{HEAD ~ The compounds} of formula I are useful both in the free base form and in {TAIL ~ the form} of acid addition salts, and, both forms are within the purview of the invention 
{ HEAD ~ The compounds } of formula I are useful both in the free base form and in { TAIL ~ the form } of acid addition salts , and , both forms are within the purview of the invention
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH