Synthesis of 3,5-disubstituted-1,2,4-oxadiazoles using tetrabutylammonium fluoride as a mild and efficient catalyst
作者:Anthony R Gangloff、Joane Litvak、Emma J Shelton、David Sperandio、Vivian R Wang、Kenneth D Rice
DOI:10.1016/s0040-4039(00)02288-7
日期:2001.2
Tetrabutylammonium fluoride (TBAF) was found to be a mild and efficient catalyst for the synthesis of 3,5-disubstituted-1,2,4-oxadiazoles. Using 0.1–1.0 equivalents of TBAF in THF for 1–24 h at room temperature, alkanoyl- and aroyloxyamidines were converted in high yield to the corresponding 3,5-disubstituted-1,2,4-oxadiazoles. A variety of R and R′ substituents were investigated.
Formation and thermal reaction of O-(N-acetylbenzimidoyl)benzamidoxime: comparison with the formation of 3,5-disubstituted 1,2,4-oxadiazoles from O-acetylarylamidoximes and O-aroylacetamidoximes
作者:Ngan Sim Ooi、David A. Wilson
DOI:10.1039/p29800001792
日期:——
Acetylation of the free base gave the title compound, which underwent a thermalcyclisation, with loss of acetamide, to give 3,5-diphenyl-1,2,4-oxadiazole. The mechanism of this reaction, in diphenyl ether, closely paralleled the thermalcyclisation of O-acetylarylamidoximes and O-aroylacetamidoximes, and is thought to involve a polar cyclisation step followed by rate-determining proton transfer. 13C N.m.r.
通过N-氯-或N-溴-琥珀酰亚胺或卤素在苯甲酰胺肟上的作用,获得了O-(苯甲酰亚胺基)苯甲酰胺肟的盐。游离碱的乙酰化得到标题化合物,将其进行热环化,损失乙酰胺,得到3,5-二苯基-1,2,4-恶二唑。在二苯醚中,该反应的机理与O-乙酰基芳酰胺肟和O-芳酰基乙酰氨基肟的热环化非常相似,并且被认为涉及极性环化步骤,随后是速率确定质子转移。记录了32种肟,a胺肟和恶二唑衍生物的13 C Nmr光谱,并记录了肟,a胺肟的取代基化学位移,计算苯环上的O-乙酰基酰胺肟,5-甲基-1,2,4-恶二唑-3-基和3-甲基-1,2,4-恶二唑-5-基。
Construction of 3,5-substituted 1,2,4-oxadiazole rings triggered by tetrabutylammonium hydroxide: a highly efficient and fluoride-free ring closure reaction of O-acylamidoximes
Tetrabutylammonium hydroxide (TBAH) is an efficient and mild alternative to tetrabutylammonium fluoride (TBAF) for base catalyzed cyclizations of 1,2,4-oxadiazoles from O-acylamidoximes. For most 3,5-substituted 1,2,4-oxadiazoles the reactions were dramatically accelerated by addition of 0.1 equiv of TBAH at room temperature. This method was also more generally applicable allowing for a wider range
exhibited outstanding GPX4 inhibitory activity with a percent inhibition up to 71.7% at 1.0 μM compared to 45.9% of RSL-3. At the cellular level, 26a could significantly induce lipid peroxide (LPO) increase and effectively induce ferroptosis with satisfactory selectivity (the value of 31.5). The morphological analysis confirmed the ferroptosis induced by 26a. Furthermore, 26a significantly restrained tumor
Compounds according to Formula (I) below:
wherein R
1
, R
2
, R
3
, and R
4
are as defined in the specification, pharmaceutically-acceptable salts, methods of making, pharmaceutical compositions containing and methods for using the same.