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methyl ester

Masao Morita, Yuichi Kobayashi
The stereoselective synthesis of resolvin D4 (RvD4) was achieved using the Wittig reaction of the C1-C10 dienal with the known C11-C22 phosphonium salt. The (S,E)-enantiomer (S)-10, corresponding to the C1-C8 part, was synthesized in 95% ee by the asymmetric transfer hydrogenation reaction of the corresponding acetylenic ketone followed by Red-Al reduction. Sharpless epoxidation of this alcohol using Ti(O-i-Pr)4/L-(+)-DIPT as a catalyst produced anti epoxy alcohol with >99% ee as the sole product in 82% yield...
March 16, 2018: Journal of Organic Chemistry
Michael M Linden, J Philipp Wagner, Bastian Bernhardt, Marcus A Bartlett, Wesley D Allen, Peter R Schreiner
Disentangling internal and external effects is a key requirement for understanding conformational tunneling processes. Here we report the s-trans/s-cis tunneling rotamerization of carbonic acid monomethyl ester (1) under matrix isolation conditions and make comparisons to its parent carbonic acid (3). The observed tunneling rate of 1 is temperature independent in the 3-20 K range and accelerates when using argon instead of neon as the matrix material. The methyl group increases the effective half-life (τeff) of the energetically disfavored s-trans-conformer from 3-5 h for 3 to 11-13 h for 1...
March 15, 2018: Journal of Physical Chemistry Letters
Lu Hu, Wuchao Zhao, Jianghua He, Yuetao Zhang
This work reveals the silyl ketene acetal (SKA)/B(C₆F₅)₃ Lewis pair-catalyzed room-temperature group transfer polymerization (GTP) of polar acrylic monomers, including methyl linear methacrylate (MMA), and the biorenewable cyclic monomers γ-methyl-α-methylene-γ-butyrolactone (MMBL) and α-methylene-γ-butyrolactone (MBL) as well. The in situ NMR monitored reaction of SKA with B(C₆F₅)₃ indicated the formation of Frustrated Lewis Pairs (FLPs), although it is sluggish for MMA polymerization, such a FLP system exhibits highly activity and living GTP of MMBL and MBL...
March 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Nobuyuki Higashi, Sho Matsubara, Shin-Nosuke Nishimura, Tomoyuki Koga
Novel thermo-responsive ABA-type triblock copolymers (poly(NAAMe n - b -NAGMe 240 - b -NAAMe n ), n = 18-72) composed of naturally occurring amino acid-based vinyl polymer blocks such as poly( N -acryloyl-l-alanine methyl ester (poly(NAAMe)) as the A segment and poly( N -acryloyl-glycine methylester)(poly(NAGMe)) as the B segment have been synthesized by the atom transfer radical polymerization (ATRP). Their thermal behaviors were analyzed in dilute aqueous solutions by turbidimetry. The turbidity curves provided two-step LCST transitions, and a flower-like micelle formation was confirmed at the temperature region between the first and second LCST transitions by dynamic light scattering, AFM and TEM...
March 15, 2018: Materials
S Thiyagarajan, V Edwin Geo, Leenus Jesu Martin, B Nagalingam
This experimental study aims to mitigate harmful emissions from a CI engine using bio-energy with carbon capture and storage (BECCS) approach. The engine used for this experimental work is a single cylinder CI engine with a rated power of 5.2 kW at a constant speed of 1500 rpm. The BECCS approach is a combination of plant-based biofuels and carbon capture and storage system. The whole investigation was done in four phases: (1) Substituting diesel with Karanja oil methyl ester (KOME) (2) Equal volume blending of Orange oil (ORG) with KOME (3) 20% blending of n-butanol (B) with KOME-ORG blend (4) Carbon capture and storage (CCS) system with zeolite based non-selective catalytic reduction (NSCR) and mono ethanolamine (MEA) based selective non-catalytic reduction (SNCR) system with KOME-ORG + B20 blend...
March 15, 2018: Environmental Technology
Florian Glaus, Darija Dedic, Priyanka Tare, Valakunja Nagaraja, Liliana Rodrigues, Jose A Ainsa, Jens Kunze, Gisbert Schneider, Ruben C Hartkoorn, Stewart T Cole, Karl-Heinz Altmann
Described is the total synthesis of the myxobacterial natural product ripostatin B and of a small number of analogs. Ripostatin B is a polyketide-derived 14-membered macrolide that acts as an inhibitor of bacterial RNA-polymerase, but is mechanistically distinct from rifamycin-derived RNA-polymerase inhibitors that are in use for tuberculosis treatment. The macrolactone ring of ripostatin B features two stereocenters and a synthetically challenging doubly skipped triene motif, with one of the double bonds being in conjugation with the ester carbonyl...
March 15, 2018: Journal of Organic Chemistry
Alessio Cimmino, Paola Nocera, Benedetto Teodoro Linaldeddu, Marco Masi, Marcin Gorecki, Gennaro Pescitelli, Lucio Montecchio, Lucia Maddau, Antonio Evidente
From the culture filtrates of Diaporthella cryptica, an emerging hazelnut pathogen, 2-hydroxy-3-phenylpropanoate methyl ester and its 3-(4-hydroxyphenyl) and 3-(1H-indol-3-yl) analogues, named crypticins A-C, were isolated together with the well-known tyrosol. Crypticins A-C were identified by spectroscopic (essentially NMR and HRESI MS) methods. The R absolute configuration (AC) of crypticin A was determined comparing its optical rotation power and ECD spectrum with those of papuline, the methyl ester of (-)(S)-phenyllactic acid isolated as the main phytotoxin of Pseudomonas syringae pv papulans, responsible for apple blister spot...
March 14, 2018: Journal of Agricultural and Food Chemistry
Wentao Huang, Yen-Hung Lin, Thomas D Anthopoulos
Combining high charge carrier mobility with ambipolar transport in light-absorbing organic semiconductors is highly desirable as it leads to enhanced charge photogeneration, and hence improved performance, in various optoelectronic devices including solar cells and photodetectors. Here we report the development of [6,6]-phenyl-C61 -butyric acid methyl ester (PC61 BM)-based ultraviolet (UV) phototransistors with balanced electron and hole transport characteristics. The latter is achieved by fine-tuning the source-drain electrode work function using a self-assembled monolayer...
March 13, 2018: ACS Applied Materials & Interfaces
Sinosh Skariyachan, Meghna Manjunath, Nikhil Bachappanavar
Acinetobacter baumannii, an opportunistic pathogen, has become multi-drug resistant (MDR) to major classes of antibacterial and poses grave threat to public health. The current study focused to screen novel phytotherapeutics against prioritized targets of Acinetobacter baumannii by computational investigation. Fourteen potential drug targets were screened based on their functional role in various biosynthetic pathways and the three dimensional structures of nine targets were retrieved from Protein Data Bank and others were computationally predicted...
March 12, 2018: Journal of Biomolecular Structure & Dynamics
Jan Klett
Lochmann-Schlosser superbases are formed by mixing alkyllithium with potassium alkoxides. These reagents could prove their synthetic usefulness and reliability in many reactions over five decades. However, despite many efforts the real source of the exceptional reactivity remained a secret. The seemingly manageable system of four components (lithium, potassium atoms, alkyl groups, and alkoxy groups) and their interaction is obscured by poor solubility and fierce reactivity. Recent progress was achieved by using neopentyllithium, leading to alkane soluble-aggregates with varying lithium/potassium content and a flexible alkyl/alkoxy ratio...
March 12, 2018: Chemistry: a European Journal
Sarisa Suriyarak, Herbert Schmidt, Pierre Villeneuve, Jochen Weiss
The mechanisms of three antimicrobial rosmarinates (methyl-RE1, hexyl-RE6, and dodecyl-RE12) were investigated against Staphylococcus carnosus LTH1502. Scanning electron microscopy was used to determine the morphology of treated cells to gain information on potential changes in the site of action of compounds. The survival data obtained from antimicrobial activity assays were fitted to a nonlinear Weibull model to assess changes in inactivation behavior. Generally, esters became more effective with increasing length of the alkyl chain, resulting in a lower concentration for inhibition and inactivation...
March 12, 2018: Journal of Food Protection
Wenming Wu, Hanli Ruan
Two new triterpenoids, 24(E)-3α,12α-dihydroxyl-lanost-9(11),24-dien-26-oid acid (1) and 3,4-seco-24(Z)-6α,7β-dihydroxyl-cycloart-4(28),24-dien-3,26-dioic-3-methyl ester (2), and ten known ones (3-12), together with eight lignans (13-20), were isolated from the stems of Schisandra glaucescens. Their structures were established on the basis of extensive spectroscopic analyses. Compounds 1-3, 5-7, 9, 11-13 and 15-18 were isolated from this species for the first time. 1 and 2 were evaluated for their in vitro cytotoxicities against the mouse cancer B16 cell line, human cancer HepG2 and MCF7 cell lines by MTT assay...
March 12, 2018: Natural Product Research
Masaaki Konishi, Tomotake Morita, Tokuma Fukuoka, Tomohiro Imura, Shingo Uemura, Hiroyuki Iwabuchi, Dai Kitamoto
We discovered that Candida floricola ZM1502 is capable of selectively producing the promising hydrophilic biosurfactants, acid-form sophorolipids (SLs), from glycerol. However, productivity was very low (approximately 3.5 g L-1 ) under the initial culture conditions. Here, we describe the design of culture medium for abundant production of acid-form SLs by C. floricola ZM1502 using waste glycerol and hydrophobic substrates in order to develop a method for SL production and disposal of waste glycerol produced by oleo-chemical industries...
March 9, 2018: Journal of Oleo Science
Scott K Ferguson, Julie W Harral, David I Pak, Katherine M Redinius, Kurt R Stenmark, Dominik J Schaer, Paul W Buehler, David C Irwin
Free hemoglobin (Hb) associated with hemolysis extravasates into vascular tissue and depletes nitric oxide (NO), which leads to impaired vascular function and could impair skeletal muscle metabolic control during exercise. We tested the hypothesis that: 1) free Hb would extravasate into skeletal muscle tissue, reducing the contracting skeletal muscle O2 delivery/O2 utilization ratio (microvascular PO2 , PO2 mv) to a similar extent as that observed following NO synthase (NOS) blockade, and 2) that the Hb scavenging protein haptoglobin (Hp) would prevent Hb extravasation and inhibit these skeletal muscle tissue effects...
March 8, 2018: Nitric Oxide: Biology and Chemistry
Zhongjian Cheng, Xinggui Shen, Xiaohua Jiang, Huimin Shan, Maria Cimini, Pu Fang, Yong Ji, Joon Young Park, Konstantinos Drosatos, Xiaofeng Yang, Christopher G Kevil, Raj Kishore, Hong Wang
Insufficient hydrogen sulfide (H2 S) has been implicated in Type 2 diabetic mellitus (T2DM) and hyperhomocysteinemia (HHcy)-related cardiovascular complications. We investigated the role of H2 S in T2DM and HHcy-induced endothelial dysfunction in small mesenteric artery (SMA) of db/db mice fed a high methionine (HM) diet. HM diet (8 weeks) induced HHcy in both T2DM db/db mice and non-diabetic db/+ mice (total plasma Hcy: 48.4 and 31.3 µM, respectively), and aggravated the impaired endothelium-derived hyperpolarization factor (EDHF)-induced endothelium-dependent relaxation to acetylcholine (ACh), determined by the presence of eNOS inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) and prostacyclin (PGI2 ) inhibitor indomethacin (INDO), in SMA from db/db mice but not that from db/+ mice...
February 14, 2018: Redox Biology
Reema Abdelkareem Abu Khalaf, Dima Sabbah, Eveen Al-Shalabi, Iyad Al-Sheikh, Ghadeer Albadawi, Ghassan Abu Sheikha
BACKGROUND: Diabetes mellitus is a major worldwide health concern that has several serious complications including retinopathy, neuropathy, nephropathy and macrovascular diseases. OBJECTIVE: Dipeptidyl peptidase-IV (DPP-IV) inhibitors, gliptins, are a new class of antidiabetic agents that potentiates the action of incretins in decreasing the blood glucose levels. METHODS: In the present study, synthesis and characterization of a series of ten N4-sulfonamido-acrylic and phthalamic acid methyl esters (3a-e and 5a-e) were achieved...
March 8, 2018: Current Computer-aided Drug Design
Kazunari Namegawa, Kyoko Iida, Kaoru Omura, Shoujiro Ogawa, Alan F Hofmann, Takashi Iida
A method for the preparation of 11α-hydroxy derivatives of lithocholic and chenodeoxycholic acids, recently discovered to be natural bile acids, is described. The principal reactions involved were (1) elimination of the 12α-mesyloxy group of the methyl esters of 3α-acetate-12α-mesylate and 3α,7α-diacetate-12α-mesylate derivatives of deoxycholic acid and cholic acid with potassium acetate/hexamethylphosphoramide; (2) simultaneous reduction/hydrolysis of the resulting △11 -3α-acetoxy and △11 -3α,7α-diacetoxy methyl esters with lithium aluminum hydride; (3) stereoselective 11α-hydroxylation of the △11 -3α,24-diol and △11 -3α,7α,24-triol intermediates with B2 H6 /tetrahydrofuran (THF); and (4) selective oxidation at C-24 of the resulting 3α,11α,24-triol and 3α,7α,11α,24-tetrol to the corresponding C-24 carboxylic acids with NaClO2 catalyzed by 2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO) and NaClO...
March 9, 2018: Lipids
Chufen Yang, Zhaolin Xue, Yinglin Liu, Jiayu Xiao, Jingrui Chen, Lijuan Zhang, Jianwei Guo, Wenjing Lin
To improve the drug release rate in well-controlled manner, a new pH-sensitive triblock amphiphilic copolymer methyl poly(ethylene glycol) ether-b-poly(β-amino esters)-b-poly lactic acid (MPEG-b-PBAE-b-PLA) and its self-assembled micelles were developed for anticancer drug delivery. The average molecular weight and molecular structure of MPEG-b-PBAE-b-PLA were confirmed by gel permeation chromatography (GPC) and1 H NMR. The formation of self-assembled micelles, the microstructures at different pH values, and the distribution of doxorubicin (DOX) were investigated by dissipative particle dynamics (DPD) simulation combined with experimental techniques...
March 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Fangyuan Guo, Dongxue Huang, Wei Zhang, Qinying Yan, Qingliang Yang, Yan Yang, Hanbing Li, Junxian Yun, Weiyong Hong, Gensheng Yang
Elastomers are largely developed for biomedical applications; however, little is reported on them although they are an effective and controllable delivery system for proteins. In the present study, we investigated the pharmacokinetics, biosecurity, and hypoglycemic effect of an insulin-loaded elastomer formulation in diabetic rats. Cylindrical insulin-loaded elastomers were fabricated using a UV cross-linking process based on methyl-acrylic-star-poly(ε-caprolactone-co-D,L-lactide) cyclic ester and methyl-bi-acrylic-poly(ε-caprolactone-b-polyethylene glycol-b-ε-caprolactone) (CLPEGCLMA)...
March 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Xiguang Zhao, Noemi Kedei, Aleksandra M Michalowski, Nancy E Lewin, Gary E Keck, Peter M Blumberg
Important strides are being made in understanding the structural features of bryostatin 1, a candidate therapeutic agent for cancer and dementia, conferring its potency for protein kinase C and the unique spectrum of biological responses which it induces. A critical pharmacophoric element in bryostatin 1 is a secondary hydroxyl, whereas a primary hydroxyl group plays the analogous role in binding of the phorbol esters to protein kinase C. Here, we describe the synthesis of a bryostatin homolog where the hydroxyl group is primary, as in the phorbol esters, and show that its biological activity is almost indistinguishable from that of the corresponding compound with the secondary hydroxyl group...
March 8, 2018: Chembiochem: a European Journal of Chemical Biology
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