or R1 is {HEAD ~ a 2 nitrobenzyloxycarbonyl} of {TAIL ~ the formula} ##STR48## wherein R9 and R10 are H, C1 C6 alkoxy, or R9 and R10 taken in combination are O CH2 O ; and 
of
or R1 is { HEAD ~ a 2 nitrobenzyloxycarbonyl } of { TAIL ~ the formula } # # STR48 # # wherein R9 and R10 are H , C1 C6 alkoxy , or R9 and R10 taken in combination are O CH2 O ; and
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH