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