Knoevenagel type condensation of 4-unsubstituted isoxazolinones with ketones or aldehydes followed by Michael addition of a nucleophile — hydride, cyanide, or phosphite— and exposure of the adduct to sodium nitrite/aqueous acetic acid and ferrous sulfate gives variously functionalised alkynes.
Iodine-catalyzed synthesis of sulfonyl isoxazoles from sodium sulfinates and isoxazol-5(4H)-ones
作者:Dong Tang、Zafar Iqbal、Jian Sun、Jingwen Ji、Minghua Yang、Zhixiang Yang
DOI:10.1016/j.tetlet.2020.152685
日期:2021.1
An efficient I2-mediated sulfonylation at 4-position of isoxazoles has been developed by employing sodium sulfinate and 3-substituted isoxazol-5(4H)-ones. This metal-free, one-pot strategy provides various sulfonyl isoxazoles under mild reaction conditions. The final product exists in the form of stable organic sodium salt, which can be purified by column chromatography under air.
Non-Decarboxylative Ruthenium-Catalyzed Rearrangement of 4-Alkylidene-isoxazol-5-ones to Pyrazole- and Isoxazole-4-carboxylic Acids
作者:Camilla Loro、Letizia Molteni、Marta Papis、Leonardo Lo Presti、Francesca Foschi、Egle M. Beccalli、Gianluigi Broggini
DOI:10.1021/acs.orglett.2c01135
日期:2022.4.29
any additive, afforded pyrazole- and isoxazole-4-carboxylic acids, respectively. The presence of an intramolecular H-bond in these substrates was the key to divert the classical mechanism toward a ring-opening non-decarboxylative path that is expected to generate a vinyl Ru-nitrenoid intermediate, the cyclization of which affords the rearranged products. A gram scale protocol demonstrated the synthetic
在没有任何添加剂的情况下,用催化量的[RuCl 2 ( p-伞花烯)] 2处理4-(2-氢氨基亚烷基)-和4-(2-羟基亚烷基)-取代的异恶唑-5(4 H )-酮,得到吡唑-和异恶唑-4-羧酸,分别。这些底物中分子内氢键的存在是将经典机制转向开环非脱羧途径的关键,预计会产生乙烯基Ru-氮烯类中间体,其环化提供重排产物。克级方案证明了这种转化的综合适用性。
Cp*Rh(III)‐Catalyzed Divergent Synthesis of N‐Heterocycles with N‐Methoxyindoleamides and Isoxazolones
pyrimido[1,2-a]indol-4-ol heteroarenes via a Cp*Rh(III)-catalyzed cascade C−Hactivation/annulation strategy employing N-methoxyindoleamides and isoxazolones is developed. Also, a framework of 3-methoxy-2,3-dihydro-[1,3,5]triazino[1,2-a]indole-4,10-dione was successfully synthesized via a Cp*Rh-catalyzedC−Hactivation/annulation/oxidation reaction between N-(methyloxy)-1H-indole-1-carboxamide and isoxazolones