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 arylhydraz ones (3a-c). Compound 3 reacts with aniline to give aryl hydrazone (5), Com pound 5 was also obtained via converting 1 into the imidazolone (4) and sub sequent treatment of 4 with aromatic diazonium salts. Compounds 1 and 12 re acted with arylidenemalononitrile (6) to yield compounds 8 and 14 respectiv ely. 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 treatmen t with hydrazine hydrate or phenyl hydrazine gives 21 and 22 respectively. Also 20 reacted with malononitrile or with ethyl cyanoacetate to give 23 an d 24, respectively.