Reaction of 1-methyluracil with phenylbenzhydrazonoyl chloride
The ambident anion of 1-methyluracil gives with phenylbenzyhydrazonoyl chloride, depending on the conditions, the N-acylation product (polar solvent, room temperature), or the O-acylation product (nonpolar solvent, heating), which rearranges to a cytosine derivative. Convenient methods have been developed for the preparation of 6-methyl-1,3-diphenyl-5,6-dihydro-5-oxopyrimido[4,3-c]triazolium chloride, a fluorescent derivative of 1-methyluracil, from the N-acylation product, and for the rapid base cleavage of the uracil ring under very mild conditions.