Molecules

215 KiB

Open AccessArticle

Synthesis of Unsymmetrical Annulated 2,2’-Bipyridine Analogues with Attached Cycloalkene and Piperidine Rings via Sequential Diels-Alder Reaction of 5,5’-bi-1,2,4-triazines

by D. Branowska

Molecules 2005, 10(1), 265-273; https://doi.org/10.3390/10010265 - 31 Dec 2005

Cited by 21 | Viewed by 7704

Abstract

Synthesis of bisfunctionalized unsymmetrical 2,2’-bipyridines 8 or their sulfonyl derivatives 12a,b are described. They were prepared via the Diels-Alder reaction of 1-methyl-4-pyrrolidin-1-yl-1,2,3,6-tetrahydropyridine (6) with 3,3’-bis(methyl- sulfanyl)-5,5’-bi-1,2,4-triazine (1). The reaction leads to the single cycloaddition product 7 which undergoes Diels-Alder reaction with cyclic enamines [...] Read more.

Synthesis of bisfunctionalized unsymmetrical 2,2’-bipyridines 8 or their sulfonyl derivatives 12a,b are described. They were prepared via the Diels-Alder reaction of 1-methyl-4-pyrrolidin-1-yl-1,2,3,6-tetrahydropyridine (6) with 3,3’-bis(methyl- sulfanyl)-5,5’-bi-1,2,4-triazine (1). The reaction leads to the single cycloaddition product 7 which undergoes Diels-Alder reaction with cyclic enamines 2a,b to give unsymmetrical 2,2’-bipyridine derivatives 8, consisting of the two different heterocyclic units: cycloalkeno[c]pyridine and 2,6-naphthyridine. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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80 KiB

Open AccessCorrection

Publication Note Concerning Molecules 2002, 7, 717-720

by Derek McPhee

Molecules 2005, 10(1), 317; https://doi.org/10.3390/10010317 - 31 Oct 2005

Cited by 1 | Viewed by 4293

Abstract

n/a Full article

191 KiB

Open AccessArticle

Asymmetric Synthesis of Double Bond Isomers of the Structure Proposed for Pyrinodemin A and Indication of Its Structural Revision

by Haruaki Ishiyama, Masashi Tsuda, Tadashi Endo and Jun’ichi Kobayashi

Molecules 2005, 10(1), 312-316; https://doi.org/10.3390/10010312 - 31 Jan 2005

Cited by 28 | Viewed by 8447

Abstract

Asymmetric synthesis of double bond isomers ( )-2 (∆¹⁵’,¹⁶’) and ( )-3 (∆¹⁴’,¹⁵’) ofthe structure (1) (∆¹⁶’,¹⁷’) proposed for pyrinodemin A, a cytotoxic bis-pyridine alkaloidwith a unique cis-cyclopent[c]isoxazolidine moiety from a [...] Read more.

Asymmetric synthesis of double bond isomers ( )-2 (∆¹⁵’,¹⁶’) and ( )-3 (∆¹⁴’,¹⁵’) ofthe structure (1) (∆¹⁶’,¹⁷’) proposed for pyrinodemin A, a cytotoxic bis-pyridine alkaloidwith a unique cis-cyclopent[c]isoxazolidine moiety from a marine sponge, has beenaccomplished. Pyrinodemin A was indicated to be a 1:1 racemic mixture of 2 fromcomparison of C₁₈and chiral HPLC analysis for pyrinodemin A and the syntheticcompounds as well as ESIMS data of oxidative degradation products of pyrinodemin A. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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349 KiB

Open AccessArticle

Syntheses, Characterization and Study of the Use of Cobalt (II) Schiff–Base Complexes as Catalysts for the Oxidation of Styrene by Molecular Oxygen

by Ali Akbar Khandar, Kamellia Nejati and Zolfaghar Rezvani

Molecules 2005, 10(1), 302-311; https://doi.org/10.3390/10010302 - 31 Jan 2005

Cited by 38 | Viewed by 12811

Abstract

Schiff-Base complexes of bis-5-phenylazosalicylaldehyde ethylenediimine and bis-5-phenylazosalicylaldehyde-O-phenylenediimine ligands with Co(II) (I and II) have been synthesized and characterized by their IR spectra and elemental analyses. These complexes catalyze the oxidation of styrene in the presence of dioxygen and excess pyridine. The effect of [...] Read more.

Schiff-Base complexes of bis-5-phenylazosalicylaldehyde ethylenediimine and bis-5-phenylazosalicylaldehyde-O-phenylenediimine ligands with Co(II) (I and II) have been synthesized and characterized by their IR spectra and elemental analyses. These complexes catalyze the oxidation of styrene in the presence of dioxygen and excess pyridine. The effect of the reaction conditions on the oxidation of styrene was studied by varying solvent, nature and amount of the catalyst and substrate. The catalytic behavior of the studied complexes was shown to be dependent on the conditions applied. In all reactions, acetophenone and 1- phenylethanol were the only observed products. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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171 KiB

Open AccessArticle

Synthesis of Analogs of Amathamide A and Their Preliminary Antimicrobial Activity

by M. Ramírez-Osuna, D. Chávez, L. Hernández, E. Molins, R. Somanathan and G. Aguirre

Molecules 2005, 10(1), 295-301; https://doi.org/10.3390/10010295 - 31 Jan 2005

Cited by 11 | Viewed by 9004

Abstract

Syntheses of three non-brominated analogs of amathamide A (1), a natural alkaloid isolated from the Tasmanian marine bryozoan Amathia wilsoni, are described. Antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomona aeruginosa, and Candida albicans was tested. Test results for amathamide A [...] Read more.

Syntheses of three non-brominated analogs of amathamide A (1), a natural alkaloid isolated from the Tasmanian marine bryozoan Amathia wilsoni, are described. Antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomona aeruginosa, and Candida albicans was tested. Test results for amathamide A (1) showed a weak activity against C. albicans and E. coli. The three non-natural analogs 2-4 proved to be inactive compounds. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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188 KiB

Open AccessArticle

An Electron Transfer Approach to the Preparation of Highly Functionalized Anthraquinones

by Abdelouahab Beziane, Thierry Terme and Patrice Vanelle

Molecules 2005, 10(1), 289-294; https://doi.org/10.3390/10010289 - 31 Jan 2005

Cited by 4 | Viewed by 8035

Abstract

A series of highly functionalized quinones was prepared by an original reaction of 2,3-bis(chloromethyl)-1,4-dimethoxyanthraquinone (6) with various nitronate anions under electron transfer reaction conditions. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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206 KiB

Open AccessArticle

Chemical and Photochemical Synthesis of Substituted Dihydro-thieno[2',3':4,5]thieno[2,3-c]quinolin-6-ones and Tetrahydro-dithieno[2,3-b:2',3'-d]thieno[2'',3''c:2'',3''c’]diquinolin-6,14-dione

by Jelena Blažević Šafarik, Jasna Dogan Koružnjak and Grace Karminski-Zamola

Molecules 2005, 10(1), 279-288; https://doi.org/10.3390/10010279 - 31 Jan 2005

Cited by 11 | Viewed by 8108

Abstract

Some new substituted dihydrothieno[2',3':4,5]thieno[2,3-c]quinolin-6-ones 9- 12 and tetrahydrodithieno[2,3-b: 2',3'-d]thieno[2'',3''-c:2'',3''-c’]diquinolin-6,14-dione (17) were prepared from the corresponding new anilides 5-8 and from the corresponding dianilide 15, respectively, by a multistep combination of chemical and photochemical reactions. All the prepared compounds are of particular interest because [...] Read more.

Some new substituted dihydrothieno[2',3':4,5]thieno[2,3-c]quinolin-6-ones 9- 12 and tetrahydrodithieno[2,3-b: 2',3'-d]thieno[2'',3''-c:2'',3''-c’]diquinolin-6,14-dione (17) were prepared from the corresponding new anilides 5-8 and from the corresponding dianilide 15, respectively, by a multistep combination of chemical and photochemical reactions. All the prepared compounds are of particular interest because they might serve as DNA intercalators in anticancer therapy. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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177 KiB

Open AccessArticle

A Direct Route to 6,6’-Disubstituted-2,2’-Bipyridines by Double Diels-Alder/retro Diels-Alder Reaction of 5,5’-bi-1,2,4-Triazines

by D. Branowska

Molecules 2005, 10(1), 274-278; https://doi.org/10.3390/10010274 - 31 Jan 2005

Cited by 13 | Viewed by 7668

Abstract

Inverse electron demand Diels-Alder reaction of functionalized 5,5’-bi-1,2,4- triazines with bicyclo[2.2.1]hepta-2,5-diene in boiling p-cymene leads to a range of 6,6’- disubstituted-2,2’-bipyridines in good yield. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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183 KiB

Open AccessArticle

Synthesis of the Key Precursor of Hirsutellide A

by Yanjie Xu, Xuemin Duan, Meiling Li, Liqin Jiang, Guangle Zhao, Yi Meng and Ligong Chen

Molecules 2005, 10(1), 259-264; https://doi.org/10.3390/10010259 - 31 Jan 2005

Cited by 8 | Viewed by 9626

Abstract

Hexadepsipeptide 2, the precursor of Hirsutellide A (1), was synthesized in an overall yield of 45% from N-Boc-Me-Gly via three coupling reactions using dicyclohexylcarbodiimide (DCC), O-(7-azabenzotriazol-1-yl)-N,N,N’,N’-tetramethyl- uronium hexafluorophosphate (HATU) and bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl), respectively. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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268 KiB

Open AccessArticle

Synthesis and Molecular Structure of Methyl 4-O-methyl-α-D-glucopyranuronate

by Ján Hirsch, Vratislav Langer and Miroslav Koóš

Molecules 2005, 10(1), 251-258; https://doi.org/10.3390/10010251 - 31 Jan 2005

Cited by 14 | Viewed by 8904

Abstract

A method for the preparation of methyl 4-O-methyl-α-D-glucopyranuronate andits single crystal X-ray structure determination are reported. The molecule adopts an almostideal ⁴C₁ (^OC₃) conformation. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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200 KiB

Open AccessArticle

Substrate Dependence in Aqueous Diels-Alder Reactions of Cyclohexadiene Derivatives with 1,4-Benzoquinone

by Takeshi Sunakawa and Chiaki Kuroda

Molecules 2005, 10(1), 244-250; https://doi.org/10.3390/10010244 - 31 Jan 2005

Cited by 8 | Viewed by 8097

Abstract

A reactivity difference based on the position of substituents on cyclohexa-1,3- diene was observed for the title reaction. The effect of water as solvent was more distinct for 1-methyl-4-isopropylcyclohexa-1,3-diene than for 2-methyl-5-isopropylcyclohexa- 1,3-diene or non-substituted cyclohexa-1,3-diene. The effect of NaCl (salting-out) and guanidium [...] Read more.

A reactivity difference based on the position of substituents on cyclohexa-1,3- diene was observed for the title reaction. The effect of water as solvent was more distinct for 1-methyl-4-isopropylcyclohexa-1,3-diene than for 2-methyl-5-isopropylcyclohexa- 1,3-diene or non-substituted cyclohexa-1,3-diene. The effect of NaCl (salting-out) and guanidium chloride (salting-in) was also large for 1-methyl-4-isopropylcyclohexa-1,3- diene. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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170 KiB

Open AccessArticle

Pd-Catalyzed Carbonyl Insertion Coupling Reactions of a Hypervalent Iodoheterocycle with Alcohols and Amines

by Shengj-Jun Luo, Yong-Xiang Ma and Yong-Min Liang

Molecules 2005, 10(1), 238-243; https://doi.org/10.3390/10010238 - 31 Jan 2005

Cited by 4 | Viewed by 8995

Abstract

The palladium-catalyzed cross-coupling carbonyl insertion reaction between 3,7-bis(N,N-dimethylamino)-10H-dibenz[b,e]iodinium iodide (1) and alcohols or amines 2 is described. Some new amides and esters 3 containing an active iodo functional group have been prepared in 65-91% yields. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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236 KiB

Open AccessArticle

A Survey on the Reactivity of Phenyliodonium Ylide of 2-Hydroxy-1,4-Naphthoquinone with Amino Compounds

by Konstantina Spagou, Elizabeth Malamidou-Xenikaki and Spyros Spyroudis

Molecules 2005, 10(1), 226-237; https://doi.org/10.3390/10010226 - 31 Jan 2005

Cited by 12 | Viewed by 8347

Abstract

The phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone reacts with aminoesters, ureas, aminoalcohols and aminophenols in refluxing dichloromethane to afford good yields of indanedione 2-carboxamido compounds, that in solution exist in an enol-amide form. The same reactants in a copper-catalyzed reaction afford mainly the corresponding N-arylo [...] Read more.

The phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone reacts with aminoesters, ureas, aminoalcohols and aminophenols in refluxing dichloromethane to afford good yields of indanedione 2-carboxamido compounds, that in solution exist in an enol-amide form. The same reactants in a copper-catalyzed reaction afford mainly the corresponding N-arylo compounds. Arylhydrazines are mainly oxidized by the ylide and arylation occurs only in a low yield. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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209 KiB

Open AccessArticle

Application of [Hydroxy(tosyloxy)iodo]benzene in the Wittig-Ring Expansion Sequence for the Synthesis of β-Benzocyclo-alkenones from α-Benzocycloalkenones

by M. Justik and G. Koser

Molecules 2005, 10(1), 217-225; https://doi.org/10.3390/10010217 - 31 Jan 2005

Cited by 49 | Viewed by 13774

Abstract

The conversion of α-benzocycloalkenones to homologous β-benzocyclo-alkenones containing six, seven and eight-membered rings is reported. This wasaccomplished via a Wittig olefination-oxidative rearrangement sequence using[hydroxy(tosyloxy)iodo]-benzene (HTIB) is the oxidant, that enables the synthesis ofregioisomeric pairs of methyl-substituted β-benzocycloalkenones. The incorporation ofcarbon-13 at C-1 of [...] Read more.

The conversion of α-benzocycloalkenones to homologous β-benzocyclo-alkenones containing six, seven and eight-membered rings is reported. This wasaccomplished via a Wittig olefination-oxidative rearrangement sequence using[hydroxy(tosyloxy)iodo]-benzene (HTIB) is the oxidant, that enables the synthesis ofregioisomeric pairs of methyl-substituted β-benzocycloalkenones. The incorporation ofcarbon-13 at C-1 of the β-tetralone nucleus was also demonstrated. The Wittig-HTIBapproach is a useful alternative to analogous sequences in which Tl(NO₃)₃·3H₂O or thePrevost combination (AgNO₃/I₂) are employed in the oxidation step. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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291 KiB

Open AccessArticle

Oxidative Dearomatization of Phenols and Anilines via λ³- and λ⁵-Iodane-Mediated Phenylation and Oxygenation

by S. Quideau, L. Pouységu, A. Ozanne and J. Gagnepain

Molecules 2005, 10(1), 201-216; https://doi.org/10.3390/10010201 - 31 Jan 2005

Cited by 49 | Viewed by 13197

Abstract

Treatment of 2-methylphenols with chloro(diphenyl)-λ³-iodane led to theirregioselective dearomatizing 2-phenylation into cyclohexa-2,4-dienone derivatives via aproposed ligand coupling reaction. In the same vein of investigation, treatment of2-methylanilines with the λ⁵-iodane 2-iodoxybenzoic acid IBX reagent led to theirregioselective dearomatization into previously undescribed ortho-quinol imines. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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216 KiB

Open AccessArticle

Addition to Electron Deficient Olefins of α-Oxy Carbon- Centered Radicals, Generated from Cyclic Ethers and Acetals by the Reaction with Alkylperoxy- λ³-iodane

by T. Sueda, Y. Takeuchi, T. Suefuji and M. Ochiai

Molecules 2005, 10(1), 195-200; https://doi.org/10.3390/10010195 - 31 Jan 2005

Cited by 12 | Viewed by 9256

Abstract

Thermal decomposition of 1-tert-butylperoxy-1,2-benziodoxol-3(1H)-one in cyclic ethers and acetals at 50 °C generates α-oxy carbon-centered radicals, which undergo an addition reaction with vinyl sulfones and unsaturated esters. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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154 KiB

Open AccessArticle

Easy and Safe Preparations of (Diacetoxyiodo) arenes from Iodoarenes, with Urea-Hydrogen Peroxide Adduct (UHP) as the Oxidant and the Fully Interpreted ¹H- and ¹³C-NMR Spectra of the Products

by Agnieszka Zielinska and Lech Skulski

Molecules 2005, 10(1), 190-194; https://doi.org/10.3390/10010190 - 31 Jan 2005

Cited by 9 | Viewed by 8553

Abstract

An easy and safe, though only moderately effective method is presented forpreparing (diacetoxyiodo)arenes, ArI(OAc)2, from iodoarenes, ArI, using thecommercially available and easily handled urea-hydrogen peroxide adduct (UHP) as theoxidant. The reactions take place in anhydrous AcOH/Ac2O/AcONa (a catalyst)mixtures, at 40 oC for 3.5 [...] Read more.

An easy and safe, though only moderately effective method is presented forpreparing (diacetoxyiodo)arenes, ArI(OAc)2, from iodoarenes, ArI, using thecommercially available and easily handled urea-hydrogen peroxide adduct (UHP) as theoxidant. The reactions take place in anhydrous AcOH/Ac2O/AcONa (a catalyst)mixtures, at 40 oC for 3.5 h to afford the purified ArI(OAc)2 in 37-78% yields. The fullyinterpreted ¹H- and ¹³C-NMR spectra of the ArI(OAc)2 products are reported. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

212 KiB

Open AccessArticle

Stereoselective Synthesis of 5-7 membered Cyclic Ethers by Deiodonative Ring-Enlargement Using Hypervalent Iodine Reagents

by Tomohito Abo, Masanori Sawaguchi, Hisanori Senboku and Shoji Hara

Molecules 2005, 10(1), 183-189; https://doi.org/10.3390/10010183 - 31 Jan 2005

Cited by 18 | Viewed by 8691

Abstract

Stereoselective synthesis of 5-7 membered cyclic ethers was achieved by deiodonative ring-enlargement of cyclic ethers having an iodoalkyl substituent. The reaction took place readily under mild conditions using hypervalent iodine compounds and an acetoxy or a trifluoroacetoxy group was introduced into the rings [...] Read more.

Stereoselective synthesis of 5-7 membered cyclic ethers was achieved by deiodonative ring-enlargement of cyclic ethers having an iodoalkyl substituent. The reaction took place readily under mild conditions using hypervalent iodine compounds and an acetoxy or a trifluoroacetoxy group was introduced into the rings depending on the hypervalent iodine reagent employed. The use of hexafluoroisopropanol (HFIP) as solvent is critical. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

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98 KiB

Open AccessEditorial

Hypervalent Iodine

by Antigoni Kotali

Molecules 2005, 10(1), 181-182; https://doi.org/10.3390/10010181 - 31 Jan 2005

Viewed by 4585

Abstract

Iodine was discovered in 1811 by French chemist Bernard Courtois and it was named by J. L. Gay Lussac in 1813.[...] Full article

(This article belongs to the Special Issue Hypervalent Iodine)

319 KiB

Open AccessReview

Optimization of Protein Therapies by Polymer-Conjugation as an Effective DDS

by Hiroko Shibata, Shinsaku Nakagawa and Yasuo Tsutsumi

Molecules 2005, 10(1), 162-180; https://doi.org/10.3390/10010162 - 31 Jan 2005

Cited by 14 | Viewed by 11635

Abstract

Due to recent advances in disease proteomics, many disease-related proteins have been found. It is expected that there will be therapeutically useful proteins among them. However, it is clinically difficult to use most proteins as effective and safe drugs because of their very [...] Read more.

Due to recent advances in disease proteomics, many disease-related proteins have been found. It is expected that there will be therapeutically useful proteins among them. However, it is clinically difficult to use most proteins as effective and safe drugs because of their very low stability and pleiotropic actions in vivo. To promote disease proteomic based drug development for protein therapies, we have attempted to develop an optimal polymer-conjugation system for improving the therapeutic potency of proteins. In this review, we introduce this innovative protein-drug system. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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229 KiB

Open AccessReview

Biodegradable Polymers for Microencapsulation of Drugs

by J. Park, M. Ye and K. Park

Molecules 2005, 10(1), 146-161; https://doi.org/10.3390/10010146 - 31 Jan 2005

Cited by 269 | Viewed by 26787

Abstract

Drug delivery has become increasingly important mainly due to the awareness of the difficulties associated with a variety of old and new drugs. Of the many polymeric drug delivery systems, biodegradable polymers have been used widely as drug delivery systems because of their [...] Read more.

Drug delivery has become increasingly important mainly due to the awareness of the difficulties associated with a variety of old and new drugs. Of the many polymeric drug delivery systems, biodegradable polymers have been used widely as drug delivery systems because of their biocompatibility and biodegradability. The majority of biodegradable polymers have been used in the form of microparticles, from which the incorporated drug is released to the environment in a controlled manner. The factors responsible for controlling the drug release rate are physicochemical properties of drugs, degradation rate of polymers, and the morphology and size of microparticles. This review discusses the conventional and recent technologies for microencapsulation of the drugs using biodegradable polymers. In addition, this review presents characteristics and degradation behaviors of biodegradable polymers which are currently used in drug delivery. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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952 KiB

Open AccessArticle

Bioadhesive Properties of Gantrez Nanoparticles

by Juan M. Irache, María Huici, Monica Konecny, Socorro Espuelas, Miguel Angel Campanero and Pau Arbos

Molecules 2005, 10(1), 126-145; https://doi.org/10.3390/10010126 - 31 Jan 2005

Cited by 69 | Viewed by 16012

Abstract

Bioadhesive nanoparticles have been proposed as carriers for the oral delivery of poorly available drugs and facilitate the use of this route. This work summarises some experiments describing the bioadhesive potential of Gantrez nanoparticles fluorescently labeled with rhodamine B isothiocyanate. The adhesive potential [...] Read more.

Bioadhesive nanoparticles have been proposed as carriers for the oral delivery of poorly available drugs and facilitate the use of this route. This work summarises some experiments describing the bioadhesive potential of Gantrez nanoparticles fluorescently labeled with rhodamine B isothiocyanate. The adhesive potential of Gantrez was found to be stronger when folded as nanoparticles than in the solubilised form. Conventional nanoparticles displayed a tropism for the upper areas of the gastrointestinal tract, with a maximum of adhesion 30 min post-administration and a decrease in the adhered fraction along the time depending on the given dose. The cross-linkage of nanoparticles with increasing amounts of 1,3-diaminopropane stabilised the resulting carriers and prolonged their half-life in an aqueous environment; although, the adhesive capacity of nanoparticles, the intensity and the relative duration of the adhesive interactions within the gut as a function of the cross-linking degree. Finally, nanoparticles were coated with either gelatin or albumin. In the first case, the presence of gelatin dramatically decreased the initial capacity of these carriers to interact with the gut mucosa and the intensity of these phenomenons. In the latter, bovine serum albumin coated nanoparticles (BSA-NP) showed an important tropism for the stomach mucosa without further significant distribution to other parts of the gut mucosa. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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253 KiB

Open AccessReview

Covalent Polymer-Drug Conjugates

by C. Elvira, A. Gallardo, J. Roman and A. Cifuentes

Molecules 2005, 10(1), 114-125; https://doi.org/10.3390/10010114 - 31 Jan 2005

Cited by 102 | Viewed by 14237

Abstract

In this work, polymer-drugs conjugates used as drug delivery systems (DDS) are revised attending to their chemical conjugation. Namely, the classification of this type of DDS is based on the conjugation sites of the reactive groups (i.e., via end groups or pendant polymer [...] Read more.

In this work, polymer-drugs conjugates used as drug delivery systems (DDS) are revised attending to their chemical conjugation. Namely, the classification of this type of DDS is based on the conjugation sites of the reactive groups (i.e., via end groups or pendant polymer groups). Advantages and limitations of these types of DDS are discussed through representative examples of polymer-drugs and polymer-proteins conjugates recently developed. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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300 KiB

Open AccessArticle

AFM study of a New Carrier Based on PLA and Salen Copolymers for Gene Therapy

by V. Nadeau and P. Hildgen

Molecules 2005, 10(1), 105-113; https://doi.org/10.3390/10010105 - 31 Jan 2005

Cited by 6 | Viewed by 10243

Abstract

The aim of this study was to synthesize novel biodegradable charged polymers to be used in DNA complexation for genetic delivery in different diseases. A new copolymer of PLA and complexed Schiff bases was synthesized in a several steps. This copolymer will be [...] Read more.

The aim of this study was to synthesize novel biodegradable charged polymers to be used in DNA complexation for genetic delivery in different diseases. A new copolymer of PLA and complexed Schiff bases was synthesized in a several steps. This copolymer will be used as a nanocarrier. Also, AFM comparative studies in tapping mode were performed; on cationic copolymer and on PLA-Schiff base copolymer, on non-oriented and oriented film and on the DNA-cationic complex. The results indicated a difference in the topology and on phase picture of AFM film with or without cationic charge. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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166 KiB

Open AccessArticle

Synthesis of PLA-b-PEG Multiblock Copolymers for Stealth Drug Carrier Preparation

by R. Quesnel and P. Hildgen

Molecules 2005, 10(1), 98-104; https://doi.org/10.3390/10010098 - 31 Jan 2005

Cited by 31 | Viewed by 8922

Abstract

An efficient method of preparing biodegradable and biocompatible multiblock copolymers from lactic acid and polyethylene glycol is proposed. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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341 KiB

Open AccessArticle

Fragrance Release from the Surface of Branched Poly (Amide) S

by F. Aulenta, M. Drew, A. Foster, W. Hayes, S. Rannard, D. Thornthwaite and T. Youngs

Molecules 2005, 10(1), 81-97; https://doi.org/10.3390/10010081 - 31 Jan 2005

Cited by 14 | Viewed by 14719

Abstract

Enzymes are powerful tools in organic synthesis that are able to catalyse a wide variety of selective chemical transformations under mild and environmentally friendly conditions. Enzymes such as the lipases have also found applications in the synthesis and degradation of polymeric materials. However, [...] Read more.

Enzymes are powerful tools in organic synthesis that are able to catalyse a wide variety of selective chemical transformations under mild and environmentally friendly conditions. Enzymes such as the lipases have also found applications in the synthesis and degradation of polymeric materials. However, the use of these natural catalysts in the synthesis and the post-synthetic modification of dendrimers and hyperbranched molecules is an application of chemistry yet to be explored extensively. In this study the use of two hydrolytic enzymes, a lipase from Candida cylindracea and a cutinase from Fusarium solani pisii, were investigated in the selective cleavage of ester groups situated on the peripheral layer of two families of branched polyamides. These branched polyamides were conjugated to simple fragrances citronellol and L-menthol via ester linkages. Hydrolysis of the ester linkage between the fragrances and the branched polyamide support was carried out in aqueous buffered systems at slightly basic pH values under the optimum operative conditions for the enzymes used. These preliminary qualitative investigations revealed that partial cleavage of the ester functionalities from the branched polyamide support had occurred. However, the ability of the enzymes to interact with the substrates decreased considerably as the branching density, the rigidity of the structure and the bulkiness of the polyamide-fragrance conjugates increased. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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2588 KiB

Open AccessReview

Polymeric Particulates to Improve Oral Bioavailability of Peptide Drugs

by Florence Delie and María José Blanco-Príeto

Molecules 2005, 10(1), 65-80; https://doi.org/10.3390/10010065 - 31 Jan 2005

Cited by 122 | Viewed by 16782

Abstract

Oral administration remains the most convenient way of delivering drugs. Recent advances in biotechnology have produced highly potent new molecules such as peptides, proteins and nucleic acids. Due to their sensitivity to chemical and enzymatic hydrolysis as well as a poor cellular uptake, [...] Read more.

Oral administration remains the most convenient way of delivering drugs. Recent advances in biotechnology have produced highly potent new molecules such as peptides, proteins and nucleic acids. Due to their sensitivity to chemical and enzymatic hydrolysis as well as a poor cellular uptake, their oral bioavailability remains very low. Despite sophisticated new delivery systems, the development of a satisfactory oral formulation remains a challenge. Among the possible strategies to improve the absorption of drugs, micro- and nanoparticles represent an exciting approach to enhance the uptake and transport of orally administered molecules. Increasing attention has been paid to their potential use as carriers for peptide drugs for oral administration. This article reviews the most common manufacturing methods for polymeric particles and the physiology of particle absorption from the gastrointestinal (GI) tract. In a second part, the use of polymeric particulate systems to improve the oral absorption of insulin is discussed. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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Open AccessReview

Polymers for DNA Delivery

by H. Eliyahu, Y. Barenholz and A. J. Domb

Molecules 2005, 10(1), 34-64; https://doi.org/10.3390/10010034 - 31 Jan 2005

Cited by 184 | Viewed by 16330

Abstract

Nucleic acid delivery has many applications in basic science, biotechnology, agriculture, and medicine. One of the main applications is DNA or RNA delivery for gene therapy purposes. Gene therapy, an approach for treatment or prevention of diseases associated with defective gene expression, involves [...] Read more.

Nucleic acid delivery has many applications in basic science, biotechnology, agriculture, and medicine. One of the main applications is DNA or RNA delivery for gene therapy purposes. Gene therapy, an approach for treatment or prevention of diseases associated with defective gene expression, involves the insertion of a therapeutic gene into cells, followed by expression and production of the required proteins. This approach enables replacement of damaged genes or expression inhibition of undesired genes. Following two decades of research, there are two major methods for delivery of genes. The first method, considered the dominant approach, utilizes viral vectors and is generally an efficient tool of transfection. Attempts, however, to resolve drawbacks related with viral vectors (e.g., high risk of mutagenicity, immunogenicity, low production yield, limited gene size, etc.), led to the development of an alternative method, which makes use of non-viral vectors. This review describes non-viral gene delivery vectors, termed "self-assembled" systems, and are based on cationic molecules, which form spontaneous complexes with negatively charged nucleic acids. It introduces the most important cationic polymers used for gene delivery. A transition from in vitro to in vivo gene delivery is also presented, with an emphasis on the obstacles to achieve successful transfection in vivo. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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Open AccessArticle

Scleroglucan: A Versatile Polysaccharide for Modified Drug Delivery

by Tommasina Coviello, Antonio Palleschi, Mario Grassi, Pietro Matricardi, Gianfranco Bocchinfuso and Franco Alhaique

Molecules 2005, 10(1), 6-33; https://doi.org/10.3390/10010006 - 31 Jan 2005

Cited by 109 | Viewed by 19209

Abstract

Scleroglucan is a natural polysaccharide, produced by fungi of the genus Sclerotium, that has been extensively studied for various commercial applications (secondary oil recovery, ceramic glazes, food, paints, etc.) and also shows several interesting pharmacological properties. This review focuses its attention on the [...] Read more.

Scleroglucan is a natural polysaccharide, produced by fungi of the genus Sclerotium, that has been extensively studied for various commercial applications (secondary oil recovery, ceramic glazes, food, paints, etc.) and also shows several interesting pharmacological properties. This review focuses its attention on the use of scleroglucan, and some derivatives, in the field of pharmaceutics and in particular for the formulation of modified-release dosage forms. The reported investigations refer mainly to the following topics: natural scleroglucan suitable for the preparation of sustained release tablets and ocular formulations; oxidized and crosslinked scleroglucan used as a matrix for dosage forms sensitive to environmental conditions; co-crosslinked scleroglucan/gellan whose delivery rate can be affected by calcium ions. Furthermore, a novel hydrogel obtained with this polysaccharide and borate ions is described, and the particular structure of this hydrogel network has been interpreted in terms of conformational analysis and molecular dynamics. Profound attention is devoted to the mechanisms involved in drug release from the tested dosage forms that depend, according to the specific preparation, on swelling and/or diffusion. Experimental data are also discussed on the basis of a mathematical approach that allows a better understanding of the behavior of the tested polymeric materials. Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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Open AccessEditorial

Macromolecules Applied to Pharmaceutical Chemistry

by Claudio J. Salomon

Molecules 2005, 10(1), 3-5; https://doi.org/10.3390/10010003 - 31 Jan 2005

Viewed by 5518

Abstract

Macromolecular and polymer science have evolved significantly over the past few years, with remarkable advances in many areas such as polymeric drugs, self-assembly systems, implant materials, drug delivery systems and controlled drug release.[...] Full article

(This article belongs to the Special Issue Macromolecules Applied to Pharmaceutical Chemistry)

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Molecules, Volume 10, Issue 1 (January 2005) – 31 articles , Pages 1-317

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