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Papers by Jose Luis Vila Castro

Research paper thumbnail of Synthesis of Alkenes by Fragmentation Reactions; Mechanistic Views; the Organic Chemistry Notebook Series, a Didactical Approach, Nº 5

This is the fifth chapter in the series published by the same authors: "The Organic Chemistry Not... more This is the fifth chapter in the series published by the same authors: "The Organic Chemistry Notebook Series, a Didactical Approach". Here we offer the mechanistic views of the synthesis of alkenes by fragmentation reactions. The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. Fragmentation reactions can conduct to the synthesis of alkenes. This is not a common method, but useful under determined conditions. For example, the fragmentation of monotoluene-p-sulphonates or methanesulphonates of suitable cyclic 1,3-diols is reviewed and the corresponding mechanism proposed. The preparation of Ecyclodecenone and cyclodecadienes by fragmentation of substituted decalylboranes is also described mechanistically. The description of the fragmentation of bicyclic compounds to afford alkenes like macrolides from acetaltosylate is also included here. The preparation of acyclic alkenes from cyclic precursors is also mechanistically described here. We have used a series of reactions reviewed by W. Carruthers, and we have proposed didactical and mechanistic views for them. This latest approach is included in the synthetic methods reviewed by W. Carruthers with respect to the "Formation of carbon-carbon double bonds".

Research paper thumbnail of Synthesis of Alkenes by Oxidative Decarboxylation of Carboxylic Acids; Mechanistic Views; the Organic Chemistry Notebook Series, a Didactical Approach, Nº 6

This is the sixth chapter in the series published by the same authors: "The Organic Chemistry Not... more This is the sixth chapter in the series published by the same authors: "The Organic Chemistry Notebook Series, a Didactical Approach". Here we offer the mechanistic views of the synthesis of alkenes by oxidative decarboxylation of carboxylic acids. The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. The oxidative decarboxylation of carboxylic acids is a useful method for generating alkenes. Here we propose the mechanism and its discussion for the application of the method of decarboxylation of diacids lacking nearby double bonds. Also, the route is explained mechanistically for the preparation of Dewar benzene. The thermal or photolytic decomposition of di-t-butyl per-esters is described. The treatment of monocarboxylic acids to afford alkenes in the presence of lead tetraacetate and copperII acetate is briefly discussed. The alkylation-decarboxylation of aromatic acids is also explained. The oxidative decarboxylation of carboxylic acids can eventually conduct to the obtaining of ketones instead of alkenes. We have used a series of reactions reviewed by W. Carruthers, and we have proposed didactical and mechanistic views for them. This latest approach is included in the synthetic methods reviewed by W. Carruthers with respect to the "Formation of carbon-carbon double bonds". Spanish title: Síntesis de alquenos por descarboxilación de ácidos carboxílicos; vistas mecanísticas; De la serie: El cuaderno de notas de química orgánica, un enfoque didáctico, Nº6.

Research paper thumbnail of Evaluación De La Toxicidad Aguda a Dosis Fijas Del Extracto De Werneria Dactylophylla (Pupusa

A study was conducted to evaluate the potential toxic effect of a lyophilized aqueous extract of ... more A study was conducted to evaluate the potential toxic effect of a lyophilized aqueous extract of Werneria dactylophylla (Pupusa) recognized for their important pharmacological properties. For its development we used the fixed dose procedure, using a limit dose of 2000 mg / kg and 5000 mg / kg of body weight, administered by orogastric route for 14 days performing observations. The selected animals were female albino Swiss mice weighing between 18 and 20 g. Results demonstrated the safety of the plant with no signs or symptoms of toxicity observed. Body weight behaved according to the growth curve of the species and there were no gross abnormalities in the studied organs, allowing to say that the LD 50 is above 5000 mg / kg, considering the product as nontoxic as the Williams' criterion. The methodology and experimental design was conducted along the lines described by the standard EPA (Environmental Protection Agency) 870.1100, OECD 425 (Organization for Economic Trade and Development), which covers the 24 most developed nations of the world, for applying the method of Acute Toxicity Class (CTA).

Research paper thumbnail of Evaluación Del Efecto Inmunomodulador Del Ácido Úsnico Sobre La Capacidad Fagocítica, Adherencia, Quimiotaxis Celular y Citotoxicidad Sobre Monocitos y Polimorfonucleares

Revista Boliviana de Quimica, 2012

This study describes the evaluation of activities cytotoxic and immunomodulating effect of the ac... more This study describes the evaluation of activities cytotoxic and immunomodulating effect of the acid usnico, secondary metabolite obtained from a lichen, Usne...

Research paper thumbnail of Synthesis of Alkenes from Ketones via Arylsulphonyl - Hydrazones; Mechanistic Views; the Organic Chemistr y Notebook Series, a Didactical Approach, Nº 7

Revista Boliviana de Quimica, 2015

This is the seventh chapter in the series published by the same authors: "The Organic Chemis... more This is the seventh chapter in the series published by the same authors: "The Organic Chemistry Notebook Series, a Didactical Approach". The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. Here we describe the mechanistic views of the synthesis of alkenes from ketones via arylsulphonylhydrazones. These methods employ aliphatic and alicyclic ketones with one a-hydrogen, that react along with toluene-p-sulphonylhydrazones and two equivalents of an alkyl-lithium or lithium diisopropylamide. The mechanism views for the transformation of pinacolone into 3,3-dimethyl-1-butene are proposed. The formation of 3-phenylpropene using phenylacetone is explained step by step. An approach is made on the obtaining of alkenes from ketones using derived enol ethers or esters by means of reductive excision or by means of coupling with organocuprates. We have used various series of reactions reviewed by W. Carruthers...

Research paper thumbnail of Determinación De Un Principio Activo De Polygonum Punctatum Elliot; Espectros Completos De RMN De STIGMAST-5-EN-3P-OL (500/125 MHZ)

Revista Boliviana de Quimica, 2017

1-cyclopenta[a]phenanthren-3-ol., and IUPAC name: The spectra set includes HMBC, HSQC and COSY st... more 1-cyclopenta[a]phenanthren-3-ol., and IUPAC name: The spectra set includes HMBC, HSQC and COSY studies. ROESY or NOESY studies were excluded. Compound 1 is found to be the major component of the alcoholic extract of roots of Polygonum punctatum (Polygonaceae), a macrophyte native species of Paraguay with varied therapeutic applications like anti-inflammatory

Research paper thumbnail of Claisen rearrangement of allyl vinyl ethers to afford alkenes, Part IV; mechanistic theoretical proposals; the organic chemistry notebook series, a Didactical approach, N° 12

Revista Boliviana de Quimica, 2017

This is the twelfth theoretical assay in the series: "The Organic Chemistry Notebook Series, a Di... more This is the twelfth theoretical assay in the series: "The Organic Chemistry Notebook Series, a Didactical Approach". The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. We have taken a series of reactions compiled by W. Carruthers in 'Some modern methods of organic synthesis', and we have proposed didactical and mechanistic views for them. This theme is included in the chapter "Formation of carbon-carbon double bonds" in the mentioned text. In the present chapter we expose more Claisen rearrangements variations. The Claisen rearrangement can be regarded as a particular case of Cope's rearrangement, hence, on the basis of the structural theory and the known mechanisms of organic chemistry, we have proposed theoretical mechanisms for the synthesis of dienes from 2methyl-3-phenyl-1,5-hexadiene at low temperature. We have proposed a mechanism for the synthesis of unsaturated aldehydes and ketones through the oxy-Cope rearrangement of 1,5-hexadienes. We've described the mechanism for the key step of the synthesis of the sesquiterpene (±)-juvabione. The mechanistic views of the synthesis of the natural germacrane sesquiterpenes are proposed. We have proposed a mechanism for the thio Claisen rearrangement of allyl vinyl sulfides in the transformation into-unsaturated carbonyl compounds, for example the preparation of 4-tridicenal and the [2,3]sigmatropic rearrangement of allylsulphonium ylids like in the preparation of -cyclocitral.

Research paper thumbnail of An analytical and experimental study of heat transfer in fixed bed

International Journal of Heat and Mass Transfer, 2002

Research paper thumbnail of An Evaluation of Video-to-Video Face Verification

Person recognition using facial features, e.g., mug-shot images, has long been used in identity d... more Person recognition using facial features, e.g., mug-shot images, has long been used in identity documents. However, due to the widespread use of web-cams and mobile devices embedded with a camera, it is now possible to realize facial video recognition, rather than resorting to just still images. In fact, facial video recognition offers many advantages over still image recognition; these include the potential of boosting the system accuracy and deterring spoof attacks. This paper presents an evaluation of person identity verification using facial video data, organized in conjunction with the International Conference on Biometrics (ICB 2009). It involves 18 systems submitted by seven academic institutes. These systems provide for a diverse set of assumptions, including feature representation and preprocessing variations, allowing us to assess the effect of adverse conditions, usage of quality information, query selection, and template construction for video-to-video face authentication.

Research paper thumbnail of Synthesis of Alkenes by Fragmentation Reactions; Mechanistic Views; the Organic Chemistry Notebook Series, a Didactical Approach, Nº 5

This is the fifth chapter in the series published by the same authors: "The Organic Chemistry Not... more This is the fifth chapter in the series published by the same authors: "The Organic Chemistry Notebook Series, a Didactical Approach". Here we offer the mechanistic views of the synthesis of alkenes by fragmentation reactions. The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. Fragmentation reactions can conduct to the synthesis of alkenes. This is not a common method, but useful under determined conditions. For example, the fragmentation of monotoluene-p-sulphonates or methanesulphonates of suitable cyclic 1,3-diols is reviewed and the corresponding mechanism proposed. The preparation of Ecyclodecenone and cyclodecadienes by fragmentation of substituted decalylboranes is also described mechanistically. The description of the fragmentation of bicyclic compounds to afford alkenes like macrolides from acetaltosylate is also included here. The preparation of acyclic alkenes from cyclic precursors is also mechanistically described here. We have used a series of reactions reviewed by W. Carruthers, and we have proposed didactical and mechanistic views for them. This latest approach is included in the synthetic methods reviewed by W. Carruthers with respect to the "Formation of carbon-carbon double bonds".

Research paper thumbnail of Synthesis of Alkenes by Oxidative Decarboxylation of Carboxylic Acids; Mechanistic Views; the Organic Chemistry Notebook Series, a Didactical Approach, Nº 6

This is the sixth chapter in the series published by the same authors: "The Organic Chemistry Not... more This is the sixth chapter in the series published by the same authors: "The Organic Chemistry Notebook Series, a Didactical Approach". Here we offer the mechanistic views of the synthesis of alkenes by oxidative decarboxylation of carboxylic acids. The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. The oxidative decarboxylation of carboxylic acids is a useful method for generating alkenes. Here we propose the mechanism and its discussion for the application of the method of decarboxylation of diacids lacking nearby double bonds. Also, the route is explained mechanistically for the preparation of Dewar benzene. The thermal or photolytic decomposition of di-t-butyl per-esters is described. The treatment of monocarboxylic acids to afford alkenes in the presence of lead tetraacetate and copperII acetate is briefly discussed. The alkylation-decarboxylation of aromatic acids is also explained. The oxidative decarboxylation of carboxylic acids can eventually conduct to the obtaining of ketones instead of alkenes. We have used a series of reactions reviewed by W. Carruthers, and we have proposed didactical and mechanistic views for them. This latest approach is included in the synthetic methods reviewed by W. Carruthers with respect to the "Formation of carbon-carbon double bonds". Spanish title: Síntesis de alquenos por descarboxilación de ácidos carboxílicos; vistas mecanísticas; De la serie: El cuaderno de notas de química orgánica, un enfoque didáctico, Nº6.

Research paper thumbnail of Evaluación De La Toxicidad Aguda a Dosis Fijas Del Extracto De Werneria Dactylophylla (Pupusa

A study was conducted to evaluate the potential toxic effect of a lyophilized aqueous extract of ... more A study was conducted to evaluate the potential toxic effect of a lyophilized aqueous extract of Werneria dactylophylla (Pupusa) recognized for their important pharmacological properties. For its development we used the fixed dose procedure, using a limit dose of 2000 mg / kg and 5000 mg / kg of body weight, administered by orogastric route for 14 days performing observations. The selected animals were female albino Swiss mice weighing between 18 and 20 g. Results demonstrated the safety of the plant with no signs or symptoms of toxicity observed. Body weight behaved according to the growth curve of the species and there were no gross abnormalities in the studied organs, allowing to say that the LD 50 is above 5000 mg / kg, considering the product as nontoxic as the Williams' criterion. The methodology and experimental design was conducted along the lines described by the standard EPA (Environmental Protection Agency) 870.1100, OECD 425 (Organization for Economic Trade and Development), which covers the 24 most developed nations of the world, for applying the method of Acute Toxicity Class (CTA).

Research paper thumbnail of Evaluación Del Efecto Inmunomodulador Del Ácido Úsnico Sobre La Capacidad Fagocítica, Adherencia, Quimiotaxis Celular y Citotoxicidad Sobre Monocitos y Polimorfonucleares

Revista Boliviana de Quimica, 2012

This study describes the evaluation of activities cytotoxic and immunomodulating effect of the ac... more This study describes the evaluation of activities cytotoxic and immunomodulating effect of the acid usnico, secondary metabolite obtained from a lichen, Usne...

Research paper thumbnail of Synthesis of Alkenes from Ketones via Arylsulphonyl - Hydrazones; Mechanistic Views; the Organic Chemistr y Notebook Series, a Didactical Approach, Nº 7

Revista Boliviana de Quimica, 2015

This is the seventh chapter in the series published by the same authors: "The Organic Chemis... more This is the seventh chapter in the series published by the same authors: "The Organic Chemistry Notebook Series, a Didactical Approach". The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. Here we describe the mechanistic views of the synthesis of alkenes from ketones via arylsulphonylhydrazones. These methods employ aliphatic and alicyclic ketones with one a-hydrogen, that react along with toluene-p-sulphonylhydrazones and two equivalents of an alkyl-lithium or lithium diisopropylamide. The mechanism views for the transformation of pinacolone into 3,3-dimethyl-1-butene are proposed. The formation of 3-phenylpropene using phenylacetone is explained step by step. An approach is made on the obtaining of alkenes from ketones using derived enol ethers or esters by means of reductive excision or by means of coupling with organocuprates. We have used various series of reactions reviewed by W. Carruthers...

Research paper thumbnail of Determinación De Un Principio Activo De Polygonum Punctatum Elliot; Espectros Completos De RMN De STIGMAST-5-EN-3P-OL (500/125 MHZ)

Revista Boliviana de Quimica, 2017

1-cyclopenta[a]phenanthren-3-ol., and IUPAC name: The spectra set includes HMBC, HSQC and COSY st... more 1-cyclopenta[a]phenanthren-3-ol., and IUPAC name: The spectra set includes HMBC, HSQC and COSY studies. ROESY or NOESY studies were excluded. Compound 1 is found to be the major component of the alcoholic extract of roots of Polygonum punctatum (Polygonaceae), a macrophyte native species of Paraguay with varied therapeutic applications like anti-inflammatory

Research paper thumbnail of Claisen rearrangement of allyl vinyl ethers to afford alkenes, Part IV; mechanistic theoretical proposals; the organic chemistry notebook series, a Didactical approach, N° 12

Revista Boliviana de Quimica, 2017

This is the twelfth theoretical assay in the series: "The Organic Chemistry Notebook Series, a Di... more This is the twelfth theoretical assay in the series: "The Organic Chemistry Notebook Series, a Didactical Approach". The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. We have taken a series of reactions compiled by W. Carruthers in 'Some modern methods of organic synthesis', and we have proposed didactical and mechanistic views for them. This theme is included in the chapter "Formation of carbon-carbon double bonds" in the mentioned text. In the present chapter we expose more Claisen rearrangements variations. The Claisen rearrangement can be regarded as a particular case of Cope's rearrangement, hence, on the basis of the structural theory and the known mechanisms of organic chemistry, we have proposed theoretical mechanisms for the synthesis of dienes from 2methyl-3-phenyl-1,5-hexadiene at low temperature. We have proposed a mechanism for the synthesis of unsaturated aldehydes and ketones through the oxy-Cope rearrangement of 1,5-hexadienes. We've described the mechanism for the key step of the synthesis of the sesquiterpene (±)-juvabione. The mechanistic views of the synthesis of the natural germacrane sesquiterpenes are proposed. We have proposed a mechanism for the thio Claisen rearrangement of allyl vinyl sulfides in the transformation into-unsaturated carbonyl compounds, for example the preparation of 4-tridicenal and the [2,3]sigmatropic rearrangement of allylsulphonium ylids like in the preparation of -cyclocitral.

Research paper thumbnail of An analytical and experimental study of heat transfer in fixed bed

International Journal of Heat and Mass Transfer, 2002

Research paper thumbnail of An Evaluation of Video-to-Video Face Verification

Person recognition using facial features, e.g., mug-shot images, has long been used in identity d... more Person recognition using facial features, e.g., mug-shot images, has long been used in identity documents. However, due to the widespread use of web-cams and mobile devices embedded with a camera, it is now possible to realize facial video recognition, rather than resorting to just still images. In fact, facial video recognition offers many advantages over still image recognition; these include the potential of boosting the system accuracy and deterring spoof attacks. This paper presents an evaluation of person identity verification using facial video data, organized in conjunction with the International Conference on Biometrics (ICB 2009). It involves 18 systems submitted by seven academic institutes. These systems provide for a diverse set of assumptions, including feature representation and preprocessing variations, allowing us to assess the effect of adverse conditions, usage of quality information, query selection, and template construction for video-to-video face authentication.