The pyrimidine sulfones 10, R = Me; Nu = OMe, NEt(2), SPh, H and 11, R
= Ph; Nu = OMe were synthesised from the dihydrothienopyrimidones 7,
R = Me, Ph by conversion to the chloro derivatives 8 followed by oxida
tion with mCPBA and reaction with the appropriate nucleophile or hydro
gen and Pd. Heating of the sulfones in 1,2,4-trichlorobenzene gave the
pyrimidine o-quinodimethanes which were intercepted in Diels-Alder re
actions to give tetrahydroquinazolines.