569-31-3Relevant academic research and scientific papers
Studies on asymmetric total synthesis of (?)-β-hydrastineviaa chiral epoxide ring-opening cascade cyclization strategy
Cheng, Maosheng,Li, Jihui,Liu, Yongxiang,Meng, Jiaxin,Qin, Qiaohua,Song, Xinjing,Wu, Tianxiao,Zhao, Dongmei,Zheng, Yang
, p. 18953 - 18958 (2020/06/08)
Herein, facile and enantioselective approaches to synthesize the core phthalide tetrahydroisoquinoline scaffold of (?)-β-hydrastineviaboth a CF3COOH-catalyzed (86% ee) and KHMDS-catalyzed (78% ee) epoxide ring-opening/transesterification cascade cyclization from chiral epoxide under very mild conditions are described. The key elements include a highly enantioselective epoxidation using the Shi ketone catalyst and an intramolecular CF3COOH-catalyzed cascade cyclization in one pot, and a late-stage C-3′ epimerization under MeOK/MeOH conditions as the key steps to achieve the first total synthesis of (?)-β-hydrastine (up to 81% ee).
An Acid-Catalyzed Epoxide Ring-Opening/Transesterification Cascade Cyclization to Diastereoselective Syntheses of (±)-β-Noscapine and (±)-β-Hydrastine
Li, Jihui,Liu, Yongxiang,Song, Xinjing,Wu, Tianxiao,Meng, Jiaxin,Zheng, Yang,Qin, Qiaohua,Zhao, Dongmei,Cheng, Maosheng
supporting information, p. 7149 - 7153 (2019/09/30)
An acid-catalyzed stereoselective epoxide ring-opening/intramolecular transesterification cascade cyclization reaction and N-Boc deprotection was found to be a successful strategy to construct the phthalide tetrahydroisoquinoline skeleton in one pot. Based on this strategy, the unified and highly diastereoselective routes for the total syntheses of (±)-β-Noscapine and (±)-β-Hydrastine were exploited.
A new total synthesis of (±)-α-noscapine
Mao, Yongjun,Song, Shuai,Zhao, Dongmei,Cheng, Maosheng
, p. 2633 - 2640 (2014/01/06)
A new, convergent total synthesis of (±)-α-noscapine was developed on a grams scale through the condensation of 3-trimethylsilyl-meconin derivative 9 and the iodized salt cotarnine derivative 20 as the key step. Staring from simple 2,3-dimethoxybenzoic acid, piperonal and 2,2-dimethoxyethanamine, through the traditional chemical processes to give the final product in 11.6% yield over 14 steps.
Short synthesis of noscapine, bicuculline, egenine, capnoidine, and corytensine alkaloids through the addition of 1-siloxy-isobenzofurans to imines
Soriano, Maria Del Pilar C.,Shankaraiah, Nagula,Santos, Leonardo Silva
experimental part, p. 1770 - 1773 (2010/05/18)
A concise diastereotioselective strategy for the synthesis of noscapine, bicuculline, and egenine (1a-c), as well as capnoidine and corytensine (2a,b), was developed using diastereoselective addition of 1-siloxy-isobenzofurans 4a and 4b to iminium ion 5 in a one-pot approach. The synthesis features the use of imine 13 obtained through Bischler-Napieralsky reaction from amine 11. The addition of ionic liquids as addictives in the reactions afforded erythro configuration in major adduct compounds. The synthetic route can also be applied in the total synthesis of promising tubulin binding agent EM105 (3).
Synthesis of phthalideisoquinoline and protoberberine alkaloids and indolo[2,1-α]isoquinolines in a divergent route involving palladium(0)- catalyzed carbonylation
Orito, Kazuhiko,Miyazawa, Mamoru,Kanbayashi, Ryo,Tokuda, Masao,Suginome, Hiroshi
, p. 6583 - 6596 (2007/10/03)
6,7,3',4'-Alkoxy-substituted 1-(2'-bromobenzoyl)-3,4-dihydroisoquinoline methiodides 17 were treated with sodium borohydride in methanol or acetic acid to give erythro-1-(2'-bromo-α-hydroxybenzyl)-2-methyl-1,2,3,4- tetrahydroisoquinolines 19. Treatment of 17 with lithium aluminum hydride in tetrahydrofuran gave the threo-isomer 20 in preference to the erythro 19. On the basis of studies on palladium(0)-catalyzed carbonylation of 2-bromo-3,4- dimethoxybenzyl alcohol to 6,7-dimethoxyphthalide, amino alcohol 19 or 20 was treated with a catalytic amount of palladium(II) acetate and triphenylphosphine in an atmosphere of carbon monoxide in the presence of chlorotrimethylsilane and potassium carbonate in boiling toluene to give the corresponding erythro- or threo-types of phthalideisoquinoline alkaloids 1 or 2, respectively. One-pot cyclization of the erythro-amino alcohols 19 was achieved by heating in N,N-dimethylformamide containing potassium carbonate to give 2,3,8,9- or 2,3,9,10-alkoxy-substituted 5,6-dihydroindolo[2,1- α]isoquinolines 3, which have a unique tetracyclic skeleton characteristic of dibenzopyrrocoline alkaloids. Similarly, palladium-(0)-catalyzed carbonylation of 1-(2'-bromobenzyl)tetrahydroisoquinolines 21 in the presence of excess potassium carbonate was found to give 8-oxoberbines 22, which on reduction with lithium aluminum hydride can be converted to protoberberine alkaloids 4.
Studies on Carboxylation of Alkoxy-Substituted Benzyl Alcohols via Direct Lithiation and Bromine-Lithium Exchange: Synthesis of Phthalides and Phthalideisoquinoline Alkaloids
Orito, Kazuhiko,Miyazawa, Mamoru,Suginome, Hiroshi
, p. 2489 - 2496 (2007/10/02)
Conversion of alkoxy-substituted benzyl alcohols to the corresponding phthalides by carboxylation via ortho lithiation and bromine-lithium exchange was studied.The method was applied to the key step in the synthesis of phthalideisoquinoline alkaloids.
Ring-cleavage of phthalidisoquinoline alkaloids by ethyl chloroformate
Von Angerer,Von Angerer,Ambros,Wiegrebe
, p. 425 - 431 (2007/10/02)
Degradation of (-)-α-narcotine (5), (-)-β-narcotine (6), and (-)-β-hydrastine (7) with ethyl chloroformate (ECF) affords the chloro-urethans 9 and 18, respectively. Diastereomer 9-I is easily hydrolyzed to the hydroxy-urethan 10, whilst 18 is converted to the methoxy-analogue 19. The stilbene lactone 11 is obtained from 9-I by treatment with DBU, the analogous stilbene 17 arises already when 7 is reacted with ECF. - Hydroxy-urethan 10 - a phenylogous aldol - is split by OH- to aldehyde 13 and to meconine (14). LiAlH4-reduction of 10 yields the stereochemically homogenous triol 15, which is cyclized to diastereomers of the 3-phenyl-isochroman 16 under acidic conditions.
Directed ortho metalation of n,n-diethyl benzamides. Methodology and regiospecific synthesis of useful contiguously tri- and tetra-substituted oxygenated aromatics, phthalides and phthalic anhydrides
De Silva,Reed,Billedeau,Wang,Norris,Snieckus
, p. 4863 - 4878 (2007/10/02)
Full experimental details for the directed ortho metalation approch to a variety of simple ortho-substituted N,N-diethyl benzamides (Table 1) and contiguously 1,2,3- and 1,2,3,4-substituted benzamides (Tables 2) are given. The efficient conversion of these benzamides (6, 10, 12, 13, 18, 19) into phthalides (9a-b, 16b-c, 17) and phthalic anhydrides (8,16a), compounds previously available by demanding, classical methods, is detailed. A short synthesis of iso-ochracinic acid (27) is described.
A New Synthesis of Phthalides by Internal Trapping in Ortho-Lithiated Carbamates Derived from Benzylic Alcohols
Paleo, M. Rita,Lamas, Carlos,Castedo, Luis,Dominguez, Domingo
, p. 2029 - 2033 (2007/10/02)
The addition of t-BuLi to a low-temperature THF solution of o-bromocarbamates 2 leads to ortho-lithiated intermediates 3, in which internal trapping by the electrophile on the side chain then takes place.This novel Parham-type anionic cyclization procedure affords the variously substituted phthalides 5 in high yields and can also be used for the preparation of lactones 8, which are useful for the synthesis of aristocularine alkaloids.
SYNTHESIS OF (Z)-3-BUTYLIDENE-6,7-DIHYDROXYPHTHALIDE
Ogawa, Yoshimitsu,Hosaka, Kunio,Chin, Masao,Mitsuhashi, Hiroshi
, p. 1737 - 1744 (2007/10/02)
(Z)-3-Butylidene-6,7-dihydroxyphthalide (2) was first synthesized from 6,7-dimethoxyphthalide (4) and its structure was synthetically confirmed.
