C-H functionalization of sp(3) centers with aluminum: a computational and mechanistic study of the Baddeley reaction of decalin.

Decalin undergoes reaction with aluminum trichloride and acetyl chloride to form a tricyclic enol ether in good yield, as first reported by Baddeley. This eye-catching transformation, which may be considered to be an aliphatic Friedel-Crafts reaction, has not previously been studied mechanistically. Here we report experimental and computational studies to elucidate the mechanism of this reaction. We give supporting evidence for the proposition that, in the absence of unsaturation, an acylium ion acts as a hydride acceptor, forming a tertiary carbocation. Loss of a proton introduces an alkene, which reacts with a further acylium ion. A concerted 1,2-hydride shift/oxonium formation, followed by elimination, leads to formation of the observed product.

Synthesis and cyclisation of 1,4-disubstituted semicarbazides.

Semicarbazides, besides possessing medicinal properties, also find wide applications in agriculture and industry. We report in this article the synthesis of the four 1,4-disubstituted semicarbazides: 1-cinnamoyl-4-phenyl semicarbazide (1), 1-oleyl-4-phenyl semicarbazides (2), 1,1',1''-tricitryl-4,4',4''-triphenyl semicarbazide (3) and 1-benzoyl-4-phenyl semicarbazide (4), by the condensation of four different hydrazides: cinnamic acid hydrazide (5), oleic acid hydrazide (6), citric acid hydrazide (7) and benzoic acid hydrazide (8). The acid hydrazides were prepared by the condensation of four different acids with phenyl isocyanate. The semicarbazides were also subjected to acid catalysed intramolecular cyclisation. The cyclisation of (1) and (2) afforded substituted 1,3,4-oxadizoles: 2-cinnamoyl-5-aminophenyl 1,3,4-oxadizoles (9) and 2-oleyl-5-aminophenl 1,3,4-oxadizoles (10), respectively, in high yield, while no cyclisation occurred in the cases of (3) and (4). The products in each case have been identified on the basis of melting points and IR spectral studies.

Phytochemical investigations on Iris germanica.

Phytochemical investigations on the methanol extract of Iris germanica resulted in the isolation of a new benzene derivative, 2'-methyl-6'-hydroxy cyclohexenyl-3-methyl-1-acetophenone ether (1). Further, another known benzene derivative, isopenol (2), also afforded two known isoflavones, irisolone (3) and irisolidone (4). The structure of the new compound was determined on the basis of spectroscopic data, including 2D-NMR experiments, while the known compounds were identified on the basis of their spectral data and existing literature evidence. The comparison of the spectral data of the irisolidone (3) with that reported for the molecule led us to revise some of the reported 1H-NMR chemical shift assignments.