Compounds of the formula ##STR1## the symbols have {TAIL ~ the meaning} described in {HEAD ~ the specification} 
Compounds of the formula # # STR1 # # the symbols have { TAIL ~ the meaning } described in { HEAD ~ the specification }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD