Some new six-membered aplysinopsin analogues were prepared from 5- dimethylaminomethylidene-2, 4, 6 (1H, 3H, 5H)-pyrimidinetriones and indole derivatives. Also 2-[[(2, 4, 6-trioxohexahydropyrimidin-5-ylidene) methyl] amino]-3- dimethylaminopropenoates were synthesized and employed in the synthesis of fused 2H- pyran-2-ones.