{HEAD ~ A process} 2, wherein R1, R2 and R3 are hydrogen and {TAIL ~ R4} is a lower alkyl group 
wherein
{ HEAD ~ A process } 2 , wherein R1 , R2 and R3 are hydrogen and { TAIL ~ R4 } is a lower alkyl group
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH