{HEAD ~ Substituents R1}, R2, R3 and R4 have {TAIL ~ the same meaning} as defined in the specification 
have
{ HEAD ~ Substituents R1 } , R2 , R3 and R4 have { TAIL ~ the same meaning } as defined in the specification
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH