A process 2 wherein said ring closure is conducted using {HEAD ~ p toluenesulfonic acid} or {TAIL ~ an ester} or p toluenesulfonyl halide with a tertiary amine 
A process 2 wherein said ring closure is conducted using { HEAD ~ p toluenesulfonic acid } or { TAIL ~ an ester } or p toluenesulfonyl halide with a tertiary amine
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH