2.4- Dioxopyrimidine

Aluminum chloride [7446-70-0] is a useful catalyst in the reaction of aromatic amines with ethyleneknine (76). SoHd catalysts promote the reaction of ethyleneknine with ammonia in the gas phase to give ethylenediamine (77). Not only ammonia and amines, but also hydrazine [302-01-2] (78), hydrazoic acid [7782-79-8] (79—82), alkyl azidoformates (83), and acid amides, eg, sulfonamides (84) or 2,4-dioxopyrimidines (85), have been used as ring-opening reagents for ethyleneknine with nitrogen being the nucleophilic center (1). The 2-oxopiperazine skeleton has been synthesized from a-amino acid esters and ethyleneknine (86—89). 

To prepare fervenulin 4-oxides 12 or toxoflavine 4-oxides 146, it is convenient to use the reaction of l,3-dimethyl-2,4-dioxopyrimidin-6-yl hydrazone 147 or N-(3-methyl-2,4-dioxopyiimidin-6-yl) iV-methylhydrazone 148 with potassium nitrate in acetic acid [75CPB1885,76CPB338,76JCS(CC)658,82JHC1309,93CPB362]. Diethyl azodicarboxylate can be used instead of potassium nitrate [76JCS(P1 )713]. 

Boiling aqueous ethanolic solutions of 2-benzothiazolylaminomethy-lenemalonates (1351) in the presence of sodium hydroxide for 30 min gave 1-substituted 2,4-dioxopyrimidine-5-carboxylic acids (1352) in 52-70% yields (79GEP2810863, 79SAP1053). 

Similarly treatment of isothiocyanates 2, 30, and 31 with 6-hydrazino-1,3-dimethyluracil (113) in acetonitrile solution yielded JV-glycosyl-2-(1,3-dimethyl-2,4-dioxopyrimidin-6-y lhydrazino)thiocarboxamides 114-... 

A comparison of aliphatic amides, cyclic amides, cyclic imides and 2,4-dioxopyrimidines (uracils) in their deprotonated and diplatinated form (Scheme 4) reveals an increasing steric shielding of the V-bonded Pt ion (Ptx). With respect to formation of stacked and partially oxidized dinuclear species, it is evident that application of the binding principles seen in the blues of cyclic amides to the uracils and imides allows for tetranuclear species only. On the other hand, the presence of an additional O-donor in the imides and uracils (and likewise the cytosines, vide infra) provides an... 

The ring opening of the isoxazole part of isoxazolo[3,4-malonic acid derivatives (XCH2Y) is supposed to give the corresponding (l,2,3,4-tetrahydro-6-(hydroxyamino)-l,3-dimethyl-2,4-dioxopyrimidin-5-yl)methylenemalonic acid derivatives, which cyclize via one of the groups X or Y to yield l,3-dimethylpyrido[2,3-d]-pyrimidine-2,4(1 /f,3//)-dione 8-oxides.306... 

The tetranuclear metal complex, [(l,2-diaminoethane)Pt(uracilate-AM,A(3)] , can be considered a special heterocalixarene, a metal analogue of calix[4]arene which functions as hosts for small molecules or ions and possesses metal binding properties, either in the cavity or at the periphery. The bridging unit of the classical calix[4]arene, usually a CH2 group, is replaced by the (en)Pt(II) unit in the Pt-complex. This change, the replacement of the p-phenol by the 2,4-dioxopyrimidine and the positive charge introduced by the metal cations, leads to a number of differences as compared with the classical calix[4]arenes. Their preparation, x-ray crystal structure, and solution behavior have been described <94JA616>. 

Succinamide stirred 20 min. at 50-60° with Pb-tetraacetate in dimethylformamide hexahydro-2,4-dioxopyrimidine. Y 94%. - This method, which gives higher yields, is more selective, of wider application, and technically simpler than the... 

Dioxopyrimidine. See Uracil Dioxothiolan 1,1-Dioxothiolan. See Sulfolane Dioxyanthrachinonum 1,8-Dioxyanthraquinone. 

CAS 66-22-8 EINECS/ELINCS 200-621-9 Synonyms 2,4-Dihydroxypyrimidine 2,4-Diketopyrimidine 2,4-Dioxopyrimidine 2,4-Dioxypyrimidine 2,4-Oxypyrimidine 2,4-Pyrimidinediol 2,4-Pyrimidinedione ... 

Ikuno and coworkers [73] studied the reaction of 4-methoxybenzenamine 287 and l,2,3,4-tetrahydro-l,3,6-trimethyl-2,4-dioxopyrimidine-5-carbaldehyde 288 with 8,8-dicyanoheptafulvene 259, which yields tetrahydrocyclo-hepta[ ]quinazoline 289 (Scheme 7.63). 

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