Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

• Alina Paffen,
• Christopher Cremer and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

• the Te(II)-catalyzed benchmark dehydrogenative phenothiazination of phenols, a reaction that we discovered in 2015 [35][36][37], under analogous conditions as previously described [30][31][32]. The results are summarized in Scheme 2. The multistep synthesis and characterization of all Te-based

• , from the standard 10 mol % to only 1 mol %, all other reaction parameters remaining identical. In these considerably more demanding conditions, PTeZ2 still performed admirably well (3aa, 45% at 3 h), significantly better than the non-catalyzed reaction (3aa, 22% after 3 h). Going from 2-methoxy towards

• -substrate interaction. Phenotellurazine-catalyzed cross-dehydrogenative couplings. Screening of new Te(II)-catalyst candidates. ODCB: ortho-dichlorobenzene. Phenotellurazine-catalyzed cross-dehydrogenative indole dimerization. Supporting Information Supporting Information File 84: Experimental section and

Oxidative hydrolysis of aliphatic bromoalkenes: scope study and reactivity insights

• Amol P. Jadhav and
• Claude Y. Legault

Beilstein J. Org. Chem. 2024, 20, 1286–1291, doi:10.3762/bjoc.20.111

• utilizing a hypervalent iodine-catalyzed oxidative hydrolysis reaction. This catalytic process provides both symmetrical and unsymmetrical dialkyl bromoketones with moderate yields across a broad range of bromoalkene substrates. Our studies also reveal the formation of Ritter-type side products by an

• the regioisomeric mixture of Ritter-type amidation side products 3. Conclusion In summary we have developed a hypervalent iodine-catalyzed synthetic method for the oxidative hydrolysis of diverse dialkyl bromoalkenes. The current approach can tolerate both symmetrical as well as unsymmetrical dialkyl

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• benzophenones 22a,b in moderate yields (Scheme 8) [38]. Again, no trend was observed depending on the structure of the chromones. 1,3-Bis(silyloxy)-1,3-butadienes The reaction of 11a–c with 1,3-bis(silyloxy)-1,3-butadienes 6a–h, catalyzed by Me3SiOTf, afforded products 23a–j with excellent diastereoselectivity

• and subsequent acid-catalyzed ring-cleavage and Knoevenagel reaction, similar to the formation of products 21 and 22. The products were formed in 54–84% yields. Again, no systematic trend was observed for the yields. Good yields were observed for dienes containing various substituents located at

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• its photochemical reactivity. The main reaction class catalyzed by excited-state polyazahelicene Aza-H so far is the redox-neutral addition of sulfinates and cyanopyridines, under elimination of cyanide, to styrenes in a three-component reaction. The proposed mechanism was derived from the redox

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• interest [12][13]. The various approaches used for selenation of aromatic compounds include directed lithiation [14][15], copper-catalyzed selenation [16][17][18], and aromatic nucleophilic substitution reactions [19][20][21][22]. Electrophilic selenium reagents (e.g., phenylselenenyl bromide) have often

• selenium center appeared to play a crucial role in the formation of the C–Se bond. AlCl3-catalyzed formation of benzoselenazole using SeO2 as electrophilic source has also been reported [35]. Quell et al. reported the syntheses of diaryl selenides and biphenol derivatives using SeO2 and phenols with one

• . have very recently reported the synthesis of the black solid 4,4'-selenodianiline without the use of catalysts, preactivation, or any blocking groups (Scheme 1) [37]. In contrast, Kim et al., utilizing a CuI-catalyzed reaction [38], have reported that 4,4'-selenodianiline is a pale brown solid, which

The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• and Figure 2). Like the oxindole scaffold, 1,2,3-triazole is also considered a privileged unit in drug discovery since compounds having this structure have a broad spectrum of biological activities, and have been widely used to create anticancer drug candidates [24][25]. The copper-catalyzed azide

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• cleavage and rearrangement reactions, which are catalyzed by AlpJ-family oxygenases, including AlpJ, JadG, and GilOII. Prior investigations established the essential requirement for FADH2/FMNH2 as cofactors when utilizing the quinone intermediate dehydrorabelomycin as a substrate. In this study, we unveil

• -dependent reactions of AlpJ-family oxygenases. Furthermore, the AlpJ- and JadG-catalyzed reactions of CR1 could be quenched by superoxide dismutase, supporting a catalytic mechanism wherein the substrate CR1 reductively activates molecular oxygen, generating a substrate radical and the superoxide anion O2

• cleavage and rearrangement in atypical angucycline biosynthesis are catalyzed by the AlpJ-family oxygenases, encompassing AlpJ, JadG, and GilOII. Biochemical analyses reveal the capability to transform the shared angucycline intermediate, dehydrorabelomycin (DHR, 1), into products with unique chemical

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• ], Reformatsky reaction [65], azalactone synthesis [66], nitro reduction [67][68], epoxide rearrangement, thiourea guanylation, and others [69][70]. In this article, we describe a simple and direct protocol for the preparation of indanones through a classical Nazarov reaction catalyzed by bismuth(III) triflate

• decarboxylated product 14. In 2010, Zhang et al. [76] developed a methodology catalyzed by In(OTf)3 for the synthesis of bicycles, and they also verified that decarboxylation occurred when the reaction remained at 80 °C for 6 h (Scheme 1). The same behavior was observed by France during the synthesis of the

• for the synthesis of 3-aryl-1-indanones. In this context, due to the formation of the previously shown derivatives 11dc,dl, we decided to explore the Nazarov reaction–decarboxylation sequence catalyzed by Bi(OTf)3 to prepare variously substituted 3-aryl-1-indanones from substrate 9. We initially

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• reactions allow the sustainable construction of C–C and C–N bonds using alcohols as hydrogen donors. In recent years, manganese complexes have been explored as efficient catalysts in these reactions. This review highlights the significant progress made in manganese-catalyzed C–C and C–N bond-formation

• importance in organic synthesis and is widely used in the pharmaceutical and other chemical industries. Palladium-catalyzed cross-coupling reactions are one of the compelling methods for building C–C and C–N bonds [1][2]. However, using organohalide reagents and harsh reaction conditions in this process

• to the scientific community [10][11][12]. In this process, first, the metal-catalyzed dehydrogenation of the alcohol provides a reactive substrate for coupling with nucleophiles and the active metal hydride species. Later, the borrowed hydrogen is used in the final step to reduce unsaturated

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• what we are discussing in this mini-review. Review Carbonylative synthesis of indoles Synthesis of indoles by Pd(0)-catalyzed carbonylation reaction of halide compounds Processes using organic halides as their starting materials involving the oxidative addition of Pd(0) to C–X bonds to give Ar–PdII–X

• complexes are important for the synthesis of heterocyclic and non-heterocyclic compounds. In 2009, Arthuis and co-workers developed a new process for the synthesis of 2-aroylindoles and 2-heteroaroylindoles by a one-pot palladium-catalyzed domino reaction that involves an initial C,N-coupling followed by

• derivatives were isolated with good yields (Scheme 1). Instead, in the Senadi et al. approach, 1-(3-amino)-1H-indol-2-yl)-1-ketones were obtained through a Pd(0)-catalyzed cascade process consisting of isonitrile insertion as carbon monoxide surrogate and a C–H cross-coupling [13]. The reaction took place in

Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• analogs have been synthesized to act as actual substrates of TSs to generate novel terpene skeletons, introduce reaction handles, and produce value-added compounds. A previous review has covered the advances of TS-catalyzed transformations of synthetic substrate analogs up to 2019 [13][42]. Here, we

• FPP is catalyzed by the C-methyltransferase SpSodMT. In 2018, the biosynthesis of an unusual homosesquiterpene, sodorifen (102, Figure 1), from Serratia plymuthica 4RX13 was elucidated [57]. The in vitro and in vivo results revealed that a SAM-dependent-C-methyltransferase catalyzed methylation and

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• herein an enantioselective palladium-catalyzed Heck–Matsuda reaction for the desymmetrization of N-protected 2,5-dihydro-1H-pyrroles with aryldiazonium salts, using the chiral N,N-ligand (S)-PyraBox. This strategy has allowed straightforward access to a diversity of 4-aryl-γ-lactams via Heck arylation

• complexity in a synthetic route. The palladium-catalyzed coupling of arenediazonium salts with olefins, the Heck–Matsuda reaction, has been instrumental in this strategy involving the desymmetrization of cyclic systems [3], especially five-membered substrates [4][5][6][7]. As we have demonstrated previously

• upward, therefore creating an asymmetric center with absolute configuration (R), in accordance with experimental results. A rationalization for the transition state that would lead to the observed outcome is depicted in Figure 2. Conclusion The palladium-catalyzed Heck–Matsuda desymmetrization of N

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

• 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

• used as the isocyanide source, the Ugi-azide reaction gives rise to ring-fused tetrazolo[1,5-a]pyrazin-6(5H)-one adducts 5. The subsequent Pd-catalyzed intramolecular Heck reaction of compounds 5 or 7 then affords 1,2,3,4-tetrohydroisoquinolines 6 and 8, respectively. Results and Discussion Following

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

• motif in bioactive compounds and the synthetic utility of its olefinic C=C bond. The most extensively explored approach to this transformation is the transition metal-catalyzed C–N coupling between azoles and vinylating agents, including vinyl halides [4], boronates [5], sulfonium salts [6][7][8], and

• agents, preferably with well-defined stereochemistry, is a nontrivial task. The addition of azoles to alkynes represents an alternative approach to N-vinylazoles. For example, Nolan and co-workers recently reported a gold-catalyzed addition of azoles to alkynes (hydroazolation; Scheme 1b) [10]. The gold

• catalysis encompassed various azoles such as pyrazole, indazole, and (benzo)triazole, exhibiting high Z-selectivity. In addition, Cao et al. reported a gold-catalyzed addition of 5-substituted tetrazoles to terminal alkynes [11]. Analogous hydroazolation reactions of alkynes have also been achieved under

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

• advantage, facilitating the formation of two or more chemical bonds in a step-economic manner [9][10][11][12][13]. In a prior study, we reported a palladium-catalyzed efficient activation of both C–I bond and the adjacent C–H bond of diaryliodonium salts in the formation of 4,5-benzocoumarin derivatives

• 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

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• may occur non-enzymatically or is catalyzed within the NnlA active site. However, an imine product has not yet been observed and further investigations of the NNG degradation mechanism are needed. Given the potential widespread presence of NnlA, it is possible that NnlA could mediate previously

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• on metal-catalyzed radical hydrochlorinations [11] and anti-Markovnikov hydrochlorination reactions, highlighting the ongoing challenges in achieving a simple addition of HCl across a simple double bond. During our literature review for this article, we identified two other significant reviews

• the metal-catalyzed hydrochlorination of alkenes based on MH HAT reactions (Scheme 23) [80]. They discovered that a combination of a cobalt catalyst, a silane, and tosyl chloride promoted the hydrochlorination of terminal unactivated alkenes. The scope of the reaction is relatively broad when

• activated alkenes [86]. Subjecting citronellol (122) to the optimized reaction conditions resulted in the formation of chloride 133 with a yield of 62% (Scheme 25). It is worth noting that the iron-catalyzed procedure tolerates free alcohols, a distinction from Carreira's protocol [80]. In 2014, the Thomas

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

• CsCCD2 belongs to a distinct branch within the CCD family. In vitro experiments confirmed that CsCCD2 catalyzed the cleavage of 7 between the 7,8- and 7',8'-double bonds, resulting in the formation of crocetin dialdehyde (8) and 3-OH-β-cyclocitral (9) [90]. Recently, Liang et al. designed a variant of

• biosynthesis of crocins in C. sativus [103]. Nagatoshi et al. identified GjUGT75L6 and GjUGT94E5 from G. jasminoides. GjUGT75L6 could catalyze the glycosylation of crocetin (1) to produce crocetin glycosyl esters 2c and 2e, and GjUGT94E5 catalyzed downstream glycosylation reactions [104]. Unexpectedly, the

• identified [105]. Specifically, GjUGT74F8 catalyzed the conversion of crocetin (1) into crocin-V (2e) and crocin-III (2c), as well as the conversion of crocin-IV (2d) to crocin-II (2b). On the other hand, GjUGT94E13 could convert crocin-II (2b) and crocin-III (2c) to crocin-I (2a) [105]. Diretto et al

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

• macrocyclizations (Scheme 1c). NAC thioester and other related mimics (such as coenzyme A (CoA), phosphopantetheine, and thiophenol) span the gap between the chemical synthesis and biosynthesis languages and expand the substrate promiscuity of TE domains. This bridge makes the in vitro TE-catalyzed macrocyclization

• several positions and also form 6–14 residue cyclic peptides [37][38]. It should be noted that TycC TE was more sensitive to the amino acid changes near the site of ring closure. The alkyne-containing analogs were conjugated to a variety of azido sugars via copper(I)-catalyzed cycloaddition to obtain the

• type B streptogramin variants [41], including pristinamycin IE (8), which belongs to the class of depsipeptide antibiotics. Similarly, the linear peptide-SNAC was prepared through the SPPS method on 2-chlorotrityl resin, and macrolactonization was catalyzed by SnbDE TE, a thioesterase from

Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to (−)-sandaracopimaradiene in the fungus Arthrinium sacchari

• Fumito Sato,
• Terutaka Sonohara,
• Shunta Fujiki,
• Akihiro Sugawara,
• Yohei Morishita,
• Taro Ozaki and
• Teigo Asai

Beilstein J. Org. Chem. 2024, 20, 714–720, doi:10.3762/bjoc.20.65

• synthesize a diterpene skeleton: After the initial cyclization of GGPP possibly catalyzed by a putative class II enzyme AsCPS, the resulting labdane or related skeleton would undergo cyclization by a putative class I enzyme AsPS. To assess this hypothesis, we conducted the functional characterization of AsPS

• organizations were discovered, these enzymes would be useful to discuss and further analyze the evolution of TCs in fungi. LRDs in fungi. A) Chemical structures of representative fungal LRDs. B) Reactions catalyzed by selected fungal bifunctional TCs. Sequence analysis of AsPS and AsCPS. A) Biosynthetic gene

• ObCPS_11g are shown. B) Proposed reactions catalyzed by AsPS, AsCPS, and acid phosphatase. Characterization of CiCPS-PS. A) GC–MS analysis of the transformant expressing CiCPS-PS and AsGGS. EICs at m/z 272 are shown. The peak marked by the asterisk is probably derived from the host strain. B) Putative

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

• efficiencies [5][6][7]. Consequently, ongoing efforts focus on advancing methodologies for synthesizing established quinazoline-based drugs and acquiring novel modified quinazoline derivatives for pharmaceutical or materials science purposes. Aromatic nucleophilic substitution [8] or metal-catalyzed reactions

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

• -light-mediated palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines, affording unsaturated γ- and ε-amino acid derivatives with diverse structures. In this methodology, the diazo compound readily transforms into a hybrid α-ester

• . 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

• crossover process [47][48][49][50]. However, activated alkyl halides are not suitable for these carboamination reactions due to the direct nucleophilic substitution of activated alkyl halides with nucleophilic reagents under the necessary alkaline conditions [51]. Recently, a Pd-catalyzed alkyl Heck

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

• polyketide portion [11][12][13][14]. One exception has been found in funiculolide biosynthesis, in which a 5-MOA-derived phthalide undergoes dearomatizing prenylation catalyzed by the UbiA-like prenyltransferase FncB (Figure 1B) [15]. In addition to prenyltransferases, transmembrane terpene cyclases play a

• acid (5-MOA)-derived meroterpenoids. (C) Reactions catalyzed by the terpene cyclases involved in DMOA-derived meroterpenoid pathways. Generation of unnatural 5-MOA-derived meroterpenoids. (A) Working concept to synthesize unnatural 5-MOA-derived meroterpenoids. SAM: S-adenosyl-ʟ-methionine; FPP

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

• (insomnia). Some recent synthetic approaches to imidazo[1,2-a]pyridine scaffolds include synthetic pathways of transition metal-catalyzed reactions [14], cyclization [15], condensation [16], heteroannular [17], and photocatalytic reactions [18]. These approaches usually involve non-trivial reaction

• 1, aromatic/heteroaromatic aldehydes 2, and isocyanides 3 to obtain the imidazo[1,2-a]pyridine derivatives 4 (Scheme 2). In general, the efficiency of the HPW-catalyzed GBB reaction is very dependent upon the type of 2-aminopyridine or isocyanide compound used, and not influenced by different

• synthesis of imidazo[1,2-a]pyridines is not as usual, given that Schiff bases from aliphatic aldehydes are found to be less stable and readily polymerize in comparison to stable Schiff bases of aromatic aldehydes. Nonetheless, our protocol for the HPW-catalyzed GBB multicomponent reaction proved to be very

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• pathway (Figure 5). Briefly, the prenyl group is attached to tryptophan through a prenylation reaction catalyzed by ShnA, followed by the decarboxylation of the carboxy group by ShnC. Subsequently, compound 2 is formed by the addition of succinimide to N15 in 1 via a reaction catalyzed by ShnB. The

• a ring-opening rearrangement. Alternatively, it is proposed that the ring-opening rearrangement precedes the methyl modification at the oxygen atom of the succinimide ring. We aim to confirm the initial step of this pathway, where tryptophan and DMAPP are catalyzed by the enzyme ShnA to form a

• reports on the biosynthetic pathways from tryptophan to quinoline rings. Through our analysis, we discovered that tryptophan in the primary metabolic pathway is primarily catalyzed by indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase (IDO and TDO), as well as canine urinary tryptophan 3