- Iodine-mediated new strategy for the synthesis of 2,5-disubstituted oxazoles from methyl ketones and TosMIC
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A new strategy has been developed for the construction of oxazoles from methyl ketones and TosMIC via self-sorting oxidative domino reaction strategy. In contrast to its usual reactivity as C–N≡C synthon in the synthesis of oxazoles, TosMIC was utilized as ammonium surrogate in the present method. The protocol is attractive in terms of readily available starting materials, metal and base free conditions, operational simplicity, C–N and C–O bond formation. A variety of 2,5-disubstituted oxazoles were prepared in moderate-to-good yields.
- Pogaku, Naresh,Krishna, Palakodety Radha,Prapurna, Y. Lakshmi
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- Dimerization of Phenylalanine: An Approach to Thiazoles and Oxazoles Involved S/O-Insertion
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We herein describe the development of a dimerization procedure for amino acids to prepare 2,5-disubstituted thiazoles and oxazoles in the presence of Na2S?9H2O and H2O, respectively. These approaches enabled the direct formation of five-membered ring systems bearing two different heteroatoms from two amino acid units. Mechanically, decarboxylation, deamination, S/O insertion, cyclization and gradient oxidation processes were involved in the oligomer formation. (Figure presented.).
- Cheng, Yan,Xiang, Jia-Chen,Wang, Zi-Xuan,Ma, Jin-Tian,Wang, Miao,Tang, Bo-Cheng,Wu, Yan-Dong,Zhu, Yan-Ping,Wu, An-Xin
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- Synthesis of 2,5-diaryloxazoles through rhodium-catalyzed annulation of triazoles and aldehydes
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An efficient synthesis of a variety of 2,5-diaryloxazole derivatives via a rhodium-catalyzed annulation of triazoles and aldehydes is achieved. Various oxazole derivatives could be obtained in good to excellent yields. A concise synthesis of antimycobaterial natural products balsoxin and texamine has been achieved using this method. This journal is
- Li, Jian,Liu, Li,Lu, Xue-Chen,Wang, Zheng-Bing,Xu, De-Feng,Xu, Yue,Zhu, Shang-Rong
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p. 24795 - 24799
(2020/07/14)
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- Catalytic C?H/C?F Coupling of Azoles and Acyl Fluorides
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A method for the palladium/copper-catalyzed direct acylation of azoles with acyl fluorides is described. This study reports the first examples of acyl fluorides being used as acylation reagents in transition-metal-catalyzed aromatic C?H bond functionalization reactions. Depending on the reaction temperature, decarbonylative coupling may also occur. Mechanistic studies suggest that the cleavage of the aromatic C?H bond, promoted by a copper-phosphine species, is not the rate-limiting step of this acylation.
- Ogiwara, Yohei,Iino, Yurika,Sakai, Norio
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p. 6513 - 6516
(2019/04/27)
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- Selective synthesis of oxazoles and pyrazines from α-bromo-1-phenylethanone using a by-product-promoted strategy
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Oxazoles and pyrazines are fundamental heterocycles that widely found in natural products or drugs. In this work, a selective strategy for oxazoles and pyrazines synthesis using α-bromo-1-phenylethanone and ammonium acetate as starting materials was reported. This methodology features mild reaction conditions, readily accessible starting materials and good chemoselectivity. Mechanistic study indicates that this reaction involves a by-product-promoted (BPP) process for the formation of oxazole, that is, the in-situ formed hydrogen bromide (HBr) during the reaction promotes the whole tandem process.
- Liu, Changhui,Zhao, Jiateng,Qiao, Yu,Huang, Wenbo,Rao, Zhonghao,Gu, Yanlong
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p. 7351 - 7357
(2018/11/23)
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- The new method of the preparation of oxazole derivatives
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The invention particularly relates to a method for synthesizing oxazole derivative, belonging to the field of synthesis of heterocyclic compounds. The technical scheme is as follows: the method comprises the following steps: reacting the raw material tosyl methyl isonitrile derivative disclosed as Formula (I) with acyl chloride disclosed as Formula (II) to obtain alpha-ketoimine chloride disclosed as Formula (III); and reacting the intermediate alpha-ketoimine chloride disclosed as Formula (III) with aldehyde (IV) in the presence of a protonic solvent and alkali to obtain 2-substituted oxazole (V). Compared with the prior art, the method uses cheap and accessible raw materials, avoids using the catalyst, lowers the cost, reduces the environmental pollution, has the advantage of mild reaction conditions, and is simple to operate and beneficial to industrial production.
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Paragraph 0058; 0059; 0060
(2017/08/25)
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- Metal-Free sp3 C-H Functionalization: PABS/I2-Promoted Synthesis of Polysubstituted Oxazole Derivatives from Arylethanones and 2-Amino-2-alkyl/arylacetic Acid
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A nonmetal-catalyzed process for the synthesis of polysubstituted oxazoles from inexpensive and readily available α-amino acids and methyl ketones is established. This reaction is proposed to achieve oxidative cleavage of C(sp3)-H bonds, followed by decarboxylation and annulation. The mild reaction conditions employed in both cases enable the tolerance of a wide range of functional groups as well as high reaction efficiency.
- Hu, Ting,Yan, Hao,Liu, Xingxing,Wu, Chaoyang,Fan, Yuxing,Huang, Jing,Huang, Guosheng
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supporting information
p. 2866 - 2869
(2015/12/18)
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- Pd-Catalyzed Csp2-H Functionalization of Heteroarenes via Isocyanide Insertion: Concise Synthesis of Di-(Hetero)Aryl Ketones and Di-(Hetero)Aryl Alkylamines
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We report herein an efficient Pd-catalyzed direct C-H bond functionalization of heteroarenes via an isocyanide insertion strategy for the synthesis of di-(hetero)aryl ketones and di-(hetero)aryl alkylamines. The methodology involves a three component reaction between an azole, a haloarene and an isocyanide resulting in the formation of an imine, which in turn is either hydrolyzed or reduced to get the desired product.
- Sharma, Upendra K.,Sharma, Nandini,Xu, Jun,Song, Gonghua,Van Der Eycken, Erik V.
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supporting information
p. 4908 - 4912
(2015/03/30)
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- One-pot total synthesis of streptindole, arsindoline B and their congeners through tandem decarboxylative deaminative dual-coupling reaction of amino acids with indoles
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This paper described a decarboxylative deaminative dual-coupling reaction of amino acids with indoles to afford BIM scaffolds and its further application to the one-pot total synthesis of natural products. This method featured a stimulating example of activating amino acids in one pot as multi-carbon building blocks for transformation into final targets which are equipped with amino acid side chain backbones. This journal is
- Xiang, Jiachen,Wang, Jungang,Wang, Miao,Meng, Xianggao,Wu, Anxin
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supporting information
p. 4240 - 4247
(2015/04/14)
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- Nickel-catalyzed decarboxylative acylation of heteroarenes by sp 2 C-H functionalization
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Nickel-catalyzed ligand-free decarboxylative cross-coupling of azole derivatives with α-oxoglyoxylic acids has been developed. This work represents the first example of decarboxylative cross-coupling reactions, in a C-H bond functionalization manner, thro
- Yang, Ke,Zhang, Cheng,Wang, Peng,Zhang, Yan,Ge, Haibo
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p. 7241 - 7244
(2014/06/23)
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- DMAP-catalyzed regel-type direct C-2 (Hetero)aroylation of oxazoles and thiazoles derivatives with acid chlorides
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A Regel-type transition-metal-free direct C-2 aroylation of (benzo)oxazoles, (benzo)thiazoles and 1,3,4-oxadiazoles with acid chlorides catalyzed by N,N-dimethyl-4-aminopyridine (DMAP) is described. This methodology is effective with several aroyl and het
- Lassalas, Pierrik,Marsais, Francis,Hoarau, Christophe
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p. 2233 - 2240
(2013/11/06)
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- Direct synthesis of 2,5-disubstituted oxazoles through an iodine-catalyzed decarboxylative domino reaction
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An efficient iodine-catalyzed synthesis of highly substituted oxazoles is presented. Starting from readily available aryl methyl ketones, β-keto esters, or styrenes, in combination with α-amino acids as amine-containing coupling partners, the corresponding 2-alkyl-5-aryl- substituted oxazoles were obtained in up to 80% yield via a decarboxylative domino reaction.
- Xu, Wei,Kloeckner, Ulrich,Nachtsheim, Boris J.
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p. 6065 - 6074
(2013/07/26)
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- Reactions of arylglyoxals with tetrasulfur tetranitrides (S4N4): Formation of 2-aroyl-5-arylimidazoles and 2-aroyl-5- aryloxazoles
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Treatment of arylglyoxal monohydrates with tetrasulfur tetranitride in p-dioxane at reflux afforded 2-aroyl-5- arylimidizoles and 2-aroyl-5-aryloxazoles in 10 to 31% and 17 to 32% yields, respectively. With non-hydrate of arylglyoxals, yields of the latter increase somewhat, whereas essentially no changes in yields of the former were observed. A mechanism is proposed for the formation of the products.
- Kong, Yung Cheol,Kim, Kyongtae
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p. 911 - 915
(2007/10/03)
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- Acylation of oxazoles by the copper-mediated reaction of oxazol-2-ylzinc chloride derivatives
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C-2 acylation of oxazole derivatives is accomplished by reaction of oxazol-2-ylzinc chloride reagents with acid chlorides in the presence of cuprous iodide. O-acylated vinylisonitriles, which are the sole product from the corresponding reaction employing
- Harn, Nancy K.,Gramer, Christine J.,Anderson, Benjamin A.
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p. 9453 - 9456
(2007/10/02)
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- Synthesis and Carbodemetalation Reactions of 4-Methyl- and 5-Aryl-2-(trimethylsilyl)oxazoles. C-C Bond Formation at C2 of the Oxazole Ring
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The title compounds 6a-d have been prepared by sequential lithiation and silylation of the corresponding 2-H oxazoles and isomerization of the resulting α-isocyano silyl enol ethers.Silyloxazoles 6a-d behave as stable 2-oxazolyl anion equivalents toward v
- Dondoni, Alessandro,Fantin, Giancarlo,Fogagnolo, Marco,Medici, Alessandro,Pedrini, Paola
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p. 3413 - 3420
(2007/10/02)
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