Studies on fused pyrimidine derivatives. Part 14. Formation and transformation of [4 + 2] cycloadducts, cyclohepta[g]quinazoline derivatives, by the reaction of 5-(arylaminomethylene)-1,3-dimethyl-6-methyleneperhydropyrimidine-2,4-diones with tropone

Abstract

The reaction of 5-(arylaminomethylene)-1,3-dimethyl-6-methyleneperhydropyrimidine-2,4-diones 3 with tropone 4 gave two diastereoisomeric [4 + 2] cycloadducts, cyclohepta[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, respectively. The chemical behaviour of the endo- and exo- adducts will be discussed. The X-ray structures of 5-(4-bromoanilino)-1,3-dimethyl-2,3,4,r-5,c-5a,10,c-10a,11-octahydro-1H-cyclohepta[g]quinazoline-2,4,10-trione, 5-(4-bromoanilino)-1,3-dimethyl-2,3,4,r-5,t-5a,10,t-10a,11-octahydro-1H-cyclohepta[g]quinazoline-2,4,10-trione and 12,14-Dimethyl-r-6b,9,10,c-10a,11,12,13,14,15,c-15b,c-15c,16-dodecahydrobenzo[c]-cyclohepta[kl]pyrimido[5,4-h]acridine-10,13,15-trione are described.