“…2-(2,6-Dimethyl-4 H -pyran-4-ylidene)-1 H -indene-1,3(2 H )-dione ( 8a ), 5-(2,6-dimethyl-4 H -pyran-4-ylidene)pyrimidine-2,4,6(1 H ,3 H ,5 H )-trione ( 8b ), 5-(2,6-dimethyl-4 H -pyran-4-ylidene)-1,3-dimethylpyrimidine-2,4,6(1 H ,3 H ,5 H )-trione ( 8c ), and 5-(2,6-dimethyl-4 H -pyran-4-ylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1 H ,5 H )-dione ( 8d ) were synthesized by general method II, according to known literature sources. ,− …”