Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... A new synthesis of trimethoprim is described, metalation of a pyrimidine has been used in the key step. An exceptional regioselectivity in the metalation of pyrimidine derivatives has been highlighted. ... A new synthesis of Trimethoprim is described, metalation of a pyrimidine ...