New beta-tricarbonyl compounds: Synthesis, reactions with urea and some thioureas

2,3-Dihydro-4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)furan-2,3-dione 1 reacted with some alkyl carbamates (3a-b) via p,p'-dimethoxy-dibenzoylketene intermediate 2 giving new beta-tricarbonyl compounds (4a-b). Then, these compounds were converted into 1,3-oxazine-2,4(3H)-dione 7 with urea and 2-thioxo-2,3-dihydropyrimidin-4(1H)-ones (6a-c) with some thiourea derivatives, respectively. Pyrimidin-4-ones (6a-c) and oxazine 7 were obtained in good yields. The structures and characterizations of new synthesized compounds were established by the H-1 and C-13 NMR, IR, UV-VIS spectroscopic data, elemental analysis, and X-ray diffraction method.