- Visible Light-Promoted Selenylation/Cyclization of Enaminones toward the Formation of 3-Selanyl-4H-Chromen-4-Ones
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A simple and efficient visible-light-promoted selenylation/cyclization of enaminones have been realized for the practical synthesis of 3-selanyl-4H-chromen-4-ones. This reaction is performed in the mild conditions, no transition metal catalyst or photocatalysts and no additional oxidants are required. In addition, the 3-selanyl-4H-chromen-4-ones could be easily converted to selanyl-functionalized pyrimidines by reacting with benzamidine substrates. (Figure presented.).
- Liu, Hao-Yang,Zhang, Jia-Rong,Huang, Guo-Bao,Zhou, Yi-Huan,Chen, Yan-Yan,Xu, Yan-Li
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supporting information
p. 1656 - 1661
(2021/02/12)
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- TBN-triggered, manipulable annulations of: O -hydroxyarylenaminones for divergent syntheses of oximinochromanones and oximinocoumaranones
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Divergent synthesis provides an indispensable route to rapid acquisition of structurally diverse chemical scaffolds from identical starting materials. Herein, we describe unprecedented divergent annulations of o-hydroxyarylenaminones promoted by tert-butyl nitrite (TBN) under mild conditions. Two different types of benzo-oxa-heterocycle, including oximinochromanones and oximinocoumaranones, were smoothly assembled with a broad substrate scope and good functional group compatibility.
- Chen, Kai,Qian, Yu-En,Xiang, Hao-Yue,Xiao, Jun-An,Yang, Hua,Zhao, Qing-Lan,Zheng, Lan
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supporting information
p. 12285 - 12288
(2021/12/07)
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- T3P mediated domino C(sp2)-H sulfenylation/annulation of enaminones and methylsulfinyls for the synthesis of chromone thioether derivatives
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A new regioselective method for the synthesis of 3-(methylthio)-4H-chromen-4-one and 3-(phenylthio)-4H-chromen-4-one derivatives has been developed. The reaction between o-hydroxy-phenyl-functionalized enaminones and methylsulfinyl derivatives using T3P gave good yields of chromone thioether derivatives. The reaction proceeds via domino chromone ring construction and C(sp2)-H bond sulfenylation under transition-metal-free conditions.
- Balakrishna,Gudipati, Ramakrishna,Kandula, Venu,Yennam, Satyanarayana,Uma Devi,Behera, Manoranjan
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supporting information
p. 2458 - 2463
(2019/02/14)
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- Zn(OTf)2-Catalyzed Formal [3 + 3] Cascade Annulation of Propargylic Alcohols with 2-Aminochromones: Accessing the Chromeno[2,3- b]pyridines
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A Zn(OTf)2-catalyzed formal [3 + 3] cascade annulation strategy for the synthesis of functionalized chromeno[2,3-b]pyridines has been developed using propargylic alcohols and 2-aminochromones as the substrates. The protocol provides a convenien
- Tong, Pei,Sun, Zhou,Wang, Shutao,Zhang, Yuan,Li, Ying
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p. 13967 - 13974
(2019/10/16)
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- Selectfluor-Mediated Tandem Cyclization of Enaminones for the Synthesis of 3-Fluorochromones
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An efficient synthesis of various 3-fluorochromones (3-fluoro-4 H -chromene-4-ones) from enamino ketones by using Selectfluor is described. The key step in the synthesis involves tandem fluorination and cyclization to form 3-fluorochromones in good yields. The significant features of this method include simple operational procedures, a high purity of the product, and excellent regioselectivity.
- Behera, Manoranjan,Chatterjee, Anindita,Kandula, Venu,Mallesham, Poosa,Raghavulu, K.,Thota, Pradeep Kumar,Yennam, Satyanarayana
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p. 2295 - 2299
(2019/12/11)
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- An Efficient Microwave-Assisted Propylphosphonic Anhydride (T3P )-Mediated One-Pot Chromone Synthesis via Enaminones
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An efficient synthesis of 4 H -chromene-4-ones via enamino ketones, with cyclization by using T3P under microwave heating is described. This is the first report for the synthesis of chromones by using T3P . Significant features of this method include short reaction times and high-purity products.
- Balakrishna,Kandula, Venu,Gudipati, Ramakrishna,Yennam, Satyanarayana,Devi, P. Uma,Behera, Manoranjan
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supporting information
p. 1087 - 1091
(2018/04/30)
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- Convenient and Rapid Synthesis of 3-Selenocyanato-4 H -chromen-4-ones
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A sequential one-pot, simple and convenient method is described for the synthesis of 3-selenocyanato-4 H -chromen-4-ones by addition, first of DMF-DMA and then of triselenodicyanide as electrophile.
- Kosso, Anne Roly Obah,Broggi, Julie,Redon, Sébastien,Vanelle, Patrice
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supporting information
p. 1215 - 1218
(2018/03/26)
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- Expedient chemoselective and catalyst-free synthesis of 3,3-difluorochroman-4-ones from o-hydroxyarylenaminones and Selectfluor
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An expedient and mild strategy for the synthesis of unconventional 2-(dimethylamino)-3,3-difluorochroman-4-one derivatives from o-hydroxyarylenaminones and Selectfluor was developed at room temperature under catalyst-free conditions. This method showed excellent chemoselectivity and great functional groups tolerance.
- Xu, Jian,Kuang, Zhijie,Song, Qiuling
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supporting information
p. 963 - 966
(2017/11/27)
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- Pot-economic synthesis of diarylpyrazoles and pyrimidines involving Pd-catalyzed cross-coupling of 3-trifloxychromone and triarylbismuth
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Abstract: The present study reveals the formation of 3,4-diarylpyrazole and 4,5-diarylpyrimidine in one-pot operation starting from 3-trifloxychromone and triarylbismuth. The complete process encompasses two steps in the one-pot operation. The first step leads to the formation of isoflavone via cross-coupling reaction of 3-trifloxychromone and triarylbismuth as a threefold arylating reagent. These isoflavones were further converted into 3,4-diarylpyrazole and 4,5-diarylpyrimidine using hydrazine hydrate and guanidinium chloride in the successive step in the same pot. Interestingly the formation of 3,4-diarylpyrazole was achieved in the shortest reaction time i.e., 30 min that too at room temperature. Overall the developed methodology provides easy access to the medicinally important diarylpyrazole and pyrimidine moiety in one-pot operation and in short reaction time. Graphical Abstract: Synopsis The work presented here describes the novel methodology for the formation of medicinally important heterocycles 3,4-diarylpyrazole and 4,5-diarylpyrimidine in one-pot operation starting from 3-trifloxychromone and triarylbismuth.
- Kumar, Abhijeet,Rao, Maddali L N
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- A facile strategy for accessing 3-alkynylchromones through gold-catalyzed alkynylation/cyclization of o-hydroxyarylenaminones
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A strategy based on tandem alkynylation of o-hydroxyarylenaminones followed by intramolecular cyclization has been developed to generate a diverse array of 3-alkynyl chromones. The functionality embedded in these key intermediates enables their facile elaboration into more diverse structures by a variety of functionalizations and ring-forming processes.
- Akram, Manjur O.,Bera, Saibal,Patil, Nitin T.
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supporting information
p. 12306 - 12309
(2016/10/22)
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- Synthesis of 3-thiophenchromone by stille cross-coupling palladium on charcoal-catalyzed ligand-free
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A new concise, facile, and efficient method for synthesis of 3-thiophenchromone was accomplished in more than over 80% yield starting from formation of the substituted 3-iodochromones and tetrathiophentins by Stille cross-coupling reaction in the presence of palladium on charcoal-catalyzed ligand-free under mild conditions.
- Yang, Qian,Zhang, Zunting,Liang, Bo
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p. 310 - 316
(2015/01/30)
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- A Convenient and Practical Synthesis of Aminopyrazoles
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A selective methodology for preparing highly substituted aminopyrazoles has been demonstrated. Starting with an acetophenol core, the corresponding substituted isoxazole is prepared in two steps. The isoxazole is transformed into a benzopyran. Alkylation
- Mitchell, David,Luo, Yumei,Mcnulty, Lu Anne M.,Buser, Jonas Y.,Mcfarland, Adam D.
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supporting information
p. 235 - 241
(2015/05/05)
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- Synthesis of novel disubstituted pyrazolo[1,5-a]pyrimidines, imidazo[1,2-a]pyrimidines, and pyrimido[1,2-a]benzimidazolescontaining thioether and aryl moieties
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A series of novel 6-[(1,3,4-thiadiazol-2-yl)sulfanyl]-7-phenylpyrazolo[1,5- a]pyrimidines, 5-phenyl-6-[(1,3,4-thiadiazol-2-yl)sulfanyl]imidazo[1,2-a] pyrimidines, and 2-phenyl-3-[(1,3,4-thiadiazol-2-yl)sulfanyl] pyrimido[1,2-a]benzimidazoles have been synthesized in four steps starting with 2-hydroxyacetophenone. The intermediate 3-[(1,3,4-thiadiazol-2-yl)sulfanyl]-4H- 1-benzopyran-4-ones reacted with pyrazol-3-amines, 5-methylpyrazol-3-amine, and 1H-imidazol-2-amine, 1H-benzimidazol-2-amine via a cyclocondensation to give the title compounds in the presence of MeONa as base, respectively. The approach affords the target compounds in acceptable-to-good yields. The new compounds were characterized by their IR, NMR, and HR mass spectra.
- Li, Gang,Zhang, Zun-Ting,Dai, Li-Yan,Du, Yin-Li,Xue, Dong
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experimental part
p. 989 - 997
(2012/08/08)
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