Romina Andrea Ocampo - Academia.edu (original) (raw)
Papers by Romina Andrea Ocampo
The synthesis of coumarins through Knoevenagel condensation is one of the mostimportant processes... more The synthesis of coumarins through Knoevenagel condensation is one of the mostimportant processes in synthetic organic chemistry and medicinal chemistry. Compoundsincluding a coumarin (2-oxo-2H-1-benzopyran) backbone have a wide range of applicationin the pharmaceutical field. Thus, many methodologies havebeen developed for the synthesisof this important class of compounds. However, some methods are always associated withtoxic and corrosive catalysts, longer reaction time, poor yield, less purity, and by-productsalong with the desired product. Furthermore, some of these processes are not efficient andenvironmentally friendly. Therefore, mild, efficient, and environmentally friendly protocolshave been developed recently by many scientists for the synthesis of coumarin derivatives viaKnoevenagel condensation with good yield and purity. In this review, we have summarizedvarious methods for the synthesis of coumarins via Knoevenagel condensation.Keywords Coumarin derivatives; efficient meth...
In recent years, green chemistry using environmentally benign reagents and conditions has become ... more In recent years, green chemistry using environmentally benign reagents and conditions has become one of the most fascinating developments in the synthesis of widely used organic compounds. This review describes the theory and importance of ultrasound as an efficient tool in the synthesis of heterocyclic compounds.
Journal of Chemical Education, 2019
Visually impaired or blind students require adjustments to the traditional hands-on activities an... more Visually impaired or blind students require adjustments to the traditional hands-on activities and methodological and didactic strategies employed by the teacher. These adaptations are based on multisensory teaching tools, which reinforce the learning of all students in general. This paper presents simple teaching resources that allow students with visual disabilities to solve problems of Organic Chemistry independently and on an equal footing with their nondisabled peers.
Proceedings of The 21st International Electronic Conference on Synthetic Organic Chemistry, 2017
With the aim of exploring the best reaction conditions for the diastereoselective synthesis of th... more With the aim of exploring the best reaction conditions for the diastereoselective synthesis of the 1,4-thiazepan-3-ones (4) and 4-thiazolidinones (5), we have studied the effect on solvent variation and the aggregation of AlCl3 and different zeolites as Lewis acid catalysts to the three-component microwave assisted reaction between 2,3:4,5-di-O-isopropylidene--Darabino-hexos-2-ulo-2,6-pyranose (1), benzotiazole (3) and thioglycolic acid (2). Based on the results of previous studies of our group, we discuss here two microwave assisted methods: multicomponent reaction in the presence of the catalysts (Method A) and sequential reaction with generation of the corresponding intermediates and subsequent addition of the catalysts coordinated to thioglycolic acid (Method B).
Open Chemistry Journal, 2019
Background: Organotin(IV) derivatives have appeared recently as potential biologically active met... more Background: Organotin(IV) derivatives have appeared recently as potential biologically active metallopharmaceuticals exhibiting a variety of therapeutic activities. Hence, it is important to study the synthesis of new organotin compounds with low toxicity that may be of pharmacological interest. Objectives: This study focuses on the synthesis of new bis-stannylated derivatives with C2 symmetry that could be tested as antifungal agents against two clinical important fungal species, Cryptococcus neoformans and Candida albicans. Methods: The radical addition of triorganotin hydrides (R3SnH) and diorganotin chlorohydrides (R2ClSnH) to bis-α,β-unsaturated diesters derived from (S)-BINOL led to the corresponding new bis-stannylated derivatives with C2 symmetry. Nine pure organotin compounds were synthesized with defined stereochemistry. Four of them were enantiomerically pure and four were diastereoisomeric mixtures. Results: All new organotin compounds were fully characterized, those wit...
Proceedings of The 16th International Electronic Conference on Synthetic Organic Chemistry, 2012
Journal of the Brazilian Chemical Society, 2015
The radical addition of triorganotin hydrides, R 3 SnH (R = n-butyl, phenyl, neophyltin), to four... more The radical addition of triorganotin hydrides, R 3 SnH (R = n-butyl, phenyl, neophyltin), to four unsaturated diesters of (11R,12R)-9,10-dihydro-9,10-ethaneanthracene-11,12-dimethanol leads to products of cyclohydrostannation with an average yield of around 80%. Whereas the addition of these hydrides to diacrylate and dimethacrylate leads to the expected mixtures containing two and four distereoisomeric cyclized products respectively, the addition to di-2-methyl-and di-2phenylcinnamate yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with a radical tandem cyclohydrostannation mechanism. Full proton (1 H), carbon 13 (13 C) and tin 119 (119 Sn) nuclear magnetic resonance (NMR) data are given.
Tetrahedron: Asymmetry, 2015
An efficient, green, and atom economic methodology for the stereoselective synthesis of C 2 symme... more An efficient, green, and atom economic methodology for the stereoselective synthesis of C 2 symmetry (3R,4R)-TTFOL diester derivatives has been developed. The procedure occurs through a (2R,3R)-TADDOL dioxolane cleavage and rearrangement under mild conditions by its reaction with a carboxylic acid in the presence of TFAA/H 3 PO 4 without the need for an inert atmosphere to give generally high yields.
Proceedings of The 18th International Electronic Conference on Synthetic Organic Chemistry, 2014
We present here the study of selective synthesis of 1,3-thiazolidin-4-ones via microwave-assisted... more We present here the study of selective synthesis of 1,3-thiazolidin-4-ones via microwave-assisted multi-component reaction under solvent-free conditions. Although, theoretically two different products are possible (benzothiazepinones 4 and thiazolidinones 5), the reaction gave only two diasteroisomers of 1,3-thiazolidin-4-ones (48-97%) in the threecomponent reaction between 2,3 : 4,5-di-O-isopropiliden-β-D-arabino-hexos-2-ulo-2,6piranosa 1, different heteroaromatics anilines 3 and mercaptoacetic acid 2 as can be seen in the scheme of Figure 1. The synthesized compounds were characterized by IR, 1 H-, 13 C, DEPT and HSQC-RMN. The stereochemistry of both the diasteroisomers was elucidated with the help of NOE experiments.
Arkivoc, 2011
In this paper we report a simple synthetic route to obtain functionalized allyltin derivatives fr... more In this paper we report a simple synthetic route to obtain functionalized allyltin derivatives from 1-ethynylcyclohexene (1), through a "one pot" procedure. Radical addition of trineophyltin hydride to 1 leads quantitatively to (Z,E)-1-(2trineophylstannylvinyl)-cyclohexene (3), a conjugated dienylstannane that, through a [4+2] cycloaddition reaction (Diels-Alder) with activated dienophiles, allows to obtain substituted bicyclic unsaturated products with specific stereochemistry and a trialkylstannyl group in allylic position.
Global change biology, Mar 27, 2016
The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought... more The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world ("International Peat Congress with over 1000…
Catalysis Communications, 2015
Proceedings of The 17th International Electronic Conference on Synthetic Organic Chemistry, 2013
Ultrasonics Sonochemistry, 2013
Here we present the preparation of a variety of diarylmethanes obtained via ultrasound Stille cou... more Here we present the preparation of a variety of diarylmethanes obtained via ultrasound Stille coupling under palladium catalysis between some substituted aryl compounds and benzyltributyltin compounds generated through sonicated Barbier reaction in a very short time reaction and excellent yield. The study reported below compares different methods to optimize the synthesis of usually unstable benzyltin derivatives and is another contribution to the investigation of Csp3-Csp2 coupling process involving benzyl-aryl reagents. Substituted carboxilated benzophenones were easily prepared in a very good yield by oxidation of some diarylmethanes. Highlights Sonicated Barbier reaction as the best route for benzyltin compounds. Simplicity, mild conditions, rate of reaction and high yields in Barbier reaction. Creation of Csp 3 benzyl center by sonicated Stille coupling. Synthesis of benzophenones by oxidation of diarylmethanes.
Journal of Organometallic Chemistry, 2013
The best reaction conditions and the syntheses of some new bis(tri-n-butylstannylated) aromatic a... more The best reaction conditions and the syntheses of some new bis(tri-n-butylstannylated) aromatic and heteroaromatic compounds by means of a Barbier-like sonochemical reaction are reported. Full 1 H-, 13 C-, and 119 Sn-NMR data of the new organotin compounds are informed.
ABSTRACT A systematic study for esterification procedures to the synthesis of BINOL diesters is d... more ABSTRACT A systematic study for esterification procedures to the synthesis of BINOL diesters is described. Reaction conditions with trifluoracetic acid anhydride (TFAA) and 85% H3PO4 were selected as the best procedure to prepare enantiomerically pure (S)-1,1′-bi-2-naphthol (BINOL) diesters VIII to XI with almost quantitative yields and very short reaction times.[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]
Proceedings of The 17th International Electronic Conference on Synthetic Organic Chemistry, 2013
The aim of this work is the synthesis of some BINOL derivatives due to their catalytic, biologica... more The aim of this work is the synthesis of some BINOL derivatives due to their catalytic, biological and medicinal activity. The rigid structure, thermal stability and C 2 symmetry of the binaphthyl molecules plays an important role in asymmetric induction. We report here a study on the radical addition of different triorganotin hydrides, R 3 SnH (R= n-Bu, Ph) to four (S)-BINOL unsaturated diesters (1,1'-binaphthyl-2-2´-diyl diacrylate; 1,1´-binaphthyl-2-2´-diyl dimethacrylate; 1,1´-binaphthyl-2-2´-diyl-(Z)-2-methyl-3-phenyl-2propenoate and 1,1´-binaphthyl-2-2´-diyl di-(Z)-2,3-diphenyl-2-propenoate).
Proceedings
We present here a new proposal for the “one pot” generation of new 4-thiazolidinones (9a–e) throu... more We present here a new proposal for the “one pot” generation of new 4-thiazolidinones (9a–e) through a multicomponent reaction under microwave irradiation conditions, using aromatic and heteroaromatic amines (8a–e), absolute ethanol as a “green” solvent and modifying the aldehyde group in the glycosidic residue, synthesized from D-mannitol. The study is focused in the variation of the irradiation times and the concentration of thioglycolic acid in order to study the possibility of controlling the structure and/or stereochemistry of the products formed in the reaction. Thiazolidinones 9a–d were obtained with a 69–82% The generation of the corresponding reaction products were monitored by TLC and CG-MS, taking reaction aliquots. The conditions reaction proved to be chemoselective depending on the excess of acid and irradiation times.
The synthesis of coumarins through Knoevenagel condensation is one of the mostimportant processes... more The synthesis of coumarins through Knoevenagel condensation is one of the mostimportant processes in synthetic organic chemistry and medicinal chemistry. Compoundsincluding a coumarin (2-oxo-2H-1-benzopyran) backbone have a wide range of applicationin the pharmaceutical field. Thus, many methodologies havebeen developed for the synthesisof this important class of compounds. However, some methods are always associated withtoxic and corrosive catalysts, longer reaction time, poor yield, less purity, and by-productsalong with the desired product. Furthermore, some of these processes are not efficient andenvironmentally friendly. Therefore, mild, efficient, and environmentally friendly protocolshave been developed recently by many scientists for the synthesis of coumarin derivatives viaKnoevenagel condensation with good yield and purity. In this review, we have summarizedvarious methods for the synthesis of coumarins via Knoevenagel condensation.Keywords Coumarin derivatives; efficient meth...
In recent years, green chemistry using environmentally benign reagents and conditions has become ... more In recent years, green chemistry using environmentally benign reagents and conditions has become one of the most fascinating developments in the synthesis of widely used organic compounds. This review describes the theory and importance of ultrasound as an efficient tool in the synthesis of heterocyclic compounds.
Journal of Chemical Education, 2019
Visually impaired or blind students require adjustments to the traditional hands-on activities an... more Visually impaired or blind students require adjustments to the traditional hands-on activities and methodological and didactic strategies employed by the teacher. These adaptations are based on multisensory teaching tools, which reinforce the learning of all students in general. This paper presents simple teaching resources that allow students with visual disabilities to solve problems of Organic Chemistry independently and on an equal footing with their nondisabled peers.
Proceedings of The 21st International Electronic Conference on Synthetic Organic Chemistry, 2017
With the aim of exploring the best reaction conditions for the diastereoselective synthesis of th... more With the aim of exploring the best reaction conditions for the diastereoselective synthesis of the 1,4-thiazepan-3-ones (4) and 4-thiazolidinones (5), we have studied the effect on solvent variation and the aggregation of AlCl3 and different zeolites as Lewis acid catalysts to the three-component microwave assisted reaction between 2,3:4,5-di-O-isopropylidene--Darabino-hexos-2-ulo-2,6-pyranose (1), benzotiazole (3) and thioglycolic acid (2). Based on the results of previous studies of our group, we discuss here two microwave assisted methods: multicomponent reaction in the presence of the catalysts (Method A) and sequential reaction with generation of the corresponding intermediates and subsequent addition of the catalysts coordinated to thioglycolic acid (Method B).
Open Chemistry Journal, 2019
Background: Organotin(IV) derivatives have appeared recently as potential biologically active met... more Background: Organotin(IV) derivatives have appeared recently as potential biologically active metallopharmaceuticals exhibiting a variety of therapeutic activities. Hence, it is important to study the synthesis of new organotin compounds with low toxicity that may be of pharmacological interest. Objectives: This study focuses on the synthesis of new bis-stannylated derivatives with C2 symmetry that could be tested as antifungal agents against two clinical important fungal species, Cryptococcus neoformans and Candida albicans. Methods: The radical addition of triorganotin hydrides (R3SnH) and diorganotin chlorohydrides (R2ClSnH) to bis-α,β-unsaturated diesters derived from (S)-BINOL led to the corresponding new bis-stannylated derivatives with C2 symmetry. Nine pure organotin compounds were synthesized with defined stereochemistry. Four of them were enantiomerically pure and four were diastereoisomeric mixtures. Results: All new organotin compounds were fully characterized, those wit...
Proceedings of The 16th International Electronic Conference on Synthetic Organic Chemistry, 2012
Journal of the Brazilian Chemical Society, 2015
The radical addition of triorganotin hydrides, R 3 SnH (R = n-butyl, phenyl, neophyltin), to four... more The radical addition of triorganotin hydrides, R 3 SnH (R = n-butyl, phenyl, neophyltin), to four unsaturated diesters of (11R,12R)-9,10-dihydro-9,10-ethaneanthracene-11,12-dimethanol leads to products of cyclohydrostannation with an average yield of around 80%. Whereas the addition of these hydrides to diacrylate and dimethacrylate leads to the expected mixtures containing two and four distereoisomeric cyclized products respectively, the addition to di-2-methyl-and di-2phenylcinnamate yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with a radical tandem cyclohydrostannation mechanism. Full proton (1 H), carbon 13 (13 C) and tin 119 (119 Sn) nuclear magnetic resonance (NMR) data are given.
Tetrahedron: Asymmetry, 2015
An efficient, green, and atom economic methodology for the stereoselective synthesis of C 2 symme... more An efficient, green, and atom economic methodology for the stereoselective synthesis of C 2 symmetry (3R,4R)-TTFOL diester derivatives has been developed. The procedure occurs through a (2R,3R)-TADDOL dioxolane cleavage and rearrangement under mild conditions by its reaction with a carboxylic acid in the presence of TFAA/H 3 PO 4 without the need for an inert atmosphere to give generally high yields.
Proceedings of The 18th International Electronic Conference on Synthetic Organic Chemistry, 2014
We present here the study of selective synthesis of 1,3-thiazolidin-4-ones via microwave-assisted... more We present here the study of selective synthesis of 1,3-thiazolidin-4-ones via microwave-assisted multi-component reaction under solvent-free conditions. Although, theoretically two different products are possible (benzothiazepinones 4 and thiazolidinones 5), the reaction gave only two diasteroisomers of 1,3-thiazolidin-4-ones (48-97%) in the threecomponent reaction between 2,3 : 4,5-di-O-isopropiliden-β-D-arabino-hexos-2-ulo-2,6piranosa 1, different heteroaromatics anilines 3 and mercaptoacetic acid 2 as can be seen in the scheme of Figure 1. The synthesized compounds were characterized by IR, 1 H-, 13 C, DEPT and HSQC-RMN. The stereochemistry of both the diasteroisomers was elucidated with the help of NOE experiments.
Arkivoc, 2011
In this paper we report a simple synthetic route to obtain functionalized allyltin derivatives fr... more In this paper we report a simple synthetic route to obtain functionalized allyltin derivatives from 1-ethynylcyclohexene (1), through a "one pot" procedure. Radical addition of trineophyltin hydride to 1 leads quantitatively to (Z,E)-1-(2trineophylstannylvinyl)-cyclohexene (3), a conjugated dienylstannane that, through a [4+2] cycloaddition reaction (Diels-Alder) with activated dienophiles, allows to obtain substituted bicyclic unsaturated products with specific stereochemistry and a trialkylstannyl group in allylic position.
Global change biology, Mar 27, 2016
The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought... more The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world ("International Peat Congress with over 1000…
Catalysis Communications, 2015
Proceedings of The 17th International Electronic Conference on Synthetic Organic Chemistry, 2013
Ultrasonics Sonochemistry, 2013
Here we present the preparation of a variety of diarylmethanes obtained via ultrasound Stille cou... more Here we present the preparation of a variety of diarylmethanes obtained via ultrasound Stille coupling under palladium catalysis between some substituted aryl compounds and benzyltributyltin compounds generated through sonicated Barbier reaction in a very short time reaction and excellent yield. The study reported below compares different methods to optimize the synthesis of usually unstable benzyltin derivatives and is another contribution to the investigation of Csp3-Csp2 coupling process involving benzyl-aryl reagents. Substituted carboxilated benzophenones were easily prepared in a very good yield by oxidation of some diarylmethanes. Highlights Sonicated Barbier reaction as the best route for benzyltin compounds. Simplicity, mild conditions, rate of reaction and high yields in Barbier reaction. Creation of Csp 3 benzyl center by sonicated Stille coupling. Synthesis of benzophenones by oxidation of diarylmethanes.
Journal of Organometallic Chemistry, 2013
The best reaction conditions and the syntheses of some new bis(tri-n-butylstannylated) aromatic a... more The best reaction conditions and the syntheses of some new bis(tri-n-butylstannylated) aromatic and heteroaromatic compounds by means of a Barbier-like sonochemical reaction are reported. Full 1 H-, 13 C-, and 119 Sn-NMR data of the new organotin compounds are informed.
ABSTRACT A systematic study for esterification procedures to the synthesis of BINOL diesters is d... more ABSTRACT A systematic study for esterification procedures to the synthesis of BINOL diesters is described. Reaction conditions with trifluoracetic acid anhydride (TFAA) and 85% H3PO4 were selected as the best procedure to prepare enantiomerically pure (S)-1,1′-bi-2-naphthol (BINOL) diesters VIII to XI with almost quantitative yields and very short reaction times.[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]
Proceedings of The 17th International Electronic Conference on Synthetic Organic Chemistry, 2013
The aim of this work is the synthesis of some BINOL derivatives due to their catalytic, biologica... more The aim of this work is the synthesis of some BINOL derivatives due to their catalytic, biological and medicinal activity. The rigid structure, thermal stability and C 2 symmetry of the binaphthyl molecules plays an important role in asymmetric induction. We report here a study on the radical addition of different triorganotin hydrides, R 3 SnH (R= n-Bu, Ph) to four (S)-BINOL unsaturated diesters (1,1'-binaphthyl-2-2´-diyl diacrylate; 1,1´-binaphthyl-2-2´-diyl dimethacrylate; 1,1´-binaphthyl-2-2´-diyl-(Z)-2-methyl-3-phenyl-2propenoate and 1,1´-binaphthyl-2-2´-diyl di-(Z)-2,3-diphenyl-2-propenoate).
Proceedings
We present here a new proposal for the “one pot” generation of new 4-thiazolidinones (9a–e) throu... more We present here a new proposal for the “one pot” generation of new 4-thiazolidinones (9a–e) through a multicomponent reaction under microwave irradiation conditions, using aromatic and heteroaromatic amines (8a–e), absolute ethanol as a “green” solvent and modifying the aldehyde group in the glycosidic residue, synthesized from D-mannitol. The study is focused in the variation of the irradiation times and the concentration of thioglycolic acid in order to study the possibility of controlling the structure and/or stereochemistry of the products formed in the reaction. Thiazolidinones 9a–d were obtained with a 69–82% The generation of the corresponding reaction products were monitored by TLC and CG-MS, taking reaction aliquots. The conditions reaction proved to be chemoselective depending on the excess of acid and irradiation times.