In {TAIL ~ a preferred form} of the invention, the formation of the imidic ester is carried out in a high boiling solvent {HEAD ~ whose presence} enables the condensation to be carried out more effectively at a high temperature than with alkanol alone 
In { TAIL ~ a preferred form } of the invention , the formation of the imidic ester is carried out in a high boiling solvent { HEAD ~ whose presence } enables the condensation to be carried out more effectively at a high temperature than with alkanol alone
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH