β-Naphthyl-substituted derivatives of pyrazole, benzodiazepine, isoxazole, and pyrimidine were synthesized by reactions of (Z)-3-chloro-3-(2-naphthyl)propenal with hydrazine, o-phenylenediamine, hydroxylamine, and formamide, respectively.(Z)-3-Chloro-3-(2-naphthyl)propenal (I), which is readily available from 2-acetylnaphthalene via Vilsmeier-Haack reaction [1], is a reactive synthon for the preparation of various organic compounds containing a naphthalene fragment. The chlorine atom at the C=C bond in molecule I is activated due to conjugation with the electron-acceptor carbonyl group, and it can readily be replaced by other functional groups. The presence in molecule I of two reactive centers (C=O and =C-Cl) makes it possible to build up various heterocyclic systems. We recently showed that (Z)-3-chloro-3-(2-naphthyl)propenal readily reacts with primary aromatic amines to give naphthylimino enamines which undergo intramolecular cyclization to naphthyl-substituted quinolines [2]. The goal of the present study was to develop methods of synthesis of various nitrogen-containing heterocycles by reactions of (Z)-3-chloro-3-(2-naphthyl)propenal (I) with a series of nucleophiles. As the latter we used hydrazine, 2,4-dinitrophenylhydrazine, o-phenylenediamine, hydroxylamine, and formamide.It is known [3] that the reaction of β-chlorovinyl ketones with hydrazine underlies a preparative procedure for the synthesis of pyrazole derivatives. We expected that analogous reaction of chloropropenal I should also lead to formation of the corresponding naphthyl-substituted heterocycle. In fact, aldehyde I reacted with hydrazine hydrate to afford 74% of 5-(2-naphthyl)pyrazole (II) which was identified on the basis of its spectral data and elemental composition. The 13 C NMR spectrum of pyrazole II was reported in [4]; however, neither procedure for preparation of this compound nor its other spectral data were given (although the authors noted that this compound was previously unknown). The molecule of naphthylpyrazole II contains an N-nucleophilic center (NH); therefore, we examined its alkylation with 2-nitropentachloro-1,3-butadiene (III) which is known as a highly reactive electrophilic agent toward various amines [5]. The reaction involved replacement of both geminal chlorine atoms in the dichloronitrovinyl fragment of III and resulted in formation of a bis-pyrazole structure, 3,4,4-trichloro-1,1-bis[5-(2-naphthyl)pyrazol-1-yl]-2-nitro-1,3-butadiene (IV) (Scheme 1).(Z)-3-Chloro-3-(2-naphthyl)propenal (I) was converted into the corresponding 2,4-dinitrophenylhydrazone (V) in 77% yield by treatment with 2,4-dinitrophenylhydrazine in ethanol in the presence of sodium acetate. However, our attempts to effect heterocyclization of hydrazone V by the action of triethylamine or pyridine or by heating at 200°C (15 h) were unsuccessful. In all cases, the initial hydrazone was recovered from the reaction mixtures. Presumably, the presence of two electron-acceptor nitro groups in the benzene ring leads to electron density transfer from the...

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By reaction of Z-3-(2-naphthyl)-3-chloro-2-propenal with semicarbazide hydrochloride and thiosemicarbazide the corresponding semicarbazone and thiosemicarbazone were obtained that underwent a heterocyclization into a pyrazole system with elimination of amide moieties and with migration of the naphthyl fragment into the position 4 of the pyrazole ring. The alkylation of 4-(2-naphthyl)pyrazole synthesized with 2-nitropentachloro-1,3-butadiene afforded 1,1-bis[4-(2-naphthyl)-pyrazol-1-yl]-2-nitrotrichloro-1,3-butadiene.Z-3-(2-Naphthyl)-3-chloro-2-propen-1-al (I) easily prepared from 2-acetonaphthone by VilsmeierHaack reaction [1] contains two reactive sites (C=O and =CCl) that permits an effective application of the compound to building up versatile heterocyclic systems including a naphthalene fragment: benzodiazepine, isoxazole, pyrimidine [2], and quinoline [3]. We formerly demonstrated that the reaction between chloropropenal I and hydrazine hydrate was a convenient procedure for preparation of 5-(2-naphthyl)pyrazole [2].The goal of this study was preparation of chloropropenal I semicarbazone and thiosemicarbazone and the attempt at their heterocyclization into a pyrazole system containing a naphthalene fragment and amide or thioamide groups respectively.Semicarbazone II and thiosemicarbazone III of chloropropenal we obtained in 8082% yield by reacting chloropropenal I with semicarbazide hydrochloride and thiosemicarbazide respectively. The IR spectra of compounds II and III obtained lacked the absorption bands of the aldehyde group and contained the bands from C=N bonds vibrations at 1563 (compound II) and 1597 cm 1 (compound III). Vibrations of the NH 2 groups of compounds II and III are characterized by absorption bands at 3473 and 3432 cm 1 respectively, and vibrations of the NH groups appeared as broadened bands in the region 32063283 cm 1 . In the 1 H NMR spectra of compounds II and III alongside the resonances from the protons of the naphthyl groups and exocyclic =CH broadened singlets were observed with the chemical shifts d 9.410.5 and 6.356.45 ppm belonging to the protons of the NH and NH 2 groups respectively.The heterocyclization of compounds II and III into a pyrazole system was effected by boiling in the glacial acetic acid. We expected to obtain pyrazole with a naphthyl fragment attached to position 5 of the ring and amide or thioamide group in position 1. However the process occurred differently and involved a loss of amide groups and a migration of the naphthyl fragment into position 4 of the pyrazole ring. Thus in both cases the same product was obtained that based on elemental analysis, 1 H NMR, IR, and mass spectra was assigned a structure of 4-(2-naphthyl)pyrazole (IV).In the mass spectrum of compound IV the molecular ion peak is present with m/z 194 and relative abundance 100%, and the elemental analysis corresponds to an empirical formula C 13 H 10 N 2 . The IR and 1 H NMR spectra of compound IV essentially differ from the spectra of 5-(2-naphthyl)-pyrazole (V) we have synthesized p...