Pyrimido pyrimidine-2,4,7-triones

Treatment of pyrimidine-2-thione 184 with A1C13 yielded 6-oxo-6,7-dihydro-4//-pyrimido[6,l-tf]isoquinolin-4-thione 185 (Equation 37) <1998MI337>. Cyclization of 6,7-diethoxy-2-propylaminocarbonyl-l,2,3,4-tetrahydroisoquinoline-l-acetonitrile using NaOMe afforded 9,10-diethoxy-2-imino-3-propyl-l,2,4,6,7,l lb-hexahydropyrimido[6,l-tf]isoquinolin-4-one <1995S863>. Cyclization of l-(2-carboxyethyl)-l,2,3,4-tetrahydroquinazoline-2,4-dione 186 in polyphosphoric acid (PPA) afforded l,2,3,5,6,7-hexahydropyrimido[3,2,T /]quinazoline-l,3,7-trione 187 (Equation 38) <1997CHE96>. 

The trione formulation (75) was supported by NMR measurements. ° It has been reported that 6-aminouracil and di-(2,4-dichlorophenyl)-benzylmalonate yield the pyrimido[l,2-c]pyrimidine (76), although no proof of structure was offered. Treatment of the 3-(p3n imidin-6-ylamino)propionic acid (77) with acetic anhydride, however, has been shown to yield compound 78 by rearrangement. ... 

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