STUDIES ON FUSED PYRIMIDINE-DERIVATIVES .14. FORMATION AND TRANSFORMATION OF 3-DIMETHYL-6-METHYLENEPERHYDROPYRIMIDINE-2,4-DIONS WITH TROPONE(2] CYCLOADDUCTS, CYCLOHEPTA[G]QUINAZOLINE DERIVATIVES, BY THE REACTION OF 5)

The reaction of -dimethyl-6-methyleneperhydropyrimidine-2,4-diones 3 w ith tropone 4 gave two diastereoisomeric [4 +2] cycloadducts, cyclohep ta[g]quinazolines 5 and 6. These products correspond to endo- and exo- approach of enamine 3 to the 2,3-double bond of tropone 4, respectivel y. The chemical behaviour of the endo- and exo-adducts will be discuss ed. The X-ray structures of tahydro-1H-cyclohepta[g]quinazoline-2,4,10 -trione, ctahydro-1H-cyclohepta[g]quinazoline-2,4,10-trione and lohept a[kl]pyrimido[5,4-h]acridine-10,13,15-trione are described.