Uracils 6-anilino- from

With dimethyl acetylenedicarboxylate, the point of attack depends mainly on the solvent. In some cases, mixtures of 7-oxo and 5-oxo compounds together with the Michael adducts of the C5 or the 6-amino group of 6-aminouracil are obtained, e.g. with 6-(methylamino)uracil. On the other hand, in the case of 6-anilino-l,3-dimethyluracil, only the two possible pyrido[2,3-solvent dependence is remarkable and only partially understood. The reactions appear to be classifiable according to (a) presence or absence of an N1 substituent and (b) the availability of protons from the solvent.165... 

Similar to the nucleobase-calixarene cmijugates described above, Shi et al. designed a caUx[4]arene derivative with a uracil moiety at the upper rim by coupling uracil acetic acid directly to a mono-anilino caUx[4]arene. The obtained It—A isotherms again indicate the formation of supramolecular complexes at the air-water interface, that rely on the base pairing between uracil and adenine moieties. Furthermore ESl-MS experiments showed that the uracil calixarene conjugate is able to recognize adenine and adenosine from other nucleotides and bases [36],... 

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