One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones
摘要:
[GRAPHICS]The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.
Green Organocatalytic Synthesis of Isoxazolines via a One-Pot Oxidation of Allyloximes
作者:Ierasia Triandafillidi、Christoforos G. Kokotos
DOI:10.1021/acs.orglett.6b03380
日期:2017.1.6
A green, sustainable, organocatalytic, and efficient synthesis of isoxazolines from allyloximes was developed. A 2,2,2-trifluoroacetophenone-catalyzed oxidation of allyloximes, utilizing H2O2 as the green oxidant, was taken advantage of in order to introduce a cheap and environmentally friendly protocol for the synthesis of substituted isoxazolines. A variety of substitution patterns, both aromatic
从烯丙基肟开发了一种绿色,可持续,有机催化和高效的异恶唑啉合成方法。利用H 2 O 2作为绿色氧化剂,利用2,2,2-三氟苯乙酮催化的烯丙基肟的氧化反应,以引入廉价且环境友好的方法合成取代的异恶唑啉。芳香族和脂肪族部分的各种取代方式都具有良好的耐受性,从而导致异恶唑啉的产率中等至优异。
Synthesis of 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines by one-pot-cyclization of dilithiated oximes with epibromohydrin
作者:Uwe Albrecht、Katrin Gerwien、Peter Langer
DOI:10.1016/j.tetlet.2004.12.031
日期:2005.2
6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines were regioselectively prepared by one-pot cyclization of dilithiated oximes with epibromohydrin. (C) 2004 Elsevier Ltd. All rights reserved.