Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• Kingdom 10.3762/bjoc.20.82 Abstract 2-(Trifluoromethylthio)benzothiazolium triflate (BT-SCF3) was used as deoxyfluorinating reagent for the synthesis of versatile acyl fluorides directly from the corresponding carboxylic acids. These acyl fluorides were reacted with amines in a one-pot protocol to form

• . Keywords: acyl fluorides; amides; benzothiazolium salts; carboxylic acids; deoxygenative reactions; Introduction Acyl fluorides are attracting much attention as versatile reagents for different applications in organic synthesis. In addition to their use as sources of fluoride ions, they are most commonly

• afford (trifluoromethyl)thioethers, while subsequent work focused on the direct deoxygenative synthesis of fluorinated thioesters from carboxylic acids [29][30][31]. In each case, the reactions proceeded smoothly under operationally simple conditions while BT-SCF3 and related BT-SRF reagents are easy-to

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• Chemistry and Center for Green Chemistry, University of Massachusetts Boston, 100 Morrissey Blvd, Boston, MA 02125, USA 10.3762/bjoc.20.81 Abstract A new method for the synthesis of heterocyclic systems containing tetrazole and tetrahydroisoquinoline is developed via the performance of one-pot Ugi-azide

• fused imidazotetrazolodiazepinones (Scheme 2A) [37]. The Gámez-Montaño group introduced a one-pot synthesis of Ugi-azide/N-acylation/Diels–Alder/dehydration reactions for isoindolin-1-one and 1,5-DS-T in a linked manner (Scheme 2B) [41]. The Ding group developed sequential Ugi-azide/Ag-catalyzed

• oxidative cycloisomerization reactions for the synthesis of 2-tetrazolyl-substituted 3-acylpyrroles (Scheme 2C) [42]. The Ding group also reported sequential Ugi-azide/Staudinger/aza-Wittig/addition/Ag-catalyzed cyclization reactions for obtaining 12-tetrazolyl-substituted (E)-5H-quinazolino[3,2-a

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• Abstract The development of a new and straightforward chemoselective method for the synthesis of uracil-based structures by combining Suzuki–Miyaura and Sonogashira–Hagihara cross-coupling is reported. The methodology was applied to synthesize a series of novel compounds. The tolerance of the combination

• a targeted enzyme [21][22][23]. One of these focus areas was the synthesis of alkyne-linked derivatives. The first alkyne-linked compound was already published in 1976, accompanied by new synthesis methods in the following years [24][25][26][27]. With the discovery of potential antiviral properties

• this work, we report a new chemoselective method for the synthesis of a series of hitherto unknown uracil-based compounds by combining Suzuki–Miyaura and Sonogashira–Hagihara cross-coupling [60][61]. The method is designed to be flexible and could also be used to synthesize other structural motifs

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• attributed to its much greater Lewis basicity compared to other azoles, likely killing the reactivity of the iodine(III) electrophile by direct coordination. The present reaction could be performed on a preparative scale. Thus, 1 mmol-scale synthesis of the vinylazoles 4aa and 4ba could be successfully

• other heteroatom nucleophiles is currently underway. Synthesis of N-vinylazoles. Scope of three-component N-alkenylation of azoles. Competition experiments and plausible reaction pathway. Preparative-scale reaction and product transformations. Reaction conditions: (a) Pd(PPh3)4, 4-MeOC6H4B(OH)2, Cs2CO3

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• straightforward synthesis of a wide-range of disubstituted BCPs from [1.1.1]propellane allows them to be easily integrated into drug discovery programmes. The case of Darapladib is one well-known example of a productive para-benzene-to-BCP bioisosteric switch [24]. By comparison, the number of bioisosteres of

• . Bennet and co-workers also reported the synthesis of 1-amino-1,2-BCPs (±)-11a–e via a similar strategy (Scheme 1C) [29]. They were able to prepare differently-substituted [1.1.1]propellanes 3b–f and subject these to strain-release amination reactions. The synthesis was shown to tolerate typical alcohol

• ) [32]. The synthesis of the corresponding 2-aza-1,5-BCHs 13 was achieved by an intramolecular photochemical [2 + 2] cycloaddition. They were able to employ this synthetic route to synthesise a variety of 1,2-BCPs (±)-14 bearing a protected amine in the bridge position. In early 2023, MacMillan and co

Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• process. Derivatization of spiroviolene for X-ray crystallography. A) Hydroboration/oxidation reaction of spiroviolene involving a borane migration process. B) Synthesis of the hydrazone derivative of spiroviolene for single-crystal X-ray diffraction. Supporting Information Supporting Information File 19

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• . Keywords: annulation; arylocyclization; 3,4-benzocoumarin; diaryliodonium salts; naphthol; Introduction Diaryliodonium salts as electrophilic reagents have attracted significant attention in the field of organic synthesis owing to their efficiency and selectivity [1][2][3][4][5][6][7]. Particularly, they

• for the synthesis of functional materials via cross-coupling reactions. Next, we extended our investigation to 1-naphthol in this reaction, and found that the arylation of 1-naphthol was achieved selectively at the C-2 position. The cascade cyclization resulted in the corresponding products 3an and

• diaryliodonium salts in a cascade cyclization, the cyclization features a copper-catalyzed activation strategy involving the cleavage of the C–I bond and esterification. The resulting cascade of selective arylation/intramolecular cyclization facilitated the synthesis of 3,4-benzocoumarin derivatives. The

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• ) is produced selectively when cellulose-containing materials, including lignocellulosic biomass, are acidified and pyrolysed [1][2]. Lab scale synthesis of this chiral material can be accomplished in a single step without special glassware [3], while large scale production of the reduction product

• the glycosidic bond using an organometallic purine or pyrimidine derivative and an electrophilic furanose derivative [23][25]. This process can result in anomeric mixtures, so 5 has potential applications in targeted synthesis, as the configuration of the pseudo-anomeric centre matches the common

• biological ribosides. This prompted an investigation of the scope of the SOCl2-mediated rearrangement, with the aim of producing useful chiral materials for synthesis. Results and Discussion The set of bicyclic systems 10a–f with a C4 alcohol were prepared starting with cyrene (2) by alkylation and then

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

• Dongxu Zhang,
• Wenyu Du,
• Xingming Pan,
• Xiaoxu Lin,
• Fang-Ru Li,
• Qingling Wang,
• Qian Yang,
• Hui-Min Xu and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73

• identical with the drimenol standard, suggesting successful synthesis of drimenol. This confirms CavC as a DMS, and the cav BGC is likely responsible for the biosynthesis of compounds 2–4. CavA, a P450, responsible for the formation of C-2 and C-3 hydroxy groups It was hypothesized that compound 1 serves as

• findings from both the heterologous expression and substrate spectrum analysis indicate the particular affinity of CavA for the C-3 position, which might be used for chemoenzymatic synthesis of C-3 hydroxylated drimanyl meroterpenoids using drimenol and its analogues as substrates. However, it is important

• efficient chemoenzymatic synthesis of DMTs or drimanyl indoles [44]. (a) Representative bioactive drimane-type sesquiterpenoids (DMTs). (b) Reported biosynthetic pathways of DMTs from fungi. Chemical structures and HPLC analysis. (a) Chemical structures of isolated sesquiterpenes 2–4 from S. clavuligerus

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• focusing on hydrochlorination reactions. Firstly, an outstanding overview, including extensive research from the former Soviet Union, was reported in 1982 by Sergeev and co-workers [12]. Secondly, the chapter on “Addition of H-X Reagents to Alkenes and Alkynes” in comprehensive organic synthesis gives a

• solution of HCl, even in the presence of secondary alcohol and ester functionalities (Scheme 5B) [45]. An application in the synthesis of Δ9-tetrahydrocannabutol, the butyl homologue of Δ9-tetrahydrocannabinol (Δ9-THC), is outlined in Scheme 5C [46]. In this case, ZnCl2 was employed as a catalyst, but

• reported. In surface-mediated reactions, the proton donor is typically Si–OH or Al–OH. For clarity in discussing subsequent reactions, we have separated the in situ HCl gas synthesis from the hydrochlorination. It is important to note that these reactions are one-pot processes rather than two-pot reactions

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• of hydrophilic oligopeptide anchors (oligo-Lys, oligo-Glu, and oligo-Arg) were synthesized. A previously reported Prato reaction adduct of a biscarboxylic acid-substituted C60 derivative was subjected to a solid phase synthesis for amide formation with N-terminal amines of peptides on resin to

• suitable for the coupling to peptides on resin, prepared by solid-phase peptide synthesis (SPPS) [35]. The detailed conditions for the amide-forming reaction were optimized using biscarboxylic acid-substituted C60 derivative 3 and a similar peptide with a primary amine derived from γ-aminobutyric acid

• (GABA) at the N-terminus of the Lys pentamer peptide on resin. Using the optimal reaction conditions, three types of hydrophilic peptide pentamers on resin, oligo-Lys (2a), oligo-Glu (2b), and oligo-Arg (2c), were subjected to the reaction with 3 for the synthesis of C60–peptide conjugates 5a–c (Figure

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• synthesis and characterization of tris(carboranyl)porphyrins of A3B-type (where “B” corresponds to the substituent responsible for bioconjugate coupling) based on the transformations of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin which was used as a basic compound for the synthesis of new boronated

• conjugates with functionalized linker groups suitable for bioconjugation or which may be efficient for PDT and BNCT improvement. Results and Discussion Synthesis Nucleophilic substitution reactions of the four p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (1) are well studied [15][16

• and the data are given in Table 1. The 11B NMR signals of compounds 5–7, 11, 12, 14, 18–20, 23, 24, and 26 are in the range from δ = −0.9 to −17.0 ppm confirming the closo-structure of the carborane polyhedra. Conclusion In this article a synthesis of A3B-type carboranylporphyrins as potential

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• the tetR regulator have been reported in several studies as methods to improve target-substance production capacity. Interestingly, Wilbanks et al. reported the structure–activity relationships of bacterial hormones in secondary metabolite biosynthesis by diversifiable synthesis [41]. The ability to

• ribosomal S12 protein mutation results in increased expression of translation factors, which leads to enhanced protein synthesis in secondary metabolism [47]. Liu et al. reported activation of the production of bohemamines 11–13, bacterial alkaloids containing a pyrrolizidine core with two unusual methyl

• higher yield of validamycin A (25) from Streptomyces hygroscopicus 5008 together with more rapid protein synthesis and sugar consumption by subjecting cultures to one or more NaOH shocks [66]. Ren et al. obtained enhanced ε-poly-ʟ-lysine (ε-PL, 26) production by acidic pH shock of Streptomyces sp. M-Z18

Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins

• Zhongwei Hua,
• Nan Liu and
• Xiaohui Yan

Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68

• -inflammatory properties, hepatorenal protection, and anticancer activity. They are often used as coloring and seasoning agents. Due to the limited content of crocins in plants and the high cost of chemical synthesis, the supply of crocins is insufficient to meet current demand. The biosynthetic pathways for

• cell suspension culture, heterologous biosynthesis, and total synthesis [16][17]. Crocins can be obtained from plant cell culture, but the production is prone to epigenetic silencing and toxic intermediates. The chemical synthesis of crocins is challenging due to the presence of numerous chiral centers

• -synuclein (αS), thereby alleviating the apoptosis of neuronal cells and cognitive impairment [30][31][32][33]. Lastly, the extract of C. sativus can also improve the chronic stress-induced loss of learning and memory by reducing the ROS level or regulating the synthesis of superoxide dismutase (SOD) and

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• conjunction with 13C NMR to investigate substrate acceptance by BaeJ-KS2 from module 4 of the bacillaene PKS. Results and Discussion Synthesis of N-acetylcysteamine thioesters Previous studies have shown that N-acetylcysteamine thioesters (SNAC esters) can be uploaded to KS domains [22][23][24][25]. Therefore

• , to investigate the function of the KS domain BaeJ-KS2 the synthesis of 13C-labelled (S)-11 as a mimic of the intermediate bound to the ACP of module 3 was performed. It was planned to introduce the 13C-labelling from (5-13C)glutamate into the γ-aminobutyrate portion of (S)-11. For this purpose, the

• = thioesterase. The black dot indicates a methyl branch introduced by the β-branching cassette. Synthesis of the BaeJ-KS2 substrate surrogates (S)-11 and (R)-11. Green dots represent 13C-labelled carbons. Supporting Information Supporting Information File 76: Experimental part and NMR spectra. Acknowledgements

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• .20.66 Abstract Chemoenzymatic strategies that combine synthetic and enzymatic transformations offer efficient approaches to yield target molecules, which have been increasingly employed in the synthesis of bioactive natural products. In the biosynthesis of macrocyclic nonribosomal peptides, polyketides

• , and their hybrids, thioesterase (TE) domains play a significant role in late-stage macrocyclization. These domains can accept mimics of native substrates in vitro and exhibit potential for use in total synthesis. This review summarizes the recent advances of TE domains in the chemoenzymatic synthesis

• for these natural products that aim to address the common issues in classical synthetic approaches and increase synthetic efficiencies, which have the potential to facilitate further pharmaceutical research. Keywords: biosynthesis; chemoenzymatic synthesis; macrocyclic peptides; macrocyclic

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• Julien Borrel Jerome Waser Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH 4306, 1015 Lausanne, Switzerland 10.3762/bjoc.20.64 Abstract We report the detailed background for the

• discovery and development of the synthesis of homopropargylic azides by the azido-alkynylation of alkenes. Initially, a strategy involving SOMOphilic alkynes was adopted, but only resulted in a 29% yield of the desired product. By switching to a radical-polar crossover approach and after optimization, a

• terminal azide, despite its implication in the synthesis of complex molecules [3][6]. Therefore, the development of a straightforward reaction to synthesize homopropargylic azides would be of general interest. The azido-alkynylation of alkenes would allow to generate the desired motif in a single step

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• enhanced economic efficiency, eco-friendly practices, and reduced waste. Catalysts with the highest enantioselectivity have been employed in the synthesis of essential chiral intermediates for drug production, such as amprenavir [12], rivaroxaban [13][14], linezolid [13] and salmeterol [7]. Therefore

• . Acknowledgements The parts of this work were published in the diploma thesis by Karel Chlumský (“Synthesis and catalytic application of chiral 2,2'-(pyridine-2,6-diyl)-bis(imidazolidine-4-ones”) and in the diploma thesis by Jan Mrkvička (“Synthesis and catalytic application of 2-(proline-2-yl)imidazole”).

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• , Latvia Latvian Institute of Organic Synthesis, Aizkraukles Str. 21, Riga, LV-1006, Latvia 10.3762/bjoc.20.61 Abstract 2-Chloro-4-sulfonylquinazolines undergo functional group swap when treated with an azide nucleophile: 1) the azide replaces the sulfonyl group at the C4 position; 2) the intrinsic azide

• quinazolines [17][18], and sulfonyl group rearrangement has been applied to functionalize purines [19], the literature lacks information on sulfonyl group migration in quinazolines. Notably, this transformation has not been previously reported, despite its potential utility in the synthesis of drugs such as

• terazosin and prazosin [20]. Herein, we report the use of the sulfonyl group dance to synthesize novel 4-azido-2-sulfonylquinazolines and their C2-selective modification in SNAr reactions. In addition, we offer an approach for the synthesis of terazosin and prazosin, known medications against hypertension

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• . Multicomponent reactions (MCRs) by virtue of high efficiency for the construction of complex chemicals, have shown the superiority in high step and atom economy in organic synthesis [25][26][27]. Over the past two decades, our group and others have developed a transition-metal-catalyzed MCR strategy involving

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• derivatization of this novel material. In this study, we report the synthesis of Li+@C60 derivatives via the thermal [2 + 2] cycloaddition reaction of styrene derivatives, achieving significantly higher yields of monofunctionalized Li+@C60 compared to previously reported reactions. Furthermore, by combining

• through chemical modification has been in high demand for its further applications, which is similar to what has been developed during the recent empty fullerene sciences. As a continuation of our studies on the synthesis of Li+@C60 derivatives, we herein focus on the modification of Li+@C60 through

• of Li+@C60 has been a major challenge. The approach we developed in this study proves highly advantageous for the selective formation of monofunctionalized Li+@C60 derivatives, holding great promise for the design, properties tuning, and synthesis of Li+@C60-based materials for future applications

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• existing ones. Keywords: GBB-3CR; imidazo[1,2-a]pyridine; microwave; phosphotungstic acid; Introduction Imidazo[1,2-a]pyridine is a privileged structure that plays an important role in organic synthesis and in the pharmaceutical industry. This scaffold is present in drugs with several biological

• green catalyst with greater chemical and thermal stability in comparison to other heteropolyacids [43]. HPW has been shown to catalyze MCRs in the synthesis of heterocyclic compounds with high efficiency and chemoselectivity (Figure 2), including functionalized benzo[c]chromeno[2,3-a]phenazine [44

• ], pyrazolo-fused benzophenazines [45], 4,5-dioxopyrrolidines [46], 1,2-dihydropyridine (1,2-DHPs) [47], pyrimido[4,5-b]quinoline-tetraones [48], tetrahydrobenzo[b]pyrans and indazolo[2,1-b]phthalazinetriones [49]. Herein, we report the synthesis of imidazo[1,2-a]pyridines via the GBB-3CR using HPW as

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• ; imidazolium; NHC; Introduction Imidazolium-derived nucleophilic heterocyclic carbenes (NHCs) have had a sustained impact across the fields of organometallic and main group chemistry, transition-metal catalysis, materials synthesis and organocatalysis [1]. Laterally annellated polycyclic NHCs offer a useful

• course. Laterally fused NHC motifs. Synthetic studies into the formation of a 3-aminoimdazo[5,1-b]oxazol-6-ium motif based on a gold-catalysed oxazole formation. DIPP = 2,6-diisopropylphenylamine; Pic = picolinate; PMP = p-methoxyphenyl. The synthesis of AImOxAu(I)Cl, AImOxCu(I)Cl, and AImOxIr(CO)2Cl

• literature substrates for catalysis studies. This work is based on Andrew D. Gillie’s doctoral thesis (“Synthesis and Applications of 4N-Substituted Oxazoles”, University of Birmingham, 2015). Funding We thank EPSRC and the School of Chemistry at the University of Birmingham for studentship support (ADG, MGW

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

• Aspergillus oryzae, will be also introduced. Review Standard reactions of fungal meroterpenoid biosynthesis The skeletal diversity within this group of compounds arises from polyketide synthesis, prenyl transfer, terpenoid cyclizations, and post-cyclization modifications [5]. In these reactions, terpenoid

• position of hydrogen atom abstraction and the subsequent skeletal reorganization reaction mode, resulting in the synthesis of a variety of skeletons. Thus, the meroterpenoid αKG-dependent dioxygenase is a highly potent biosynthetic enzyme, and the structure of the product can be easily altered by

• pathways Furthermore, there are examples of the enzymatic synthesis of plant-derived pharmaceutical meroterpenoids through the heterologous expression of a combination of fungal and plant biosynthetic enzymes. The biosynthetic enzymes StbA (polyketide synthase, PKS) and StbC (prenyltransferase, PT) from

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• catalysis and bioimaging [24][25][26]. In addition, such systems provide a convenient platform for creating chemo- and biosensors for rapid analysis of the ionic composition of the environment [27][28]. Results and Discussion The starting compound for the synthesis of N-acylated 2-(aminomethylene)benzo[b

• in acetonitrile. However, the simplest and most effective method was the addition of a catalytic amount of HClO4 [14]. Although studies on photoacylotropic systems have been carried out for some time [14][16], only within the framework of this work, a method for the preparative synthesis of

• reaction occurred catalytically in the presence of HClO4. A special technique for the preparative synthesis of photoproducts was developed. For the first time in the course of studying N→O acylotropic migrations, O-acylated photoproducts were comprehensively characterized by IR, 1H and 13C NMR spectroscopy