M. J. Vilaplana

Synthesis of the novel chiral 1,3-amino alcohol 8-N,N-bis(ferrocenylmethyl)amino-menthol and its use as catalyst in the enantioselective addition of diethylzinc to aldehydes

Abstract Optically active 8-N,N-bis(ferrocenylmethyl)aminomenthol 5, obtained by condensation of (−)-aminomenthol with ferrocenecarboxaldehyde followed by N-alkylation with (ferrocenylmethyl)trimethylammonium iodide and further reduction, was found to catalyze (5 mol%) the enantioselective ethylation of aromatic, aliphatic and organometallic aldehydes to secondary alcohols with high enantioselectivities (up to 95%) at room temperature.

6π-electrocyclization of azahexa-1,3,5-trienes: a new entry to a regiospecific synthesis of 3-aryl(heteroaryl)pyridines

Abstract Aza Wittig reaction of iminophosphoranes derived from ethyl α-azido-β-aryl(pyrazolyl)propenoates with α,β-unsaturated aldehydes leads to aldimines which by heating undergo electrocyclic ring-closure through the 3-azahexa-1,3,5-triene moiety to give 3-aryl(pyrazolyl)pyridines in a completely regiospecific fashion. However, iminophosphoranes derived from ethyl α-azido-β-furyl(thienyl)propenoates furnish a mixture (1.2:1 ratio) of the corresponding furo- or thieno-pyridine(2-azahexa-1,3,5-triene electrocyclization product) and 3-furyl(thienyl)pyridine(3-azahexa-1,3,5-triene electrocyclization product).

An efficient preparation of novel ferrocene derivatives via aza Wittig reaction and X-ray structure of bis(β-ferrocenylvinyl)carbodiimide

Novel ferrocene derivatives such as β-ferrocenylvinylheterocumulenes and ferrocene-containing imidazole rings have been easily prepared from β-ferrocenylvinyliminophosphorane 3 by Aza Wittig reactions.

One pot conversion of alkyl halides into thiols under mild conditions

Abstract Alkyl halides are converted into the corresponding thiols in good yields at room temperature under neutral conditions by reaction with 1-(2-hydroxyethyl)-4,6-diphenyl-pyridine-2-thione.

Iminophosphorane-mediated synthesis of fused uracils. A faclle one-pot preparation of pyrimido[4,5-d]pyrimidine derivatives

Abstract The aza Wittig-type reaction of iminophosphoranes 3, 5-[(N-Arylimino)methyl]-6-[(triphenylphosphoranylidene)amino]-1, 3-dimethyl uracils, with aromatic isocyanates leads to the functionalized pyrimido[4,5-d]pyrimidines 4. Iminophosphoranes 5, prepared from 3 by selective reduction with sodium borohydride, undergo dihydropyrimido annelation by reaction with isocyanates to give 7-amino-6-aryl-1,3-dimethyl-1,2,3,4,5,6-hexahydropyrimido[4,5-d]pyrimidines 6.

Electrocyclization of 3-azahexa-1,3,5-trienes: A convenient iminophosphorane-mediated preparation of 4-arylpyridines

Aza Wittig reaction of iminophosphoranes 1, derived from α-azido- α,β-unsaturated esters and β-arylpropenals 2 leads to 4-arylpyridines in moderate to good yields.

Study on the mutagenicity of nifurtimox and eight derivatives with the l-arabinose resistance test of Salmonella typhimurium

The mutagenicity of nifurtimox (nfx) and 8 nfx analogues has been investigated with the L-arabinose forward-mutation assay of Salmonella typhimurium. The nfx analogues tested were obtained by replacing the 3-methyl-4-yl-tetrahydro-1,4-thiazine-1,1-dioxide group of the parent compound with the following other groups: indazol-1-yl (1); pyrazol-1-yl (2); benzimidazol-1-yl (3); 1,2,4-triazol-4-yl (4); 1-methyl-3-methylthio-1,2,4-triazol-4-yl-5-thione (5); 3,5-bis(methylthio)-1,2,4-triazol-4-yl (6); 1-adamantyl (7); 4,6-diphenylpyridin-1-yl-2-one (8). The mutagenic activity of each chemical was determined by the standard plate-incorporation test, in the presence or absence of the S9 activation mixture. The 9 compounds were mutagenic and exhibited linear dose-mutagenic response relationships. They were direct-acting mutagens and showed a nearly 1000-fold range in mutagenic potency from chemical 1 to nfx. In most cases, the addition of S9 mixture to the test plates decreased the mutagenicity of compounds. This effect was particularly noticeable in the case of chemicals 1-3, 5 and 7 where a more than 70% decrease in mutagenic activity was observed in the presence of the S9 mixture. The mutagenic potency of compounds in the Ara test showed a negative linear correlation with previously reported antitrypanosomal activity. Thus, chemicals 6 and 8 with in vitro activities against Trypanosoma cruzi clearly superior to that of nfx showed 2 of the lowest mutagenic potencies in the Ara test and these were only somewhat higher than the mutagenicity of the reference drug.

Vinyliminophosphorane-mediated preparation of 2-arylquinoline and 4-aryl-1-azaanthraquinone derivatives. X-Ray crystal structure of 1,2-dihydro-3H-indazolo[2,3-a]quinolin-4-one

Abstract The reaction of the iminophosphorane derived from 3-azidocyclohexen-2-enone with substituted cinnamyl aldehydes affords 2-aryl-tetrahydroquinoline derivatives, which are easily converted into 2-arylquinolines. By contrast, iminophosphorane derived from 2-azidocyclohex-2-enone reacts only with α,β-unsaturated aldehydes without substituent at β-position to give 5,6-dihydro-8(7H)quinolinones. The iminophosphorane derived from 2-azido-1,4-naphthoquinone reacts with substituted cinnamyl aldehydes providing directly 4-aryl-1-azaanthraquinones. The crystal and molecular structure of 1,2-dihydro-3H-indazolo[2,3-a]quinolin-4-one has been solved by X-Ray analysis.

P,N-Heterodifunctional ligands by selective Staüdinger reaction of β-substituted vinylazides with (Z)-1,2-bis(diphenylphosphanyl)ethene and formation of cyclometalled complexes of palladium(II) of these ligands — crystal and molecular structure of a new chiral cyclometallaphosphoraniminophosphane of palladium(II)

Abstract Staudinger reactions of the β-aryl-, heteroaryl- and ferrocenylvinylazides ( 2 ) with ( Z )-1,2-bis(diphenylphosphanyl)ethene afford the P , N -ligands ( 3 ) in good yields. Reaction of 3 with dichlorobis(benzonitrile)palladium(II) leads to the Pd(II) metallacycle derivatives 5 . The molecular structure of 5e has been determined by X-ray crystallography. The electrochemical behavior of this compound is also reported.

SYNTHETIC APPLICATIONS OF VINYLIMINOPHOSPHORANES BASED ON THE REACTIVITY OF THE VINYL SIDE CHAIN : PREPARATION OF DIHYDROPYRIDINES

Abstract New reactions of vinyliminophosphoranes with aldehydes involving an initial nuclcophilic attack of the β-carbon atom of the vinyl side chain on the carbonylic carbon atom is reported. The resulting bctaines undergo either intra- or intermolecular cyclization to give pyridines or dihydropyridines.