The goal of this work was to characterise the interfacial behaviour of amphiphilic β-cyclodextrins modified at the primary face. It was considered that the oil/water system with spread modified cyclodextrins at the interface adequately mimics the interface encountered in the nanoprecipitation process, used for the preparation of nanocapsules. The effect of the presence of spread amphiphilic β-cyclodextrins upon the interfacial behaviour of the Miglyol oil/water system was assessed from interfacial tension (γi) measurements at 20 °C. The results reveal the diminution of γi for all studied amphiphilic cyclodextrins. The highest reduction in γi was observed for the β-CDs modified at the primary face for which the lowering in γi was comprised between 14 and 18 mN m−1. For β-CD-C6, a β-CD substituted at the secondary face, the decay of γi was much less pronounced (about 9 mN m−1). The results show also the influence of the hydrocarbon chain length upon the reduction in γi: the cyclodextrin substituted with an aliphatic chain containing six carbons, '6-N-CAPRO-β-CD', was more efficient than a β-CD substituted with the aliphatic chain containing 14 carbons ('6-N-MYRISTO-β-CD'). The presence of a NH amine function in the skeleton of the hydrocarbon chain conferred to the studied amphiphilic molecules an increased performance in lowering γi of the system. Surface pressure (π)–area (A) compression isotherms of the modified CDs at the air/water interface provided additional light on the interfacial behaviour of these molecules. The data from the interfacial tension measurements corroborated those from the nanocapsule formation and provided evidence that substitution at the primary face with a relatively short aliphatic chain (six carbons) containing an amine function yielded homogenous and smaller in size nanocapsules.

The purpose of this study was to synthesize and characterize amphiphilic β-cyclodextrins modified on the primary face with substituents of varying chain lengths (C6 and C14) and bond types (ester or amide). We also aimed to evaluate the potentiality of the new amphiphilic β-cyclodextrins as excipients for the preparation and optimization of nanocapsules without using surface-active agents. Amphiphilic β-cyclodextrin derivatives were characterized by 1H-nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, mass spectroscopy, differential scanning calorimetry, and elemental analysis. Nanocapsules prepared by nanoprecipitation were characterized by particle size and zeta potential determination and freeze fracture followed by transmission electron microscopy. The appropriate amphiphilic β-cyclodextrin and its optimum concentration to be used were determined. Formation and characteristics of the nanocapsules were highly dependent on the structural properties of the modified cyclodextrin, its behavior in the oil–water interface and the viscosity and miscibility of the organic solvent with water. Physical stability after 5-month storage was also evaluated. The results indicated that derivatives with 6C aliphatic chains on the primary face proved to be the most efficient among the amphiphilic β-CDs in this study. They avoid the use of surfactants in parenteral formulations of nanocapsules. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91: 1214–1224, 2002

With the aim of exploring relationships between the chemical structure and the physico-chemical properties of amphiphilic beta-cyclodextrin, a reappraisal of the obtaining of pure heptakis (2,3-di-O-hexanoyl)-beta-cyclodextrin (beta-CDC(6)) was undertaken. In this paper the chemical characterization of the newly synthesized beta-CDC(6) and its ability to form mixed structures with dimyristoylphosphatidylcholine (DMPC) are reported. Miscibility of the two amphiphiles is examined: (i) in monolayers formed at the air-water interface by analyzing the surface pressure-area isotherms; and (ii) in fully hydrated mixtures by differential scanning calorimetry (DSC) and X-ray diffraction at small and wide angles. Results demonstrate that the beta-cyclodextrin derivative is partially miscible to the phospholipid: intimate mixing occurs at beta-CDC(6) molar ratios smaller than 7-15 mol%, depending on the dimensional scale considered, while beyond these compositions phase separation is observed. At the air-water interface, the miscibility region of the two compounds shows non-ideal behavior characterized by the non-additivity of the molecular areas in the mixed monolayers. At the three-dimension level, the formation of a beta-CDC(6)/DMPC mixed lamellar phase occurs except at beta-CDC(6) molar ratios close to 5 mol% at which a highly ordered structure is depicted below the solid-to-liquid state transition of the DMPC hydrocarbon chains. At beta-CDC(6) contents higher than 7 mol%, the mixed assemblies coexist with excess amphiphilic cyclodextrin which then forms a separated hexagonal structure.

2,3-Diazido-2,3-dideoxy-beta-D-mannopyranoside derivatives were synthesized in order to prepare beta-glycosides of 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid, a rare moiety of bacterial oligosaccharides, A direct glycosyl donor, 4,6-di-O-acetyl-2,3-diazido-2,3-dideoxy-alpha-D-mannopyranosyl bromide, was prepared, and its synthetic capacity was tested in glycosylation reactions. An indirect route was also elaborated: 3-azido-3-deoxy-beta-D-glucopyranosides were converted into beta-D-mannopyranosides. The cis vicinal diazido function successfully tolerated the conditions of mild acidic hydrolysis, tritylation, Jones oxidation, TEMPO oxidation, acetolysis, and bromination with TiBr4.

Studies on the synthesis of amphiphilic ß-cyclodextrins to possibly obtain self-assemblying supramolecular aggregates have been carried out particularly in the last decade by many researchers by grafting alkyl chains of variable length (C2-C18) on the primary or secondary faces. In order to modify the cyclodextrin molecule, the reaction type most frequently used is electrophilic attack at the hydroxyl groups. However, it is evident that the selective and efficient modification of cyclodextrins is very complicated due to the difference of reactivity of hydroxyl groups in different positions, electronic reasons and steric factors of the torus. The large number of hydroxyl groups in the molecule (21 for ß-cyclodextrin) results in statistical problems of selective polysubstitution (1–3).

A glycophospholipid consisting in a derivative of N,N'-acylated and bisphosphorylated 2,3-dideoxy-2,3-diamino-D-glucose, bearing a 6-aminocaproyl side chain as spacer arm at carbon 6 (PPDm2-B), has been synthesized and its effect on murine macrophages evaluated. The synthesis started from 2,3-diamino-D-glucose, which was best obtained from glucosamine essentially by known procedures, since attempts to use another known precursor (3-nitroglycoside) led to unexpected results. Selective N-acylation was performed with the hydroxysuccinimide ester of (D)-3-benzyloxymyritic acid followed by esterification of the sole primary hydroxyl function by 6-azidocaproylchloride and phosphorylation of the resulting 1,4-diol by treatment with tetrabenzyl pyrophosphate. Hydrogenation on a Pd on carbon catalyst permitted the isolation of 6-(6-aminohexanoyl)-2,3-dideoxy-2,3-di-[(R)-3-hydroxy-tetradecanamido ] -alpha-D-glucopyranose 1,4-diphosphate (PPDm2-B). In mouse macrophages, PPDm2-B enhanced the lipopolysaccharide (LPS)-dependent secretion of tumor necrosis factor alpha (TNF-alpha), and inhibited the LPS-induced desensitization of these cells. The data suggest that PPDm2-B interacts in a serum-independent way with an LPS receptor different from CD14, and involved in endotoxin tolerance. Binding studies of a fluorescent derivative of PPDm2-B indicated that the expression of this unknown receptor is down-regulated during in vitro culture of the cells. Owing to its spacer arm, PPDm2-B could thus be a promising tool for future studies of this receptor.

A set of heterocyclic N-acetamidinium hydrochlorides were prepared from the corresponding N-acetonitriles. The antiparasitic screening showed that, while all amidines are practically inactive, some nitriles present leishmanicide properties.

We established previously that lipopolysaccharide (LPS) can induce the expression of LPS-binding sites on bone marrow cells (BMC). We now report that staurosporine (STP), a glycosylated indolocarbazole alkaloid with potent inhibitory activity for various protein kinases, can induce the same effect. With both agents, the newly expressed LPS receptor was found to be CD14. The STP-induced effect was independent of its protein kinase inhibitory activity because several other protein kinase inhibitors, such as the indolocarbazole K-252a, the bisindolylmaleimide RO-31-8220, the perylenequinone calphostin C, and the isoquinolinesulfonamide H7, did not induce CD14 expression. The observation that the STP analog K-252a with an identical polyaromatic aglycon moiety was inactive yet the analog UCN-01 with an identical glycoside ring was active suggests that the induction of CD14 expression is triggered by the sugar moiety of STP. Three lines of evidence show that the mechanism of CD14 expression induced by STP differs from that induced by LPS: (i) unlike LPS, STP can stimulate BMC from LPS-unresponsive C3H/HeJ mice, (ii) LPS and STP effects are additive at a saturating dose of LPS, and (iii) the protein kinase inhibitor K-252a inhibits the LPS-induced but not STP-induced stimulation. Therefore, our findings show that both a protein kinase-dependent (LPS-induced) and a protein kinase-independent (STP-induced) mechanism can lead to the expression of the LPS receptor CD14 on BMC. We also found that the STP-induced stimulation of BMC is modulated by cyclosporin A, vinblastine, and verapamil. This observation may suggest that the inducible effect of STP could be initiated by its interaction with P-glycoprotein, a membrane pump with drug efflux function that plays a critical role in the multidrug resistance of cancer cells.

A series of benzophenone derivatives has been synthesized and evaluated as inhibitors of HIV-1 reverse transcriptase (RT) and the growth of HIV-1 in MT-4 cells. Through the use of the structure-activity relationships within this series of compounds and computational chemistry techniques, a binding conformation is proposed. The SAR also indicated that the major interactions of 1h with the RT enzyme are through hydrogen bonding of the amide and benzophenone carbonyls and pi-orbital interactions with the benzophenone nucleus and an aromatic function separated from the benzophenone by a suitable spacer group. The crystal structure of compound 1h has been determined. A number of compounds with potent inhibitory activity against HIV-1 RT and HIV in cellular assays at levels comparable with AZT and our efforts to identify a metabolically stable analogue are described.

Refractoriness (tolerance) to endotoxin effects, such as induction of tumor necrosis factor alpha (TNF-alpha) secretion, can be elicited in vitro in macrophages by preexposure of cells to endotoxin (lipopolysaccharide [LPS]) itself. The aim of this study was to determine whether this phenomenon is due to negative feedback mediated by the free radical nitric oxide (NO) produced by cells when they are activated by LPS. Among several efficient inhibitors of NO production, NG-monomethyl-L-arginine did not induce concomitant inhibition of TNF-alpha secretion. Mouse macrophages that were exposed to LPS in the presence of NG-monomethyl-L-arginine partially maintained the ability to secrete TNF-alpha in response to a second LPS stimulation, compared with cells preexposed to LPS alone, thus suggesting that NO is involved in part in LPS-induced desensitization of cells. Furthermore, direct exposure of cells to the NO-generating compounds sodium nitroprusside and S-nitroso-N-acetylpenicillamine mimicked LPS-induced desensitization. However, low concentrations of a synthetic lipid (lipid M4) that is structurally analogous to the reducing end of the lipid A moiety of LPS induced desensitization of mouse macrophages without concomitant production of NO. Taken together, these data suggest that although NO actually takes part in LPS-induced desensitization of mouse macrophages, additional and yet unknown mechanisms must also exist.

The title disaccharides were synthesized by mercuric cyanide-catalyzed condensation of methyl (4,5,7,8-tetra-O-acetyl-3-deoxy-alpha-D-manno-oct-2-ulopyranosyl bromide)onate and allyl 2-[(3 R)-3-acetoxy-tetradecanamido]-3-O-benzyl-2-deoxy-beta-D-glucopyranoside, followed by phosphorylation of the alcoholic function of the amino sugar. The phosphorylated anomers were separated by chromatography and deprotected by conventional methods. Polymeric material was obtained by copolymerisation, catalyzed by peroxosulphate and N,N,N',N"-tetramethylethylenediamine, of the alpha anomer with acrylamide; it contained ca. one disaccharide unit for 18 acrylamide residues.

Synthesis of the alpha-methyl glycosides of 5-O-methyl-, 5-O-benzyl-8-O-methyl-, and 5,7,8-tri-O-methyl-3-deoxy-D-manno-oct-2-ulosonic acid 4-phosphates are described. The corresponding 'reducing' glycose, formed upon hydrolysis at pH 4 and 100-degrees-C, immediately eliminates the phosphate group. The olefinic acids thus produced from 5-O-methyl-, and from 5-O-benzyl-8-O-methyl 4-phosphates are not stable under these conditions: they are transformed into 4,7- and 4,8-anhydro-derivatives which have no ethylenic protons and show negligible absorption in the region 220-300 nm. The olefinic acid produced from the 5,7,8-tri-O-methyl derivative is unable to form such an anhydro-derivative: two ethylenic protons are present in its H-1 NMR spectrum and, like other conjugated olefinic alpha-keto acids, it has a strong UV absorption band (lambda-max 235 nm, epsilon 8000).

One of the strategies adopted for the development of a bivalent conjugate vaccine against invasive nontyphoidal Salmonella consists of linking the O-antigen component of S. Typhimurium and S. Entertidis lipopolysaccharides to the carrier protein CRM197, a non-toxic variant of diphtheria toxin. The conjugation reaction uses the reducing end residue 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) of the core to which the O-antigen chain is bound (OAg-core). OAg-core chains are cleaved from the lipid A directly in the fermentation broth by mild acid treatment. Kdo has been reported to undergo structural changes under these conditions and therefore the Kdo at the reducing end was thoroughly analysed to verify its structural integrity. For this purpose, low molecular mass OAg-core chains extracted from S. Typhimurium wild type bacteria and core oligosaccharides extracted from S. Typhimurium bacteria mutated not to produce O-antigen repeats were characterized by GLC-MS, MALDI-TOF-MS and NMR spectroscopy. Moreover, a combination of 1H–1H and 1H–13C experiments confirmed the linkage positions, sequence and structure of the octasaccharide core with 5-linked Kdo present at the reducing end in its native structure: α-GlcpNAc-(1→2)-α-Glcp-(1→2)-α-Galp-(1→3)-[α-Galp-(1→6)]-α-Glcp-(1→3)-[α-Hepp-(1→7)]-α-Hepp-(1→3)-α-Hepp-(1→5)-Kdo.

The title compound (PE-Kdo) was isolated after hydrolysis of the lipopolysaccharides of Escherichia coli K-12 strain W3100 and Salmonella minnesota strains R4 and R7, and the location of the 2-aminoethyl phosphate group at position 7 was established by 13C-n.m.r. spectroscopy. Derivatives of PE-Kdo were acetylated, silylated, and methylated in order to evaluate their usefulness for analysis by g.l.c.-m.s.

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ChemInformVolume 20, Issue 8 Natural Products ChemInform Abstract: Chemistry of Bacterial Endotoxins. Part 5. Synthesis of 1,5-Lactones of 3-Deoxy-D-manno-2-octulopyranosonic Acid (KDO). F.-I. AUZANNEAU, F.-I. AUZANNEAU Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this authorD. CHARON, D. CHARON Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this authorL. SZABO, L. SZABO Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this authorC. MERIENNE, C. MERIENNE Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this author F.-I. AUZANNEAU, F.-I. AUZANNEAU Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this authorD. CHARON, D. CHARON Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this authorL. SZABO, L. SZABO Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this authorC. MERIENNE, C. MERIENNE Equipe"Endotoxines"Centre Natl. Rech. Sci., Centre Etudes Pharm., Univ. Paris-Sud, 92290 Chatenay-Malabry, FranceSearch for more papers by this author First published: February 21, 1989 https://doi.org/10.1002/chin.198908311Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume20, Issue8February 21, 1989 RelatedInformation

An unambiguous synthesis of methyl 3-deoxy-α-d-manno-2-octulopyranosidono-1,5-lactone from methyl (methyl 3-deoxy-α-d-manno-octulopyranosid)onate via the 7,8-O-isopropylidene derivative is described. Treatment of the 4,5-stannylene derivative of this acetal with benzyl bromide gave the 1,5-lactone from which the protecting groups were removed. The acetylated 1,5-lactone was produced by acetylation of ammonium 3-deoxy-d-manno-2-octulosonate or treatment of the pyridinium salt with dicyclohexylcarbodi-imide and acetylation. No lactone was produced when only HO-7 was unsubstituted. When treated with an excess of 2-methoxypropene, methyl (methyl 3-deoxy-α-d-manno-2-octulopyranosid)onate afforded the 4,5:7,8-di-O-isopropylidene derivative, from which the 7,8-acetal group could be removed selectively.

AbstractThe synthesis of the phosphates (Ia) and (Ie), the aminoethyl derivative (Ib) and the pyrophosphates (Ic) and (Id) is described.

An attempt was made to identify the molecular structures that are present in bacterial LPS and induce the production of intracellular and extracellular pools of IL 1 by peritoneal macrophages of the mouse and by human monocytes. Activities of glycolipids and carbohydrates prepared by synthesis, and structurally related to the hydrophobic (Lipid A) and to the polysaccharide (PS) regions of LPS were compared with those induced by Bordetella pertussis endotoxin and by fragments derived therefrom. Both isolated regions of this LPS (PS and Lipid A) were able to induce IL 1 synthesis by monocytes and macrophages. Among the synthetic glycolipids employed, propyl-2-deoxy-2-[(3R)-3-hydroxytetrade-canamido]-4-O-pho sph ono-6-O-tetradecanoyl-beta-D-glucopyranoside (glycolipid M9) induced IL 1 secretion more efficiently than Lipid A and LPS, whereas the amounts of intracellular IL 1 produced upon induction by these three substances were comparable. Macrophages from C3H/HeJ mice were unresponsive to Lipid A and to glycolipid M9, but produced IL 1 when incubated with PS or with a hydrophilic fragment isolated after methanolysis of the endotoxin. However, all synthetic derivatives of 3-deoxy-D-manno-2-octulosonic acid (KDO) used in this study failed to induce IL 1 production by both mouse macrophages and human monocytes. The implications of these findings for a more precise comprehension of the molecular mechanism of LPS-induced activation of macrophages, and the relations between the molecular structures required for the induction of IL 1 production vs cytostatic activity in macrophages, are discussed.

Partially methylated and acetylated 3-deoxyoctitols and 3-deoxyheptitols were prepared from synthetic derivatives of 3-deoxy-d-manno-octulosonic acid and 3-deoxy-d-arabino-heptulosonic acid, espectively, by derivatisation procedures used in methylation analysis (hydrolysis, carbonyl- and carboxyl-reduction, methylation, and acetylation). The compounds so obtained were characterised by g.l.c. and g.l.c.-m.s., and their retention times and fragmentation patterns are reported.