Microwave-Assisted Synthesis of 2-Aryl-2-oxazolines, 5,6-Dihydro-4<i>H</i>-1,3-oxazines, and 4,5,6,7-Tetrahydro-1,3-oxazepines
作者:María C. Mollo、Liliana R. Orelli
DOI:10.1021/acs.orglett.6b03122
日期:2016.12.2
general procedure for the synthesis of 5- to 7-membered cyclic iminoethers by microwave-assisted cyclization of ω-amido alcohols promoted by polyphosphoric acid (PPA) esters is presented. 2-Aryl-2-oxazolines and 5,6-dihydro-4H-1,3-oxazines were efficiently prepared using ethyl polyphosphate/CHCl3. Trimethylsilyl polyphosphate in solvent-free conditions allowed for the synthesis of hitherto-unreported
提出了通过微波辅助多磷酸(PPA)酯促进的ω-氨基醇的环化反应合成5至7元环亚氨基醚的第一个通用程序。使用聚磷酸乙酯/ CHCl 3有效地制备了2-芳基-2-恶唑啉和5,6-二氢-4 H -1,3-恶嗪。在无溶剂条件下,多磷酸三甲基甲硅烷基酯可合成迄今未报道的4,5,6,7-四氢-1,3-氧杂氮杂pine。该方法具有良好的收率和优异的收率,并且反应时间短。在手性底物中研究了PPA酯的反应机理和作用。
PROCESS FOR PREPARING HETEROCYCLES
申请人:KUEBELBAECK Thomas
公开号:US20100076186A1
公开(公告)日:2010-03-25
Provided is a process for preparing a heterocycle by catalytic reaction of an aromatic dinitrile with an amino alcohol, wherein the process includes: initially charging into a reaction vessel the amino alcohol and a catalyst to produce a reaction mixture; adding the aromatic dinitrile into the reaction mixture, which is maintained at a reaction temperature, wherein no solvent other than the amino alcohol of formula (III) is added to the reaction mixture prior to and/or during the catalytic reaction; and after completion of the catalytic reaction, completely replacing, or substantially completely replacing, unreacted amino alcohol with a nonpolar solvent to obtain the heterocycle, wherein the unreacted amino alcohol is present in an amount of not more than 20 wt. %, preferably 3-10 wt. % or less, based on a total weight of the heterocycle.
The use of phosphonium anhydrides for the synthesis of 2-oxazolines, 2-thiazolines and 2-dihydrooxazine under mild conditions
作者:Maria J. Petersson、Ian D. Jenkins、Wendy A. Loughlin
DOI:10.1039/b818310d
日期:——
β-Hydroxy amides6 and 7 were treated with triphenylphosphonium anhydride trifluoromethane sulfonate (3), or the cyclic analogue 4, to generate 2-oxazolines 5 and 8 under mild conditions. The reaction was optimised by examining the number of equivalents of reagents 3 or 4, or diisopropylethyl amine required to best effect cyclisation. The effects of altering the reaction temperature, reaction time,
The preparation of 2-oxazolines and related N-containing heterocycles from the corresponding hydroxyamides using XtalFluor-E ([Et2NSF2]BF4) as a cyclodehydration agent is described. A wide range of heterocycles are obtained under mild conditions in good to excellent yields. (C) 2012 Elsevier Ltd. All rights reserved.