Synthesis and characterization of polyesters from renewable cardol

The preparation and thermal characteristics of new polyesters from cardol, a renewable monomer obtained as a by-product of the cashew industry, are reported. Cardol - a diol component of the natural product cashew nut shell liquid (CNSL) was isolated and reacted with adipoyl chloride and terephthaloyl chloride in a 1:1 molar ratio in hexane and toluene as solvents at 170 °C under nitrogen atmosphere. The cardol based polyesters [poly(cardyl adipate) and poly(cardyl terephthalate)] were produced in good yields of up to 63 and 54%, respectively. The polymers were analysed by FT-IR for functional groups elucidation and by combined thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for thermal stability. The cardol-based polyesters were thermally stable up to about 400 °C. The thermal stability of poly(cardyl terephthalate) was higher than that of poly(cardyl adipate) under similar conditions. All prepared polyesters were insoluble in common laboratory solvents at room temperature

Growth of nanocrystalline thin films of metal sulfides [CdS, ZnS, CuS and PbS] at the water–oil interface

Simple one pot reactions between thiobiuret complexes [M(SON(CNiPr2)2)2], (M = Cd, Zn, Pb or Cu) in toluene and aqueous Na2S lead to well-defined assemblies of nanocrystals. High quality thin films of CdS, ZnS, CuS and PbS nanoparticulates adhered to the interface are produced and are transferable to glass and other substrates. The effect of reaction parameters on the nature and properties of the deposits are examined. The films are characterized by high-resolution transmission electron microscopy, X-ray diffraction, scanning electron microscopy, transport property measurements, X-ray photoelectron and absorption spectroscopy. The ability to obtain thin films of several nanocrystalline semiconductors from a single precursor set significantly expands the scope of a reaction scheme that is still in its infancy

Synthesis of amine functionalized mesoporous silicas templated by castor oil for transesterification

Mesoporous silicas were synthesized via a surfactant-templated sol-gel route using castor oil as the templating agent under acidic medium. The resulting silicas were subsequently amine functionalized with 3-aminopropyltriethoxysilane (NH2-MTS), [3-(2-aminoethylamino)-propyl]trimethoxysilane (NN-MTS), and [3-(diethylamino)propyl]trimethoxysilane(DN-MTS) to introduce surface basicity. Surface physicochemical properties were characterized by field emission gun scanning electron microscopy (FEGSEM), nitrogen porosimetry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). As-synthesised materials exhibit type IV adsorption-desorption isotherms characteristic of mesoporous structures. Clusters of spherical shaped materials were observed by FEGSEM, suggesting growth of silica occurs within colloidal dispersions. High-resolution N 1s XP spectra and DRIFT spectra confirmed the presence of amine groups in the organo-amine functionalised mesoporous silicas. The amine functionalised mesoporous silicas were active for the transesterification of tributyrin with methanol, with conversion found to increase from NH2-MTS< NN-MTS< DN-MTS

Synthesis of bifunctional monomers by the palladium-catalyzed carbonylation of cardanol and its derivatives

The authors thank the Royal Society Leverhulme Africa Program for funding this project.A 1,2-bis(di-tert-butylphosphinomethyl)benzene-modified palladium catalyst has been used to synthesize bifunctional monomers of different chain lengths from cardanol. Short-chain derivatives of cardanol, such as (E)-3-(dodec-8-enyl)phenol; HOPhC12-ene, (E)-3-(undec-8-enyl)phenol; HOPhC11-ene, (E)-3-(dec-8-enyl)phenol; HOPhC10-ene, and 3-(non-8-enyl)phenol; HOPhC9-ene, were synthesized by the metathesis of cardanol with symmetrical internal alkenes. These derivatives were methoxycarbonylated to produce monomers with different chain lengths such as methyl-16-(3-hydroxyphenyl)hexadecanoate; HOPhC15COOMe, methyl-13-(3-hydroxyphenyl)tridecanoate; HOPhC12COOMe, methyl-12-(3-hydroxyphenyl)dodecanoate; HOPhC11COOMe, methyl-11-(3-hydroxyphenyl)undecanoate; HOPhC10COOMe, and methyl-10-(3-hydroxyphenyl)decanoate; HOPhC9COOMe, respectively. Polymerization of the synthesized monomers produced oligomers that consist of up to seven monomer units as confirmed by MALDI-TOF-MS. Lactone formation was also observed in some cases under polymerization conditions.PostprintPostprintPeer reviewe

Isomerization of anacardic acid:a possible route to the synthesis of an unsaturated benzolactone and a kairomone

Crystalline unsaturated lactone, 8-hydroxy-3-tridecyl-1H-isochromen-1-one (6) has been synthesized by isomerization of anacardic acid having heterogeneous alkyl side chains (a mixture of mono-, di-, and tri-unsaturated anacardic acid) (1). Hydrogenation of 8-hydroxy-3-tridecyl-1H-isochromen-1-one produced a saturated lactone, 8-hydroxy-3-tridecyl-3,4-dihydroisochromen-1-one (7). Isomerization of monoene anacardic acid resulted in a crystalline isoanacardic acid, (E)-2-hydroxy-6-(pentadec-1-enyl)benzoic acid (8) as a major product. This was then metathesized with 2-butene to give 3-prop-1-enylphenol (10). Both isomerization reactions used a 1,2-bis(ditertiarybutylphosphinomethyl)benzene modified palladium catalyst. The two products, 8-hydroxy-3-tridecyl-1H-isochromen-1-one and (E)-2-hydroxy-6-(pentadec-1-enyl)benzoic acid have been crystallographically characterized. Practical applications: Unsaturated lactones are structural elements often found in natural products, which have medicinal value. Benzolactones derived from anacardic acid reported in this work have some structural similarity with lactones such as massoia lactone having medicinal value. Therefore with this idea in mind, the unsaturated benzolactones reported in this work will be tested for their anti pathogenic activity. 3-Propylphenol is used in combination with racemic 1-octen-3-ol and p-cresol to prepare a kairomone for tsetse fly traps. Results from this work describe the suitability of anacardic acid for synthesizing 3-propylphenol. The fact that 3-propylphenol can be synthesized from anacardic acid, a component of cashew nut shell liquid is of particular interest since most of the areas affected with tsetse flies are suitable for growing cashew plants. This means the raw materials (CNSL) for synthesis of 3-propylphenol will be obtained from within the same region where the kairomone is to be applied, although we appreciate that specialized facilities would be required for the types of transformation described.</p

Polyamidoamine Dendrimers for Enhanced Solubility of Small Molecules and Other Desirable Properties for Site Specific Delivery: Insights from Experimental and Computational Studies

Clinical applications of many small molecules are limited due to poor solubility and lack of controlled release besides lack of other desirable properties. Experimental and computational studies have reported on the therapeutic potential of polyamidoamine (PAMAM) dendrimers as solubility enhancers in pre-clinical and clinical settings. Besides formulation strategies, factors such as pH, PAMAM dendrimer generation, PAMAM dendrimer concentration, nature of the PAMAM core, special ligand and surface modifications of PAMAM dendrimer have an influence on drug solubility and other recommendable pharmacological properties. This review, therefore, compiles the recently reported applications of PAMAM dendrimers in pre-clinical and clinical uses as enhancers of solubility and other desirable properties such as sustained and controlled release, bioavailability, bio-distribution, toxicity reduction or enhancement, and targeted delivery of small molecules with emphasis on cancer treatment