Chemical and Pharmaceutical Bulletin p. 222 - 230 (1998)
Update date:2022-07-29
Topics:
Horie, Tokunaru
Shibata, Kenichi
Yamashita, Kazuyo
Fujii, Kenichi
Tsukayama, Masao
Ohtsuru, Yoshizumi
2',4'-Bis(benzyloxy)-3',6'-dimethoxychalcones (5), which were obtained from the dibenzyl ether of 2,4-dihydroxy-3,6-dimethoxyacetophenone (3), were oxidatively rearranged with thallium (III) nitrate in methanol and the resultant products were converted into 7-hydroxy-5,8-dimethoxyisoflavones (8) by hydrogenolysis, followed by cyclization. The isoflavones were quantitatively demethylated to 5,7-dihydroxy-8-methoxyisoflavones (2) via their acetates. The isomeric 5,7-dihydroxy-6-methoxyisoflavones (1) were also synthesized from the chalcones, obtained from 2,3-dimethoxy- (16) or 2- isopropoxy-3-methoxy-4,6-bis(benzyloxy)acetophenones (21), by a similar method. On the other hand, the isoflavones with two hydroxy groups at the 2'- and 4'-positions were easily synthesized by the following method. Treatment of the rearranged product from 2,2',4,4'-tetrakis(benzyloxy)-3'6'- dimethoxychalcone (5f) with hydrochloric acid (HCl) in acetic acid afforded 2',4',7-tris(benzyloxy)-5,8-dimethoxyisoflavone (10f). The 5-methoxy group in the isoflavone was quantitatively cleaved to give the corresponding 5- hydroxyisoflavone (11f), which was isomerized to 2',4',7-tris(benzyloxy)-5- hydroxy-6-methoxyisoflavone (25f) in the presence of anhydrous potassium carbonate. Hydrogenolysis of the two 5-hydroxyisoflavones proceeded smoothly to give 2',4',5,7-tetrahydroxy-8-(2f) and 6-methoxyisoflavones (1f), respectively. The 13C-NMR spectra of these isoflavones supported the proposed structures of polyhydroxyisoflavones. The proposed structures of two natural isoflavones were revised.
View MoreNanjing Fayekong Chemcial Co.,Ltd(expird)
Contact:86-25-58813444
Address:Rm 1503, Unit 1, Building 5, Zijinnanyuan, Nanjing, Jiangsu, China
Chengdu Green Young Biopharmaceutical INC
Contact:+86-28-85337952
Address:1-B-26,Tianhe Industry Park, No.1480 of Tianfu Road,Chengdu,P.R.China,610000
Jiacheng-Chem Enterprises Limited(expird)
Contact:86-571-86711508
Address:19 Floor, CIBC Holley International Building, No. 198,Wuxing Road, Hangzhou, China,310020
Zhejiang Peptites Biotech Co.,Ltd
website:http://www.peptide-china.com
Contact:86-575-83835818
Address:No.8,Hengyizhi Road,Sanjie Town,Shengzhou City,Zhejiang,China
Changzhou BaoKang Pharmaceutical & Chemical Co., Ltd
Contact:(86) 519-88782201 88784080 88785278
Address:Henglin town, changzhou,Jiangsu
Doi:10.1039/P19810003186
(1981)Doi:10.1002/jccs.200300124
(2003)Doi:10.1016/j.mencom.2019.05.018
(2019)Doi:10.1007/BF00673338
()Doi:10.1039/c8cc00980e
(2018)Doi:10.1016/S0014-827X(03)00165-4
(2003)