Alkyl heteroaromatics as building blocks in organic synthesis: The reactivity of alkyl azoles toward electrophilic reagents

Oxazolone (1) couples with aromatic diazonium salts to yield the arylhydrazones (3a-c). Compound 3 reacts with aniline to give aryl hydrazone (5), Compound 5 was also obtained via converting 1 into the imidazolone (4) and subsequent treatment of 4 with aromatic diazonium salts. Compounds 1 and 12 reacted with arylidenemalononitrile (6) to yield compounds 8 and 14 respectively. Also compounds 1, 12 condensed with an aromatic aldehydes to yield 11 and 17. Compounds 11, 17 reacted further with one molecule of malononitrile to give compounds 8 and 14, respectively. Compound 20 which was generated in situ by heating phenacylthiocyanate (19) in acetic anhydride on treatment with hydrazine hydrate or phenyl hydrazine gives 21 and 22 respectively. Also 20 reacted with malononitrile or with ethyl cyanoacetate to give 23 and 24, respectively.