β-咔啉结构广泛存在于生物活性分子之中,为探索非酸性反应条件下合成β-咔啉衍生物的方法,以色胺类化合物和醛类为原料,以改进的Pictet-Spengler反应为关键步骤,再经氧化脱氢合成4个多取代β-咔啉化合物(2a~2d),其结构经1 H NMR和MS(E...β-咔啉结构广泛存在于生物活性分子之中,为探索非酸性反应条件下合成β-咔啉衍生物的方法,以色胺类化合物和醛类为原料,以改进的Pictet-Spengler反应为关键步骤,再经氧化脱氢合成4个多取代β-咔啉化合物(2a~2d),其结构经1 H NMR和MS(ESI)确证。经过对Pictet-Spengler反应步骤中物料比、溶剂、反应温度与时间进行考察后发现:在色胺类化合物为2.0 mmol,醛为3.0 mmol,六氟异丙醇钙为0.4 mmol,二氯甲烷为20.0 mL,室温反应24 h的最优条件下,四氢-β-咔啉化合物中间体(1a~1d)的收率为75%~89%,反应存在取代基效应,含芳香性基团底物收率较高。展开更多
The cis-l-substituted-6,7-dihydroxy-l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid esters 3 can be obtained in a highly diastereoselective fashion through 1,3-induction Pictet- Spengler (P-S) cyclization of the L-DO...The cis-l-substituted-6,7-dihydroxy-l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid esters 3 can be obtained in a highly diastereoselective fashion through 1,3-induction Pictet- Spengler (P-S) cyclization of the L-DOPA (3,4-dihydroxyphenylalanine) methyl ester with aromatic or aliphatic aldehydes under acidic conditions. Their epimers 4 are also obtained as minor products.展开更多
An acid catalyzed oxa-Pictet-Spengler reaction‘on water leading to the synthesis of a variety of l-aryl-6,7-dimethoxyisochro-mans is described.The aqueous chemistry is a much cleaner,efficient,cheaper and simple meth...An acid catalyzed oxa-Pictet-Spengler reaction‘on water leading to the synthesis of a variety of l-aryl-6,7-dimethoxyisochro-mans is described.The aqueous chemistry is a much cleaner,efficient,cheaper and simple method for synthesis.The scope of reactions was extended to thia-Pictet-Spengler reaction to afford the some isothiochromans.展开更多
Comprehensive Summary.Nitrogen-containing bridged-heterocycles and indoles are key subunits of many natural products and pharmacologically active molecules.We herein present a bimetallic Cu/Ir catalyzed asymmetric all...Comprehensive Summary.Nitrogen-containing bridged-heterocycles and indoles are key subunits of many natural products and pharmacologically active molecules.We herein present a bimetallic Cu/Ir catalyzed asymmetric allylation of ketimine esters and(E)-4-indolyl allyl carbonates followed by acid-promoted Pictet-Spengler cyclization sequences,enabling stereodivergent synthesis of chiral indole fused 9-azabicyclo[4.2.1]nonanes containing an eight-membered ring with one tertiary and two quaternary stereogenic centers.This one-pot sequential protocol features step economy,good substrate tolerance,and excellent stereoselective control.展开更多
The Pictet-Spengler/transamination cascade reaction enables modular synthesis of marinoquinoline analoviphrough three-component indole ring-expansion/cyclization in the manner of novel N1–C2 cleavage of indoles.Thi...The Pictet-Spengler/transamination cascade reaction enables modular synthesis of marinoquinoline analoviphrough three-component indole ring-expansion/cyclization in the manner of novel N1–C2 cleavage of indoles.This metal-free protocol exhibits very broad functional group tolerance with up to quantitative yields. Preliminarystudies on the antitumor activity of the resultant marinoquinoline analogues reveal that the indolyl-attachedpyrrolo[2,3-c]quinoline product (5d) shows great potential (IC50 of 0.32 μg/mL to HeLa cells) as a promisinganticancer agent in clinic.展开更多
A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalyticall...A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalytically asymmetric Pictet-Spengler cyclization/lactamization cascade reaction generating the key tetracyclic lactam skeleton;(b)asymmetricα-alkylation of carbonyl group induced by Evans'chiral auxiliary with excellent diastereoselectivity;(c)a highly efficient one-pot desulfurization/hydrogenation/debenzylation transformation using Raney Ni under hydrogen atmosphere;as well as(d)an intramolecular Vorbürggen reaction constructing the quaternary ammonium motif and the final cagelike skeleton.展开更多
文摘The cis-l-substituted-6,7-dihydroxy-l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid esters 3 can be obtained in a highly diastereoselective fashion through 1,3-induction Pictet- Spengler (P-S) cyclization of the L-DOPA (3,4-dihydroxyphenylalanine) methyl ester with aromatic or aliphatic aldehydes under acidic conditions. Their epimers 4 are also obtained as minor products.
文摘An acid catalyzed oxa-Pictet-Spengler reaction‘on water leading to the synthesis of a variety of l-aryl-6,7-dimethoxyisochro-mans is described.The aqueous chemistry is a much cleaner,efficient,cheaper and simple method for synthesis.The scope of reactions was extended to thia-Pictet-Spengler reaction to afford the some isothiochromans.
基金supported by the National Key R&D Program of China(2023YFA1506700)NSFC(22071186,22071187,22101216,22271226,and 22371216)National Youth Talent Support Program.
文摘Comprehensive Summary.Nitrogen-containing bridged-heterocycles and indoles are key subunits of many natural products and pharmacologically active molecules.We herein present a bimetallic Cu/Ir catalyzed asymmetric allylation of ketimine esters and(E)-4-indolyl allyl carbonates followed by acid-promoted Pictet-Spengler cyclization sequences,enabling stereodivergent synthesis of chiral indole fused 9-azabicyclo[4.2.1]nonanes containing an eight-membered ring with one tertiary and two quaternary stereogenic centers.This one-pot sequential protocol features step economy,good substrate tolerance,and excellent stereoselective control.
基金Support by the National Natural Science Foundation of China(Nos.22271244 and 22071211)the Hunan Provincial Natural Science Foundation of China(Nos.2023JJ40561 and 2022JJ40359)+1 种基金the Hunan Provincial Health Commission Foundation(B202313020111)Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(No.2022C02)is gratefully acknowledged.
文摘The Pictet-Spengler/transamination cascade reaction enables modular synthesis of marinoquinoline analoviphrough three-component indole ring-expansion/cyclization in the manner of novel N1–C2 cleavage of indoles.This metal-free protocol exhibits very broad functional group tolerance with up to quantitative yields. Preliminarystudies on the antitumor activity of the resultant marinoquinoline analogues reveal that the indolyl-attachedpyrrolo[2,3-c]quinoline product (5d) shows great potential (IC50 of 0.32 μg/mL to HeLa cells) as a promisinganticancer agent in clinic.
基金supported by Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation,CAMS Innovation Fund for Medical Sciences(CIFMS,No.2022-I2M-3–002)。
文摘A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalytically asymmetric Pictet-Spengler cyclization/lactamization cascade reaction generating the key tetracyclic lactam skeleton;(b)asymmetricα-alkylation of carbonyl group induced by Evans'chiral auxiliary with excellent diastereoselectivity;(c)a highly efficient one-pot desulfurization/hydrogenation/debenzylation transformation using Raney Ni under hydrogen atmosphere;as well as(d)an intramolecular Vorbürggen reaction constructing the quaternary ammonium motif and the final cagelike skeleton.
