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 {HEAD ~ the invention} 
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 { HEAD ~ the invention }
OTH OTH 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 HEAD HEAD HEAD HEAD HEAD HEAD