Synthesis of some novel fused oxo- and thiopyrimidines via an intramolecular Friedel-Crafts reaction

1H-Indeno[1,2-d]pyrimidine-2,5(3H,9bH)-dione derivatives 2(a-i) and 2,3-dihydro-2-thioxo-1H-indeno[1,2-d]pyrimidine-5(9bH)-ones 20-q) were synthesized via an intramolecular Friedel-Crafts reaction between the aryl and ester group of ethyl 6-methyl-4-aryl-2-oxo-1,2,3,4-tetrahydropyrimidine-5carboxylates 1a-i, and their thioxo analogs using AlCl3 and acetyl chloride in nitrobenzene. Yields of the products, after washing with THF, were of the order of 45-69%. IR and NMR spectroscopy together with elemental analysis were used for identification of these compounds.