The one step synthesis of 2,4-dialkyl and 2,4-diaryl substituted 5,6-d
ihydrocyclobuta[d]pyrimidines (12a,b) as new precursors for pyrimidine
ortho-quinodimethanes and their trapping with different dienophiles a
nd C-60 is reported. (C) 1997 Elsevier Science Ltd.