J. Gonzalo Rodríguez

Synthesis, structure and anti-fungal activity of 3-(2′-nitrovinyl)indoles

Abstract 3-(2′-Nitrovinyl)indoles 7—18 have been prepared in good yields by condensation of 3-formylindoles with nitroalkanes. Analyses of 1H NMR data suggest that the indolic system has an extended conjugation through the ethylene double bond and the nitro group. 3-(2′-Methyl-2′-nitrovinyl)indole 9 and 2-methyl-3-(2′-methyl-2′-nitrovinyl)indole 13 show anti-fungal activity against Candida albicans similar to that of ketoconazole. In contrast, all the nitrovinylindoles (except 12 and 13) show high activity against Trichomonas vaginalis similar to that of metronidazole.

A new advanced method for heterogeneous catalysed dechlorination of polychlorinated biphenyls (PCBs) in hydrocarbon solvent

The dechlorination of PCBs with solid hydrazine hydrochloride catalysed by palladium, in an organic solvent, yields biphenyl in short reaction times. The catalyst system can be efficiently reused for several cycles. Ultrasonication of the heterogeneous catalysed reaction increases the dechlorination rate remarkably. The reactivity of the CCl bond on the PCB ring are in the order meta>para≫ortho.

A new advanced method for heterogeneous catalysed dechlorination of 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes in hydrocarbon solvent

Abstract A new advanced method for dechlorination of 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes in organic solvent catalysed by palladium on carbon support and solid hydrazine hydrochloride yields benzene in short reaction times. The catalyst system can be efficiently reused for several cycles. Ultrasound radiation of the heterogeneous catalyst reaction increases remarkably the rate of dechlorination.

Synthesis of aspidospermidine alkaloids from 1,2,3,4-tetrahydrocarbazole: Total stereoselective synthesis of (±)-18-noraspidospermidine

The reactivity of the 1,2,3,4-tetrahydrocarbazol-4-one derivatives has been analysed and applied to the synthesis of (±)-18-noraspidospermidine (1b). This was synthesised, starting from 4-(1′,3′-dioxolan-2′-yl)cyclohexanone which was successively transformed to 3-methyl-3-(3′-nitropropyl)-1,2,3,4-tetrahydrocarbazol-4-one and to the imine tetracycle 13 by means of nickel boride catalyst. The reduction of 13 to the natural cis D ring junction was carried out with the LiAlH4AlCl3 system. The construction of the E-ring was carried out by a Pummerer type reaction from thecis-7-tosyl-1-phenylthioacetamide derivative 17 by oxidation followed by intramolecular cyclisation, desulfurization and reduction to 1b.

Synthesis of nanostructures based on 1,4- and 1,3,5-phenylethynyl units with π-extended conjugation. Carbon networks dendrimer base units

Abstract A convenient and efficient synthesis of 3,5-di(silylethynyl)phenylacetylene and p -[3,5-di(silylethynyl)phenylethynyl]phenylacetylene has been carried out. These compounds serve to prepare nanometer-sized conjugated 1,4- and 1,3,5-phenylethynyl oligomers, by means of cross-coupling with a convenient haloaryl derivative, catalysed by palladium(II), in excellent yields. The phenylethynyl homologues show fluorescence emission, the wavelength of which is displaced by approximately 20 nm by each phenylethynyl unit increasing the conjugate chain.

Synthesis of carbon dendron nano-chains with π-extended conjugation based on linear 1,4-phenylethynyl and 1,5-naphthylethynyl subunits

A convenient and efficient synthesis of 3,5-di(trimethylsilylethynyl)phenylacetylene and p-[3,5-di(trimethylsilylethynyl)-1-phenylethynyl]phenylacetylene and the naphthylethynyl homologues terminal acetylenes of 5-(N,N-dimethylamino)naphthylethyne have been carried out. These terminal acetylene compounds serve to prepare nanometer-sized conjugated 1,3,5-tri(ethynylphenyl)benzene and 1,3,5-tri(ethynylnaphthyl)benzene oligomers, by means of heterocoupling with 1,3,5-triiodobenzene, catalysed by palladium, in excellent yields. Both the ethynylphenyl or ethynylnaphthyl homologues chains show fluorescence emission radiation, with important quantum yield.

Synthesis of 1,5-naphthylethynyl nanostructure networks with extended π-conjugation. Effective heterocoupling catalyzed by palladium under a compatible CO2 atmosphere

Abstract The synthesis of a new extended π-conjugated 5-N,N-dimethylaminonaphthyl family was undertaken by palladium-catalyzed cross-coupling reaction between a protected 5-iodonaphthylethynyl and 1-ethynyl-5-(N,N-dimethylamino)naphthalene. Under an argon atmosphere, only the homocoupling product 1,4-(N,N-dimethylamino)naphthyl-1,3-butadiyne was isolated, in excellent yield. However, under a compatible and pure carbon dioxide atmosphere, the cross-coupling product was obtained in excellent yield.

π-Extended conjugate phenylacetylenes. Synthesis of 4-[(E) and (Z)-2-(4-ethenylphenyl)ethenyl]pyridine. Dimerization, quaternation and formation of charge–transfer complexes

Abstract The conjugate (E)- and (Z)-(4′-pyridylethenyl)-4-phenylethyne (E-4 and Z-4 ) has been satisfactorily prepared by two different routes: (a) by dehydrohalogenation of 4′-pyridylethenyl-4-phenyl-β-chloroethene; (b) by the Wittig reaction between p-(iodobenzyl)(triphenyl)phosphine ylide and 4-pyridinecarboxaldehyde, E/Z isomer separation, and cross-coupling with 2-methyl-but-3-yn-2-ol followed the propanone elimination. The Glaser oxidative dimerization of (Z)-4 yields (Z,Z)-1,4-di[(4′-pyridylethenyl)-4-phenyl]-buta-1,3-diyne in good yield, (Z,Z)-5 . (E,E)-5 was obtained by phase transfer oxidative dimerisation of (E)-4 in presence of their N-methyl salt (E)-10 . Mono- and di-N-methylated salts of conjugate (E,E)-5 and (Z,Z)-5 , were obtained by quaternation with iodomethane. The (Z,Z)-5 di-N-methylated salt forms charge–transfer complexes with TCNE, TCNQ and TMPD.

Synthesis and X-ray structure of 1,4-bis[4-(N,N-dimethylamino)phenyl]buta-1,3-diyne: charge-transfer complex with acceptors

4-(N,N-dimethylamino)phenylethyne has been satisfactorily prepared by the Wittig reaction between chloromethylene(triphenyl)phosphine ylide and 4-(N,N-dimethylamino)benzaldehyde, followed by hydrochloric acid elimination. 1,4-Bis[4-(N,N-dimethylamino)phenyl]-buta-1,3-diyne was obtained by oxidative dimerization in good yield. The dimer forms a 1 : 1 charge-transfer complex with TCNE, an X-ray structure analysis of which is reported.

Synthesis of 1,4-di(n-pyridyl)buta-1,3-diyne and formation of charge-transfer complexes. X-Ray structure of 1,4-di(3-pyridyl)buta-1,3-diyne

Ethynylpyridines have been satisfactorily prepared by two different routes: (a) the Wittig reaction between chloromethylene(triphenyl)phosphine ylide and a pyridinecarbaldehyde, followed by elimination of hydrogen chloride; (b) from the 2-methyl-4-(n-pyridyl)but-3-yn-2-ol intermediate, by elimination of acetone. 1,4-Di(n-pyridyl)buta-1,3-diynes are obtained by oxidative dimerization in good yield. An X-ray structure of the 3-substituted dimer is reported. Mono- and di-methyl salts of the 3-substituted diyne have been obtained and the charge-transfer complexes with tetramethyl-p-phenylenediamine (TMPD) are formed.