Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• : farnesyl pyrophosphate; FAD: flavin adenine dinucleotide; NADPH: nicotinamide adenine dinucleotide phosphate. (B) HPLC profiles of the metabolites from Aspergillus oryzae transformants. The chromatograms were extracted at 254 nm. (C) Structures of metabolites detected or isolated in this study. Note that

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• metabolic genes for ease of gene transfer and high substance production capabilities [10][11]. The expression of trt4 (polyketide synthase, PKS), trt2 (prenyltransferase, PT), trt5 (methyltransferase, MT), trt8 (flavin-dependent monooxygenase, FMO), and trt1 (meroterpenoid cyclase, CYC) in A. oryzae NSAR1

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• using heme-containing oxygenases (cytochrome P450 monooxygenases, styrene/indole monooxygenases, flavin-containing monooxygenases, Baeyer–Villiger monooxygenases, etc.) or non-heme iron oxygenases (naphthalene dioxygenases, multicomponent phenol hydroxylases) [5][6][7][8]. The synthetic approaches

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• distinct mechanism is employed in the biosynthesis of valanimycin, an aliphatic azoxy natural product. This involves the N-hydroxylation of isobutylamine, mediated by the flavin-dependent monooxygenase VlmH [15][16][17], and the following formation of O-(ʟ-seryl)-isobutylhydroxylamine by the tRNA-utilizing

• Supporting Information File 1). They encode five genes that are also present in the biosynthetic gene clusters of valanimycin [19] and KA57-A [20]: the putative two-component flavin-dependent monooxygenase similar to VlmH/VlmR, the homologous protein of VlmA, and two additional hypothetical proteins similar

• the two-component flavin-dependent monooxygenase Ady3/Ady10, as in the valanimycin biosynthesis mediated by VlmH/VlmR [15][16][17]. The hydroxylamine would be conjugated to alanyl-tRNA to form an ester intermediate by the function of the tRNA-utilizing enzyme Ady7, which is homologous to VlmA. In

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• catalyzed by flavin-dependent monooxygenases [12][13][14][15][16], the carbon transfer is mediated either by tetrahydrofolate-dependent formyl [17] or by acyl-CoA-dependent acyl transferases [13][15][16]. It is widely assumed that the oxidation precedes the formylation or acylation [17][18][19][20][21][22

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• by side chain cross-linking of bromotryptophan and an organoboron moiety. Bromotryptophans are accessible by enzymatic bromination utilising cross-linked enzyme aggregates (combiCLEAs) containing an FAD-dependent tryptophan halogenase, a flavin reductase and an alcohol dehydrogenase [73][74]. For

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• the starting material for synthesizing adduct 204 (Scheme 39) [123]. A synthesis and a self-assembly of flavin-functionalized fullerene derivative 205 consisting of [60]PCBM and isoalloxazine moieties attached at both ends of a linear 12-carbon aliphatic spacer, based on the same acid (Scheme 40), was

• derivatives of N,N-(tetrachlorophthaloyl)dehydroabietylamine, 198–201. The synthetic route to methano-bridged diferrocenylfullerene 202. The synthetic route to 1-(3-(benzoyl)propyl)-1-phenyl[6,6]-C60 203. The synthetic route to methanofullerene 204. The synthetic route to C60-functionalized flavin 205. The

Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines

• Wilfred J. M. Lewis,
• David M. Shaw and
• Jeremy Robertson

Beilstein J. Org. Chem. 2021, 17, 334–342, doi:10.3762/bjoc.17.31

• ]. Proteins coded by three of these genes (LgnA, LgnB, and LgnD) were shown to assemble legonindolizidines A (1) and B (2) – from proline, threonine, and a fatty acid component – which are then converted by LgnC, a flavin-dependent monooxygenase, into the corresponding legonmycins (3 and 4) via a sequence of

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• photosynthetic reaction center for photosynthesis could be realized. König and co-workers demonstrated the use of a flavin–Zn(II)–cyclen assembly (Figure 4) to convert benzyl alcohol to benzaldehyde upon irradiation [20]. This reaction could be performed in both organic and aqueous phases, with a photooxidation

• quantum yield of 3.8 × 10−2 and 0.4, respectively. In contrast, for flavins without the zinc(II)–cyclen unit, only small amounts of product were observed, and the quantum yield was 30 times lower compared to that of the assembly with the flavin chromophore possessing a binding site. The mechanism may be

• explained as follows: the zinc(II)–cyclen complex can absorb light and facilitate the intramolecular electron transfer from benzyl alcohol to the excited flavin, and thus the benzaldehyde and the photoreduced flavin were produced. The study indicates the significance of connecting a photosensitizer and a

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• photochemical [2 + 2] cycloaddition of tert-butyl 2-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)acetate (322) and thiobenzophenone (184a) was applied to prepare thietane 323 as a model compound for photolyses in a comparative flavin-induced cleavage study of oxetanes and thietanes [89] (Scheme 60). 2,5

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• ], vanadium-dependent bromoperoxidases [61][62], or methyltransferases [63]). In addition, enzymes typically classified as tailoring enzymes, such as flavin-dependent monooxygenases [64] and cytochrome P450s (CYPs) [65], were reported to be involved in noncanonical terpene cyclization. Furthermore, both

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

• the corresponding chiral alcohol 142 with a diastereomeric excess of 96% (Scheme 45). The same group explored the practicality of direct electrochemical regeneration of a flavin-dependent monooxygenase as a catalyst for the asymmetric electrochemical epoxidation of styrenes [81]. They showed that upon

• (StyA, StyB, and an NADH-regenerating enzyme) and two cofactors (NADH and FAD), with only an oxygenase component and its flavin prosthetic group (Scheme 46). In 2004, Liese reported the asymmetric sulfoxidation of thioanisole 145 with high productivity and excellent enantioselectivity using a

A photochemical determination of luminescence efficiency of upconverting nanoparticles

• Baptiste Amouroux,
• Clément Roux,
• Jean-Claude Micheau,
• Fabienne Gauffre and
• Christophe Coudret

Beilstein J. Org. Chem. 2019, 15, 2671–2677, doi:10.3762/bjoc.15.260

• particles (70 nm) [34] and recruiting the flavin-containing coenzymes as 1O2 sensitizers. In the skin, typical number of dyes per femtoliter is expected to be 750. This would correspond to an absorbance of 0.0014 in 1 cm of pure water according to a molar extinction coefficient of ca. 11300 L mol−1 cm−1. To

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• , PQS is produced through hydroxylation of position 3 by the NADH-dependent flavin mono-oxygenase PqsH [32]. This biosynthetic cascade is also responsible for the generation of the pqs-related metabolites DHQ, 2-AA, and HQNO as well as other AQs having different lengths of the alkyl chain [29][30

The enzymes of microbial nicotine metabolism

• Paul F. Fitzpatrick

Beilstein J. Org. Chem. 2018, 14, 2295–2307, doi:10.3762/bjoc.14.204

• solvent isotope effects established that the reaction catalyzed by LHNO is the same as other flavin amine oxidases, direct hydride transfer from the uncharged amine to the flavin (Scheme 4) [19][20]. Hydrolysis to form 6-hydroxypseudooxynicotine occurs in solution after release of the oxidized amine from

• bond of the substrate methyl group by hydride transfer [40]. The resulting 4-aminobutryrate is likely a substrate for a chromosomally-encoded aminotransferase, producing α-ketoglutarate and succinate semialdehyde. Mao (γ-N-methylaminobutyrate oxidase) contains noncovalently-bound flavin and catalyzes

• been cloned and characterized [10]. DHPH contains FAD and requires NADH and oxygen [41], and the sequence of the protein is similar to that of salicylate hydroxylase, although the sequence identity is only 21%. This allowed identification of the enzyme as a flavin-dependent phenol hydroxylase, a

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• nitrogen heteroarenes. Keywords: aerobic oxidation; bioinspired Flavin mimics; nitrogen heteroarenes; organo catalytic; oxidative dehydrogenation; Introduction By virtue of their presence in bioactive natural products and active pharmaceutical ingredients, nitrogen heterocycles and heteroaromatics form

• electron-withdrawing substrates were favored in this case. A slight modification (5 mol % phd, 1 mol % ZnI2 and 1 mol % PPTS) of the existing procedure afforded indoles 62 from indolines 61. Bioinspired flavin mimics were also used as catalysts for oxidative dehydrogenation of dihydropyridines 63 and

• , phd = 1,10-phenanthroline-5,6-dione. Oxidative dehydrogenation with Flavin mimics. o-Quinone based bioinspired catalysts for the synthesis of dihydroisoquinolines. Cobalt-catalyzed aerobic dehydrogenation of Hantzch 1,4-DHPs and pyrazolines. Mechanism of cobalt-catalyzed aerobic dehydrogenation of

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• flavin derivatives in general are well-known blue-light absorbing photocatalysts, which can oxidize a variety of substrates under aerobic conditions with oxygen as terminal oxidant. Flavins were studied extensively for the oxidation of alcohols, amines, methylbenzenes, styrenes, and phenylacetic acids [9

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

• Vincent M. Rotello

Beilstein J. Org. Chem. 2016, 12, 1638–1646, doi:10.3762/bjoc.12.161

• just starting to move into nanoparticles. As with the polymers, we started off studying the interactions of recognition element-functionalized nanoparticles with monovalent guests – in this case our old friend flavin where we showed modulation of the flavin redox potentials [21]. Taking this research

• one step further, we created a nanoparticle with a mixed monolayer consisting of hydrogen bonding and aromatic staking sidechains. When we incubated this NP with flavin we observed an increase in binding over time, i.e., we were able to template the particle to the guest [22]. We have since

• with our rather neurotic Weimaraner Trudy, allowing us to get double duty from our toil. Flavoenzyme model system for determining the role of aromatic stacking in flavin redox processes. Reprinted with permission from [10]. Copyright (1997) American Chemical Society. Recognition element-functionalized

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• that already at the stage of the first post-PKS modifications, the alnumycin (37) pathway differs from the above mentioned routes (Scheme 8). Prior to pyran cyclisation, the lateral ring of precursor 48 is hydroxylated by the combined action of the two-component flavin-containing monooxygenase (FMO

• ) AlnT and the flavin reductase AlnH [33]. No 3HAD homolog is present in the gene cluster that could catalyse a similar reaction as in the above mentioned examples. Instead, the oxidoreductase AlnO was proposed to catalyse the stereoselective reduction of the ketone at C15 in 49. The pyran 51 would then

• any cofactors, in spite of its flavin adenine dinucleotide (FAD) binding site [98][99]. The reaction mechanisms and biosynthetic enzymes involved in the rearrangement of versicolorin B (106) to demethylsterigmatocystin (107) have also been discussed controversely. Up to four genes (aflM, aflN, aflX

Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides

• Andrew W. Truman

Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120

• McbD, respectively, for microcin B17) that cooperate to catalyse heterocyclisation of specific serine and cysteine residues in McbA, and a flavin-dependent dehydrogenase (the “B-protein”, McbC for microcin B17) that oxidises these heterocycles. These early in vitro studies indicated that the “C-protein

• oxidatively decarboxylated cysteine residue onto a Dha residue derived from serine (Figure 5A). Extensive in vitro experiments indicate that decarboxylation of cysteine precedes 1,4-addition and is catalysed by a flavoprotein (EpiD) in epidermin biosynthesis [66][67], which uses flavin mononucleotide (FMN) to

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• processes and is known to transfer single electrons, hydrogen atoms and hydride ions to a substrate. In this way it may contribute in redox reactions as either a one- or two-electron mediator thus proving itself as a necessary molecule for the flavin-dependent enzymatic reactions in biological systems. The

• two major coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), account for the vitamin activity in human nutrition [13]. RF is among the most widely studied compounds in terms of photostability and degradation in aqueous and organic solvents. It shows strong absorption at 223

• excited triplet state of RF [24][36][59] whereas the excited singlet state plays a role in the formation of LC and CDRF [14][24][35][42]. The excitation of the RF molecule on the absorption of light takes place very rapidly as the life spans of flavin excited singlet and triplet states are approximately 5