1218-82-2Relevant academic research and scientific papers
Metal-Free, DBU-Mediated, Microwave-Assisted Synthesis of Benzo[c]xanthones by Tandem Reactions of Alkynyl-1,3-diketones
Liang, Yi-En,D. Barve, Balaji,Kuo, Yao-Haur,Fang, Hsu-Wei,Kuo, Ting-Shen,Li, Wen-Tai
, p. 505 - 511 (2020/12/01)
A base-mediated, green, microwave-assisted efficient preparation of a diverse benzoxanthone library from variety of readily accessible γ-alkynyl 1,3-diketones is reported. The synthesis is based on tandem reactions involving intramolecular cyclization, propargyl-allenyl isomerization, and electrocyclization in one pot. Some of the benzoxanthones are also synthesized by the one-pot reaction of 1,3-diketone and alkynyl bromide under basic heating conditions. This transformation also results in the construction of one new C?C bond and one new C?O bond. (Figure presented.).
Microwave assisted efficient synthesis of flavone using ZnO nanoparticles as promoter under solvent-free conditions
Unde, Pradip J.,Thorat, Nitin M.,Patil, Limbraj R.
, p. 1133 - 1136 (2019/04/05)
A simple and highly efficient protocol for synthesis of flavones from 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in presence of ZnO nanoparticles as a promoter in thermal as well as microwave irradiation under solvent-free conditions have been demonstrated. The catalyst is inexpensive, stable, can be easily recycled/reused for several cycles with consistent activity and observed almost same yield confirming the stability of the catalyst. It is believed that the present approach will become an alternative route for the conventional reactions. Because in this protocol, yield is quite high, short reaction time, simple work up, catalyst can be recycled as well as it is free of any hazardous by-products formation during workup.
Rhodium(III)-catalyzed one-pot synthesis of flavonoids from salicylaldehydes and sulfoxonium ylides
Cheng, Kang,Chen, Jinkang,Jin, Licheng,Zhou, Jian,Jiang, Xinpeng,Yu, Chuanming
, p. 392 - 398 (2019/09/03)
Rh(III)-catalyzed C–H activation of salicylaldehyde followed by an insertion reaction with sulfoxonium ylides and cyclization is applied to the synthesis of flavonoids. This one-pot strategy exhibits good functional group tolerance and gives flavones in moderate-to-good yields.
One-Pot Allan–Robinson/Friedl?nder Route to Chromen-/Quinolin-4-ones through the Domino Acetylative Cyclisation of 2-Hydroxy-/2-Aminobenzaldehydes
Rai, Vijai K.,Verma, Fooleswar,Sahu, Ganeshwar P.,Singh, Manorama,Rai, Ankita
, p. 537 - 544 (2018/02/09)
The domino synthesis of 2-phenyl-4H-chromen-4-ones and quinolin-4-ones through acetylation of 2-hydroxy-/2-aminobenzaldehydes with α-haloketones followed by intramolecular oxa-/azaheterocyclisation is reported. This method represents a new extension of the Allan–Robinson and Friedl?nder reactions, and uses N-heterocyclic-carbene catalysis to construct the target molecules in good to excellent yields: 86–95 % for the chromen-4-ones, and 83–96 % for the quinolin-4-ones. This approach has the advantages of operational simplicity, ambient reaction conditions, and no by-product formation.
Synthesis of 4H-Chromen-4-one Derivatives by Intramolecular Palladium-Catalyzed Acylation of Alkenyl Bromides with Aldehydes
Yue, Yixia,Peng, Jinsong,Wang, Deqiang,Bian, Yunyun,Sun, Peng,Chen, Chunxia
, p. 5481 - 5486 (2017/05/24)
The palladium-catalyzed intramolecular acylation of alkenyl bromides and aldehydes was developed for an efficient synthesis of 4H-chromen-4-ones. With Pd(PPh3)4/Xphos as the catalyst and K2CO3 as the base, this protocol was applied to synthesize a small library of diversely functionalized flavonoids in moderate to good yields in 1,4-dioxane.
Identification and structure activity relationship of novel flavone derivatives that inhibit the production of nitric oxide and PGE2 in LPS-induced RAW 264.7 cells
An, Ji-Young,Lee, Hwi-Ho,Shin, Ji-Sun,Yoo, Hyung-Seok,Park, Jong Seon,Son, Seung Hwan,Kim, Sang Won,Yu, Jihyun,Lee, Jun,Lee, Kyung-Tae,Kim, Nam-Jung
, p. 2613 - 2616 (2017/05/10)
In an effort to identify novel anti-inflammatory compounds, a series of flavone derivatives were synthesized and biologically evaluated for their inhibitory effects on the production of nitric oxide (NO) and prostaglandin E2 (PGE2), representative pro-inflammatory mediators, in LPS-induced RAW 264.7 cells. Their structure-activity relationship was also investigated. In particular, we found that compound 3g displayed more potent inhibitory activities on PGE2 production, similar inhibitory activities on NO production and less weak cytotoxicity than luteolin, a natural flavone known as a potent anti-inflammatory agent.
L-ascorbic acid: A green and competent promoter for solvent-free synthesis of flavones and coumarins under conventional as well as microwave heating
Dengale, Rohit Arvind,Thorat, Nitin Madhu,Thopate, Shankar Ramchandra
, p. 734 - 741 (2017/02/05)
Background: An expeditious approach has been developed for the synthesis of two distinct classes of benzopyrones viz. flavones and coumarins under solvent-free conditions. L-Ascorbic acid was found to be an effective promoter under microwave irradiation and conventional heating. Various benzo-α-pyrones and benzo-γ-pyrones were synthesized with overall good yields. The present protocol is highly facile and needs no column chromatography for purification and therefore it would serve as an effective and compatible method under both microwave irradiation and conventional heating. Results: The catalytic ability of L-ascorbic acid was investigated for the synthesis of flavones and coumarins. For this purpose, cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanedione and Pechmann coumarin synthesis, reactions were selected. And accordingly, it was observed that one mole of L-ascorbic acid was necessary for the completion of reaction. In all the cases, the desired flavones were smoothly generated with good to excellent yields; indicating its excellent tolerance for various functional groups. However, electron donating groups favors coumarin synthesis under these conditions. All the reaction mixtures were carefully analyzed and NMR indicates high conversions and lack of side products. Conclusion: We have developed L-ascorbic acid-promoted, solvent-free and simple method for the synthesis of benzo-α-pyrones and benzo-γ-pyrone under microwave irradiation as well as conventional heating in good to excellent yields. The notable advantages of this method are solvent-free conditions, inexpensive and efficient eco-friendly promoter, and shorter reaction time and can be carried out under air. This methodology is highly facile and requires no column chromatography for purification. The resulting flavones and coumarins are versatile building blocks in the construction of heterocyclic architectures, dominant in natural products. Further studies of exploiting the efficiency of L-ascorbic acid as a promoter in synthesis of various heterocyclic compounds are in progress.
Ammonium acetate promoted rapid and efficient synthesis of γ-Benzopyranones and 3,4-dihydropyrimidin-2(1H)-ones/thiones under solventfree conditions: A parallel scrutiny of microwave irradiation versus conventional heating
Thorat, Nitin M.,Dengale, Rohit A.,Thopate, Shankar R.,Rohokale, Sandeep V.
, p. 574 - 583 (2015/10/05)
Simple and highly efficient approach for the synthesis of γ-Benzopyranones and 3,4-Dihydropyrimidin-2(1H)-ones/thiones using ammonium acetate as a promoter under thermal as well as microwave irradiation using solvent-free conditions has been demonstrated.
A versatile approach to flavones via a one-pot Pd(II)-catalyzed dehydrogenation/oxidative boron-Heck coupling sequence of chromanones
Lee, Jun,Yu, Jihyun,Son, Seung Hwan,Heo, Jinyuk,Kim, Taelim,An, Ji-Young,Inn, Kyung-Soo,Kim, Nam-Jung
, p. 777 - 784 (2016/01/12)
A variety of flavones were expediently synthesized from readily accessible chromanones via a one-pot sequence involving Pd(ii)-catalyzed dehydrogenation and oxidative boron-Heck coupling with arylboronic acid pinacol esters. In particular, the use of arylboronic acid pinacol esters was found to significantly improve the yield of the reaction.
An efficient and green synthesis of flavones using natural organic acids as promoter under solvent-free condition
Thorat, Nitin M.,Kote, Santosh R.,Thopate, Shankar R.
, p. 601 - 605 (2014/07/21)
An efficient and eco-friendly synthesis of flavones, promoted by naturally occurring acids, via cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3- propanediones using conventional and microwave heating under solvent-free condition is described.
