The free base, generated from the hydrochloride with aqueous OH-, can be metallated (LDA, -78o) at the methylene group. Subsequent reaction with a ketone provides a route to otherwise inaccessible pyridyloxiranes: Tetrahedron Lett., 35, 3175 (1994). Similarly, reaction of the lithio derivative with an imine gives a pyridylaziridine, generally in good yield: J. Org. Chem., 60, 2279 (1995). The free base has also been used for the protection of OH groups as 2-picolyl derivatives, relatively stable to acid (HF, TFA) but selectively cleaved by electrolytic reduction: Acta Chem. Scand. B, B37, 475 (1983); J. Chem. Res. (Synop.), 22 (1977). For a study of the base-catalyzed alkylation of p-t-butylcalix[5]arene, see: J. Org. Chem., 61, 2407 (1996).
