Pyrazinium Di(hydrogen sulfate) as a Novel,Highly Efficient and Homogeneous Catalyst for the Condensation of Enolizable Ketones with Aldehydes,Acetonitrile and Acetyl Chloride

A highly efficient protocol for the synthesis of β‐acetamido ketone or ester derivatives in the presence of pyrazinium di(hydrogen sulfate) {Py(OSO₃H)₂} as a novel, green and homogeneous solid acid catalyst at room temperature is described. One‐pot multi‐component condensation of enolizable ketones or alkyl acetoacetates with aldehydes, acetonitrile and acetyl chloride affords the title compounds in high to excellent yields and in relatively short reaction times. In this work, the efficiency of our recently reported solid acid catalyst, saccharin sulfonic acid (Sa‐SO₃H), in the synthesis of β‐acetamido ketones/esters is also studied. Moreover, in this research, some new β‐acetamido ketones and esters (i.e. one complex structure) are prepared.     

Radiation synthesis of poly[(dimethylaminoethyl methacrylate)-co-(diallyl dimethyl ammonium chloride)] hydrogels and its application as a carrier for notoginsenoside delivery

Novel pH/temperature sensitive hydrogel was synthesized by radiation induced copolymerization and cross-linking of dimethylaminoethyl methacrylate (DMAEMA) and diallyldimethyl ammonium chloride (DADMAC). Reactivity ratio of DADMAC (r₁) and DMAEMA (r₂) was determined as 1.02 and 0.98, which means that poly(DMAEMA-co-DADMAC) is an azeotropic copolymer. Content of DADMAC, i.e., charge density of the hydrogel was found to influence their properties significantly. Compared with polyDMAEMA hydrogel, poly(DMAEMA-co-DADMAC) showed enhanced equilibrium degree of swelling (EDS). Low critical solution temperature (LCST) of the hydrogel increased with the charged density. Content of DADMAC had no effect on the pH dependence of the final gel. Aiming at its application as a carrier for Chinese herb extract delivery system, the embedment and pH/temperature dependence of controlled release were investigated using notoginsenoside as a model drug. The maximum embedment amount of notoginsenoside was obtained in a gel containing 3 mol.% DADMAC. The temperature dependence and pH dependence of notoginsenoside release followed the same trend as that of EDS, for instance, higher ratio of notoginsenoside release occurred at 25 °C and pH 1.7, at which higher EDS was obtained. By these means, the release of notoginsenoside can be controlled by adjusting the pH, ionic strength, temperature of solution as well as the composition and structure of the gel.     

Synthesis of SAPO-41 from a new reproducible route using H3PO3 as the phosphorus source and its application in hydroisomerization of n-decane

In the new reproducible route, phosphorous acid (H₃PO₃) or the mixture of H₃PO₃ and phosphoric acid (H₃PO₄) are used as the phosphorus source to synthesize microporous silicoaluminophosohates. It is found that gels containing H₃PO₃ favor the formation of SAPO-41 materials. With only H₃PO₃ as the phosphorus source, pure SAPO-41 phase can be prepared with high crystallinity. When the mixture of H₃PO₃ and H₃PO₄ is used as the phosphorus source, the crystallization of SAPO-41 can be accelerated. Raman and XRD results show that SAPO-41 can be formed after crystallizing for 12 h. The dosage of the template di-n-propylamine (DPA) can be reduced in the mixed phosphorus source system. The SAPO-41 has been used to prepare catalysts for the hydroisomerization of n-decane. High selectivity of isomerization (89.5%) has been observed even at high conversion (88%) over the Pt/SAPO-41.     

Direct synthesis of Poly(Ԑ-Caprolactone)-block-poly (glycidyl methacrylate) copolymer and its usage as a potential nano micelles carrier for hydrophobic drugs

Ring-opening (ROP) and enzymatic copolymerization (ECP) are among the most widely used approaches for synthesizing copolymers of polycaprolactone (PCL). It involves multiple-step reactions and the utilization of enzymes that make the process a lot more complicated, time consuming, and expensive. Atom transfer radical polymerization (ATRP) has been adopted to synthesize a novel amphiphilic copolymer in our study. The study presents a method to eliminate the ROP/ECP multiple steps in monomer polymerization thus making the process simpler and smoother. The synthesis of cationic polymer micelles copolymer of PCL-PGMA (polycaprolactone grafted poly glycidyl methacrylate) was carried out using direct functionalization of hydroxy group in crude PCL to achieve a higher degree of functionalization, i.e., 12.8% for macroinitiator. FTIR and ¹H-NMR confirmed the successful synthesis of the copolymer with better control over the molecular weight with a PDI (1.84). DSC and XRD results showed the reduction of crystallinity by 86.81%, making copolymer more compatible for drug delivery application. The synthesized copolymer was further converted to nano-micelles drug carrier having an average size of 96.08 ± 21.22 nm. The drug encapsulation efficiency achieved was 60.0 ± 1.7%, and nano-micelles rendered a slow and controlled release of naproxen with long-term storage stability.     

Preparation of a novel biodegradable film by co-fermentation of straw and shrimp shell with Aureobasidium pullulans and Photobacterium sp. LYM-1

The green and high-value recycling of shrimp shell and straw remains a worldwide problem. This study aimed to investigate the potential utilization of a fermentation broth (FB) which contains shrimp shell and straw as a new source for preparation of biodegradable films. Aureobasidium pullulans and Photobacterium sp. LYM-1 were used in the fermentation. The cellulase activity was 115.92 U/mL and chitinase activity was 17.89 U/mL in FB. The polysaccharides concentration in FB was 1.05 mg/mL after 7 days of fermentation. An eco-friendly PVA-reinforced FB biodegradable film (FBBF) was successfully prepared and the effect of different plasticizers and surfactants on the mechanical, structural, and impermeability properties of the film was determined. The formation of new bonds between PVA and FB was proved by FTIR spectroscopy. The FBBF containing 0.25 % (w/v) glycerol and 0.01 % (v/v) tween-20 showed better strength properties. Elongation and water-swelling properties were highly improved by adding 0.2 % (m/v) citric acid. According to FE-SEM images, the smooth and tight surface of citric acid added FBBF was observed. Interestingly, the FBBF film showed good heat/moisture capacity, antifungal, and degradation properties. This report reveals a new green, and high-value recycling of straw and shrimp shell by the co-fermentation with A. pullulans and Photobacterium sp. LYM-1. It is also a novel way for the preparation of biodegradable film.