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