5-Formyl-l,3-dimethyluracil

Azido-5-formyl-l,3-dimethyluracil is cyclized with hydrazines to afford pyrazolo[3,4-reaction with triphenylphosphine in benzene result in the formation of isoxazolo[3,4-c/]pyrimidine and pyrimido[4,5-[Pg.182]

Chloro-5-formyl-l,3-dimethyluracil is a starting material that is easily accessible by Vilsmeier formylation of the commercially available 1,3-dimethylbarbituric acid (71YZ1372). 

Chloro-5-formyl-l,3-dimethyluracil reacts, furthermore, with 2-aminothiophenole in the presence of l,5-diazabicyclo-[4,3,0]non-5-ene (DBN) via a Smiles rearrangement to afford pyrimido[4,5-6][l, 4]benzothi-azine, while, without base, a simple condensation-substitution step leads to the formation of pyrimido[4,5- ]-[ 1,5]benzothiazepines (85UP1) (Scheme 104). 

Obtained by reaction of 5-formyl-l,3-dimethyluracil-dl with 2,4-pentanedione in the presence of sodinm ethoxide in ethanol on heating for 3 h [4098],... 

Azido-6-formyl-l,3-dimethyluracil (473) is cyclized with hydrazines to form l-substituted-5,7-dimethyl-1 //-pyrazolo[3,4-. 

Dihydro-2(l,3-dimethyluracil-5-yl)-l,3,4-oxadiazole was obtained in 53% yield by the [3+2] cycloaddition of diazomethane to the formyl group of l,3-dimethyl-5-formyluracil <1997T7045>. The reaction of l-acetyl-2-benzyl-hydrazine with methyl glyoxalate in toluene afforded an oxadiazolidine derivative <1996TL4323>. 

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