Synthesis of certain l-menthol compounds

Abstract

nuclidine are approximately additive and lead to an average reduction in pKa of 2.8 pK units per benzo substitution. This relationship is shown in Figure 2.Experimental Anhydrous HOAc was prepared by distillation from triacetyl borate following Eichelberger. and LaMer (5). Analysis of the distillate by the method of Bruckenstein ( 7) revealed no detectable H20. The -0. l N HCI04 titrant in anhydrous HOAc was prepared by adding 5.1 mi acetic anhydride to 2.2 ml of 70% HC104 in 70 ml HOAc. The mixture was then diluted to 250 ml with HOAc and allowed to stand for several days before use. The NaOAc was dried at 110'C for 24 hr prior to the preparation of the standard solution.The titrations were carried out in a constant temperature bath at 25' f 0.5'C using a Leeds and Northrup Model 7403-A2 pH meter. A Leeds and Northrup #1199-72 glass electrode was used as the indicating electrode, and the reference electrode was a modified calomel electrode containing a saturated solution of NaCI, NaC104, and Hg2C12 in anhydrous HOAc (4). Samples containing -0.06 meq base in 20 ml HOAc were titrated with the HCIO4 titrant using a 10-ml microburet. Prepurified N2, dried by passing through a Drierite drying tower and saturated with HOAc by bubbling through anhydrous HOAc, was passed over the solutions throughout the titrations.The preliminary experiment was run in anhydrous HOAc with a Sargent S-300072-15 combination electrode. The 0and mchloroaniline, used as references, were purified by distillation. Literature Cited(1) Bruckenstein.