- Copper-catalyzed direct coupling of benzoxazin-2-ones with indoles for the synthesis of diverse 3-indolylbenzoxazin-2-ones: Access to natural cephalandole A
-
A novel and facile copper-catalyzed direct coupling for the synthesis of diverse and functionalized 3-indolyl benzoxazin-2-ones from benzoxazin-2-ones and indoles has been developed. This newmethodology offers an easy and rapid approach to a variety of 3-indolylbenzo[b][1,4]oxazin-2-ones in high yield. As an application of this protocol, a gram-scale synthesis of naturally occurring cephalandole A has also been accomplished.
- Pandit, Rameshwar Prasad,Shim, Jae-Jin,Kim, Sung Hong,Lee, Yong Rok
-
-
Read Online
- Hypervalent Iodine(III)-Promoted Radical Oxidative C-H Annulation of Arylamines with α-Keto Acids
-
A novel catalyst-free radical oxidative C-H annulation reaction of arylamines with α-keto acids toward benzoxazin-2-ones synthesis under mild conditions was developed. This hypervalent iodine(III)-promoted process eliminated the use of a metal catalyst or additive with high levels of functional group tolerance. Hypervalent iodine(III) was both an oxidant and a radical initiator for this reaction. The synthetic utility of this method was confirmed by the synthesis of the natural product cephalandole A.
- Long, Lipeng,Wang, Jieyan,Gu, Liuqing,Yang, Shiguang,Qiao, Liang,Luo, Guotian,Chen, Zhengwang
-
p. 12084 - 12092
(2021/08/24)
-
- An efficient synthesis and biological evaluation of novel analogues of natural product Cephalandole A: A new class of antimicrobial and antiplatelet agents
-
Cephalandole A 2, a small indole alkaloid isolated from the Taiwanese orchid Cephalanceropsis gracilis (Orchidaceae), exhibits anticancer activity. Surprisingly, this natural product has not been evaluated for any other biological activity so far. To discover other novel potential of Cephalandole A 2, an efficient and economic synthetic protocol for novel Cephalandole A analogues 21a-o has been developed, in only 3 steps from using indole, and applied for their biological activity. Biological testing showed that Cephalandole A 2 and its novel analogues 21a-o exhibited potential antimicrobial and antiplatelet activity in preliminary assay. To the best of our knowledge, this is the first report of Cephalandole A 2 and its novel synthetic analogues 21a-o as a new class of antimicrobial and antiplatelet agents. In this study, 2 and other analogues i.e., 21b, 21d, 21i and 21o showed promising antimicrobial activity against the phytopathogenic bacteria and fungi. Cephalandole A 2, 21c, 21f and 21i, also showed potent antiplatelet activity.
- Sharma, Vashundhra,Jaiswal, Pradeep K.,Kumar, Krishan,Saran, Mukesh,Mathur, Manas,Swami, Ajit K.,Chaudhary, Sandeep
-
-
- Visible-light-induced C(sp3)-H activation for a C-C bond forming reaction of 3,4-dihydroquinoxalin-2(1: H)-one with nucleophiles using oxygen with a photoredox catalyst or under catalyst-free conditions
-
A convenient photocatalyzed oxidative coupling reaction of 4-alkyl-3,4-dihydroquinoxalin-2(1H)-one and its derivatives with a variety of nucleophiles was developed with a ruthenium photoredox catalyst and oxygen under a household compact fluorescent light. With a slower reaction rate, the cross coupling transformation can be achieved in the absence of an external photocatalyst with a similar isolated yield. An application to the synthesis of natural product cephalandole A was also demonstrated.
- Akula, Pavan Sudheer,Hong, Bor-Cherng,Lee, Gene-Hsiang
-
p. 19580 - 19584
(2018/06/11)
-
- Microwave-assisted one-pot efficient synthesis of functionalized 2-oxo-2-phenylethylidenes-linked 2-oxobenzo[1, 4]oxazines and 2-oxoquino[1, 4]oxalines: Synthetic applications, antioxidant activity, SAR and cytotoxic studies
-
A microwave-assisted, environmentally benign green protocol for the synthesis of functionalized (Z)-3-(2-oxo-2-phenylethylidene)-3, 4-dihydro-2H-benzo[b][1, 4]oxazin-2-ones (11a-n) in excellent yields (upto 97%) and (Z)-3-(2-oxo-2-phenylethylidene)-3, 4-dihydroquinoxalin-2(1H)-ones (14a-h) (upto 96% yield) are reported. The practical applicability of developed methodology were also confirmed by the gram scale synthesis of 11a, 14c and 14e; synthesis of anticancer alkaloid Cephalandole A 16 (89% yield). All the synthesized compounds 11a-n, 14a-h and 16 were assessed for their in vitro antioxidant activities in DPPH radical scavenging and FRAP assay. In DPPH assay, compounds 11a, 14c and 14e, the most active compounds of the series, were found to show IC50 value of 10.20 ± 0.08 μg/mL, 9.89 ± 0.15 μg/mL and 8.97 ± 0.13 μg/mL, respectively in comparison with standard reference (ascorbic acid, IC50 = 4.57 μg/mL). Whereas, in FRAP antioxidant assay seven compounds (11c, 11e, 11i, 11k, 11l, 14d and 14h) displayed higher antioxidant activity in comparison to the reference standard BHT (C0.5FRAP = 546.2 μM). Moreover, the cytotoxic studies of the compounds 11a, 14c, 14e and 14h were found to be non-toxic in nature in 3T3 fibroblast cell lines using MTT assay.
- Sharma, Vashundhra,Jaiswal, Pradeep K.,Yadav, Dharmendra K.,Saran, Mukesh,Prikhodko, Jaroslav,Mathur, Manas,Swami, Ajit K.,Mashevskaya, Irina V.,Chaudhary, Sandeep
-
p. 988 - 1004
(2018/01/17)
-
- “On water” ultrasound-assisted one pot efficient synthesis of functionalized 2-oxo-benzo[1,4]oxazines: First application to the synthesis of anticancer indole alkaloid, Cephalandole A
-
For the first time, an efficient, simple, synthetic green protocol for the one-pot synthesis of functionalized 2-oxo-benzo[1,4]oxazines 24–29 in water under ultrasound irradiation is presented. As compared to conventional methods, the present protocol avo
- Jaiswal, Pradeep K.,Sharma, Vashundhra,Prikhodko, Jaroslav,Mashevskaya, Irina V.,Chaudhary, Sandeep
-
p. 2077 - 2083
(2017/05/10)
-
- Iron-catalyzed oxidative sp3 carbon-hydrogen bond functionalization of 3,4-dihydro-1,4-benzoxazin-2-ones
-
A novel and efficient iron-catalyzed sp3 carbon-hydrogen bond functionalization of benzoxazinone derivatives has been developed. For the first time, benzoxazin-2-ones were used as substrates in an oxidative dehydrogenative coupling reaction. The experiments were performed under mild reaction conditions to construct alkyl-aryl C(sp3)-C(sp2) bonds. The application of this method to the gram-scale synthesis of natural product cephalandole A has been accomplished in a 3-step sequence. A plausible one electron oxidation involved mechanism is proposed.
- Huo, Congde,Dong, Jie,Su, Yingpeng,Tang, Jing,Chen, Fengjuan
-
p. 13341 - 13344
(2016/11/18)
-
- A pharmaceutical active compound synthesis method of Cephalandole A
-
The invention relates to a synthetic method of Cephalandole as a drug active compound A. The synthetic method comprises the steps: in the presence of acid, carrying out a reaction on benzoxazole and (1H-benzpyrole-3-group) formate carbonyl in an organic solvent to obtain the Cephalandole A as the drug active compound. With the adoption of the synthetic method, as the purity and the yield of a product are high, and the temperature is proper, a new reaction method is provided to chemical synthesis of the compound, and the synthetic method has good research values and potentials.
- -
-
Paragraph 0024; 0025
(2017/02/02)
-
- Unexpected TFA-catalyzed tandem reaction of benzo[d]oxazoles with 2-oxo-2-arylacetic acids: Synthesis of 3-aryl-2H-benzo[b][1,4]oxazin-2-ones and cephalandole A
-
A convenient and efficient method for the TFA-catalyzed synthesis of 3-aryl-2H-benzo[b][1,4]oxazin-2-ones via a tandem reaction of benzo[d]oxazoles with 2-oxo-2-arylacetic acids was reported for the first time. The efficiency of this transformation was demonstrated by compatibility with a wide range of functional groups. The synthetic utility of this method was confirmed by the synthesis of the natural product cephalandole A. Moreover, a plausible mechanism for the formation of 3-aryl-2H-benzo[b][1,4]oxazin-2-ones involving ring-opening and cyclization steps is proposed. The present synthetic route to 3-aryl-2H-benzo[b][1,4]oxazin-2-ones could be readily scaled up to gram quantity without difficulty.
- Yan, Shaoxi,Ye, Leping,Liu, Miaochang,Chen, Jiuxi,Ding, Jinchang,Gao, Wenxia,Huang, Xiaobo,Wu, Huayue
-
p. 16705 - 16709
(2014/05/06)
-
- Synthetic studies of cephalandole alkaloids and the revised structure of cephalandole A
-
A synthesis of the originally proposed 2-(1H-indol-3-yl)-4H-3,1-benzoxazin- 4-one structure of the alkaloid cephalandole A (1) led to a structural revision, and the isolated natural product has now been identified as the previously known compound 3-(1H-in
- Mason, Jeffrey J.,Bergman, Jan,Janosik, Tomasz
-
experimental part
p. 1447 - 1450
(2009/04/05)
-