The method 1, wherein step is carried out by treating the compound of {HEAD ~ the formula} in {TAIL ~ DMF} in the presence of 20 to 40 molar equivalents of POCl3 
in
The method 1 , wherein step is carried out by treating the compound of { HEAD ~ the formula } in { TAIL ~ DMF } in the presence of 20 to 40 molar equivalents of POCl3
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH