Methylation of compound 3 with iodomethane in {HEAD ~ the presence} of {TAIL ~ a base}, such as sodium hydride, provides N methylated product of structure 5 
of
Methylation of compound 3 with iodomethane in { HEAD ~ the presence } of { TAIL ~ a base } , such as sodium hydride , provides N methylated product of structure 5
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH