25856-12-6Relevant academic research and scientific papers
Green preparation method of isoxazole compound participating in water-soluble vitamin E
-
Paragraph 0097-0101, (2021/11/03)
The invention provides a green synthesis method of an isoxazole compound represented by the formula (III), wherein the aldehyde oxime compound represented by the formula (I) is a substrate and is in an aqueous solution of a surfactant with a mass concentration 1 wt % - 5 wt % in N - chlorosuccinimide. The alkyne compound represented by the formula (II) is reacted 6 - 16h at room temperature under the common action of the basic substance, and the resulting reaction solution is post-treated to obtain the isoxazole compound represented by the formula (III). Water serves as a reaction solvent, the use amount of the organic solvent is reduced, and zero emission of the solvent is realized.
Unusual Reactivity of 4-Vinyl Isoxazoles in the Copper-Mediated Synthesis of Pyridines, Employing DMSO as a One-Carbon Surrogate
Kumar, Pravin,Kapur, Manmohan
, p. 5855 - 5860 (2020/07/30)
An efficient protocol for the synthesis of nicotinate derivatives and tetrasubstituted pyridines through a copper-mediated cleavage of isoxazoles has been developed. The highlight of the work is the observation of an unusual reactivity of 4-vinyl isoxazoles under the reaction conditions. DMSO serves as a one-carbon surrogate generating an active methylene group during the reaction to form two C-C bonds. This protocol provides a facile and an expeditious approach for the assembly of densely substituted N-heterocyclic compounds.
Catalyst control in positional-selective C-H alkenylation of isoxazoles and a ruthenium-mediated assembly of trisubstituted pyrroles
Kumar, Pravin,Kapur, Manmohan
, p. 2134 - 2138 (2019/03/26)
High levels of catalyst control are demonstrated in determining the positional selectivity in C-H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C-H alkenylation product via ruthenium and copper co-catalysis leads to an efficient method for the assembly of densely substituted pyrroles.
Complementary regioselective synthesis of 3,5-disubstituted isoxazoles from ynones
Liu, Xiaochen,Hong, Dongsub,She, Zhigang,Hersh, William H.,Yoo, Barney,Chen, Yu
, p. 6593 - 6606 (2018/10/05)
Two regioselective synthetic routes towards 3,5-disubstituted isoxazoles from ynones are reported. One route takes place via first converting the ynones to ynone O-methyl oximes, followed by a palladium-catalyzed intramolecular cyclization. The other invo
Direct synthesis of 4-fluoroisoxazoles through gold-catalyzed cascade cyclization-fluorination of 2-alkynone O-methyl oximes
Jeong, Yunkyung,Kim, Bom-I,Lee, Jae Kyun,Ryu, Jae-Sang
, p. 6444 - 6455 (2014/08/05)
A tandem protocol for the synthesis of fluorinated isoxazoles has been developed via catalytic intramolecular cyclizations of 2-alkynone O-methyl oximes and ensuing fluorination. The reactions proceed smoothly at room temperature in the presence of 5 mol
Cyclometallated gold(III) complexes as effective catalysts for synthesis of propargylic amines, chiral allenes and isoxazoles
Kung, Karen Ka-Yan,Lo, Vanessa Kar-Yan,Ko, Hok-Ming,Li, Gai-Li,Chan, Pui-Ying,Leung, King-Chi,Zhou, Zhongyuan,Wang, Ming-Zhong,Che, Chi-Ming,Wong, Man-Kin
, p. 2055 - 2070 (2013/08/23)
A series of cyclometallated gold(III) complexes [Au(CN)Cl2] 1a-l (HCN=arylpyridines) and a PEG-linked complex 1m were synthesized. Complexes 1a-m are effective in catalyzing the synthesis of propargylic amines, chiral allenes and isoxazoles. Six-membered ring cyclometallated gold(III) complexes 1f-l exhibited higher catalytic activity than five-membered ring cyclometallated gold(III) complexes 1a-e. The diastereoselectivity of propargylic amines could be tuned by using chiral aldehyde and/or amine substrates. Excellent enantioselectivities (90-98% ee) were achieved in chiral allene synthesis. Chiral allene racemization could be minimized by using 1f as catalyst. The PEG-linked catalyst 1m is the most catalytically active towards synthesis of propargylic amines, in which case a product turnover of 900 was achieved. Moreover, 1m could be repeatedly used for 12 reaction cycles, leading to an overall turnover number of 872. Copyright
