of a compound of formula i can alternatively be prepared by oxidizing the corresponding compound of formula i oxidation of a compound of formula i using one equivalent of sodium periodate or hydrogen peroxide yields the corresponding sulfoxide derivative oxidation of a compound of formula i using potassium permanganate or excess hydrogen peroxide yields the corresponding sulfonyl derivative alternatively the sulfoxide and sulfonyl derivatives can be prepared by treating compounds of formula i with m chloroperbenzoic acid treating a compound of formula i with an equivalent of m chloroperbenzoic acid for from 2 to 24 hours at room temperature yields the corresponding sulfoxide derivative treating a compound of formula i or a sulfoxide derivative of a compound of formula i with two equivalents of m chloroperbenzoic acid for 2 to 24 hours at room temperature or for a shorter time with slight heating yields the corresponding sulfonyl derivative the compounds of formula i form acid addition salts with inorganic and organic acids these acid addition salts frequently provide useful means for isolating the products from reaction mixtures by forming the salt in a medium in which it is insoluble the free base may then be obtained by neutralization e g with a base such as sodium hydroxide any other salt may then be formed from the free base and the appropriate inorganic or organic acid illustrative are the hydrohalides especially the.