Kinetic resolution of iodophenylethanols by Candida antarctica lipase and their application for the synthesis of chiral biphenyl compounds

The kinetic resolution of (+/-)-iodophenylethanols was carried out using lipase from Candida antarctica and in some cases the enantiomeric excesses were high (up to >98%). Enantiomerically enriched (S)-iodophenylethanols produced by the enzymatic resolution process were used in the synthesis of chiral biphenyl compounds by the Suzuki reaction with good yields (63-65%). (C) 2010 Elsevier Ltd. All rights reserved.

An epoxide ring-opening approach for a short and stereoselective synthesis of icetexane diterpenoids

A new approach for the synthesis of the core skeleton of icetexane diterpenoids is presented and deals with an epoxide ring-opening reaction by metallated aromatic compounds. Employing this strategy, a short synthesis of an icetexane analogue of brussonol was achieved in just four steps from 2-allyl-cyclohexanone. (C) 2009 Elsevier Ltd. All rights reserved.

Influence of Reaction Conditions on Synthesis of PAni/MnO(2) Composites

An investigation of the parameters as aniline: MnO(2) and temperature on synthesis of polyaniline/MnO(2) composites was performed. The composites were chemically prepared in H(2)SO(4) media using different aniline: MnO(2) ratios at 0 degrees C. After the ratio optimization, the syntheses were performed at 20 degrees C. The polyaniline/MnO(2) composites were characterized by scanning electron microscopy (SEM), ultraviolet-visible, near infrared and infrared spectroscopic techniques. Composites obtained with a uniform, homogeneous and thicker coating of polyaniline films under oxide was considered as the best condition for synthesis.

Synthesis of a PEG-bipolar-dimyristoylphosphatidylethanoline

The problem of drug delivery has been of continuous research interest to the biomedical scientific community. The basic problem of drug delivery is to facilitate the transport of medication via the bloodstream to the target organs. This process can be significantly hampered by the hydrophobic nature of most medications. Pharmaceutical compounds and in particular chemotherapeutics (which are a specific area of research at the Cornell Medical Center and the Sloan-Kettering Institute) tend to be extremely hydrophobic. Blood is a hydrophilic environment, so the hydrophobic drugs simply cannot dissolve in the bloodstream. As a result they cannot be transported successfully to the target tissues. For example, Sloan-Kettering possesses compounds that kill cancer cells 100ln vitro, yet those same compounds are virtually inactive in vivo because of their insolubility in the blood. It was our purpose, therefore, to develop an appropriate and successful drug delivery system.

Selective Synthesis of Oxacalix[6]arenes and Mixed Oxacalix[4]arenes

Calixarenesare macrocycles composed of benzene rings meta linked to each other by one carbon atom. These exotic compounds can be used for a variety of purposes including metalleaching for environmental cleanup, surface technology, luminescent probes, nuclear waste treatment, among others. A variety of calixarenesexist, including azacalix[n]arenesthiocalix[n]arenes(where n = the number of benzene rings) and oxacalix[n]arenes; these macrocycles use nitrogen, sulfur and oxygen, respectively, as the atom whichlinks the benzene rings together. My research has focused on synthesizing oxacalix[6]arenes (“hexamer”) in high yield, which is a synthetic challenge because it is generally accepted that oxacalix[n>4]arenes will thermodynamically decompose to the oxacalix[4]arene (“tetramer”); i.e. heating the reaction mixture will yield the tetramer, not the hexamer. To generate the hexamer, “trimer”precursors have been synthesized, in the hopes of facilitating hexamer ring closure.

Synthesis of 2-oxo-16-(3', 4'-methylenedioxyphenyl)-trans-15-hexadecene

This work presents the progress made towards synthesizing 2-oxo-16-(3', 4'methylenedioxyphenyl)-trans-15-hexadecene, an antimycobacterial compound that was originally isolated from the leaves of Piper Sanctum. The hydrocarbon chain of the molecule was synthesized first by opening a 15-pentadecanolactone ring by means of HI, and performing an E2 elimination reaction on the molecule followed by an organolithium reaction with CH3Li. Hexadec-15-en-2-one that was afforded this way was later reacted with 5-bromobenzo[d][1,3]dioxole following the appropriate Heck reaction protocol that allows for the formation of a palladium catalyzed carbon-carbon bond. The modes of action of 2-oxo-16-(3', 4'-methylenedioxyphenyl)-trans-15hexadecene are comparable to the ones of rifampicin, a marketable drug that has been successfully used in the treatment of tuberculosis in the past. Additionally, this compound can serve as an intermediate towards the synthesis of 2-oxo-16-(3', 4' methylenedioxyphenyl)-hexadecane and 2-oxo-14-(3', 4' -methylenedioxyphenyl) tetradecane, both strong inhibitors of the growth of Mycobacterium tuberculosis. Lastly, due to Multi-Drug Resistant tuberculosis, there has been an increasing need to find alternative cures for tuberculosis. Therefore, the work on 2-qxo-16-(3', 4'methylenedioxyphenyl)-trans-15-hexadecene is not only chemically interesting but it is also biologically important.

Hydroalumination of seleno acetylenes: a versatile generation and reactions of alpha-aluminate vinyl selenide intermediates in the highly regio and stereoselective synthesis of telluro(seleno)ketene acetals

The hydroalumination of butylseleno acetylenes with DIBAL-H followed by addition of n-butyllithium generated in situ the (Z)-butylseleno vinyl alanates intermediates which were captured with C(4)H(9)TeBr furnishing the (E)-telluro(seleno)ketene acetals exclusively. The isomers with opposite stereochemistry (Z)-telluro(seleno)ketene acetals were obtained by the reduction of phenylseleno acetylenes with lithium di-(isobutyl)-n-butyl aluminate hydride (Zweifel's reagent) followed by reaction of (E)-phenylseleno vinyl alanates intermediates with C(4)H(9)TeBr. (c) 2008 Elsevier Ltd. All rights reserved.

Fast and efficient synthesis of pyrano[3,2-c]quinolines catalyzed by niobium(V) chloride

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis of poly(styrene-co-methyl methacrylate)-based ionomers and their Langmuir and Langmuir-Blodgett (LB) film formation

Poly(styrene-co-methyl methacrylate) (PS-PMMA) ionomers with several degrees of sulfonation were synthesized and characterized by infrared, UV-vis, and NMR spectroscopies, elemental analysis, and differential scanning calorimetry (DSC). Stable Langmuir films could be produced with PS-PMMA with 3 and 6 mol % of sulfonation, while PS-PMMA 8% exhibited material loss to the water subphase, probably due to its higher solubility. Surface pressure and surface potential isotherms with PS-PMMA 3% spread onto salt-containing subphases pointed to a film behavior characteristic of the polyelectrolyte effect, where charge repulsion governs the film properties. The Langmuir-Blodgett films of this ionomer were successfully transferred onto various substrates, as confirmed by UV-vis and FTIR spectroscopies. Using cycling voltammetry, we show that LB films from PS-PMMA 3% can be applied in selective sensing of dopamine, even in the presence of interferents such as ascorbic acid.

Synthesis of potentially bioactive PABA-related N-(aminoalkyl)lactamic amino acids and esters via selective SNAr reactions

Potentially bioactive N-(aminoalkyl)lactamic amino acids and esters were synthesized in satisfactory to good yields by SNAr reactions of aromatic acids with N-(3-aminopropyl)lactams followed by esterification with tertiary amino alcohols. The addition-elimination SNAr mechanism was confirmed by NMR and MS measurements.

Synthesis of 4-aminoquinoline analogues and their platinum(II) complexes as new antileishmanial and antitubercular agents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)