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Title: Studies on the base-promoted conversion of conjugated alkynyl esters to alpha-substituted alpha-allenyl esters.
Creator: He, Yuanjun, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: We report here the development of an efficient method for the conversion of a variety of conjugated alkynyl esters to alpha-substituted conjugated allenyl esters (racemic) through the use of strong amide bases. Substantially improved yields over typical enolate formation conditions were observed with the use of two equivalents of lithium diisopropylamide. Trapping studies indicate that the second equivalent of base likely leads to the dianion intermediate which upon addition of methyl iodide...
Show moreWe report here the development of an efficient method for the conversion of a variety of conjugated alkynyl esters to alpha-substituted conjugated allenyl esters (racemic) through the use of strong amide bases. Substantially improved yields over typical enolate formation conditions were observed with the use of two equivalents of lithium diisopropylamide. Trapping studies indicate that the second equivalent of base likely leads to the dianion intermediate which upon addition of methyl iodide and trimethylsilyl chloride gives mixtures of alpha-substituted conjugated allenyl and beta,gamma-alkynyl deconjugated esters. Further optimization revealed that additive salts such as LiCl lead primarily to the allenyl product while the use of HMPA as a cosolvent gives the beta,gamma-alkynyl deconjugated alkylation product. The role of base, base concentration and electrophile on product yield and selectivity is also discussed. The optimized conditions resulting from our study of this reaction establishes this method as a viable synthetic tool for the production of alpha-substituted allenyl esters. A new method to prepare racemic alpha-tributylstannyl-alpha-allenyl esters from precursor conjugated alkynyl esters in good yields is reported. Key features of the optimized reaction conditions include the use of multiple equiv. of lithium diisopropylamide in THF with LiCl as a key additive. The allenyl tin reagent reacts with aldehydes in the presence of Lewis acid to give homopropargyl alcohol or allenyl alcohol products depending on the reaction conditions. The addition of boron trifluoride etherate to a solution of the allenyltin and aldehyde gives the homopropargyl alcohol. However, allenyl alcohol products are obtained exclusively with the addition of tin tetrachloride to the allenyl stannane rapidly followed by the addition of aldehyde. The effect of other Lewis acids and reaction variables such as solvent and temperature on the yield and relative stereochemistry of the products will also be described. The Mitsunobu coupling reaction of sterically hindered phenols and alcohols is greatly accelerated by the use of high reaction concentration in combination with sonication. The rate acceleration effect observed with our protocol may simply be based on the high concentration with the sonic waves providing efficient mixing of the highly viscous reaction mixture and generating localized hot spots, or in part, the result of an enhancement of a radical reaction pathway.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12120
Subject Headings: Chemistry, Organic
Format: Document (PDF)

Title: Identification of the diterpene cyclase and elucidation of early steps in the pseudopterosin biosynthetic pathway.
Creator: Kohl, Amber Celeste, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The pseudopterosins and seco-pseudopterosins are diterpene glycosides isolated from the marine soft coral, Pseudopterogorgia elisabethae . These compounds exhibit anti-inflammatory and analgesic activity greater than the industry standard, indomethacin. The overall goal of this research was to complete biosynthetic studies and enzymology related to the development of a biotechnological production method of the pseudopterosins and seco-pseudopterosins. We aimed to examine early steps in the...
Show moreThe pseudopterosins and seco-pseudopterosins are diterpene glycosides isolated from the marine soft coral, Pseudopterogorgia elisabethae . These compounds exhibit anti-inflammatory and analgesic activity greater than the industry standard, indomethacin. The overall goal of this research was to complete biosynthetic studies and enzymology related to the development of a biotechnological production method of the pseudopterosins and seco-pseudopterosins. We aimed to examine early steps in the biosynthetic pathway in order to gain detailed knowledge of the biosynthesis and enzymology of the system. Prior to examination of the biosynthetic pathway leading to the pseudopterosins, we developed both in vivo and in vitro systems to test putative precursors and demonstrated that pseudopterosin A is a precursor to pseudopterosins B--D. We also identified and confirmed the intermediacy of the pseudopterosin diterpene cyclase product using a radioactivity-guided isolation. The bicyclic structure of the diterpene cyclase product suggests that the pseudopterosins and seco-pseudopterosins are derived from this common bicyclic intermediate. The isolation of the pseudopterosin diterpene cyclase product provided us with an assay for the purification of the enzyme involved in its production. We identified the diterpene cyclase in aqueous extracts of P. elisabethae and plan to utilize the amino acid sequence for identification of the gene. This represents the first isolation of a biosynthetic enzyme from a marine coral. Moreover, various characterization studies indicated that the enzyme displays certain similar characteristics to other terpenoid cyclases isolated from terrestrial sources. In previous investigations, P. elisabethae was found only in the Bahamian and West Indian region, but we discovered P. elisabethae in the Florida Keys. Furthermore, due to the distinctive chemistry in the Florida Keys P. elisabethae, plausible early biosynthetic intermediates were isolated that are not present in the Bahamian population. We evaluated these compounds as intermediates in the biosynthesis of the pseudopterosins. The data obtained further supports the assumption of a common biosynthetic origin of the pseudopterosins and seco-pseudopterosins.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/12026
Subject Headings: Chemistry, Biochemistry, Chemistry, Organic
Format: Document (PDF)

Title: Base Promoted 5-endo-dig Cyclizations of Non-Conia-ene Propargyl Ethers: A Mechanistic Investigation.
Creator: Hintze, Silas Q., Lepore, Salvatore D., Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description: Herein, we discuss a novel method for the synthesis of decorated 2,5-dihydrofurans. The base promoted 5-endo-dig cyclization of non-Conia-ene propargyl ethers produces 2,2 disubstituted dihydrofurans. Central to the reaction is the presence of an acidic C–H bond which is activated by an adjacent aromatic heterocycle. The transformation is viable with a wide range of substituents, including N, O, and S containing heterocycles, substituted phenyl rings, and alkyl groups. The cyclization...
Show moreHerein, we discuss a novel method for the synthesis of decorated 2,5-dihydrofurans. The base promoted 5-endo-dig cyclization of non-Conia-ene propargyl ethers produces 2,2 disubstituted dihydrofurans. Central to the reaction is the presence of an acidic C–H bond which is activated by an adjacent aromatic heterocycle. The transformation is viable with a wide range of substituents, including N, O, and S containing heterocycles, substituted phenyl rings, and alkyl groups. The cyclization proceeds within 30 seconds at room temperature under the action of potassium tert-butoxide. This work stands apart from the current literature due to the absence of transition metal catalysts and/or harsh reaction conditions. A thorough mechanistic investigation is undertaken to better understand the nature of this unprecedented reaction.
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Date Issued: 2024
PURL: http://purl.flvc.org/fau/fd/FA00014376
Subject Headings: Cyclization (Chemistry), Chemistry, Organic
Format: Document (PDF)

Title: Bioactive terpene production associated with Caribbean gorgonians from the genera Pseudopterogorgia and Eunicea: Discovery of a sustainable production method.
Creator: Newberger, Nealie C., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Research directed toward renewable, non-destructive sources of bioactive marine derived compounds, is becoming more important everyday. Marine soft corals known as sea whips are a prolific source of such biologically active compounds. One particular organism, Eunicea fusca, possesses diterpene arabinose glycosides with potent antiinflammatory activity that rival the industry standard indomethicin. Fuscocide B is known to inhibit phorbol myristate acetate (PMA)-induced ear edema in murine...
Show moreResearch directed toward renewable, non-destructive sources of bioactive marine derived compounds, is becoming more important everyday. Marine soft corals known as sea whips are a prolific source of such biologically active compounds. One particular organism, Eunicea fusca, possesses diterpene arabinose glycosides with potent antiinflammatory activity that rival the industry standard indomethicin. Fuscocide B is known to inhibit phorbol myristate acetate (PMA)-induced ear edema in murine models, is a minor secondary metabolite and it is therefore difficult to acquire in large quantities. Alternatively, fuscol and eunicol, are known to have similar antiinflammatory activity and are major secondary metabolites which are structurally similar to fuscocide B and are also produced by E. fusca. We have found that fuscol and eunicol can be extracted from the holobiont, and Symbiodinium (Symbiodinium sp.) cells isolated from E. fusca. Similarly, diterpene glycosides, known as pseudopterosins, have been isolated from the the holobiont, and purified Symbiodinium of Pseudopterogorgia elisabethae. Pseudopterosins are also known to possess anti-inflammatory and analgesic properties superior to that of existing drugs. Since many chemically unique metabolites demonstrating bioactive properties have been introduced into pre-clinical and clinical trials I-III5 and the supply issue has been duly highlighted, it has become advantageous to determine the source of these compounds in each of the above mentioned species and determine if a renewable, non-destructive source can be maintained. Data has been presented suggesting that the actual source of the pseudopterosins is not the coral, but actually the dinoflagellate symbiont associated with Pseudopterogorgia elisabethae. Therefore, we have examined cryopreservation of the dinoflagellate symbionts, induction of terpene biosynthesis in the dinoflagellate symbionts, as well as various cell culture techniques in order to better understand the ecological role of terpene biosynthesis in the symbionts and the host corals. The data obtained in the following studies reveals a bacterial source for the production of bioactive secondary metabolites from Eunicea fusca and lends support to a possible bacterial producing trend in gorgonians.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/12224
Subject Headings: Biology, Oceanography, Chemistry, Biochemistry, Chemistry, Organic
Format: Document (PDF)

Title: FERROCENYLMETHYLATION OF 1,1-DIARYLALKENES.
Creator: FERNANDEZ, ROSA MIRTA, Florida Atlantic University
Abstract/Description: The ferrocenylrnethylation of the following compounds was studied using (ferrocenylmethyl)trimethylammonium iodide: 1, 1-di(p-anisyl)- ethene (I), 1, 1-di(p- anisyl)propene (II), 1- (p- anisyl)-1-phenylethene (III), 1, 1- diphenylethene (IV), 1, 1- di(p- dimethylaminophenyl )ethene (V) and 1, 1-di(p-dimethylaminophenyl)propene (VI). I is ferrocenylmethylated exclu,sively on its side-chain, one or both vinyl hydrogens being replaced by ferrocenylmethyl groups depending on the ratio of...
Show moreThe ferrocenylrnethylation of the following compounds was studied using (ferrocenylmethyl)trimethylammonium iodide: 1, 1-di(p-anisyl)- ethene (I), 1, 1-di(p- anisyl)propene (II), 1- (p- anisyl)-1-phenylethene (III), 1, 1- diphenylethene (IV), 1, 1- di(p- dimethylaminophenyl )ethene (V) and 1, 1-di(p-dimethylaminophenyl)propene (VI). I is ferrocenylmethylated exclu,sively on its side-chain, one or both vinyl hydrogens being replaced by ferrocenylmethyl groups depending on the ratio of ferrocenylmethylating agent to I, concentration of the reaction mixture, reaction time, solvent and temperature. II is substituted only on its side-chain to give a mono-ferrocenylmethylated product. III is ferrocenylmethylated slowly. IV fails to react. Mono-ferrocenylmethylation of V occurs principally on its side- chain; more extensive ferrocenylmethylation occurs both on the side-chain and on the rings at the position ortho to dimethylamino. VI reacts quite indiscriminately both on the side-chain and on the rings.
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Date Issued: 1977
PURL: http://purl.flvc.org/fcla/dt/13837
Subject Headings: Chemistry--Research, Chemistry, Organic, Methylation
Format: Document (PDF)

Title: New stereoselective reactions to form amido alkyl c-n and vinyl triflate c-o bonds via carbocation intermediates & ultrafast silicon fluorination methodologies for applications in pet imaging.
Creator: Alhuniti, Mohammed, Lepore, Salvatore D., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: We report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to...
Show moreWe report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to produce the desired conversion of these chlorosulfites to amides though with low catalytic turnover. Improving the turnover without deteriorating the stereochemical outcome was eventually accomplished by a careful selection of the reagent addition sequence and through the removal of gaseous byproducts. This Ritter-like coupling reaction proceeds in good yields with secondary cyclic alcohols under mild conditions. The stereochemical outcome likely due to fast nucleophilic capture of a non-planar carbocations (hyperconjomers) stabilized by ring hyperconjugation.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004262
Subject Headings: Intermediates (Chemistry), Nuclear medicine, Organometallic chemistry, Physical organic chemistry, Reaction mechanisms (Chemistry), Tomography, Emission
Format: Document (PDF)

Title: Toward the synthesis of organic moieties for use in luminescent lanthanide materials: from benzodithiophene based linkers to a series of 2,3 pyridinedicarboxylate coordination polymers.
Creator: Ramirez, Amanda Lyn Staggers., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The main focus of this thesis is to present the structural and photophysical characteristics of the coordination polymers [Ln(C7H3NO4)(C7H4NO4)(H2O)]n (Ln is Pr, Nd, Sm, Eu, and Tb), as well as attempting to synthesize the novel organic linker 4,4'(4,8-Dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-diyl)dibenzoic acid (BDTDC). Various lanthanide salts were coordinated with 2,3-pyridinecarboxylate (2,3- pydc) via hydrothermal synthesis. ... Progress was made toward the synthesis of a novel metal...
Show moreThe main focus of this thesis is to present the structural and photophysical characteristics of the coordination polymers [Ln(C7H3NO4)(C7H4NO4)(H2O)]n (Ln is Pr, Nd, Sm, Eu, and Tb), as well as attempting to synthesize the novel organic linker 4,4'(4,8-Dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-diyl)dibenzoic acid (BDTDC). Various lanthanide salts were coordinated with 2,3-pyridinecarboxylate (2,3- pydc) via hydrothermal synthesis. ... Progress was made toward the synthesis of a novel metal-organic framework linker BDTDC. Synthesis of the intermediate benzo[1,2-b:4,5-b']dithiophene as well as the determination of the crystal structure, were performed successfully and are reported herein.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362561
Subject Headings: Metathesis (Chemistry), Supramolecular chemistry, Organic compounds, Synthesis, Macromolecules, Synthesis
Format: Document (PDF)

Title: DIASTEREOSELECTIVE ADDITION OF H-PHOSPHINATES TO ALKENYL KETONES UNDER PHASE-TRANSFER CONDITIONS AND SYNTHESIS OF BRIDGED BICYCLIC COMPOUNDS FOR BIOLOGICAL EVALUATION.
Creator: Yadavalli, Krishna Prasad, Lepore, Salvatore D., Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description: In the present dissertation, we discuss the development of a stereoselective method for the production of phosphorus compounds that utilizes a phospha-Michael addition reaction. Separately, the design and synthesis of compounds that contain an all-carbon bridged bicyclic scaffold is reported; these compounds were used in initial SAR studies in different in vivo models. In Chapter one is presented a mechanistic framework to develop a highly diastereoselective method catalyzed by phase transfer...
Show moreIn the present dissertation, we discuss the development of a stereoselective method for the production of phosphorus compounds that utilizes a phospha-Michael addition reaction. Separately, the design and synthesis of compounds that contain an all-carbon bridged bicyclic scaffold is reported; these compounds were used in initial SAR studies in different in vivo models. In Chapter one is presented a mechanistic framework to develop a highly diastereoselective method catalyzed by phase transfer chemistry leading to phosphinate compounds. In this method, phosphinate nucleophiles were added to various alkenyl ketones as Michael acceptors using crown ethers as phase transfer agents to obtain highly diastereoselective products with the generation of a carbon-based quaternary centers. A closed transition state mechanism is proposed to describe the diastereoselectivity observed in the reactions that is consistent with product outcome as established by X-ray crystallography. Analysis using the 31P NMR technique is also reported to ascertain the diastereomeric ratios in product formation. Using products obtained with the newly developed method, we disclose for the first time a novel phospha-heterocycle with high control of stereochemistry. Relative stereochemistry of the phosphorus containing heterocycle was reported using 2D NMR analysis. In Chapter two focus is placed on the use of acrylates as Michael acceptors in both the diastereoselective and enantioselective studies of phospha-Michael addition. In the asymmetric method development, screening of various chiral catalysts and development of HPLC method to quantify the enantiopurity of products obtained under reaction conditions are reported. The role of crown ether catalysts towards diastereoselectivity is reported.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014015
Subject Headings: Bridged bicyclic compounds, Chemistry, Organic, Organic compounds--Synthesis
Format: Document (PDF)

Title: Water content, organic content, and carbon and nitrogen composition of medusae from the northeast Pacific.
Creator: Larson, R. J., Harbor Branch Oceanographic Institute
Date Issued: 1986
PURL: http://purl.flvc.org/FCLA/DT/3353781
Subject Headings: Medusae, Biochemistry, Carbon, Nitrogen, Water, Organic and biological chemistry
Format: Document (PDF)

Title: Carbohydrate Recognition of Bi-pyridine Bridged Peptide Receptor.
Creator: Johnson, Claudia A., Cudic, Predrag, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: A novel carbohydrate receptor based on the structure of the antibiotic polymxin B was synthesized. The receptor was a cyclic heptapeptide. which was bridged using 2, 2'-bi pyridine-5,5"- dicarboxylic acid. The association constants of the receptor and a variety of sugars were determined using UV /Vis and fluorescence spectroscopy and observed log K0 values are in the range from 3 .8 to 4.1 for the pentoses, logKa 3.3 to 3.8 for the hexoxes and 0 to 2.9 logKa values from 0-2.9 for...
Show moreA novel carbohydrate receptor based on the structure of the antibiotic polymxin B was synthesized. The receptor was a cyclic heptapeptide. which was bridged using 2, 2'-bi pyridine-5,5"- dicarboxylic acid. The association constants of the receptor and a variety of sugars were determined using UV /Vis and fluorescence spectroscopy and observed log K0 values are in the range from 3 .8 to 4.1 for the pentoses, logKa 3.3 to 3.8 for the hexoxes and 0 to 2.9 logKa values from 0-2.9 for disaccharides and logKa of2.6 to 3.11 for the charged sugars. We demonstrated that polymixin based receptors are capable of binding various monosaccharide substrates in aqueous media, displaying structure selectivity with respect to monosaccharide ring size.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00000776
Subject Headings: Protein engineering, Neuropeptides--Receptors, Chemistry, Organic, Cellular recognition
Format: Document (PDF)

Title: Chemical Studies of Caribbean Marine Organisms.
Creator: Vansach, Tifanie, West, Lyndon M., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The projects described in this dissertation concentrated on investigating Caribbean species for qualitative and quantitative chemical differences. Chapter one includes a brief update on the status of natural products as drugs, a discussion of the biodiversity of Caribbean marine organisms as well as a discussion about the chemistry of algae and sponges. In chapter two, an experiment to test for possible effects of warmer, more acidic water and how that will impact coral reef organisms was...
Show moreThe projects described in this dissertation concentrated on investigating Caribbean species for qualitative and quantitative chemical differences. Chapter one includes a brief update on the status of natural products as drugs, a discussion of the biodiversity of Caribbean marine organisms as well as a discussion about the chemistry of algae and sponges. In chapter two, an experiment to test for possible effects of warmer, more acidic water and how that will impact coral reef organisms was conducted. Six common Caribbean coral reef sponge species were grown in seawater for 24 days ranging from values experienced at summer-maxima (temperature = 28 ºC; pH = 8.1) to those predicted for the year 2100 (T = 31 ºC; pH = 7.8). For each species, attachment rates, growth, and survival were similar between temperature and pH levels. Only two metabolite concentrations varied significantly between treatments but were similar to baseline levels. In chapter three, a chemical survey of Florida Keys algae was performed using MeOH extraction and HP-20 SPE with varying Me2CO:H2O solutions. 1H NMR spectra were collected for each fraction and analyzed for interesting signals. A Laurencia sp. was extracted and found to contain the known compound isodactylyne (61) with the structure determined using spectroscopic analyses. In chapter four, a Laurencia obtusa specimen was investigated to determine the compound causing oxygenated signals between 4.50 – 4.80 ppm in the 1H NMR spectra observed in chapter three. A large scale extraction and fractionation was performed and the compound was determined to be 1-O-palmitoyl-2-O-myristoyl-3-O-(6-sulfo-α- D-quinovo-pyranosyl)-glycerol (63). In chapter five, the isolation and structural elucidation of a new compound, furocaespitanenone (64) and two known compounds (10R)- and (10S)-10-O-methylfurocaespitanelactol 65 and 66, from a Laurencia sp. collected off of the Florida Keys using MeOH extraction and HP-20 column chromatography is described. A potential biosynthesis of 64 from furocaepsitane (68) is proposed.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013274
Subject Headings: Marine organisms, Caribbean, Algae--chemistry, Sponges--Caribbean Sea, Chemistry
Format: Document (PDF)

Title: Catalytic Asymmetric Isomerizations of Alkynes To Allenes And Their Diastereoselective Functionalization Facilitated By An Organomanganese Auxiliary.
Creator: Roy, Animesh, Lepore, Salvatore D., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The present dissertation research is largely focused on the methods to synthesize highly substituted allene derivatives from alkynes in conjugation with carbonyl-containing functional groups. A key aspect of this research involves methylcyclopentadienylmanganese dicarbonyl (MMD), an inexpensive and air-stable organometallic auxiliary linked to alkynyl carbonyls via an η2-bond. This auxiliary influences bond formation to achieve enhanced stereoselectivity without itself undergoing any chemical...
Show moreThe present dissertation research is largely focused on the methods to synthesize highly substituted allene derivatives from alkynes in conjugation with carbonyl-containing functional groups. A key aspect of this research involves methylcyclopentadienylmanganese dicarbonyl (MMD), an inexpensive and air-stable organometallic auxiliary linked to alkynyl carbonyls via an η2-bond. This auxiliary influences bond formation to achieve enhanced stereoselectivity without itself undergoing any chemical transformation. Chapter 1 accounts various examples of such transition metal auxiliaries including MMD. Typically conjugated alkynyl carbonyls do not isomerize to thermodynamically less favored allenes. However, with the MMD auxiliary in place, alkynyl carbonyl compounds undergo facile 1,3-proton shifts in the presence of a mild base to produce allene isomers. Although allenyl aldehydes are important building blocks, we note that direct methods to prepare them nonracemically are not known. Chapter 2 describes the development of a new cinchonine-based phase transfer catalyst to access non-racemic allenyl aldehydes from MMD-complexed alkynyl aldehydes. With the manganese auxiliary in place, nonracemic allenyl aldehydes were obtained in a weakly basic biphasic reaction system via enantioselective protonation conditions. Chapter 3 describes the second use of the MMD auxiliary to direct nucleophilic addition reactions to allenyl aldehydes for the preparation of 2,3-allenols diastereoselectively. In the absence of the MMD auxiliary, nucleophilic reactions to the carbonyl group of axially chiral allenyl aldehydes is poorly diastereoselective, which is a long-standing problem. We observed that, in addition to leading to non-racemic allenyl aldehydes, the MMD auxiliary could also be used to improve diastereoselectivity in carbonyl additions due to its proximal position on the 2,3-bond of the allenyl aldehyde. Chapter 4 describes the use of allenyl esters as metathesis quenching agents. It was observed that the addition of an allenyl ester after a metathesis reaction was complete; facilitate the removal of most ruthenium metal impurities using simple silica chromatographic purification.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004918
Subject Headings: Transition metal catalysts., Stereochemistry., Chemistry, Organic., Chemistry, Physical and theoretical., Asymmetric synthesis.
Format: Document (PDF)

Title: Synthesis of allenyl carbonyls and their use as heterodienes in a novel inverse electron demand hetero-Diels-Alder reaction.
Creator: Bromfield, Deborah Christina Deirdre., Florida Atlantic University, Lepore, Salvatore D.
Abstract/Description: We report the development of a novel hetero-Diels-Alder reaction involving the use of allenyl carbonyls as heterodienes. We have described the synthesis of a variety of allenyl carbonyls via a base promoted and manganese mediated isomerization of alkynyl carbonyls for use in methodology studies. In our model studies, a variety of enamines were utilized effectively as dienophiles to form "hydrolyzed" Diels-Alder adducts while investigating optimal reaction conditions. Initial studies towards...
Show moreWe report the development of a novel hetero-Diels-Alder reaction involving the use of allenyl carbonyls as heterodienes. We have described the synthesis of a variety of allenyl carbonyls via a base promoted and manganese mediated isomerization of alkynyl carbonyls for use in methodology studies. In our model studies, a variety of enamines were utilized effectively as dienophiles to form "hydrolyzed" Diels-Alder adducts while investigating optimal reaction conditions. Initial studies towards the synthesis of an allenyl ester tethered to an aldehyde for an eventual application in an intramolecular Diels-Alder reaction were performed. Possible mechanisms were proposed while computational studies were performed in attempt to rationalize product selectivity.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13222
Subject Headings: Diels-Alder reaction, Ring formation (Chemistry), Heterocyclic compounds, Organic compounds--Synthesis, Carbonyl compounds--Synthesis, Alkenes, Organic nitro chemistry
Format: Document (PDF)

Title: Development and applications of nucleophile assisting leaving groups (NALGs) with Titanium (IV) and Grignard reagents.
Creator: Li, Songye., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: We report here the development of very efficient aryl- and quinolinyl- sulfonate based leaving groups, termed Nucleophile Assisting Leaving Groups (NALGs), which substantially accelerate the rate of nucleophilic substitution reactions with metal halides. Detailed synthesis and kinetics study are described herein. Our synthesized NALGs have shown great reactivity towards poor nucleophiles and/or substrates traditionally considered too hindered to undergo nucleophilic attack. The abundant...
Show moreWe report here the development of very efficient aryl- and quinolinyl- sulfonate based leaving groups, termed Nucleophile Assisting Leaving Groups (NALGs), which substantially accelerate the rate of nucleophilic substitution reactions with metal halides. Detailed synthesis and kinetics study are described herein. Our synthesized NALGs have shown great reactivity towards poor nucleophiles and/or substrates traditionally considered too hindered to undergo nucleophilic attack. The abundant existence of halide, azide and amine in natural products demands new synthetic pathway. To fulfill this requirement, new mild stereoretentive halogenations (chlorination, bromination and iodination) reactions have also been developed for secondary cyclic alcohols using NALGs involving titanium (IV) reagents. The novel methodology can be extended to Azidation reactions as well with titanium (IV) azide, in which Ti (N3)4 is the first time being engaged in organic synthesis. Beased on the NALGs theory we discover the chlorosulfite can be a simplest NALG and applied as the intermediate in mild one-pot stereoretentive halogenations (chlorination and bromination) using titanium (IV) halides as catalysts or stoichiometric reagents. These reactions were found to be particularly efficient for cyclic alcohols. Finally, an efficient mild bromination and iodination reaction for primary and secondary alcohols with Grignard reagents is also reported. This reaction exhibits the generality with substrates with various leaving groups. The important features of this reaction are that, for the first time, bromide formation using Grignard reagents without the Cu (I) catalysts.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3183130
Subject Headings: Chemical kinetics, Chemical reaction, Condition and laws of, Organic compounds, Synthesis, Organotransition metal compounds, Intermediates (Chemistry), Organic reaction mechanisms
Format: Document (PDF)

Title: Development of Nucleophile Assisting Leaving Groups (NALGs) and new stereoselective reactions using titanium(IV) reagents.
Creator: Mondal, Deboprosad., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: We report here the development of very efficient sulfonate based leaving groups, termed Nucleophile Assisting Leaving Groups (NALGs), to accelerate the rate of nucleophilic substitution reactions involving poor nucleophiles and/or substrates traditionally considered too hindered to undergo nucleophilic attack. Indeed NALGs have shown exceptional ability in improving rate of nucleophilic substitution reactions. New very mild stereoretentive halogenations and azidation reactions have also been...
Show moreWe report here the development of very efficient sulfonate based leaving groups, termed Nucleophile Assisting Leaving Groups (NALGs), to accelerate the rate of nucleophilic substitution reactions involving poor nucleophiles and/or substrates traditionally considered too hindered to undergo nucleophilic attack. Indeed NALGs have shown exceptional ability in improving rate of nucleophilic substitution reactions. New very mild stereoretentive halogenations and azidation reactions have also been developed for secondary cyclic alcohols using NALGs involving titanium(IV) reagents. This reaction is particularly significant since the carbon-halogen bond is found widely in natural products and is used extensively as a synthesis intermediate. Azide is also a synthetically important functional group from which a variety of biologically important functional groups are conveniently obtained. Though stereoretentive chlorination and bromination reactions are known, we have developed, for the first time, a stereoretentive azidation reaction using titanium(IV) azide, a reagent not previously used in organic synthesis. During our development of stereoretentive reactions, we eventually developed very efficient, mild, two-step one-pot stereoretentive halogenations (chlorination and bromination) using titanium(IV) halides as catalysts or stoichiometric reagents. These reactions were found to be particularly efficient for cyclic alcohols. An efficient one pot stereoretentive amidation reaction for secondary cyclic alcohols is also reported. The important features of this reaction are that, for the first time, chlorosulfite (prepared in situ from alcohol using thionylchloride) has been used as a leaving group and titanium(IV) fluoride as an activator., Utilization of those two reagents is unique as thionylchloride has never been used for nucleophilic substitution reactions except in chlorination procedures. In addition, this work has found new and creative applications for titanium (IV) fluoride, a reactant rarely used in organic synthesis. Further exploiting the unique reactivity of titanium(IV), reactions of alkenes with various nucleophiles have been developed with this reagent in both catalytic and stoichiometric quantities. It was observed that a-substituted aromatic conjugated alkenes dimerize to generate important indan class of compounds which are very important in the polymer industry. In addition, non conjugated unactivated alkenes react with various nucleophiles to yield the adduct.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/3159264
Subject Headings: Chemical reaction, Condition and laws of, Organic compounds, Synthesis, Chemical templates, Intermediates (Chemistry), Organotransition metal compounds, Organic reaction mechanisms
Format: Document (PDF)

Title: Non-metal catalyzed cyclization of α-alkynyl hydrazines to form azaproline derivatives: a mechanism study.
Creator: Nagy, Edith, Maity, Pradip, Lepore, Salvatore D.
Date Issued: 2012-04-06
PURL: http://purl.flvc.org/fcla/dt/3349037
Subject Headings: Synthetic organic chemistry, Alkynes, Non-metal catalyzed cyclization, Derivatization --proline, Pyrazolines -- Derivatives, Biochemical models, Hydrazines
Format: Document (PDF)

Title: An extraction optimization and determination of the absolute configuartion of clathric acid.
Creator: Rueda de Leon, Rolando, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Current research in natural products has heavily focused on the identification of potent biologically active compounds, specifically for drug development. The project detailed in this thesis focuses on the extraction of compounds from marine invertebrates as well as defining the absolute configuration for a compound. Utilizing marine invertebrates, the sonications method developed in this thesis provides an alternative approach to rapidly extract compounds for primary screening. This method...
Show moreCurrent research in natural products has heavily focused on the identification of potent biologically active compounds, specifically for drug development. The project detailed in this thesis focuses on the extraction of compounds from marine invertebrates as well as defining the absolute configuration for a compound. Utilizing marine invertebrates, the sonications method developed in this thesis provides an alternative approach to rapidly extract compounds for primary screening. This method is viable compared to a traditional overnight extraction method, without suffering compound degredation... Previously, clathric acid was isolated from an unknown Clathria sp. This compound is a bibyblic C-21 terpenoid shown to have mild antimicrobial activity against gram positive bacteria. With only its relative configuration established, additional amounts of clathric acid were required to define the overall absolute configuration. Identifying the Clathria sp. to be Clathria compressa, through spicule analysis, additional sponge tissues were then collected off the coast of Boca Raton, Florida to isolate additional quatities of clathric acid. The absolulte configuration was determined through circular dichroism and the octant rule to establish a final configuration for clathric acid's four carbon stereocenters to be: (3S, 7S, 8R, and 12S).
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3355874
Subject Headings: Organic compounds, Analysis, Extraction (Chemistry), Natural products, Therapeutic use, Marine biotechology, Marine resources, Research, Sponges, Ecology
Format: Document (PDF)

Title: Manganese-promoted rearrangement of alkynyl carbonyls to allenyl carbonyls with emphasis on asymmetric induction using chiral bases.
Creator: Khoram, Anita, Florida Atlantic University, Lepore, Salvatore D., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordinations followed by a based-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. In this work we employed HPLC equipped with a chiral column to determine the enantiomeric excess. Deuterium labeling experiments suggested that the alkyne/allene rearrangement reaction involved an intermediate cumenolate. We also demonstrated that the reaction required a ligand on manganese...
Show moreThe conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordinations followed by a based-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. In this work we employed HPLC equipped with a chiral column to determine the enantiomeric excess. Deuterium labeling experiments suggested that the alkyne/allene rearrangement reaction involved an intermediate cumenolate. We also demonstrated that the reaction required a ligand on manganese for an amine base to be used catalytically. Phosphines were tested as a possible ligand because they are neutral two electron donors that binds to transition metals through their lone pairs. It was observed that the rate of the reaction decreased from 24hr to 3hr by use of phosphine as a ligand. It was also confirmed that amine base with pKa lower then DBU (pKa = 13.6) would not carry out the isomerization. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. Alkoxy base were also used in isomerization that demonstrated enantioselectivity.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13158
Subject Headings: Carbonyl compounds--Synthesis, Organic compounds--Synthesis, Allene, Alkenes, Methathesis (Chemistry), Isomerism
Format: Document (PDF)

Title: Hemisynthesis and Characterization of Cyclopheophorbides.
Creator: Mortezaei-Rad, Mitra, Florida Atlantic University, Louda, J. William, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Cyclopheophorbides absorb light at higher wavelengths (> 670 run) as compared to their precursor pyropheophorbides ( ~ 666 run) and are strong antioxidants. Therefore they could potentially be used as photosensitizers in photodynamic therapy, although this study does not focus on the pharmacology aspect of this class of compounds. The overall goal of this study was to hemisynthesize, purify and characterize certain cyclopheophorbides from both chlorophyll a and b families. The known...
Show moreCyclopheophorbides absorb light at higher wavelengths (> 670 run) as compared to their precursor pyropheophorbides ( ~ 666 run) and are strong antioxidants. Therefore they could potentially be used as photosensitizers in photodynamic therapy, although this study does not focus on the pharmacology aspect of this class of compounds. The overall goal of this study was to hemisynthesize, purify and characterize certain cyclopheophorbides from both chlorophyll a and b families. The known hemisynthesis of 13^2,17^3-cyclopheophorbide a enol was repeated. A major success in the purification process was achieved by utilizing polystyrene divinylbenzene (PS-DVB a.k .a. PRP-1 TM) as the stationary phase in reversed phase flash chromatography. Altering (TMS)2-NNa with (TMS)2-NLi was found to increase yields. 13^2,17^3 -mesocyclopheophorbide a enol was successfully hemisynthesized as a novel compound. Methyl-3-devinyl-3-[1-hexyloxy]ethyl pyropheophorbide a (HPPH-ME), was prepared, purified and molecular characteri zation on the compound was performed. Hemisynthesis ofHPPH-CYCLO from HPPH-ME was attempted, but was unsuccessful. Zinc and copper pyropheophorbide a methyl esters were prepared with the intent of forming of zinc and copper CYCLO. Hemisynthesis of corresponding metalloCYCLO from both insertion of the metal inside the CYCLO core and cyclizations of metal derivatives of pyropheophorbide a methyl ester were unsuccessful. Chlorophyll b was successfully extracted from green algae Chiarella and purified in mg lots (100%) utilizing RP-LPLC and with a binary solvent gradient program. Pheophorbide b methyl ester and pyropheophorbide b methyl ester were made and characterized. Hemisynthesis of CYCLO-b was unsuccessful likely due to the altered reactivity of pyropheophorbide b (vs. -a) methyl ester. To reduce the reactivity, reduction of formyl group of pyropheophorbide b methyl ester with NaBH4 was performed. Still, formation of a CYCLO derivative was not achieved. Chromatographic purification, mass and NMR characterization of CYCLO, mesoCYCLO, HPPH-ME and all precursor compounds are reported. 2D NMR of most of these compounds are reported here for the first time.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00000872
Subject Headings: High performance liquid chromatography, Organometallic chemistry, Organic compounds--Spectra, Organophosphorus compounds
Format: Document (PDF)

Title: The synthesis and reactivity of nucleophile assisting leaving groups.
Creator: Cohn, Pamela., Florida Atlantic University, Lepore, Salvatore D.
Abstract/Description: The synthesis and reactivity of Nucleophile Assisting Leaving Groups was studied in order to assess the rate enhancement of nucleophilic substitution reactions. Various Nucleophile Assisting leaving groups were synthesized, all of them containing a coordinating arm positioned ortho to an electrophilic center on a benzene ring. The various coordinating arms had novel geometries and binding properties. Their reactivity was studied with a variety of metal salts and the kinetics of the reactions...
Show moreThe synthesis and reactivity of Nucleophile Assisting Leaving Groups was studied in order to assess the rate enhancement of nucleophilic substitution reactions. Various Nucleophile Assisting leaving groups were synthesized, all of them containing a coordinating arm positioned ortho to an electrophilic center on a benzene ring. The various coordinating arms had novel geometries and binding properties. Their reactivity was studied with a variety of metal salts and the kinetics of the reactions was studied with 1H-NMR spectroscopy. This method provided a quantitative measurement of the rate enhancement observed in the substitution reactions from the rate constants obtained. In the case of certain crown ether-containing substrates, NMR experiments suggest that the mechanism of substitution proceeds in two steps, the first being a pre-coordination of the metal salt with the coordinating arm, followed by a conversion of the complex to products.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13375
Subject Headings: Chemical reaction, Conditions and laws of, Organic reaction mechanisms, Intermediates (Chemistry), Organotransition metal compounds
Format: Document (PDF)

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Chemistry, Organic (7)	+ -
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Florida Atlantic University (15)	+ -
Lepore, Salvatore D. (8)	+ -
Alhuniti, Mohammed (1)	+ -

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