Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• -derived NHPI esters has found application in the total synthesis of natural products, including the plant metabolite denobilone A and the highly oxidized dibenzocyclooctadiene lignans heteroclitin J and kadsulignan E [55]. Activation via charge-transfer complex formation Under conditions where oxidative

• [119] (Scheme 37A). Recently, Lumb and co-workers showcased the use of NHPI esters in key radical cyclizations, allowing the synthesis of diverse dibenzocyclooctadiene lignans [55] (Scheme 37B). A Ru-catalyzed cyclization was employed to construct the quaternary stereocenter in taiwankadsurin A

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• the total synthesis of (−)-psychotriasine (202), (−)-calycanthidine (203), and (−)-chimonanthine (204). Synthesis of structurally diverse lignans (Zhu, 2022) [103]: Lignans are structurally diverse natural compounds generated biosynthetically by the oxidative dimerization of phenylpropanoids [104

• ]. Despite the wide oxidative diversity, classic lignans bearing a C8–C8’ bond can be biosynthetically traced back to coniferyl alcohol (Scheme 18). Commonly, lignans possess important pharmacological properties including antimicrobial, anti-inflammatory, immunosuppressive activities, etc. [105]. At the same

• determinant factor for either 8,8’-cis- or 8,8’-trans-cyclization to furan heterocycle cation 218, which serves as the hypothetical common scaffold of the plan. Diverting this mechanistic route to different lignans is possible by introducing nucleophilic additives (e.g., MeOH), oxidants (e.g., Cu(OTFA)2), or

Sinensiols H–J, three new lignan derivatives from Selaginella sinensis (Desv.) Spring

• Qinfeng Zhu,
• Beibei Gao,
• Qian Chen,
• Tiantian Luo,
• Guobo Xu and
• Shanggao Liao

Beilstein J. Org. Chem. 2022, 18, 1410–1415, doi:10.3762/bjoc.18.146

• treatment of cholecystitis, hepatitis, nephritis, eczema and bleeding [6]. Previous phytochemical studies showed the presence of flavonoids, lignans, glucosides and pigments in the plant [7][8] while pharmacological evaluations showed that some of the compounds possessed anti-oxidant and antiviral

Terpenoids from Glechoma hederacea var. longituba and their biological activities

• Dong Hyun Kim,
• Song Lim Ham,
• Zahra Khan,
• Sun Yeou Kim,
• Sang Un Choi,
• Chung Sub Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58

• , lignans, flavonoids, and phenolic compounds that show anti-inflammatory, cytotoxic, and/or cytoprotective effects [3][4][5][6][7]. However, bioactive terpenoids of G. hederacea var. longituba with antineurodegenerative effects remain largely unknown. In this study, nine terpenoids (1–9) including five new

Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities

• Meifang Wu,
• Xiangdong Su,
• Yichuang Wu,
• Yuanjing Luo,
• Ying Guo and
• Yongbo Xue

Beilstein J. Org. Chem. 2022, 18, 200–207, doi:10.3762/bjoc.18.23

• diversity of the secondary metabolites from the genus Wikstroemia. Keywords: coumarin glucosides; flavonoids; lignans; structure elucidation; Wikstroemia nutans; Introduction The genus Wikstroemia (Thymelaeaceae) contains approximately 62 species, which are widespread throughout the subtropical regions of

• antimicrobial activities. This is the first report of the isolation of coumarins, flavonoids, lignans and phenylpropanoid glycosides from W. nutans, while compounds 1–3, 8, and 11 was encountered from the genus Wikstroemia for the first time. Our work will enrich the chemistry and structure diversity of natural

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• [14], lignans [15], and oxylipins [21] with cytotoxic, anti-inflammatory, or potential neuroprotective activities. In order to search for minor constituents of other structure classes in C. sinensis twigs, the MeOH extract and the four solvent-partitioned fractions were further investigated to afford

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• extended their method towards the asymmetric syntheses of furofuran lignans 203 from chiral bislactones 202. Furofuran lignans 203 were synthesized in good to excellent enantioselectivity (Scheme 63). Conclusion and Future Directions Extensive studies of electroorganic reactions have opened alternative

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• combine the structural moieties of flavonoids and phenylpropanoids (lignans). Among the group of flavonolignans, the medicinally most important ones can be found in Silybum marianum (L.) Gaertn., the milk thistle. The phenolic secondary metabolites of this plant have been intensively studied due to their

Stereochemistry of ring-opening/cross metathesis reactions of exo- and endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitriles with allyl alcohol and allyl acetate

• Piotr Wałejko,
• Michał Dąbrowski,
• Lech Szczepaniak,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 1893–1901, doi:10.3762/bjoc.11.204

• ., annonaceous acetogenins [3][4], lignans [5][6], iso- and neurofurans [7][8], as well as macrodiolides [9]. These substances exhibit a diverse biological activities including antitumor, antimicrobial, etc. [10][11][12]. Stereoselective construction of substituted tetrahydrofurans is still a challenging task in

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• previously reported the formation of a number of diaryl tetrahydrofuran lignans under acidic or buffered conditions utilising the high reactivity of electron-rich benzylic alcohols to assist in the rapid and high yielding formation of the tetrahydrofuran ring [13][14][15][16][17][18]. The two

• sterically congested 7b. We have noticed a similar process in the synthesis of other THF lignans [15][16]. To test this hypothesis we stirred a sample of isomer 7b in 1:1 2 M HCl (aq)/THF and found that after 24 hours obtained a mixture of 7a to 7b with isomer 7a being predominant. This highlights the

Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products

• Taiki Kojima,
• Rika Obata,
• Tsuyoshi Saito,
• Yasuaki Einaga and
• Shigeru Nishiyama

Beilstein J. Org. Chem. 2015, 11, 200–203, doi:10.3762/bjoc.11.21

• -type products were synthesized from the hydrodimer. Keywords: boron-doped diamond (BDD) electrode; cathodic reduction; electrochemistry; electrosynthesis; neolignan; Introduction Numerous lignans and neolignans were found as secondary plant metabolites, and many of them are known to exhibit

• interesting biological activities [1]. Due to their plausible roles as defense substances of plants, lignans, neolignans, and their congeners are promising candidates for agricultural chemicals, and some of their antioxidant and/or anti-inflammatory properties may be utilized for biological research and as

• lead structures for chemotherapeutic agents. Despite consisting of two phenylpropane (C6–C3) fragments, the variety of carbon frameworks provides a huge library of lignans and neolignans [2][3][4]. As a result of their structural diversity, they have been targets of synthetic and biological

Trogopterins A–C: Three new neolignans from feces of Trogopterus xanthipes

• Soyoon Baek,
• Xuikui Xia,
• Byung Sun Min,
• Chanil Park and
• Sang Hee Shim

Beilstein J. Org. Chem. 2014, 10, 2955–2962, doi:10.3762/bjoc.10.313

• -60, HeLa, and MCF-7) were evaluated. Compounds 1–3 had moderate cytotoxic effects against HL-60 cells even though the activities were not significant. Thus, Trogopterus feces could be a potential source of lignans with cytotoxic activity. Experimental General Methods Optical rotations were measured

Lanostane- and cycloartane-type triterpenoids from Abies balsamea oleoresin

• Serge Lavoie,
• Charles Gauthier,
• Jean Legault,
• Sylvain Mercier,
• Vakhtang Mshvildadze and
• André Pichette

Beilstein J. Org. Chem. 2013, 9, 1333–1339, doi:10.3762/bjoc.9.150

• ]. Since then, more than 277 secondary metabolites have been isolated, and mainly identified as terpenoids, flavonoids and lignans [3]. Balsam fir Abies balsamea (L.) Mill., a popular Christmas tree in Canada, has been used traditionally by North American aboriginal people as an antiseptic, tuberculosis

Short synthesis of the common trisaccharide core of kankanose and kankanoside isolated from Cistanche tubulosa

• Goutam Guchhait and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 705–709, doi:10.3762/bjoc.9.80

• from C. tubulosa and have shown promising medicinal activity such as hepatoprotective and vasorelaxant activities [4][5][6]. Most of the compounds isolated from C. tubulosa and related species are phenylethyl oligosaccharides, iridoids, terpenes and lignans [4][5][6][7]. Recently, Yoshikawa et al

Zanthoxoaporphines A–C: Three new larvicidal dibenzo[de,g]quinolin-7-one alkaloids from Zanthoxylum paracanthum (Rutaceae)

• Fidelis N. Samita,
• Louis P. Sandjo,
• Isaiah O. Ndiege,
• Ahmed Hassanali and
• Wilber Lwande

Beilstein J. Org. Chem. 2013, 9, 447–452, doi:10.3762/bjoc.9.47

• same genus as rich in alkaloids [3][4][5], which constitute the most abundant class of compounds in this genus, while coumarins [6], lignans [3] and triterpenoids, especially limonoids [7], are the minor constituents. Different classes of alkaloids have been found and reported from Zanthoxylum species

Bioactive selaginellins from Selaginella tamariscina (Beauv.) Spring

• Chao Yang,
• Yutian Shao,
• Kang Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2012, 8, 1884–1889, doi:10.3762/bjoc.8.217

• circulation [3]. Phytochemical and pharmacological studies on genus Selaginella led to identifications of numerous bioactive compounds, including biflavonoids, alkaloids, and lignans, with broad biological activities, including antivirus, antifungal, antibacterial, cytotoxic, and anti-inflammatory properties

• diseases. The role of free radicals in ageing, in cancer, and in cardiovascular, neurodegenerative and other diseases is more and more widely accepted [21][22]. Antioxidants are attracting increasing scientific and clinical attention. Natural phenolic compounds (flavonoids, lignans, phenolic acids

First synthesis of 2-(benzofuran-2-yl)-6,7-methylene dioxyquinoline-3-carboxylic acid derivatives

• Wentao Gao,
• Jia Liu,
• Yun Jiang and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 210–217, doi:10.3762/bjoc.7.28

• intermediates which may be responsible for the observed antitumor activity of lignans [23][24]. The presence of the methylenedioxy moiety in some other bioactive molecules drastically alters their pharmacological properties. For example, among the tested 2-phenylquinolin-4-ones (2-PQs) with potent cytotoxicity