{HEAD ~ R0} is {TAIL ~ hydrogen}, or an aliphatic, cycloaliphatic or aromatic radical containing from 1 to 9 carbon atoms, or OR2, or ##STR28## R1 is hydrogen or an aliphatic, cycloaliphatic or aromatic radical containing from 1 to 9 carbon atoms, or R3 O R4, or ##STR29## R2 is hydrogen, or an aliphatic, cycloaliphatic or aromatic radical having from 1 to 9 carbon atoms, or R3 
is
{ HEAD ~ R0 } is { TAIL ~ hydrogen } , or an aliphatic , cycloaliphatic or aromatic radical containing from 1 to 9 carbon atoms , or OR2 , or # # STR28 # # R1 is hydrogen or an aliphatic , cycloaliphatic or aromatic radical containing from 1 to 9 carbon atoms , or R3 O R4 , or # # STR29 # # R2 is hydrogen , or an aliphatic , cycloaliphatic or aromatic radical having from 1 to 9 carbon atoms , or R3
HEAD HEAD HEAD HEAD HEAD REL 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 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH