Lauroyl Chloride Research Articles

Synthesis of Lipophilic Poly-Lauroyl-(+)-Catechins and Radical-Scavenging Activity

Lipophilic catechins were synthesized to improve absorption into living bodies and obtain new antioxidants effective in lipid bilayers. The hydroxyl (OH) groups of (+)-catechin was acylated randomly using lauroyl chloride. The mixture was separated by preparative HPLC, and 3-lauroyl-, 3',4'-dilauroyl- and 3,3',4'-trilauroyl-catechins (3-LC, 3',4'-LC, and 3,3',4'-LC) were obtained, their structures being determined by (1)H NMR. Their radical scavenging activity was measured in a ethanol solution using the 1,1-diphenyl-2-picrylhydrazyl radical, and was compared with that of (+)-catechin. The activity of 3-LC was almost same as that of (+)-catechin, but those of 3',4'-LC and 3,3',4'-LC were small, showing that the blocking of phenolic OH groups in the B ring lowered the activity. The scavenging activity on lipophilic radicals in a liposome system was also measured, and the activities were in the order of 3-LC > 3',4'-LC = (+)-catechin. These results suggested that radical scavenging activity in the lipid membrane depended not only on the number and the relative positions of phenolic OH groups of catechins but also on affinity to the membrane.

Synthesis and properties of biodegradable plastic films obtained by microwave-assisted cellulose acylation in homogeneous phase

Microwave-induced esterification of cellulose in homogeneous phase has been investigated. Cellulose was first solubilized in the solvent system LiCl/ N,N-dimethylacetamide and then esterified by lauroyl chloride in the presence of N,N-dimethyl-4-aminopyridine. Microwave activation resulted in a drastic reduction of reaction time (1 min) compared to conventional heating. The mechanical and thermal properties of the plastic films obtained were established and a preliminary study of their biodegradability has been performed. To cite this article: C. Satgé et al., C. R. Chimie 7 (2004) .

Chemical Valorization of Forest and Agricultural By-Products. Obtention, Chemical Characteristics, and Mechanical Behavior of a Novel Family of Hydrophobic Films

Abstract Esterification of hemicelluloses of the xylan family was performed in order to produce hydrophobic films. Acylation reactions were carried out with lauroyl chloride in the N,N-dimethylacetamide/lithium chloride homogeneous system using 4-dimethylaminopyridine as activator and were induced by microwave irradiation. In the experimental conditions used, 108 and 172% mass ratios were obtained for the dodecyl-grafted xylan and heteroxylan, respectively. The degrees of substitution (DS) were 1.3 (maximum 2) for xylan and 1.2 (maximum 2.1) for heteroxylan. These products were further characterized by FT-IR spectroscopy. The mechanical and thermomechanical behavior of this new family of hydrophobic films were analyzed and compared to those obtained from cellulose with a similar DS by the means of tensile tests. Our results indicate that the dodecyl-grafted xylan film presents the best rigidity—resistance to traction ratio.

Chemical Valorization of Forest and Agricultural By-Products. Obtention, Chemical Characteristics, and Mechanical Behavior of a Novel Family of Hydrophobic Films

Esterification of hemicelluloses of the xylan family was performed in order to produce hydrophobic films. Acylation reactions were carried out with lauroyl chloride in the N,N-dimethylacetamide/lithium chloride homogeneous system using 4-dimethylaminopyridine as activator and were induced by microwave irradiation. In the experimental conditions used, 108 and 172% mass ratios were obtained for the dodecyl-grafted xylan and heteroxylan, respectively. The degrees of substitution (DS) were 1.3 (maximum 2) for xylan and 1.2 (maximum 2.1) for heteroxylan. These products were further characterized by FT-IR spectroscopy. The mechanical and thermomechanical behavior of this new family of hydrophobic films were analyzed and compared to those obtained from cellulose with a similar DS by the means of tensile tests. Our results indicate that the dodecyl-grafted xylan film presents the best rigidity—resistance to traction ratio.

Engineering of dendrimer surfaces to enhance transepithelial transport and reduce cytotoxicity.

To evaluate the cytotoxicity, permeation, and transport mechanisms of PAMAM dendrimers and surface-modified cationic PAMAM dendrimers using monolayers of the human colon adenocarcinoma cell line, Caco-2. Cytotoxicity was determined using the MTT assay. The effect of dendrimers on monolayer integrity was determined from measurements of transepithelial electrical resistance (TEER) and [14C]mannitol apparent permeability coefficient (Papp). The Papp of dendrimers through monolayers was measured in both the apical (A)-to-basolateral (B) and B --> A directions at 4 degrees C and 37 degrees C and also in the presence and absence of ethylenediamine tetraacetic acid (EDTA) and colchicine. The cytotoxicity and permeation of dendrimers increased with both concentration and generation. The cytotoxicity of cationic dendrimers (G2, G3, G4) was greater than that of anionic dendrimers (G2.5, G3.5) but was reduced by conjugation with lauroyl chloride: the least cytotoxic conjugates were those with six attached lauroyl chains. At 37 degrees C the Papp of cationic dendrimers was higher than that of anionic dendrimers and, in general, increased with the number of attached lipid chains. Cationic dendrimers decreased TEER and significantly increased the Papp of mannitol. Modified dendrimers also reduced TEER and caused a more marked increase in the Papp of mannitol. The Papp values of dendrimers and modified dendrimers were higher in the presence of EDTA, lower in the presence of colchicine, and lower at 4 degrees C than at 37 degrees C. The properties of dendrimers may be significantly modified by surface engineering. Conjugation of cationic PAMAM dendrimers with lauroyl chloride decreased their cytotoxicity and increased their permeation through Caco-2 cell monolayers. Both PAMAM dendrimers and lauroyl-PAMAM dendrimer conjugates can cross epithelial monolayers by paracellular and transcellular pathways.

Rapid homogeneous esterification of cellulose induced by microwave irradiation

The aim of this work is the esterification of cellulose with long chain acyl chloride in homogeneous media induced by microwave irradiation. The system used was cellulose/lauroyl chloride/ N, N-dimethylacetamide/LiCl and N, N-dimethylaminopyridine as a catalyst. The use of microwave resulted in a dramatic drop in reaction time: 1 min irradiation was sufficient, compared with 30 min to 2 days, when conventional heating is used. We studied the degrees of substitution (DS), weight increase and molar yields in function of lauroyl chloride and N, N-dimethyl-4-aminopyridine amounts. We also determined mechanical and thermal properties of a sample with DS=2.4 and the biodegradability for samples with DS ranging from 0.7 to 2.6.

Selective Protection Strategies in the Synthesis of TRIS-Fatty Ester Derivatives

A methodology for the selective synthesis of lipophilic acyl derivatives of the glycinamido triol (1) with either one, two, or three fatty ester groups has been established. Peracylation of (1), with palmitoyl chloride gave the triacylated derivative. Conversion of (1) into the acetonide, followed by acylation with either palmitoyl chloride or lauroyl chloride, and acetal hydrolysis provided the monoacylated derivatives. Treatment of (1) with trimethyl orthoacetate gave the orthoacetate derivative. Mild hydrolysis provided the monoacetate/diol. Acylation of the two hydroxyl groups with palmitoyl chloride gave the dipalmitate/acetate. Selective cleavage of the acetate group afforded the dipalmitate of (1). Analogous chemistry with trimethyl orthoformate provided the same dipalmitate via the orthoformate, monoformate/diol, and dipalmitate/formate. A more robust synthesis of the dipalmitate was achieved by converting the hydroxyl group of the acetonide of (1) into a tert-butyldiphenylsilyl ether, followed by acetal hydrolysis, palmitoylation of the liberated hydroxyl groups, and desilylation.

Esterification of cellulose-enriched agricultural by-products and characterization of mechanical properties of cellulosic films

Two agricultural by-products, wheat bran and maize bran have been examined for their suitability to be transformed into biomaterials by esterification by lauroyl chloride. Influence of biochemical characteristic of cellulose (cellulose content, viscosity-average degree of polymerization, crystallinity) was studied on eight samples enriched in cellulose after chemical removal of heteroxylans and lignin. After an acidic pre-treatment, esterification was carried out with lauroyl chloride and an optimized reaction time of 8h was used.Chemical compositions were similar for all cellulose esters obtained, but cellulose content of initial material had a marked influence on the amount of esterified product. A film was easily obtained by casting and the mechanical (tensile strength and elongation), thermomechanical and calorimetric properties were determined. The possible role of grafted fatty acid as internal plasticizer was finally discussed.

Friedel-crafts reactions of pendant vinyl groups in macroporous monosized poly(meta-divinylbenzene) and poly(para-divinylbenzene) particles

Residual vinyl groups in macroporous monosized polymer particles of poly(meta-DVB) and poly(para-DVB) prepared with toluene and 2-EHA as porogens have been reacted with aluminum chloride as Friedel–Crafts catalyst with and without the presence of lauroyl chloride. In the reaction between aluminum chloride and pendant vinyl groups a post-crosslinking by cationic polymerization takes place. A reaction occurring simultaneously is the addition of HCl to the double bonds. The progress of these reactions was studied by characterization of vinyl group conversion, pore size distribution, specific surface area, morphology, and swelling behavior. In the reaction with aluminum chloride the poly(para-DVB) particles showed a substantially higher conversion of pendant vinyl groups than the particles made of poly(meta-DVB) independent of porogen type. The reaction with aluminum chloride led to a reduced swelling in organic solvents and an increased rigidity of the particles prepared with toluene as porogen. This is confirmed by an increase in the total pore volume in the dry state and a change in the pore size distribution of these particles. Also in the reaction with lauroyl chloride poly(para-DVB) particles have shown a higher conversion of pendant vinyl groups than poly(meta-DVB) particles and the acylation was almost complete at the early stage of the reaction. The swelling in organic solvents is reduced as a result of the incorporation of acyl groups into the particles prepared with toluene as porogen. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1366–1378, 2000

Chemical lipophilization of soy protein isolates and wheat gluten

Chemical modification of soy protein isolate and wheat gluten can be used to investigate the influence of the chemical composition and the structure of the proteins on the final product properties and to adjust these properties to meet specific demands. Proteins were lipophilized by adding different levels of lauroyl chloride to aqueous protein dispersions. At optimum reaction conditions, incorporation rates of lauroyl chains to the protein were 400 and 300 μmol/g proteins for soy protein isolate and wheat gluten, respectively. The study showed that it was possible to lipophilize proteins in an aqueous medium, even with the protein significantly high in concentration.

Characterization of chemical and solid state structures of acylated chitosans

A series of acylated chitosans were synthesized by reacting chitosan with hexanoyl, decanoyl, and lauroyl chlorides. The chemical structures of these polymers were characterized by elemental analysis, IR, 1H-NMR, 13C-NMR, and GPC. These results suggested that the degree of substitution was 4 per monosaccharide ring. These acylated chitosans exhibited an excellent solubility in organic solvents such as chloroform, benzene, pyridine, and THF and transparent films were obtained from these solutions. Dynamic mechanical analyses (DMA) showed that all acylated chitosans have two phase transitions in the solid state. The first transition at −10, −42, and −40°C are attributable to the glass transition ( T g) of H-, D-, and L-chitosans, respectively. The second one around 88°C may be attributed to the transition related to the structure formed by the side chains. WAXS analyses indicate that these polymers form a layered structure in solid state and the layer spacing d increases linearly with increasing the length of side chains.

Acidic activation of cellulose and its esterification by long-chain fatty acid

Cellulose-enriched residues from wheat bran can be transformed in bioplastics after esterification of the cellulose by lauroyl chloride. Before the esterification reaction, an activation step with a swelling of the sample in dilute acid and subsequent drying was required. This activation had a marked influence on the amount of esterified product and its degree of substitution. Using pure cellulose as well as cellulose-enriched agricultural residues, we have shown that the cellulose was totally recovered after this pretreatment and that partial hydrolysis of cellulose chains occurred during the drying step, which probably improved the accessibility to chemical reagents. The possible role of sulfuric acid as catalyst for the esterification reaction of the cellulose by lauroyl chloride was discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1933–1940, 1999

Friedel—Crafts Acylation on Porous Divinyl Benzene Polymer Particles: A Reaction Kinetic Process Studied by Mid- and Near-Infrared Spectroscopy

Porous poly(para-divinylbenzene) and poly(meta-divinylbenzene) particles were synthesized from para-divinylbenzene and meta-divinylbenzene monomers with toluene and 2-ethylhexanoic acid as porogens. The residual vinyl groups in the particles were thereafter reacted with lauroyl chloride by using the Friedel–Crafts reaction. The conversion of vinyl groups was followed by analyzing polymer particles taken from the reaction mixture at different time intervals. Infrared spectroscopy in both the mid- and near-infrared region was used as the analytical technique. The intensity changes in the overtone absorption at 1628 nm due to the vinyl bonds were used as the basis for the quantification of the reaction. Spectra of the particles in the mid-IR region provide understanding of the changes taking place in the polymer matrix during the acylation reaction. The results indicated that the reaction took place at a faster rate in the polymer particles synthesized from para-DVB monomer compared with the poly(meta-DVB) particles. The polymer particles synthesized with toluene as porogen react faster than the polymer particles prepared with 2-ethylhexanoic acid as the porogen. The analysis also indicated that the acylation takes place at the early stages of the reaction and the product formed transforms into more stable products at the latter stages. On the basis of the infrared analysis, mechanisms for the formation of the different products are proposed.

Functionalized 2-Pyridyl-Substituted Metallo-1,2-enedithiolates. Synthesis, Characterization, and Photophysical Properties of (dppe)M{S(2)C(2)(2-pyridine(ium))(CH(2)CH(2)OR")} and (dppe)M[{S(2)C(2)(CH(2)CH(2)-N-2-pyridinium)}](+) (R" = H, Acetyl, Lauroyl; M = Pd, Pt; dppe = 1,2-Bis(diphenylphosphino)ethane).

The complexes (dppe)M{S(2)C(2)(2-pyridine)(CH(2)CH(2)OC(O)CH(3))} (dppe = 1,2-bis(diphenylphosphino)ethane; M = Pd, Pt) were prepared from 1-(2-pyridyl)-4-acetoxy-2-bromobutan-1-one and the corresponding (dppe)M(SH)(2) complexes. The acetyl group was removed from the metal complexes to yield the corresponding alcohols, (dppe)M{S(2)C(2)(2-pyridine)(CH(2)CH(2)OH)}. The lauroyl derivatives (dppe)M{S(2)C(2)(2-pyridine)(CH(2)CH(2)OC(O)(CH(2))(10)CH(3))} were prepared by esterifying the alcohols with lauroyl chloride. The alkylated pyridinium complexes [(dppe)M{S(2)C(2)(CH(2)CH(2)-N-2-pyridinium)}](+) were generated by the addition of either p-toluenesulfonyl chloride or bis(triazole) o-chloroaryl phosphate to (dppe)M{S(2)C(2)(2-pyridine)(CH(2)CH(2)OH)}. [(dppe)Pd{S(2)C(2)(CH(2)CH(2)-N-2-pyridinium)}][BPh(4)] crystallizes in the P&onemacr; space group with a = 9.1924(2) Å, b = 16.0191(2) Å, c = 17.4368(3) Å, alpha = 106.292(2) degrees, beta = 96.235 degrees, and gamma = 95.183(2) degrees. The molecule is best described as a square planar palladium complex with a planar metallo-1,2-enedithiolate which is coplanar with the alkylated pyridinium. The pyridinium-substituted platinum 1,2-enedithiolate complexes have a 1,2-enedithiolate to heterocycle pi charge-transfer transition (ILCT) that is the lowest lying band. Like [(dppe)Pt{S(2)C(2)(2-pyridinium)(H)}](+), [(dppe)Pt{S(2)C(2)(CH(2)CH(2)-N-2-pyridinium)}](+) is luminescent in room-temperature solution with two emissive states assigned to the ILCT singlet and triplet. The lifetime of the (1)ILCT is 0.2 ns, (1)phi = 0.002, while the lifetime of the (3)ILCT is 8.3 &mgr;s, (3)phi = 0.01 (DMSO). While [(dppe)Pt{S(2)C(2)(CH(2)CH(2)-N-2-pyridinium)}](+) is emissive, the [(dppe)Pt{S(2)C(2)(2-pyridinium)(CH(2)CH(2)OR")}](+) complexes are weak emitters at best in solution with triplet quantum yields of <0.0001 (DMSO). These photophysical studies suggest that the heterocycle and the 1,2-enedithiolate must be coplanar in the ILCT excited states for the complexes to be emissive in room-temperature solution.

Preliminary study of formation of films from cellulose‐enriched agricultural by‐products

Two agricultural by-products, sugar-beet pulp and wheat bran, have been examined for their suitability to be transformed into bioplastics by esterification by lauroyl chloride. Influence of cellulose content was studied on eleven samples enriched in cellulose after chemical or enzymatic removal of pectins from sugar-beet pulp and heteroxylans from wheat bran. After a pretreatment by immersion in 0.5 mol/L sulfuric acid, esterification was carried out with lauroyl chloride. Neither the amount of cellulose nor the extraction treatment had a marked influence on the formation of plastic. A film could be obtained from all the wheat-bran samples, including samples with low cellulose content, but only from one sugar-beet pulp sample. The crystallinity of the cellulose in sugar-beet pulp and wheat bran were different. The nature of cellulose could be responsible for the failure of sugar-beet pulp residues to form plastic.

Preparation and enhancing effect of 1-(N,N-dimethylamino)-2-propanol dodecanoate (DAIPD) on the transepidermal penetration of clonidine, hydrocortisone, and indomethacin through shed snake skin

1-( N, N-Dimethylamino)-2-propanol dodecanoate (DAIPD), a new biodegradable penetration enhancer was prepared by condensing lauroyl chloride with 1-( N, N-dimethylamino)-2-propanol. The penetration enhancing effects of DAIPD on the transdermal delivery of clonidine, hydrocortisone, and indomethacin were evaluated using shed snake skin ( Elaphe obsoleta) as the model membrane. Azone was used as a typical enhancer for comparison. DAIPD showed a 1.2-2-times greater promoting effect than azone for the above-cited drugs. In vitro biodegradability of DAIPD was demonstrated in the presence of porcine esterase. The results indicate that DAIPD increases markedly the transdermal delivery of several types of drug substances.

A novel non-mineral oil-based adjuvant. I. Efficacy of a synthetic sulfolipopolysaccharide in a squalane-in-water emulsion in laboratory animals.

Sulfolipopolysaccharides (SLPs) were synthesized by reaction of the synthetic polysucrose polymer Ficoll-400 with chlorosulfonic acid and lauroyl chloride in anhydrous medium. Hydrophobic derivatives were obtained by addition of a small number of sulfate and a large number of lipid groups. Gel-permeation high-performance liquid chromatography (g.p.-h.p.l.c.) exhibited a wide range in molecular weight of both Ficoll-400 and SLP polymers. The calculated weight-average molecular weight (Mw) of Ficoll-400 and SLP using polystyrene polymers as references was 187,000 and 380,000 respectively, exhibiting a twofold increase in molecular weight upon derivatization. Adjuvanticity of hydrophobic SLPs with 0.2 sulfate and 1.5 lipid groups per sucrose monomer, a squalane-in-water emulsion (S/W), SLP incorporated into S/W (SLP/S/W), and a mineral oil-based emulsion (O/W) was investigated in combination with different antigens in mice and guinea-pigs. Antibody responses in serum against ovalbumin (OVA), dinitrophenylated bovine serum albumin (DNP-BSA), inactivated influenza virus strain MRC-11 (MRC-11), a mixture of three influenza virus strains (iFlu3) and inactivated pseudorabies virus (iPRV) were measured by either haemagglutination (HA), haemagglutination inhibition (HI) or serum neutralization (SN). Vaccines were prepared by simply mixing one volume of antigen with one volume of adjuvant solution. Antibody titres after one or two injections with these antigens were enhanced significantly by SLP/S/W, SLP, S/W and O/W and in most studies, SLP/S/W was demonstrated to be more effective than either the two constituent components or the O/W adjuvant.(ABSTRACT TRUNCATED AT 250 WORDS)

Preparation and Characterization of Mixed Anhydrides of O-Acylarylcarbohydroximic Acid

A number of N,O-diacylhydroxylamines have been prepared by the reaction of potassium salts of hydroxamic acids with variety of acylating agents which include: benzoyl, p-nitrobenzoyl, anisoyl, p-chlorobenzyl and lauroyl chlorides in dioxane under reflux. The structure of resulting N,O-diacylhydroxylamines has been determined by spectral analysis, Attempted have been made to prepare mixed anhydrides of several N,O-diacylhydroxylamines by the acylation reaction in the cold (below 10 °C) using acetyl, benzoyl, p-nitrobenzoyl, anisoyl and p-toluensulfonyl chlorides as acylating agents in dioxane using triethylamine as a base. Structures of the resulting mixed anhydrides have been elucidated by spectral methods.

Diamide analogues of phosphatidyl choline as potential anti-AIDS agents

Acylation of 3-tetrahydropyran-2-yloxypropane-1,2-diamine with dodecanoyl chloride (lauroyl chloride) and hexadecanoyl chloride (palmitoyl chloride) followed by O-deprotection afforded racemic diamide analogues of 1,2-diglycerides which were converted by sequential treatment with 2-chloro-1,3,2-dioxaphospholan-2-one and trimethylamine into the corresponding diamide analogues of phosphatidyl choline. One of these compounds shows moderate anti-HIV activity.

Pyrylium Salts with Long Alkyl Substituents, II 2,4-Dimethyl-6-undecylpyrylium Perchlorate and Derived Pyridinium Salts

The crystalline title pyrylium salt was obtained by SnCl4 catalysed acylation of mesityl oxide with lauroyl chloride followed by treatment with perchloric acid and column chromatography. This new pyrylium salt was converted in high yields into the corresponding pyridine and N-substituted pyridinium salts (N-methyl, N-phenyl, N-(4-n-butylphenyl), and N-dodecyl) whose proton (300 MHz) and carbon-13 (75 MHz) NMR spectra are presented.