Abstract
Reaction of hydrazonoyl halides 1 with 2-(aroylmethyl)-6-methylpyrimidin-4(3H)-ones 3 proved to be site selective and gave 2-(3-acetyl-1,5-diarylpyrazol-4-yl)-6-methylpyrimidin-4(3H)-ones 5 via dehydrative cyclisation of the hydrazone intermediates 4. The structures of both 4 and 5 were elucidated by spectral data and alternative synthesis. The mechanism of the reaction was discussed.