- Palladium-catalyzed cross coupling reactions of oxazol-2-ylzinc chloride derivatives
-
Oxazol-2-ylzinc chloride derivatives were prepared by transmetallation of the corresponding oxazol-2-yllithium species. The palladium-catalyzed cross coupling reactions of the resulting organometallic reagents were investigated with aryl halides and organotriflates.
- Anderson, Benjamin A.,Harn, Nancy K.
-
-
Read Online
- A 2, 5 - diaryl five-membered heterocyclic aromatic preparation method
-
The invention relates to a 2, 5 - diaryl five-membered heterocyclic aromatic preparation method, the method is to turn the diaryl Iodized salt compounds, five-membered heterocyclic aromatic compound, catalyst, ligand, alkali and solvent are mixed uniformly, in 100 °C -140 °C lower sealing reaction for 24 hours, the reaction solution obtained after the reaction is complete; the reaction solution are often gauge extraction, drying, concentration, column chromatography separation to obtain the 2, 5 - diaryl five-membered heterocyclic aromatic compounds. The invention belongs to a pot of reaction of the atom economy, simple operation, high yield, can realize the large-scale production, in functional organic material, biological active compounds and pharmaceutical synthesis of better industrial application prospect.
- -
-
Paragraph 0068; 0069; 0070
(2019/05/15)
-
- Divergent Conversion of N-Acyl-isoxazol-5(2 H)-ones to Oxazoles and 1,3-Oxazin-6-ones Using Photoredox Catalysis
-
The fragmentation of N-acyl-isoxazol-5-ones using visible light photoredox catalysis has been disclosed. The catalyst-controlled divergent mechanisms, namely the oxidative and reductive quenching catalytic cycle, are utilized. Various oxazoles and 1,3-oxazin-6-ones are selectively obtained from the same isoxazol-5-one skeleton under mild conditions.
- Mei, Mingjing,Anand, Devireddy,Zhou, Lei
-
supporting information
p. 3548 - 3553
(2019/05/24)
-
- Synthesis of 2,5-disubstituted oxazoles: Via cobalt(III)-catalyzed cross-coupling of N -pivaloyloxyamides and alkynes
-
An efficient synthesis of 2,5-disubstituted oxazoles via Co(iii) catalysis is described herein. The synthesis is achieved under mild conditions through [3+2] cycloaddition of N-pivaloyloxyamides and alkynes. The reaction operates through an internal oxidation pathway and features a very broad substrate scope. The one-step synthesis of natural products such as texamine and balsoxin has been demonstrated via this protocol.
- Yu, Xiaolong,Chen, Kehao,Wang, Qi,Zhang, Wenjing,Zhu, Jin
-
supporting information
p. 1197 - 1200
(2018/02/09)
-
- Nickel-catalyzed C?H arylation of benzoxazoles and oxazoles: Benchmarking the influence of electronic, steric and leaving group variations in phenolic electrophiles
-
Electronic, steric and leaving group effects for Ni-catalyzed direct arylations using C?O electrophiles were benchmarked. The scope of arylations with pivalates was general with respect to both the electronics on the electrophile and the azoles. Furthermore, the arylation of azoles with tosylates, mesylates and carbamates with varying electronics was explored, and showed electronic trends similar to those of the pivalate reactions. Finally, the relative rate of arylation of 5-methyl benzoxazole with two electronically-similar electrophiles bearing different leaving groups was established. The results from these studies implicate the following order of relative reactivity: mesylates>pivalates>carbamates.
- Steinberg, Deborah F.,Turk, Morgan C.,Kalyani, Dipannita
-
supporting information
p. 2196 - 2209
(2017/03/24)
-
- Synthesis of Substituted Oxazoles by Visible-Light Photocatalysis
-
A simple and practical method for the synthesis of substituted oxazoles has been developed using readily available α-bromoketones and benzylamines by visible-light photocatalysis at room temperature. The process, which requires 1 mol % of [Ru(bpy)3]Cl2 photocatalyst with K3PO4 and CCl3Br, is effective for accessing a variety of valuable oxazole compounds. The synthetic utility of our protocol was also demonstrated by preparing a natural product, texaline.
- Chatterjee, Tanmay,Cho, Ji Young,Cho, Eun Jin
-
p. 6995 - 7000
(2016/08/30)
-
- Direct C-H bond arylation of (benzo)oxazoles with aryl chlorides catalyzed by N-heterocyclic carbene-palladium(II)-1-methylimidazole complex
-
The direct C-H bond arylation of (benzo)oxazoles with aryl chlorides was achieved catalyzed by a well-defined NHC-Pd(II)-Im complex. Under the optimal conditions, various aryl chlorides were successfully applied as the arylating reagents to achieve the 2-aryl (benzo)oxazoles in acceptable to high yields, providing a convenient and alternative method for the direct C-H bond arylation of (benzo)oxazoles and enriching the chemistry of the NHC-Pd(II) complex in organic synthesis.
- Shen, Xiao-Bao,Zhang, Yun,Chen, Wen-Xin,Xiao, Zheng-Kang,Hu, Ting-Ting,Shao, Li-Xiong
-
supporting information
p. 1984 - 1987
(2014/05/06)
-
- Practical oxazole synthesis mediated by iodine from α-bromoketones and benzylamine derivatives
-
The reagent system of I2/K2CO3 could efficiently promote the oxazole synthesis from α-bromoketones and benzylamine derivatives in DMF. This method was not only suitable for 2,5-diaryl oxazole synthesis but also for 2,4,5-trisubstituted oxazole and 5-alkyl/alkenyl oxazole synthesis. Furthermore, this method was successfully applied to a one-step synthesis of a natural product halfordinol in 62% yield.
- Gao, Wen-Chao,Wang, Ruo-Lin,Zhang, Chi
-
p. 7123 - 7128
(2013/10/22)
-
- Synthesis of oxazoles through copper-mediated aerobic oxidative dehydrogenative annulation and oxygenation of aldehydes and amines
-
A fragment-assembling strategy is used to form oxazoles from aryl acetaldehydes, amines, and molecular oxygen under mild conditions (see scheme). The transformation is highly efficient with the removal of six hydrogen atoms, including the cleavage of four C(sp3)-H bonds. Copyright
- Xu, Zejun,Zhang, Chun,Jiao, Ning
-
supporting information
p. 11367 - 11370
(2013/01/15)
-
- Simple and efficient preparation of 2,5-disubstituted oxazoles via a metal-free-catalyzed cascade cyclization
-
A practical and simple synthesis of 2,5-disubstituted oxazoles was developed via an iodine-catalyzed tandem oxidative cyclization. A wide range of common commercial aromatic aldehydes can be used as reaction substrates, which displayed excellent functional group compatibility in this reaction.
- Wan, Changfeng,Gao, Linfeng,Wang, Qiang,Zhang, Jintang,Wang, Zhiyong
-
supporting information; experimental part
p. 3902 - 3905
(2010/11/04)
-
- Palladium-catalyzed direct arylations of heteroarenes with tosylates and mesylates
-
(Chemical Equation Presented) A toss up: A highly active palladium complex enabled the first direct arylation of heteroarenes through C-H bond functionalization using tosylates or mesylates as electrophiles with ample scope.
- Ackermann, Lutz,Althammer, Andreas,Fenner, Sabine
-
supporting information; experimental part
p. 201 - 204
(2009/04/10)
-
- Ligandless microwave-assisted Pd/Cu-catalyzed direct arylation of oxazoles
-
(Chemical Equation Presented) An efficient microwave-assisted palladium/copper co-mediated direct arylation of oxazoles with aryl bromides under ligandless conditions has been developed. The method is functional group tolerant and provides rapid access to medicinally relevant compounds in good yields. Coupled to the van Leusen oxazole ring synthesis, this methodology is illustrated by an expedient two-step synthesis of the four 2,5-diaryloxazole alkaloids texamine, texaline, balsoxin, and O-Me-halfordinol from commercially available starting materials.
- Besselievre, Francois,Mahuteau-Betzer, Florence,Grierson, David S.,Piguel, Sandrine
-
p. 3278 - 3280
(2008/09/19)
-
- 2,5-SUBSTITUTED OXAZOLE DERIVATIVES AS PROTEIN KINASE INHIBITORS FOR THE TREATMENT OF CANCER
-
Certain oxazole-based compounds exhibiting ATP-utilizing enzyme inhibitory activity, methods of using compounds exhibiting ATP-utilizing enzyme inhibitory activity, and compositions comprising compounds exhibiting ATP-utilizing enzyme inhibitory activity, are disclosed.
- -
-
Page/Page column 61; 64
(2010/11/29)
-
- Substituted Oxazoles: Synthesis via Lithio Intermediates
-
Reactions of 2-α-, 2-, 4-, and 5-lithiooxazoles are used to prepare various substituted derivatives.Previously unrecognized time dependence for the reaction of a 2-lithiooxazole with benzaldhyde is described, and a rationale for this behavior is offered.Competitive reactions occur when the readily available 2,5-diphenyloxazole is treated with n-butyllithium.Deprotonation of the ortho position of the 2-phenyl group and addition of n-butyl to the 2-position of the oxazole compete with the desired 4-lithiation.The use of sec-butyllithium/catalytic lithium tetramethylpiperidide allows preferential formation of 4-lithio-2,5-diphenyloxazole.This intermediate has been converted to the 4-bromo, -methyl, -hydroxybenzyl, -benzoyl, and -trialkylsilyl derivatives.Lithiation of 2,4-diphenyloxazole and subsequent trimethylsilylation occur readily at the 5-position.Deprotonation of 2-alkyloxazoles occurs at the α-carbon in preference to ring sites.Further reaction of an α-phenyl-2-oxazolemethanol methoxymethyl ether with base and acetyl chloride leads to an acyloin derivative.Chromic acid oxidation is used to prepare both 2- and 4-benzoyloxazoles.The formation of an 2-ethoxyoxazole from 2-oxazolone vis Meerwein salt chemistry is described.
- Whitney, Scott E.,Rickborn, Bruce
-
p. 3058 - 3063
(2007/10/02)
-