- Xanthine oxidase inhibitors from the heartwood of Vietnamese Caesalpinia sappan
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From the MeOH extract of Vietnamese Caesalpinia sappan, a novel biogenetically exclusive benzindenopyran, with a new carbon framework, neoprotosappanin (1), and a new compound, protosappanin A dimethyl acetal (3), were isolated together with protosappanin E-2 (2), neosappanone A (4), and 13 previously reported phenolic compounds (5-17). Their structures were elucidated on the basis of spectroscopic data. Compounds 1-4, 7, 13, and 15-17 showed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and sappanchalcone (17) showed the most potent activity with an IC 50 value of 3.9 μM, comparable to that of positive control allopurinol (IC50, 2.5 μM). The kinetic study of these inhibitors indicated that they are competitive inhibitors, the same as allopurinol, except for 1 and 16 which are noncompetitive inhibitors.
- Nguyen, Mai Thanh Thi,Awale, Suresh,Tezuka, Yasuhiro,Le Tran, Quan,Kadota, Shigetoshi
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- A visible-light-induced cascade reaction of etherification/C-C cyclization: Efficient synthesis of dibenzo[: B, d] oxepin-7(6 H)-ones
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A visible-light-induced palladium-catalyzed cascade reaction was developed by etherification/C-C coupling cyclization of α-bromoacetophenones with phenols. A series of dibenzo[b,d]oxepin-7(6H)-one derivatives were efficiently synthesized by using this method in good yields. Furthermore, this method was applied to the synthesis of protosappanin A. The protocol has advantages such as simple reaction conditions, wide range of substrates and high reaction efficiency.
- Fu, Wanyong,Yu, Aixia,Jiang, Hongshuo,Zuo, Minghui,Wu, Hongfeng,Yang, Zhongwen,An, Qi,Sun, Zhizhong,Chu, Wenyi
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- A original haematoxylin A and its derivative chemical whole synthetic method
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The invention discloses a biochemical total synthetic method for protosappanin A and derivatives thereof. The synthetic method for protosappanin A and derivatives thereof comprises the main steps: taking a dibenzo[d,f]oxepane-3-one compound as a raw material, performing cyan addition on carbonyl, performing reduction, Tiffeneau-Demjanov rearrangement, deprotection and other reactions, so as to synthesize the protosappanin A derivatives with the total yield of 85% or more. Chemical total synthesis of protosappanin A compounds is developed for the first time. The synthetic method is simple to operate, reduced in synthetic difficulty because routine chemical reaction methods are employed, mild in reaction conditions, friendly to environment, simple in post-treatment and high in yield, and has good industrialization production prospect.
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Paragraph 0104; 0105; 0106; 0107; 0108; 0109
(2017/08/25)
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- Total synthesis of protosappanin A and its derivatives via palladium catalyzed ortho C-H activation/C-C cyclization under microwave irradiation
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A total synthesis method for protosappanin A, which is a complex natural product with many biological activities, was developed with 6 linear steps. Dibenzo[b,d]oxepinones as the key intermediates of the synthetic route were prepared by a palladium-catalyzed ortho C-H activation/C-C cyclization under microwave irradiation. 25 derivatives of protosappanin A were obtained.
- Liu, Jiaqi,Zhou, Xuan,Wang, Chenglong,Fu, Wanyong,Chu, Wenyi,Sun, Zhizhong
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p. 5152 - 5155
(2016/05/02)
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