The 3-anilinoenones 3a,b were prepared from the corresponding 3-dimethyl-aminopropenones. The reactivity of 3a,b towards a variety of carbon and nitrogen nucleophiles as well as naphthoquinones is reported.

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1‐Substituted‐3‐dimethylaminopropenones 1a‐d reacted with acetylacetone and with ethyl acetoacetate to yield regioselectively 2,3,6‐trisubstituted pyridines. Refluxing 1a‐d in acetic acid/ammonium acetate resulted in the formation of 6‐substituted‐3‐aroylpyridines, whereas refluxing in acetic acid alone afforded 1,3,5‐triaroylbenzene.

Synthesis of new azolyl azoles and azinyl azoles from the reaction of compounds 1, 4 and 7 with phenyl isothiocyanate is reported. Compound 10 reacts with benzene diazonium chloride to yield either phenylhydrazones 11 and 12 or the triazoloquinoline 13. J. Heterocyclic Chem., 42, 483 (2005).It is known that a methylene group attached to nitrogen atoms of azoles is activated toward electrophilic reagents and this feature has stimulated recent interest in the utility of azolylmethyl ketones as building block in heterocyclic chemistry [1][2][3][4][5][6][7]. In conjunction with previous work [7][8][9], we now report the synthesis of the title compounds 1, 4, 7 and 10. As part of our ongoing program, we decided to synthesize new N-heteroarylazoles in order to explore the biological properties and the pyrolysis in the gas phase.Compounds la and 1b react with phenyl isothiocyanate in dimethylformamide (DMF) in the presence of potassium hydroxide and after acidification of the reaction mixture compounds 2a and 2b are obtained. Analysis of 13 Cnmr data of compounds 2a and 2b shows a signal at ca. 190 ppm which is assigned to the presence of conjugated carbonyl carbon (CO) and the signal corresponding to the methylene group was not observed. NOE experiments show that the Z isomer of compound 2 was preferred over the E isomer indicating that the Ph and the R groups are close to each other (Figure 1). Similarly, compounds 4a and 7 react with phenyl isothiocyanate to yield compounds 5 and 8 but these compounds could not be isolated. However, when compounds 2b, 5a and 8 were treated with chloroacetone or phenacyl bromide in the presence of potassium hydroxide thiophene derivatives 3, 6, and 9 were formed and isolated in good yields (see Schemes 1 and 2). Compounds 4b, 10a and 10b failed to react with phenyl isothiocyanate under a variety of experimental conditions; diphenylthiourea was the only product isolated from these reactions.

The condensed aminothiophenes 5–7a,b react with 1,4-naphthoquinone in refluxing ethanol to yield products of addition followed by hydrogen sulfide elimination in a Diels–Alder type reaction. When the reaction is carried out under microwave irradiation a dipolar addition occurred affording products of substitution at C-l. Compounds 5–7a,b coupled with aromatic diazonium salts to yield arylazo derivatives 15 and 16 where coupling occurred at C-1. The condensed aminothiophenes 5–7a,b reacted with dimethylformamide dimethylacetal to yield amidines 17–19.