- Electrochemical oxidative cyclization of: N -allylcarboxamides: Efficient synthesis of halogenated oxazolines
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Herein, we reported an efficient and sustainable intramolecular electrochemical cyclization of N-allylcarboxamides for the synthesis of various halogenated oxazolines. This method was conducted in a simple undivided cell by employing lithium halogen salts
- He, Yanyang,Liu, Chenwei,Wu, Xiao-Feng,Yin, Yanzhao,Yin, Zhiping
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supporting information
p. 663 - 667
(2022/01/22)
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- Electrochemical intramolecular haloheterocyclization reactions using 1,2-dihaloethanes as halogenating reagents
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Electrochemistry has a lot of inherent advantages in organic synthesis and many cyclization reactions have been achieved under electrochemical conditions. However, the electrochemical intramolecular haloheterocyclization of N-alkenylamides using bulk and common chemicals such as 1,2-dihaloethanes as halogenating reagents are less studied. Herein, we have developed an electrochemical intramolecular haloheterocyclization of N-alkenylamides to prepare 2-oxazolines, 2-thiazolines, 1,3-oxazines and isoxazolines using readily available 1,2-dihaloethanes as halogenating reagents. This protocol is a convergent strategy integrating several reactions, such as N-alkenylamide chlorooxygenation, chlorosulfuration, bromooxygenation and bromosulfuration. The reaction avoids the use of catalysts, reductants, oxidants, metal salts and iodine reagents, which makes it more sustainable and renewable.
- Gu, Li-Jun,Li, Ming,Li, Xiangguang,Liu, Yang,Zhang, Chi,Zhao, Na,Zhou, Ya-Qin
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supporting information
(2021/12/30)
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- CuBr2-promoted intramolecular bromocyclization of N-allylamides and aryl allyl ketone oximes
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A new and easy-to-perform route to 2-oxazolines amd isoxazolines was reported. Using CuBr2 as both the bromide source and the reaction promoter, bromocyclization of N-allylamides and allyl ketone oximes proceeded readily, leading to oxazolines
- Yang, Chun-Hua,Xu, Zhong-Qi,Duan, Lili,Li, Yue-Ming
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p. 6747 - 6753
(2017/10/26)
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- Synthesis of oxazolines and oxazines
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A process of preparing an oxazoline or oxazine compound of the formula STR1 wherein X is an atom selected from the group of oxygen and sulfur, R is selected from the group consisting of C1-10 alkyl, C1-10 fluoroalkyl, aryl and substituted-aryl, and n is 2 or 3 comprising ring-closing a compound of the formula STR2 wherein X is an atom selected from the group of oxygen and sulfur, R is selected from the group consisting of C1-10 alkyl, C1-10 fluoroalkyl, aryl, and substituted aryl, n is 2 or 3, and Y is a bromine or chlorine atom in the presence of a basic reagent consisting essentially of a fluoride salt supported on an inorganic solid substrate is disclosed together with the compounds, 5-bromomethyl-2-phenyl-1,3-oxazoline, 5-methylene-2-phenyl-1,3-oxazine and 4,4-dimethyl-2-vinyl-1,3-oxazoline.
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- Synthesis of Δ2-1,3-oxazolines and Δ2-1,3-oxazines using potassium fluoride on alumina
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Potassium fluoride (40%) on alumina was used as a basic reagent for the ring closure of N-(β- or γ-haloalkyl)amides to give Δ2-1,3-oxazolines and Δ2-1,3-oxazines, respectively. Various 2-alkyl and 2-aryl derivatives were synthesized in moderate to high yield under relatively mild conditions (KF/Al2O3, solvent, room temperature). The procedure also facilitated simple workup and purification of the products. New compounds synthesized by this method are: 5-bromomethyl-2-phenyl-Δ2-1,3-oxazoline, 4,4-dimethyl-2-vinyl-Δ2-1,3-oxazoline, and 5-methylene-2-phenyl-Δ2-1,3-oxazine. The last compound represents the first authentic example of a 5-functionally substituted oxazine without substitution in the 4- or the 6-position.
- Mitchell,Benicewicz
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p. 675 - 677
(2007/10/02)
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