18 pl of deionized water was substituted for the alkali. The mixture was heated at full steam bath temperature for 1 hr, carefully removed, and allowed to cool and crystallize. The crystalline material was recovered by filtration and washing with cold ethanol, 43 mg, sinters at 165", begins to foam and melt at 174", and is complete at 182O, Le., essentially identical with the starting 2-octanol (potassium sulfate).

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NOTES 461analytically pure material was 0.15 g (81 %), m.p. 153-154" (decamp.).Anal. Calcd. for C15H18N305S2: C, 48.65; H, 4.86. Found: C, 48.52; H, 5.02. Cotlversion of the Toluenesulfor~ic Acid Salt toAnl~ydrober~zylpet~icilli~z The salt 3 (100 mg, 0.27 mmoles) was suspended in methylene chloride (2ml) and an ice-cold saturated sodium bicarbonate solution (2 ml) was added. The salt dissolved when this mixture was shaken. The yellowish aqueous layer was removed and the methylene chloride layer was passed through a short column of anhydrous sodium sulfate. The column was washed with methylene chloride and the dry solution of the base 4 (volume, 3 ml) was treated with a solution of phenylacetic acid (37 mg, 0.27 mmole) in methylene chloride (1 ml) and then with a solution of diisopropylcarbodiimide (34 mg, 0.27 mmole) in methylene chloride (1 ml). The reaction mixture was left for 20 h at room temperature and the solvent was then removed. The crystalline residue was triturated with ether and the ether-insoluble material was recrystallized twice from isopropyl alcohol, giving 43 mg (52 % from 3) of anhydrobenzylpenicillin, n1.p. 148-15O0, identical with the compound prepared from Penicillin G on the basis of its infrared spectrum and an undepressed mixture melting point. An examination of the pK,'s of a series of phenacyl 'onium salts has indicated that the acidifying effects of the 'onium groups increase in the order arsonium < phosphonium < sulfonium. The acidifying effects of the 'onium atom substituents increase in the order methyl < 11-butyl < phenyl. These observations have been accounted for in terms ofprc-rlx overlap between the carbanion and the heteroatom of the 'onium group.Canadian Journal of Chemistry, 46,461 (1968) The discovery and use of ylids containing a variety of heteroatom groups has given rise to questions regarding the relative effectiveness with which the different 'onium groups (X in 2) provide stabilization for the adjacent carbanion.It is well recognized, especially on the basis of infrared (1) and x-ray crystallographic (2) evidence on phenacylides (4), that considerable 'For part XV in this series, see A. W. Johnson and S. C. K. Wong, Can. J. Chem. 44, 2793Chem. 44, (1966.2Author to whom inquiries should be addressed at The Chemistry Department, University of North Dakota, Grand Forks, North Dakota, U.S.A. stabilization is afforded the carbanion by delocalization of the negative charge through the carbon portion of the ylids (i.e. through the carbonyl group in 2). However, it also appears that the 'onium group (X in 2) must provide conjugative stabilization of the carbanion in order for such ylids to have any finite existence. The stabilization probably is via pn: -dn: overlap between the carbanion and the 'onium group if the latter has available empty, low-energy d-orbitals (3). Such is the case with arsonium, phosphonium, and sulfonium ylids.We wish to report some recent pKa determinations which indicate the relative effectiveness of the groups X in increasing the acidity of the...

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