{HEAD ~ R1} and R2 are independently {TAIL ~ H}, C1 C18 alkyl; or R1 in combination with R2 forms a saturated 5 or 6 membered heterocycle that is a piperidine, a morpholine, a pyrrolidine or a piperazine 
independently
{ HEAD ~ R1 } and R2 are independently { TAIL ~ H } , C1 C18 alkyl ; or R1 in combination with R2 forms a saturated 5 or 6 membered heterocycle that is a piperidine , a morpholine , a pyrrolidine or a piperazine
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH 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