Enzymatic Synthesis of 1‐Alkyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate Using a Novel Lysoplasmalogen‐Specific Phopholipase D

Many phospholipase Ds (PLDs) are known to catalyze transphosphatidylation as well as hydrolysis of phospholipids. Transphosphatidylation of lysoplasmalogen (LyPls)‐specific phospholipase D (LyPls‐PLD), which catalyzes hydrolysis of ether lysophospholipids such as LyPls and 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine (Lyso‐PAF), still remains unclear. This study aims to reveal the transphosphatidylation activity of LyPls‐PLD, that is, the production of cyclic ether lysophospholipid. The enzymatic reaction is conducted in a buffer system, and the reaction products of a novel LyPls‐PLD from Thermocrispum sp. are investigated using mass spectrometry (MS). MS analyses demonstrate the reaction products to consist of 100% 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate (cLyPA) and choline from Lyso‐PAF; however, 1‐alkenyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate from 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine and 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphoethanolamine is not produced. These results are expected to help in elucidating the catalytic mechanism of LyPls‐PLD, that is, the rate‐limiting step, and indicate LyPls‐PLD to be useful for the one‐pot synthesis of cLyPA. Practical Applications: A novel phospholipase D, LyPls‐PLD, can exclusively synthesize cLyPA from Lyso‐PAF using a one‐step enzymatic reaction without an organic solvent. cLyPA could be expected to show bioactivities similar to those of cyclic phosphatidic acid, which promotes normal cell differentiation, hyaluronic acid synthesis, antiproliferative activity in fibroblasts, and inhibitory activity toward cancer cell invasion and metastasis.     

Synthesis and properties of poly(acrylonitrile‐co‐p‐trimethylsilylstyrene) and poly(acrylonitrile‐co‐p‐trimethylsilylstyrene‐co‐styrene)

Copolymerization of acrylonitrile (AN) with p‐trimethylsilylstyrene (TMSS) was carried out at 60°C in bulk and in solution in the presence of 2,2′‐azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M₁) and TMSS (M₂) were determined to be r₁ = 0.068 and r₂ = 0.309. The effects of the AIBN concentration and that of the chain transfer agent CCl₄ on the molecular weights (MWs) of the copolymers were investigated. An increase in the concentrations of AIBN or CCl₄ in solution led to a decrease in MW. Poly(AN‐co‐TMSS‐co‐St) was synthesized in solution using AIBN as the initiator. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St varied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermooxidative stabilities of poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) were investigated. The differential scanning calorimeter technique was used to determine the compatibility of the poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) with commercial poly(AN‐co‐St). All the blends show a single glass transition temperature, which indicates the compatibility of the blend components. The surface film morphology of the blends mentioned above was examined by X‐ray photoelectron spectroscopy. The data obtained indicate that the silicon‐containing copolymer is concentrated in the surface layer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1920–1928, 2000     

Improvement of the production of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate‐co‐4‐hydroxybutyrate) terpolyester by manipulating the culture condition

BACKGROUND: The aim of this work is to enhance the production of terpolyester poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate‐co‐4‐hydroxybutyrate) (P(3HB‐co‐3HV‐co‐4HB)) produced by a locally isolated bacterium, Cupriavidus sp. USMAA2‐4. The monomer composition was varied by supplementing different carbon precursors and by manipulating the culture condition through one‐stage cultivation. The effect of C/N ratio and different concentrations of carbon source and precursors were investigated in order to produce higher content of this terpolyester. Although research on this biodegradable polyester is abundant, studies on terpolyester P(3HB‐co‐3HV‐co‐4HB) are still limited. RESULTS: Supplementation of oleic acid in accumulation medium increased the bacterial growth and polyhydroxyalkanoate (PHA) accumulation. It was also shown that medium consisting of assorted carbon precursors at C/N 20 gave relatively high dry cell weight and P(3HB‐co‐3HV‐co‐4HB) content. Various compositions of terpolyester were obtained when the concentration of oleic acid and 4HB precursors were manipulated. The combination of oleic acid with γ‐butyrolactone and 1‐pentanol was found to be the best combination to produce high PHA content (81 wt%). The composition of monomer in P(3HB‐co‐3HV‐co‐4HB) was produced in the range 8–13 mol% for 3HV and 9–24 mol% for 4HB, respectively. CONCLUSIONS: The production of P(3HB‐co‐3HV‐co‐4HB) in shake‐flasks successfully produced 81 wt% of PHA content. This manipulated culture condition can be used at larger scale to provide modeling for the production of terpolyester in a bioreactor. Copyright © 2012 Society of Chemical Industry     

Beziehungen zwischen algistatischer Aktivität und physikalisch‐chemischen Eigenschaften von 5‐Amino‐1‐aryl‐1H‐tetrazolen

A series of 20 5‐amino‐1‐aryl‐1H‐tetrazoles was synthesized by diazotation of corresponding 1‐amino‐3‐aryl‐guanidines and tested for growth‐inhibiting activity against autotrophic Chlorella vulgaris cultures. In the used tests the different algae growth was quantified by photometric measurements at 680 nm. From obtained dosage‐effectivity relationships the reciprocal values of isoeffective concentrations c ₅₀ were derived and defined as activity parameters A in QSAR (quantitative structure‐activity relationship) studies. It could be shown that the algistatitic activity (log A) of the tested heterocycles strongly depends on hydrophobicity described by their octan‐1‐ol/water partition coefficients (log P). The calculated linear relationships between log A and log P can be significantly improved by separate treatment of meta‐/para‐ and ortho‐substituted compounds or using an indicator variable to describe the lower activity of ortho‐substituted 5‐ami‐no‐1‐aryl‐1H‐tetrazoles in common regression equations. The results are discussed and compared with analogous QSAR found for earlier tested series of N‐heterocycles and compounds with urea structure.     

Zur physikalisch‐chemischen Charakterisierung von 5‐Amino‐1‐aryl‐1H‐tetrazolen: Elektronische Molekülparameter aus der thermischen Isomerisierung zu 5‐Arylamino‐1H‐tetrazolen

The known thermal isomerization of 5‐amino‐1‐aryl‐1H‐tetrazoles ( A ) into corresponding 5‐arylamino‐1H‐tetrazoles ( HB ) was used to derive physicochemical parameters characterizing the electronic substituent effect on isomerism and dissociation equilibria. For a series of 26 tetrazoles A as starting materials the equilibrium constants (pK_i) of isomerization in boiling ethylene glycol at 197 °C and the dissociation constants (pK_a) of the NH‐acidic tetrazoles HB were determined by potentiometric titration of rapidly cooled equilibrium mixtures in water and ethanol/water with KOH at 25 °C. The pK values are closely correlated with Hammett′s electronic substituent constants σ and can be used as electronic molecule parameters in QSAR or QSPR (QSAR = quantitative structure‐activity relationship; QSPR = quantitative structure‐property relationship) studies.     

Preparation of acrylamide‐based poly‐HIPEs with enhanced mechanical strength using PVDBM‐b‐PEG‐emulsified CO2‐in‐water emulsions

Poly(vinyl acetate‐alt‐dibutyl maleate)‐block‐poly(ethylene glycol) (PVDBM‐b‐PEG) copolymers were synthesized via reversible addition–fragmentation chain transfer radical polymerization and used as emulsifiers to form stable CO₂‐in‐water high internal phase emulsions (C/W HIPEs). Then, highly interconnected cellular polyacrylamide (PAM) and poly(acrylamide‐co‐N‐hydroxymethyl acrylamide) [P(AM‐co‐HMAM)] poly‐HIPEs with enhanced mechanical strength were prepared based on the stable C/W HIPEs. The porous structures of the PAM poly‐HIPEs, as well as morphology and compressive modulus, could be influenced by the surfactant concentration and the length of the CO₂‐philic tails of the surfactants. PAM poly‐HIPEs with the smallest average pore diameter (11.12 ± 0.62 μm) and the highest compressive modulus (22.65 ± 0.10 MPa) could be obtained by using the short CO₂‐philic chains of the PVDBM‐b‐PEG surfactant at a high concentration (1.0 wt %). Moreover, with the copolymerization of N‐hydroxymethyl acrylamide (HMAM) comonomers with acrylamide, the compressive modulus of the obtained P(AM‐co‐HMAM) poly‐HIPEs was three times higher than that of PAM poly‐HIPEs. Both PAM and P(AM‐co‐HMAM) poly‐HIPEs were employed as scaffolds to guide H9c2 cardiac muscle cellular growth. Fluorescence images showed that a smaller average pore size and a narrower pore‐size distribution were helpful for cell growth and proliferation on these materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46346.     

Copper‐Mediated and ‐Catalyzed o‐DPPB‐Directed Allylic Substitution

Complete control of chemo‐, regio‐ and stereoselectivity in the course of copper‐catalyzed and ‐mediated allylic substitution could be obtained with the ortho‐diphenylphosphanyl (o‐DPPB) function as a reagent‐directing leaving group. Complete chirality transfer by way of a syn‐addition process has been achieved for cyclic and acyclic systems. Readily available Grignard reagents may be employed as nucleophiles and the directing o‐DPPB group can be recovered quantitatively. The reaction requires neither cooling nor an excess of organometallic reagent.     

Studies on ethylene‐propylene‐diene rubber modification by N‐chlorothio‐N‐butyl‐benzenesulfonamide

N‐Chlorothiosulfonamides have been used to modify ethylene‐propylene‐diene rubber (EPDM) to enhance the compatibility of EPDM in, e.g., natural rubber (NR)/butadiene rubber (BR)/EPDM blends for ozone resistance. N‐Chlorothio‐N‐butyl‐benzenesulfonamide (CTBBS) was selected as a representative for N‐chlorothiosulfonamides. In this study, we found that CTBBS behaves differently with various types of EPDM. Three types of EPDM were selected: ethylidene norbornene (ENB)‐EPDM, hexadiene (HD)‐EPDM, and dicyclopentadiene (DCPD)‐EPDM. HD‐EPDM showed the greatest effectiveness toward CTBBS‐modification. However, this EPDM is not commercially available anymore. On the opposite side, DCPD‐EPDM showed the lowest reactivity so that almost no modification could be realized. The result with ENB‐EPDM was, that upon application of CTBBS to ENB‐EPDM, gelation occurred and, therefore, a low amount of modification was achieved. With the limited modification efficiency for ENB‐EPDM, there is no significant improvement when applying the modified ENB‐EPDM into NR/BR/EPDM blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Heme Oxygenase Inhibition by 1‐Aryl‐2‐(1H‐imidazol‐1‐yl/1H‐1,2,4‐triazol‐1‐yl)ethanones and Their Derivatives

Previous studies by our research group have been concerned with the design of selective inhibitors of heme oxygenases (HO‐1 and HO‐2). The majority of these were based on a four‐carbon linkage of an azole, usually an imidazole, and an aromatic moiety. In the present study, we designed and synthesized a series of inhibition candidates containing a shorter linkage between these groups, specifically, a series of 1‐aryl‐2‐(1H‐imidazol‐1‐yl/1H‐1,2,4‐triazol‐1‐yl)ethanones and their derivatives. As regards HO‐1 inhibition, the aromatic moieties yielding best results were found to be halogen‐substituted residues such as 3‐bromophenyl, 4‐bromophenyl, and 3,4‐dichlorophenyl, or hydrocarbon residues such as 2‐naphthyl, 4‐biphenyl, 4‐benzylphenyl, and 4‐(2‐phenethyl)phenyl. Among the imidazole‐ketones, five ( 36 – 39 , and 44 ) were found to be very potent (IC₅₀<5 μM ) toward both isozymes. Relative to the imidazole‐ketones, the series of corresponding triazole‐ketones showed four compounds ( 54 , 55 , 61 , and 62 ) having a selectivity index >50 in favor of HO‐1. In the case of the azole‐dioxolanes, two of them ( 80 and 85 ), each possessing a 2‐naphthyl moiety, were found to be particularly potent and selective HO‐1 inhibitors. Three non‐carbonyl analogues ( 87 , 89 , and 91 ) of 1‐(4‐chlorophenyl)‐2‐(1H‐imidazol‐1‐yl)ethanone were found to be good inhibitors of HO‐1. For the first time in our studies, two azole‐based inhibitors ( 37 and 39 ) were found to exhibit a modest selectivity index in favor of HO‐2. The present study has revealed additional candidates based on inhibition of heme oxygenases for potentially useful pharmacological and therapeutic applications.     

Polyhydroxybutyrate/acrylonitrile‐g‐(ethylene‐co‐ propylene‐co‐diene)‐g‐styrene blends: Their morphology and thermal and mechanical behavior

Polyhydroxybutyrate (PHB) is a biodegradable bacterial polyester emerging as a viable substitute for synthetic, semicrystalline, nonbiodegradable polymers. An elastomer terpolymer of acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene (AES) was blended with PHB in a batch mixer and in a twin‐screw extruder to improve the mechanical properties of PHB. The blends were characterized with differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy, and impact resistance measurements. Despite the narrow processing window of PHB, blends with AES could be prepared via the melting of the mixture without significant degradation of PHB. The blends were immiscible and composed of four phases: poly(ethylene‐co‐propylene‐co‐diene), poly(styrene‐co‐acrylonitrile), amorphous PHB, and crystalline PHB. The crystallization of PHB in the blends was influenced by the AES content in different ways, depending on the processing conditions. A blend containing 30 wt % AES presented impact resistance comparable to that of high‐impact polystyrene, and the value was about 190% higher than that of pure PHB. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Chitosan‐modified d‐α‐tocopheryl poly(ethylene glycol) 1000 succinate‐b‐poly(ε‐caprolactone‐ran‐glycolide) nanoparticles for the oral chemotherapy of bladder cancer

Oral chemotherapy is quickly emerging as an appealing option for cancer patients. It is less stressful because the patient has fewer hospital visits and can still maintain a close relationship with health care professionals. Three kinds of nanoparticles made from commercial poly(ε‐caprolactone) (PCL) and self‐synthesized d‐α‐tocopheryl poly(ethylene glycol) 1000 succinate ‐b‐poly(ε‐caprolactone‐ran‐glycolide) [TPGS‐b‐(PCL‐ran‐PGA)] diblock copolymer were prepared in this study for the oral delivery of antitumor agents, including chitosan‐modified PCL nanoparticles, nonmodified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles, and chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles. First, the TPGS‐b‐(PCL‐ran‐PGA) diblock copolymer was synthesized and structurally characterized. Chitosan was adopted to extend the retention time at the cell surface and thus increase the chance of nanoparticle uptake by the gastrointestinal mucosa and improve the absorption of drugs after oral administration. The resulting TPGS‐b‐(PCL‐ran‐PGA) nanoparticles were found to be of spherical shape and around 200 nm in diameter with a narrow size distribution. The surface charge of the TPGS‐b‐(PCL‐ran‐PGA) nanoparticles could be reversed from anionic to cationic after surface modification. The chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles displayed a significantly higher level of cellular uptake compared with the chitosan‐modified PCL nanoparticles and nonmodified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles. In vitro cell viability studies showed the advantages of the chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles over Taxol in terms of their cytotoxicity against human RT112 cells. In summary, the oral delivery of antitumor agents by chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles produced results that were promising for the treatment of patients with bladder cancer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2118–2126, 2013     

A DFT Study on the Structures and Energies of Isomers of 4‐Amino‐1,3‐dinitro‐1,2,4‐triazol‐5‐one‐2‐oxide: New High Energy Density Compounds

Isomers of 4‐amino‐1,3‐dinitrotriazol‐5‐one‐2‐oxide (ADNTONO) are of interest in the contest of insensitive explosives and were found to have true local energy minima at the DFT‐B3LYP/aug‐cc‐pVDZ level. The optimized structures, vibrational frequencies and thermodynamic values for triazol‐5‐one N‐oxides were obtained in their ground state. Kamlet‐Jacob equations were used to evaluate the performance properties. The detonation properties of ADNTONO (D=10.15 to 10.46 km s⁻¹, P=50.86 to 54.25 GPa) are higher compared with those of 1,1‐diamino‐2,2‐dinitroethylene (D=8.87 km s⁻¹, P=32.75 GPa), 5‐nitro‐1,2,4‐triazol‐3‐one (D=8.56 km s⁻¹, P=31.12 GPa), 1,2,4,5‐tetrazine‐3,6‐diamine‐1,4‐dioxide (D=8.78 km s⁻¹, P=31.0 GPa), 1‐amino‐3,4,5‐trinitropyrazole (D=9.31 km s⁻¹, P=40.13 GPa), 4,4′‐dinitro‐3,3′‐bifurazan (D=8.80 km s⁻¹, P=35.60 GPa) and 3,4‐bis(3‐nitrofurazan‐4‐yl)furoxan (D=9.25 km s⁻¹, P=39.54 GPa). The  NH₂ group(s) appears to be particularly promising area for investigation since it may lead to two desirable consequences of higher stability (insensitivity), higher density, and thus detonation velocity and pressure.     

Thermo‐ and pH‐ responsive copolymers: Poly(n‐Isopropylacrylamide‐co‐IAM) copolymers

Poly(N‐isopropylacrylamide) (NIPAAm) is well known as a smart material with good thermal sensitivity and favorable biocompatibility. A series of new smart hydrogels, NIPAAm copolymerized with IAM (itaconamic acid; 4‐amino‐2‐methylene‐4‐oxobutanoic acid), were synthesized through radical solution polymerization in this work. Poly(NIPAAm‐co‐IAM) can respond to the changes of temperature as well as pH value. Such a characteristic is due to the fact that IAM contains not only a hydrophilic acrylic acid moiety but also an acrylamide moiety to be thermal and pH sensitive. The experimental results show that the lower critical solution temperature (LCST) of the copolymer increases as the molar fraction of IAM increases. Moreover, based on the current experimental data, 3 wt % of Poly(NIPAAm‐co‐IAM) aqueous solution in this study exhibits a phase transition temperature (37.8°C) close to the human body temperature in the buffer solution of pH 7 possibly to be useful in drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42367.     

But‐2‐ene‐1,4‐diamine and But‐2‐ene‐1,4‐diol as Donors for Thermodynamically Favored Transaminase‐ and Alcohol Dehydrogenase‐Catalyzed Processes

Both cis‐ and trans‐but‐2‐ene‐1,4‐diamines have been prepared and efficiently applied as sacrificial cosubstrates in enzymatic transamination reactions. The best results were obtained with the cis‐diamine. The thermodynamic equilibrium of the stereoselective transamination process is shifted to the amine formation due to tautomerization of 5H‐pyrrole into 1H‐pyrrole, achieving high conversions (78–99%) and enantiomeric excess (up to >99%) by using a small excess of the amine donor. Furthermore, when the reaction proceeded, a strong coloration was observed due to polymerization of 1H‐pyrrole. A structurally related compound, cis‐but‐2‐ene‐1,4‐diol, has been utilized as cosubstrate in different alcohol dehydrogenase (ADH)‐mediated bioreductions. In this case, high conversions (91–99%) were observed due to a lactonization process. Both strategies are convenient from both synthetic and atom economy points of view in the production of valuable optically active products.

     

Zur physikalisch‐chemischen Charakterisierung von 5‐Amino‐1‐aryl‐1H‐tetrazolen: Kinetik der Verteilung im Zweiphasensystem Octan‐1‐ol/Wasser

The kinetics of distribution of 27 5‐amino‐1‐aryl‐1H‐tetrazoles in the two‐phase system octan‐1‐ol/water were investigated UV/Vis‐spectrophotometrically at various temperatures. Studies on relationships between the obtained firstorder rate constants (logk₁, logk₂) and the hydrophobicity of the tetrazoles described by their partition coefficients (logP) show a nearly constant rate of transport from the aqueous to the organic phase (k₁) above logP = 1,5 while the reverse rate (k₂) strongly depends on hydrophobicity. In the whole logP range investigated the kinetic behaviour can be described by bilinear relationships between logk and logP corresponding to known kinetic models for distribution processes in two‐layer systems.     

New synthesis methods for polypropylene‐co‐ethylene‐propylene rubber

In this research, the reinforcement of polypropylene (PP) was studied using a new method that is more practical for synthesizing polypropylene‐block‐poly(ethylene‐propylene) copolymer (PP‐co‐EP), which can be used as a rubber toughening agent. This copolymer (PP‐co‐EP) could be synthesized by varying the feed condition and changing the feed gas in the batch reactor system using Ziegler–Natta catalysts system at a copolymerization temperature of 10°C. The ¹³C‐NMR tested by a 21.61‐ppm resonance peak indicated the incorporation of ethylene to propylene chains that could build up the microstructure of the block copolymer chain. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA) results also confirmed these conclusions. Under these conditions, the morphology of copolymer trapped in PP matrix could be observed and the copolymer T_g would decrease when the amount of PP‐co‐EP was increased. DMA study also showed that PP‐co‐EP is good for the polypropylene reinforcement at low temperature. Moreover, the PP‐co‐EP content has an effect on the crystallinity and morphology of polymer blend, i.e., the crystallinity of polymer decreased when the PP‐co‐EP content increased, but tougher mechanical properties at low temperature were observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3609–3616, 2007     

Synthesis and characterization of tetrakis‐ derivatives of bisphenol‐A with 4‐phenylazoaniline and 5‐(4‐aminophenylazo)‐25,26,27‐tribenzoyloxy‐ 28‐hydroxycalix[4]arene

The synthesis of tetrakis‐ derivatives of bisphenol‐A containing azo groups at their 2,2′,6,6′‐positions is reported. Novel examples of bisphenol‐A, coupled with diazonium salts and derived from 4‐phenylazoaniline and 5‐(4‐aminophenylazo)‐25,26,27‐tribenzoyloxy‐28‐hydroxycalix [4]arene, have been synthesized. It has been observed that the coupling reaction of diazonium salt obtained from 4‐phenylazoaniline with bisphenol‐A gives tetrakis‐ while those derived from 5‐(4‐aminophenylazo)‐25,26,27‐tribenzoyloxy‐28‐hydroxycalix [4]arene give partially substituted bisphenol‐A analogues. The newly prepared tetrakis‐azo substituted bisphenol‐A compounds ( 1 and 2 ) are characterized by using UV‐vis, FT‐IR, ¹H‐NMR spectroscopic methods as well as elemental analysis techniques. These azo compounds give rise to bathochromic shifts in the absorption spectra, which can even be detected by “naked eye.” © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Microbial conversion of androst‐1,4‐dien‐3,17‐dione by Mucor racemosus to hydroxysteroid‐1,4‐dien‐3‐one derivatives

BACKGROUND: A large number of bacterial, fungal and microalgal species are able to bio‐transform steroid compounds. Among them, fungi from the Mucor genus have been shown to mediate hydroxylation, oxidation, and desaturation by the double bond formation and epoxidation of various steroid substances. Mucor racemocus has not been studied for its ability to modify androst‐1,4‐dien‐3,17‐dione, a pharmaceutically important steroid precursor. RESULTS: The filamentous fungus M. racemosus was applied for bioconversion of androst‐1,4‐dien‐3,17‐dione (ADD, I ) in a 5‐day fermentation. Microbial metabolites were purified chromatographically and identified on the basis of their spectral data as 17β‐hydroxyandrost‐1,4‐dien‐3‐one ( II ), 14α‐hydroxyandrost‐1,4‐dien‐3,17‐dione ( III ), 15α‐hydroxyandrost‐1,4‐dien‐3,17‐dione ( IV ), 15α,17β‐dihydroxyandrost‐1,4‐dien‐3‐one ( V ), 14α,17β‐dihydroxyandrost‐1,4‐dien‐3‐one ( VI ), and 6β,17β‐dihydroxyandrost‐1,4‐dien‐3‐one ( VII ). CONCLUSION: Observed modifications included hydroxylation at C‐6β, C‐14α, C‐15α positions and 17‐carbonyl reduction. The best fermentation conditions for production of hydroxysteroid‐1,4‐dien‐3‐one derivatives were found to be 25 °C at 150 rpm for 5 days with a substrate concentration of 0.5 g L^?1. Copyright © 2009 Society of Chemical Industry     

Preparation and characterization of cyhalothrin‐loaded poly(2‐hydroxyethyl methacrylate)‐co‐polylactide (PHEMA‐co‐PLA) ultrafine particles

Poly(2‐hydroxyethyl methacrylate)‐co‐polylactide (PHEMA‐co‐PLA) and its corresponding cyhalothrin‐loaded ultrafine particles were successfully synthesized and prepared, respectively. The chemical structures of the copolymers have been confirmed by Fourier transform infrared spectroscopy (FTIR), ¹H‐nuclear magnetic resonance (¹H‐NMR), ¹³C‐nuclear magnetic resonance (¹³C‐NMR), and thermogravimetric analysis (TGA). Furthermore, the particle size, the cyhalothrin loading content (LC), and the cyhalothrin release behavior were investigated. PHEMA‐co‐PLA proved to be a good material for the preparation of ultrafine particles for lipophilic pesticide delivery. The developed cyhalothrin‐loaded PHEMA‐co‐PLA ultrafine particles showed good dispersity in water and sustained release behavior. In addition, it is easy to be prepared by both nanoprecipitation method and emulsion/solvent evaporation method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Highly Regio‐ and Stereoselective Iodohydroxylation of Non‐ Heteroatom‐Substituted Allenes: An Efficient Synthesis of 4‐[3′‐Hydroxy‐2′‐iodoalk‐1′(Z)‐enyl]‐2(5H)‐furanone Derivatives

An efficient protocol for the highly regio‐ and stereoselective synthesis of 4‐(3′‐hydroxy‐2′‐iodoalk‐1′(Z)‐enyl)furan‐2(5H)‐one derivatives via selective iodohydroxylation of non‐heteroatom‐substituted allenes, i.e., 4‐allenyl‐2(5H)furanones, has been developed. The regio‐ and stereoselectivity of this reaction may be controlled by the electronic and steric effects of the furanone ring.