cis-Hydrindenol 13a. To a stirred solution of 189 mg (0.5 mmol) of p-toluenesulfonylhydrazone 18 and 4 mL of tetramethylethylenediamine in 3 mL of anhydrous ether at 0 °C under nitrogen was added dropwise 3 mL of a 1 M solution of methyllithium in diethyl ether. The reaction mixture was stirred overnight at room temperature. Then, 20 mL of water was carefully added, and the organic layer was separated, washed several times with water, and dried over anhydrous magnesium sulfate. Concentration afforded 94 mg of crude material which was subjected to preparative TLC (silica gel, 1:1 benzene/EtOAc) to give 74 mg (76%) of colorless oil: NMR (CDC13) 0.93 (s,3 ), 1.08 (d, J -6 Hz, 3 H), 3.22-3.77 (m, 2 H), 5.53 (hr s, 2 H);

were recorded over long periods of time. The change in potential was of the same order as the drift of the blank. The pH of the solutions used in the liquid membrane studies was taken immediately following the completion of the study because the pH changed so rapidly. Hence no comparison could be made with the solid electrode studies.The results obtained with the solid membrane electrode in phosphate and borate buffers did not differ significantly. Therefore, it was concluded that phosphate must interfere in the alkylation step rather than in the cyclization reaction. CONCLUSIONSThe ion-selective electrodes used in this study offered a rapid, continuous, and simple method for the measurement of rate constants without a flow-through system. It is suggested that other electrodes could similarly be applied in reaction mechanism studies and in the determination of rate constants.

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