肽基烯烃肽模拟物用作生物活性化合物或用作其他肽基等排体的中间体。C=C 键的 N 端侧可以很容易地从 α-氨基酸以光学纯的形式制备。以光学纯形式合成 C 端结构单元更具挑战性。我们开发了一种化学酶立体选择性方法,用于通过各种反应组装成肽基烯烃的光学活性 C 端结构单元。它们包括亲电子醛和亲核砜、鏻盐、膦酸盐和二硒化物。前手性二酯到相应羟基酯的关键酶水解引入了光学活性。随后化学反应的顺序,无论是保护-水解-功能化还是功能化-水解-保护,
peptidomimetics serve as biologically active compounds or as intermediates for other peptidyl isosteres. We developed a chemoenzymatic stereoselective approach to opticallyactive γ-hydroxy sulfones to be assembled into peptidyl olefins by the Julia reaction. Key enzymatic hydrolysis of prochiral diesters to the corresponding hydroxy esters introduces optical activity. The sequence of the subsequent
Chiral building-blocks by chemoenzymatic desymmetrization of 2-ethyl-1,3-propanediol for the preparation of biologically active natural products
作者:Isidoro Izquierdo、Maria T Plaza、Miguel Rodrı́guez、Juan Tamayo
DOI:10.1016/s0957-4166(99)00020-8
日期:1999.2
2-Ethyl-1,3-propanediol 1 and its related di-O-acetate 2 were desymmetrized by partial chemoenzymatic acetylation and deacetylation, by Pseudomonas fluorescens lipase (Amano P.; PFL), to (R)-1-O-acetyl-2-ethyl-1,3-propanediol 3. On treatment of 3 with I-2/Ph3P/imidazole the related (S)-1-O-acetyl-2-ethyl-3-iodopropanol 4 was obtained and transformed into the corresponding triphenylphosphonium salt 5. Reaction of [(S)-3-acetoxy-2-ethylpropylidene] triphenylphosphorane 6, prepared from 5, with 2,3 :4,5-di-O-isopropylidene-beta-D-arabino-hexos-2-ulopyranose 7 gave (2)-3-C-acetoxymethyl-1,2,3,4,5-pentadeoxy-6,7:8,9-di-O-isopropylidene-beta-D-manno-dec-4-ene-6-ulo-6,10-pyranose 8 which was hydrogenated to 9 and subsequently deacylated to 10. Treatment of 10 with Me2CO/H+ caused a rearrangement to (3R,4R,5S,6R,9R)-9-ethyl-5-hydroxy-3,4-isopropylidenedioxy-1,7-dioxaspiro[5.5]undecane 11, which closely matched the skeleton of the talaromycins. (C) 1999 Elsevier Science Ltd. All rights reserved.
Enzymatic process for stereo-selective preparation of chemical compounds in hydrofluorocarbon solvents
申请人:Saul Joseph Philip Simon
公开号:US20070128705A1
公开(公告)日:2007-06-07
A process for preparing a second compound stereo-selectively is described. The process comprises reacting a substrate comprising at least one first compound with a reagent in the presence of a biological catalyst and a solvent comprising at least one (hydro)fluorocarbon so as to convert a first compound into the second compound.
METHOD OF ENCAPSULATING A NUCLEIC ACID IN A LIPID NANOPARTICLE HOST
申请人:BOWMAN Keith A.
公开号:US20170196809A1
公开(公告)日:2017-07-13
Encapsulated nucleic acid nanoparticles of uniformly small particle size are produced by intersecting one or more nucleic acid streams with one or more lipid streams. The encapsulated nucleic acid nanoparticles include a nucleic acid encapsulated within a lipid nanoparticle host. Uniformly small particle sizes are obtained by intersecting an aqueous nucleic acid stream and a stream of lipids in organic solvent at high linear velocities and with total organic solvent concentrations less than 33%.