A positively charged substituent may be introduced into the side chain by first activating the hydroxyl group of L???OH by converting it to a suitable leaving group such as a triflate, mesylate, tosylate, iodide, chloride, bromide, and the like, and then displacing the resulting leaving group with a compound Q??????Rq??? such as N-methyl-imidazole, N-(2-hydroxyethyl)-imidazole, 1-methyl-4-aza-1-az