5-Acetyluracil

In a study of the catabolic pathway of pyrimidines, it was found that the reduction of uracil was blocked almost completely by 5-cyanouracil (XXXV) in an in vitro test with the rat enzyme dihydropyrimidine dehydrogenase [303]. 5-Halogenated uracils and thymine are weakly active in this regard, and 5-acetyluracil and 5-trifluoromethyluracil are completely inert. 

Acetyluracil — Ethyl 2-hydroxy-4-methyl-5-pyrimidinecarboxylate (XXXVI), which is prepared by the cyclization of the ureidomethylene derivative of aceto-acetic ester, can be caused to rearrange into 5-acetyluracil (XXXVII) in dilute alkali [304]. Compound (XXXVII) can also be prepared from diketene and ethyl carbamate, followed by treatment with ethyl orthoformate and cyclization with ammonia [305]. 

Acetyluracil can cause the production of certain pyrimidine-specific antibodies [306]. This interesting activity is responsible for the antibody precipitation of some mouse myeloma proteins [307]. 

The Meg X-chain dimer appears to have at least three distinct binding sites. One is located on the rim of the funnel-shaped cleft, a second is at the constriction between funnel and cavity, and a third is at the bottom of the cavity. These sites bind a whole range of compounds including -dansyl lysine, colchicine, 1,10-phenanthroline, methadone, morphine, meperidine, 5-acetyluracil, caffeine, theophylline, menadione, triacetin, and other compounds (Schiffer et al, 1973). 

Identification of a-aminocarboxylic acids as 5-acetyluracil-l-acetic acids... 

A soln. of alanine in 2 iV NaOH warmed 5 min. with a-acetyl- -ethoxy-N-ethoxy-carbonylacrylamide 5-acetyluracil-l-a-methylacetic acid. Y 75-100%.—The products are useful derivatives of a-aminocarboxylic acids. They are immune to hydrolysis by strong acids and may be used for the determination of N-terminal moieties in proteins. F. e., also from peptides and proteins, s. J. H. Dewar and G. Shaw, Soc. 1961, 3254. 

Related findings were reported by Eisen and his collaborators, who showed that mouse myeloma protein, MOPC 315, which has anti-Dnp activity, also combines weakly with 5-acetyluracil, caffeine, and riboflavin, and somewhat more strongly with menadione (2-methyl-1,4-naphthaquinone) (105). None of these compounds is closely related structurally to the dinitrophenyl group. Cross-reactions with 5-acetyluracil of anti-Dnp antibodies induced in some but not all rabbits and guinea pigs were also observed (106). 

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