... Previously, these pterins have been synthesized by an oxidative conden- sation of 2,4,5 ... No. 01540418, SYNTHESIS 307 01740304, and 02740264, from Ministry of Education, Science and Culture ... D.; Reibnegger, G.; Werner, ER; Wachter, H. Pteridines 1989, 1, 3. (18) Matsuura ...