Ruben A. Alonso

Antifungal activity of Melia azedarach fruit extract

Abstract The ethanol extract of Melia azedarach ripe fruits showed fungistatic (MIC 50–300 mg/ml) and fungicidal (MFC 60–500 mg/ml) against Aspergillus flavus, Fusarium moniliforme, Microsporum canis and Candida albicans.

One pot synthesis from the elements of symmetrical and unsymmetrical triaryl-phospines, -arsines and -stibines by the SRN1 mechanism

Abstract The reactions of elemental phosphorus, arsenic and antimony with sodium metal in liquid ammonia form “M−1“ species that react with haloarenes under irradiation to form symmetrical triaryl derivatives of these metals by the SRN1 mechanism in fair to good yields. Further reaction with sodium metal gives a derivative nucleophile (diarylphosphide and diarylarsenide ions) that reacts with another haloarene under irradiation to form unsymmetrical phosphines and arsines.

SRN1 reactions of aryl halides with carbanions initiated by sodium amalgam in liquid ammonia

Abstract The reaction of 1-chloronaphthalene with acetone ( 2a ) and acetophenone ( 2b ) enolate ions was initiated by sodium amalgam [Na(Hg)] in liquid ammonia giving good yields of the substitution products 3a and 3b respectively. 2-Chloroquinoline and 2-chloropyridine gave good yields of substitution product with 2b , and moderate to good yields with 2a . 4-Bromobenzophenone and 2a gave 78% of the substitution product 5 . With aryl halides whose radical anions fragment fast and consequently close to the Na(Hg) surface, such as bromobenzene and p -bromoanisole, only dehalogenation products were observed. However, when benzonitrile was used as a redox catalyst, about 50% of the substitution product 6 was obtained with p -bromoanisole and 2a . However, with the more reactive carbanionic nucleophile, such as anthrone anion 4 , good yields of the substitution product 7 were obtained with bromobenzene. In all these reactions neither reduction of the aromatic moiety nor the ketone functionality was observed. It is therefore suggested that Na(Hg) amalgam initiates these S RN 1 reactions.

On the reactivity of dimsyl anion with aryl radicals

Abstract We demonstrated that l-iodoadamantane, iodobenzene and 2-chloroquinoline do not react with dimsyl anion in DMSO, in sharp contrast with results previously reported.

Sonochemistry in SRN1 reactions in liquid ammonia at room temperature

Abstract p -Iodoanisole and 1-halonaphthalenes (Cl, Br, I) react with Ph 2 P − ions in liquid ammonia by the S RN 1 mechanism at room temperature stimulated by ultrasound.

ALTERNATIVE SYNTHESIS OF 2-ARYLPROPANOIC ACIDS FROM ENOLATE AND ARYL HALIDES

Arylpropanoic acids, a type of non-steroidal antiinflammatory drug, have been prepared in liquid ammonia by photo-radical nucleophilic substitution of halogenoarenes with sodium N,N-dimethylacetamide enolate followed by methylation and hydrolysis. Rapid substitution occurred in many cases with good to excellent yields of arylpropanoic acids. The title compounds have also been prepared by arylation of sodium acetone enolate with methylation and oxidation in a haloform reaction.