A convenient synthesis of polysubstituted 6-imino-1,3-oxazines (3,5,9)
from corresponding ketene dithioacetals has been described and their
conversion to pyrimidin-6-one (6) and pyrazolo[3,4-d]pyrimidine (8) st
udied. The oxazines synthesized, have shown a significant hepatoprotec
tive activity.