4- Amino-1,3-dimethyl-5-nitrosouracil

The same 6-amino-5-nitrosouracil is converted by phenacyl bromide-pyridine into a 6-hydroxy-7-phenyllumazines [77H(6)1907]. Condensation with phenacylidenetriphenylphosphoranes and dimethyl acetylenedicar-boxylate gives lumazine derivatives [76CC588 81 H( 15)757 82JHC949] (Scheme 67). 

C6H7N302 1 -methyl-2-nitro-5-vinyl-1 H-imidazole 39070-08-1 351.15 29.788 2 7373 C6H8N403 1,3-dimethyl-4-amino-5-nitrosouracil 6632-68-4 460.65 40.117 1,2... 

Pb-tetraacetate added portionwise during 5 min. to a soln. of l,3-dimethyl-6-amino-5-nitrosouracil in glacial acetic acid, and stirred 18 hrs. at room temp, under Ng l,3,7,9-tetramethyl-2,4,6,8(lH,3H,7H,9H)pyrimido[5,4-g]pteridinetetrone 5-oxide. Y 67%. E. C. Taylor, Y. Maki, and A. McKillop, J. Org. Chem. 37, 1601 (1972). 

The regioselectivity of the Timmis synthesis is demonstrated by condensation of the 4-amino-5-nitrosouracil (8), leading to l,3-dimethyl-6-phenyllumazine (7) with phenylac-etaldehyde or to the 7-phenyl isomer 9 with acetophenone ... 

Amino-l,3-dimethyl-5-nitrosouracil in water treated with 1 N NaOH, and stirred 2 hrs. at room temp. 4,5-diimino-l,3-dimethyl-2-imidazolidone. Y 79%. F. e. s. K. Klemm and W. Priisse, A. 1974, 1882. 

Amino-l,3-dimethyl-5-nitrosouracil heated 1 hr. at ISO with POCI3 in dimethyl-formamide -> 8-dimethylaminotheophylline. Y 72%. F. e. s. F. Yoneda, T. Mat-sumura, and K. Senga, Chem. Commun. 1972, 606. 

Amino-l,3-dimethyl-5-nitrosouracil stirred ca. 10 min. at 0-2° with equimolar amounts of salicylaldehyde and 80%-hydrazine hydrate in dimethylformamide, then gently refluxed for 3 hrs. l,3-dimethyl-6-o-hydroxyphenyl-7-azalumazine. Y 85%. F. e. s. F. Yoneda et al., J. Heterocyclic Chem. 7, 1443 (1970). 

A mixture of 6-amino-l,3-dimethyl-5-nitrosouracil, phenacyl bromide, and tri-phenylphosphine refluxed 0.5 hr. in tetrahydrofuran, aq. 10%-NaOH added, and refluxing resumed for 0.5 hr. l,3-dimethyl-7-phenyllumazine. Y 67%. F. e. s. K. Senga, H. Kanazawa, and S. Nishigaki, Chem. Commun. 1976, 588. 

Amino-l,3-dimethyl-5-nitrosouracil (270), reported last year as a highly versatile precursor for the purine and pteridine ring systems, has again found use (Scheme 63) in a new synthesis of 6-hydroxy-pteridines (271). Photo-decomposition of 6-azido-l,3-dimethyluracil as a solution in a secondary or primary amine has been used as a convenient method of preparing 6-alkylamino-5-amino-uracils. The procedure has now been extended ... 

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