排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
Jason L. Nyrop Arash Soheili Rong Xiang Fanyu Meng Jacob H. Waldman Xiujuan Jia Rubina Giarre Parmar Benjamin W. Thuronyi J. Michael Williams Lisa DiMichele Michel Journet Bonnie J. Howell Bing Mao Ian W. Davies Steven L. Colletti Laura Sepp‐Lorenzino Erin N. Guidry 《Journal of polymer science. Part A, Polymer chemistry》2014,52(8):1119-1129
Synthetic polymers represent a modifiable class of materials that can serve as adjuvants to address challenges in numerous biomedical and medicinal chemistry applications including the delivery of siRNA. Polymer‐based therapeutics offer unique challenges in both synthesis and characterization as compared to small molecule therapeutics. The ability to control the structure of the polymer is critical in creating a therapeutic. Reported herein, are batch and flow polymerization processes to produce amphiphilic terpolymers through a Lewis acid BF3OEt2‐catalyzed polymerization. These processes focus on controlling reaction variables, which affect polymer structure in this rapid, exothermic, nonliving cationic polymerization. In addition to analytical characterization of the polymers, the in vivo activity of the polymer‐siRNA conjugates is also highlighted—demonstrating that the method of synthesis does affect the in vivo activity of the resulting polymer conjugate. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1119–1129 相似文献
2.
Chiral fluorinated hydroxyketones were synthesized with excellent ee (>98%) and yield by a chemo- and stereoselective reduction of prochiral methyl/trifluoromethyl diketones using commercially available ketoreductase enzymes. By using p- and m-trifluoroacetyl substituted acetophenones, we demonstrate that ketoreductases can selectively differentiate between methyl and trifluoromethyl ketones within the same molecule. As a result, useful catalysts were identified that eliminated the need for costly and time-consuming protection/deprotection of the ketone moiety, enabling a more convergent synthesis of hydroxyketones. Further, a route to chiral methyl hydroxyketones is provided where an enzyme selectively reduces the unactivated ketone. 相似文献
3.
Leonard WR Belyk KM Conlon DA Bender DR DiMichele LM Liu J Hughes DL 《The Journal of organic chemistry》2007,72(7):2335-2343
A novel three-step synthesis of the highly functionalized antifungal agent CANCIDAS (caspofungin acetate, 2) is described, starting from the natural product pneumocandin B0 (1). The highlights of the synthesis include a stereoselective formation of a phenylthioaminal, a remarkable chemoselective, high-yielding, one-step borane reduction of a primary amide, and a stereoselective substitution of the phenylthioaminal with ethylenediamine producing 2 in a 45% overall yield. 相似文献
4.
A two-dimensional steady-sate analysis of semi-infinite brittlecrack growth at a constant subcritical rate in an unboundedfully-coupled thermoelastic solid under mixed-mode thermomechanicalloading is made. The loading consists of normal and shear tractionsand heat fluxes applied as point sources (line loads in theout-of-plane direction). A related problem is solved exactly in an integral transformspace, and robust asymptotic forms used to reduce the originalproblem to a set of integral equations. The equations are partiallycoupled and exhibit operators of both Cauchy and Abel types,yet can be solved analytically. The temperature change field at a distance from the moving crackedge is then constructed, and its dominant term is found tobe controlled by the imposed heat fluxes. The role of this termis, indeed, enhanced if the heat fluxes serve to render thecrack as a net heat source/sink for the solid, as opposed tobeing a transmitter of heat across its plane. More generally,the influence of the thermoelastic coupling on this field, aswell as other functions, is found to increase with crack speed. 相似文献
5.
Amita Gupta Alexei Yu Ganin Parmanand Sharma Vikrant Agnihotri LM Belova KV Rao Mikhail E Kozlov AA Zakhidov RH Baughman 《Pramana》2002,58(5-6):1051-1059
We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show
a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are
found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there
exists no report in literature on any BiNi compound which is magnetic. 相似文献
6.
Smitrovich JH DiMichele L Qu C Boice GN Nelson TD Huffman MA Murry J 《The Journal of organic chemistry》2004,69(6):1903-1908
The stereochemical outcome of the asymmetric Michael reaction of pseudoephedrine amide enolates changes dramatically in the presence of LiCl. Reaction of the enolate in the absence of LiCl results in formation of the anti Michael adduct with high selectivity, whereas in the presence of lithium chloride the syn adduct is favored. This method provides access to enantiomerically enriched trans-3,4-disubstituted delta-lactones from the anti Michael adducts by a two step reduction/lactonization sequence. Information obtained from NMR studies indicates that, under both enolization conditions, the (Z)-enolate is formed. A model to explain the turnover in selectivity based on NMR evidence is presented. 相似文献
7.
Unique tandem Heck-lactamization naphthyridinone ring formation between acrylanilides and halogenated pyridines 总被引:1,自引:0,他引:1
Cvetovich RJ Reamer RA DiMichele L Chung JY Chilenski JR 《The Journal of organic chemistry》2006,71(22):8610-8613
The Heck coupling of acrylanilides with 4-bromo-2-chloro-3-iodo-pyridine using palladium acetate can produce bis-Heck products or undergo an unusual tandem Heck-lactamization ring formation to generate 5-chloro-1-aryl-1,6-naphthyridin-2(1H)-ones. 相似文献
8.
DiMichele L Menzel K Mills P Frantz D Nelson T 《Magnetic resonance in chemistry : MRC》2006,44(11):1041-1043
Regioselective halogen/metal exchange reactions were carried out on a series of 3-substituted- 1,2-dibromoarenes. Product mixtures were quenched with CO2 to form the corresponding benzoic acid analogs to facilitate HPLC and NMR analysis. Substitution at the 3-position could readily be assigned on the basis of 2D HMBC long-range correlations, while assignment at the 2-position was not as straightforward. The use of three-bond J(CH) coupling constant measurements, extracted from 1-D 1H coupled 13C experiments, were necessary to render unequivocal regio assignments. 相似文献
9.
An improved protocol for N-acetyl enamine formation is disclosed which involves LiBr-mediated addition of MeLi to substituted nitriles. The resulting enamides are isolated in high yields and excellent purity which permits subsequent hydrogenation at very low catalyst loading. 相似文献
10.
A practical synthesis of a COX-2-specific inhibitor 总被引:2,自引:0,他引:2
Davies IW Marcoux JF Corley EG Journet M Cai DW Palucki M Wu J Larsen RD Rossen K Pye PJ DiMichele L Dormer P Reider PJ 《The Journal of organic chemistry》2000,65(25):8415-8420
A number of synthetic strategies to the Cox-2 specific inhibitor 1 have been described. These studies have led to the identification of a novel pyridine construction using annulation of ketone 2 using a vinamidinium species 29 and ammonia in 97% assay yield. Three approaches to the synthesis of ketone 2 are described that allow for its preparation in large quantities in >65% overall yield from methyl 6-methylnicotinate. 相似文献