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Search for "intermediate" in Full Text gives 2111 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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

Graphical Abstract
  • 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
  • a previously unrecognized facet of these enzymes as cofactor-independent oxygenases when employing the hydroquinone intermediate CR1 as a substrate. The enzymes autonomously drive oxidative ring cleavage and rearrangement reactions of CR1, yielding products identical to those observed in cofactor
  • 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
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Published 23 May 2024

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

  • Naziha Tarannam,
  • Prashant Kumar Gupta,
  • Shani Zev and
  • Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

Graphical Abstract
  • germacradienyl cation, and 1,11-cyclization resulting in the humulyl cation [14][15]. Deprotonation of the intermediate germacradienyl cation yields germacrene A, a doorway towards the synthesis of many eudesmane and guaiane sesquiterpene hydrocarbons through its reprotonation-induced transannular reactions
  • (Scheme 1) [16]. As an alternative to deprotonation, the germacradienyl cation can be captured by water to yield the sesquiterpene alcohol hedycaryol, which is an important intermediate towards the synthesis of sesquiterpene alcohols [17]. The reprotonation of (R)-(+)-1 germacrene A or hedycaryol at the
  • analyze the intermediates formed from germacrene A and hedycaryol. These carbocations are key mechanistic branching points in different sesquiterpene synthases and calculation of their relative energy trends can explain the preference for (6,6) or (5,7) intermediate carbocations. Considering that the
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Published 23 May 2024

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

Graphical Abstract
  • products (Scheme 5). Interestingly, the dearomatized intermediate resulting from the reaction of base and Mn3 was isolated and characterized by X-ray analysis during the mechanistic investigation. In 2018, Kempe et al. disclosed that the choice of the base plays a critical role in the BH method for the
  • , respectively. The proposed mechanism suggested that the active amido species (Mn5-a) was formed by treating Mn5 with the base. Then, the alkoxy intermediate Mn5-b is formed by reaction with the alcohol followed by release of an aldehyde and formation of the manganese hydride Mn5-c. The released aldehyde
  • mesitylene (Scheme 13). The formation of manganese(III) alkoxide intermediate Mn7-a, was believed to be the first step in the reaction mechanism which then releases the aldehyde under formation of hydride complex, Mn7-b. Then, the alcohol reacts with the hydride complex under release of hydrogen gas and
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Published 21 May 2024

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

  • Maksim V. Kvach,
  • Stefan Harjes,
  • Harikrishnan M. Kurup,
  • Geoffrey B. Jameson,
  • Elena Harjes and
  • Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

Graphical Abstract
  • . Recently, a combination of the CDA inhibitor (4R)-2′-deoxy-2′,2′-difluoro-3,4,5,6-tetrahydrouridine (cedazuridine, Ib, Figure 1B) with the anticancer drug decitabine was approved as an oral pill (i.e., C-DEC or ASTX727) for the treatment of patients with intermediate or high-risk myelodysplastic syndrome
  • cytosine deamination involves a nucleophilic attack at the C4 position by a Zn2+-activated water molecule [40][41][42], it was proposed to employ transition state analogues and mimetics of the tetrahedral intermediate formed as inhibitors of these enzymes [43][44][45][46][47]. More than 30 compounds have
  • considered for the development of new nucleobases mimicking transitions states and an intermediate of cytosine deamination to improve potency of DNA-based A3 inhibitors. A) Deamination of cytosine, dC and C as individual nucleosides or as part of a polynucleotide chain. B) Previously described CDA inhibitors
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Published 15 May 2024

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

  • Tural N. Akhmedov,
  • Ajeet Kumar,
  • Daken J. Starkenburg,
  • Kyle J. Chesney,
  • Khalil A. Abboud,
  • Novruz G. Akhmedov,
  • Jiangeng Xue and
  • Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

Graphical Abstract
  • high reactivity of intermediate 7a (Scheme 4). After optimizing the successful synthesis of alkoxylated and diketone derivatives of 7a, we were intrigued to investigate whether other dicyanopyrazinoquinoxaline derivatives could undergo a similar transformation. To assess the efficacy of the reaction
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Published 08 May 2024

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

  • Luca Julianna Tóth,
  • Kateřina Krejčová,
  • Milan Dejmek,
  • Eva Žilecká,
  • Blanka Klepetářová,
  • Lenka Poštová Slavětínská,
  • Evžen Bouřa and
  • Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

Graphical Abstract
  • pyridobenzoxazole derivative 2 was designed based on the modified approach published by Dejmek et al. (Scheme 1) [24]. In this work, we first synthesized the intermediate 6 from readily available 2′,5′-dihydroxyacetophenone (5) following a published procedure [27]. This compound was then easily converted to the
  • ], and thus avoiding the use of base, leading to the desired intermediate 14 in good yield. Compound 14 was then coupled with ʟ-tyrosine methyl ester followed by deprotection of the amino acid carboxyl group by LiOH⋅H2O. As in the previous base-mediated saponification, here we also received a product of
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Published 06 May 2024

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

Graphical Abstract
  • Supporting Information File 1 for details). Given the presence of the 4-aryl-γ-lactam motif in the phosphodiesterase-4 inhibitor rolipram, and in a synthetic intermediate for the baclofen drug, the Heck products 4bg and 4bq were used as starting material for their syntheses. N-Tosylated lactams 4bg and 4bq
  • palladium(II)–N,N-ligand complex (II), to which the pyrrolidine substrate coordinates (III). Next, migratory insertion takes place generating the alkylpalladium species (IV), which upon a sequence of β-elimination (V) and hydride insertion leads to alkylpalladium intermediate (VI). Finally, upon
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Published 29 Apr 2024

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

Graphical Abstract
  • , reacting BT-SCF3 with carboxylic acids 1 under similar conditions provides (trifluoromethyl)thioesters 3 via a concerted deoxytrifluoromethylthiolation process from tetrahedral intermediate A affording thiocarbamate by-product B [31]. To test whether thioester species could act as intermediates in the
  • the acyl fluoride with addition/elimination of fluoride to a thioester intermediate and independent deoxyfluorination of a second equivalent of the acid substrate by the released −SCF3 anion both operating under the reaction conditions. This allows for the reduction in the loading of BT-SCF3 to sub
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Published 23 Apr 2024

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

Graphical Abstract
  • . The initial Ugi-azide four-component reaction constructs the tetrazole motif while the subsequent intramolecular Heck reaction assembles the tetrahydroisoquinoline. The one-pot reaction avoids the intermediate purification which has favorable PASE in the synthesis of heterocyclic compounds
  • azide (3, 1 mmol) and isocyanide 4 (1 mmol) in MeOH was stirred at 40 °C for 24 h. After the reaction was complete, the solvent was evaporated under vacuum to give the crude Ugi adduct 5, which was used in the Heck reaction without further purification. To a solution of the crude intermediate 5 in MeCN
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Published 23 Apr 2024

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

Graphical Abstract
  • intermediate. A second effect appears to play a more important role and could be related to the structure of the starting material. The 6-position is part of an enamine and an α,β-unsaturated carbonyl structure, as depicted in Scheme 3. According to the mesomeric structure of the enamine, the 6-position could
  • also investigated, but no desired product could be obtained. In fact, starting material 2 appears to be too unreactive to undergo a Suzuki reaction. Reversing the reaction steps gave the desired intermediate 5-bromo-6-phenyl-1,3-dimehtyluracil, which turned out to be unstable. This could be the reason
  • why the desired product could not be synthesized at the first attempt. Therefore, the synthesis of the desired product from starting material 2 appears to be unlikely. It is reasonable to assume that this finding is due to the instability of the intermediate formed, as the desired product has been
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Published 22 Apr 2024

(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

Graphical Abstract
  • -cubanes (Scheme 9B) [51]. Partial deprotection of diester 88 led to acid 89 as a key intermediate and in situ activation of the acid as the hypervalent iodine complex enabled a photoredox decarboxylative amination to 1,2-cubane 90. Alternatively, conversion of the acid moiety of 89 to redox active esters
  • -containing 2-oxa-1,4-BCH 110b via Mykhailiuk’s synthesis [59]. 2-Oxa-1,4-BCH 110f, which contained a bridgehead ester in addition to the pendant primary iodide, was found to be a versatile synthetic intermediate. Substitution of the primary iodide with acetate or azide led to alcohol 111 and amine 113
  • methylation of the intermediate diacid. As for the 1,2-cubanes, the authors were able to derivatise this general building block into a range of other 1,3-cubanes via metallophotoredox catalysis using acid 167 and redox active esters 168 and 169 (Scheme 17B) [51]. Arylation (to 170), amination (to 171) and
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Published 19 Apr 2024

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

Graphical Abstract
  • synthetic intermediate of 2 to spiroviolene. By taking advantage of the DFT transition state analysis of the hydroboration reaction of a key intermediate, as well as NOE correlation analysis of the resultant product, Snyder and co-workers have reassigned the right structure of spiroviolene to 1. However
  • deoxyconidiogenol (4, Scheme 1A) by several terpene cyclases from fungus (PcCS, PchDS, PrDS) [15][16], which involves a 1,11-10,14 cyclization of GGPP, followed by 1,2-alkyl shift and a 2,10-cyclization, to give the key C3 cationic intermediate IM-1. A key 1,2-hydride shift from C2 to C3, which was observed in the
  • isotope labeling experiments [6], followed by a 2,7-cyclization, afforded C6 cationic intermediate IM-3 with cyclopiane skeleton. Quench of the cation IM-3 with water would give 4, while upon two 1,2-alkyl shifts of IM-3, followed by deprotonation of cation IM-4, would give spiroviolene (1). On the other
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Published 18 Apr 2024

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

Graphical Abstract
  • of butylated hydroxytoluene (BHT) into the template reaction. Remarkably, we observed that the desired product was not formed, suggesting a radical pathway. Subsequently, we investigated the bond-formation sequence in the benzocyclization reaction. A possible intermediate of 3al’ was prepared and
  • tested in the reaction under the standard conditions, however, product 3aa was not obtained. Based on the literature known results and the experimental evidences [35][36], we proposed a plausible reaction mechanism (Scheme 2b). The reaction started with the formation of radical intermediate A from
  • diaryliodonium salt 2a. Naphthol 1a forms intermediate B with A after participation with the Cu(II) catalyst. Intermediate B generates C by radical substitution. A final intramolecular transesterification yields the benzocoumarin product 3aa. Conclusion In summary, we have employed ortho-ester-substituted
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Published 18 Apr 2024

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

Graphical Abstract
  • possibility is that NNG has several physiological functions and fates. For example, a natural product nitronate intermediate was recently shown to have two fates within Streptomyces achromogenes var. streptozoticus NRRL 3125 [46]. This nitronate intermediate was shown to be O-methylated to form O
  • -methylnitronate, and subsequently incorporated into enteromycin. Alternatively, the intermediate could be denitrified by a nitronate monooxygenase (NMO) to produce NO2−. NnlA could replace NMO as the denitrifying enzyme in NNG producing bacteria, however, a BLAST search of NnlA in the genome of Streptomyces
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Published 17 Apr 2024

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

Graphical Abstract
  • ]octane ring-system via the chlorosulfite intermediate. Analogous allylic alcohols with endocyclic and exocyclic unsaturations underwent chlorination without rearrangement due to formation of allylic cations. The rearrangement was also demonstrated using Appel conditions, which gave similar results via
  • the alkoxytriphenylphosphonium intermediate. Several reactions of the products were investigated to show the utility of the rearrangement. Keywords: bicyclic ring; cyrene; levoglucosenone; rearrangement; thionyl chloride; Introduction The 6,8-dioxabicyclo[3.2.1]octane derivative levoglucosenone (1
  • some sulfites 13b,d,e, attributed to the reduced steric hindrance in the chlorosulfite intermediate allowing for the second alcohol to approach prior to rearrangement. The isolation of these materials suggested that dialkyl sulfite formation could compete with the rearrangement if the neighbouring
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Published 16 Apr 2024

Advancements in hydrochlorination of alkenes

  • Daniel S. Müller

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

Graphical Abstract
  • the higher-substituted carbon atom to furnish intermediate species C. The irreversibility of the hydride addition and the regioselectivity thereof were supported by a deuterium labelling study with PhSiD3. The next steps involve homolytic cleavage of the cobalt–carbon bond to yield a carbon-centered
  • radical D which is then trapped by TsCl to produce the corresponding alkyl chloride E. Detailed mechanistic studies on a related reaction were recently reported by Shenvi and co-workes [84]. These studies alternatively suggest that intermediate C could also be the result not of a non-simultaneous addition
  • of the Co–H to the alkene but of a step-wise radical addition. A similar procedure was reported by Herzon [85]. His study focused on the use of two reductants, triethylsilane and 1,4-dihydrobenzene (DHB) (Scheme 24). He showed that in the presence of DHB, the intermediate radical could be trapped by
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Published 15 Apr 2024

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

Graphical Abstract
  • second ketosynthase of the polyketide synthase BaeJ involved in bacillaene biosynthesis (BaeJ-KS2). For this purpose, both enantiomers of a 13C-labelled N-acetylcysteamine thioester (SNAC ester) surrogate of the proposed natural intermediate of BaeJ-KS2 were synthesised, including an enzymatic step with
  • of a ketoreductase (KR) domain in module 1, the starter unit was initially suggested to be α-hydroxyisocaproate [14], but later it was shown that the KR of module 3 acts twice, in the reduction of the β-ketoacyl intermediate of the elongation step of module 3 and in the reduction of the α
  • -ketoisocaproate starter unit with introduction of an S configured stereocentre (highlighted in red in Scheme 1) [15]. The domain organisation of module 3 containing no enoylreductase (ER) domain furthermore suggests the formation of an α,β-unsaturated intermediate, and not a full reduction at this stage, in
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Published 05 Apr 2024

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

Graphical Abstract
  • responsible for the structural diversity of natural products, both NRPS and PKS contain thioesterase (TE) domains in the final elongation module, which contribute to terminating biosynthesis [13][14]. Typically, TE domains cleave the thioester bond between the last PCP or ACP domain and the intermediate of
  • terminal polyketide synthases (PKSs) in juvenimicin biosynthesis in 2017 [75], which presented a chance to accomplish the chemoenzymatic total syntheses of tylactone and the juvenimicins (Scheme 7). To generate an appropriately activated tylactone hexaketide intermediate 49, two key fragments, aldehyde 42
  • depsipeptide ring and broad tolerance for structural variation [84]. To simplify the synthetic process and expedite the comprehensive structure–activity relationship analysis, they modified the preparation of the linear chain elongation intermediate and conjugated the late-stage P450-catalyzed selective
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Published 04 Apr 2024

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

Graphical Abstract
  • stereoisomers, ent-CPP and syn-CPP. Class II TCs can also generate further structural diversity through hydride shifts, methyl shifts, and/or skeletal rearrangement of the labdadienyl+ diphosphate intermediate which is formed by the initial bicyclization. Following this class II TC-mediated cyclization, class I
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Published 03 Apr 2024

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

Graphical Abstract
  • would initially involve the addition of azide radicals to an alkene, generating a carbon-centered radical. Then, different trapping of this intermediate could be performed (Scheme 1B). First, C-centered radicals are known to recombine with metal-acetylides, in particular copper [27]. Reductive
  • elimination of the organometallic intermediate would lead to the desired product (Scheme 1B, reaction 1). Unfortunately, this approach will not be compatible in the case of azidation since the copper, azides and alkynes present in the mixture are expected to undergo alkyne–azide cycloaddition reactions [28
  • minimized diazide formation. Next, a solvent screening was performed as it can vastly influence reaction proceeding via a carbocation intermediate. Alkynyltrifluoroborates have a low solubility in chlorinated solvents but are well soluble in acetonitrile. Although this solvent has been used in similar
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Published 03 Apr 2024

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

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  • first attempts in iPrOH did not provide the starting material conversion. The reaction in THF resulted in the full conversion of the starting material, but the analysis of the crude product revealed the quantitative formation of hydrolysis product 5a. Assuming the instability of intermediate 2a, a one
  • hydrolysis product 5a. In MeCN the conversion to derivative 2a was stopped at 50% and was not facilitated by an extra addition of sulfinate. To our delight, in MeOH we observed the formation of intermediate 2a over 5 hours, and after the subsequent addition of sodium azide product 4a was isolated in 31
  • % purity) [26] provided a more selective reaction, no water-based work-up was needed and the pure product was obtained by simple recrystallization from ethanol in yields up to 88%. The oxidation step thiol → sulfoxide was fast and full conversion to the intermediate was achieved in one hour for most
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Published 28 Mar 2024

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

Graphical Abstract
  • alkylpalladium radical with the release of dinitrogen. The radical intermediate selectively adds to the double bond of a 1,3-diene or allene, followed by the allylpalladium radical-polar crossover path and selective allylic substitution with the amine substrate, thereby leading to a single unsaturated γ- or ε
  • intermediate B should be ruled out from this methodology (Scheme 4b). The product Z-6i was subjected to the standard conditions, but Z-6i was obtained in 100% recovery yield. Therefore, the E/Z selectivity of the MCRs with allenes could be determined by the allylic substitution process (Scheme 4c). Using HPd
  • ) Radical trapping experiments with TEMPO. b) Exclusion of possible intermediate. c) Subjecting the product Z-6i to the standard conditions. d) The control reaction with HPd(PPh3)2Cl. e) UV–visible absorption analysis. Proposed mechanisms for the carboamination of 1,3-dienes or allenes with diazo esters and
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Published 27 Mar 2024

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

Graphical Abstract
  • key role in diversifying the structures of fungal meroterpenoids [16]. For example, (6R,10′R)-epoxyfarnesyl-DMOA methyl ester, a common intermediate with a linear terpenoid moiety, is known to be recognized by five different enzymes, namely Trt1, AusL, AdrI, InsA7, and InsB2, resulting in conversion
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Published 20 Mar 2024

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

  • Michael O. Akintubosun and
  • Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

Graphical Abstract
  • Hygromycin A is a broad-spectrum antibiotic that contains an aminocyclitol moiety essential for bioactivity [6][7]. The biosynthesis of the aminocyclitol has been proposed to proceed through six steps starting from glucose-6-phosphate through a myo-inositol intermediate to the final methylenedioxy
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Published 14 Mar 2024

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

Graphical Abstract
  • resulting cation intermediate at C-4' to induce an acyl shift, forming the steroid-like structure of 7 with a 6-6-6-5 ring (Figure 2). Swapping terpenoid cyclases in heterologous expression systems A search of the genome database for Trt1-homolog CYCs revealed the enzyme AusL (41% identity with Trt1) in
  • -6-6-5-membered andrastin E (9) (Figure 2) [8]. Like Trt1, AusL and AdrI create the common cation intermediate from 6, but they deprotonate the cationic intermediate from H-1' and H-11, respectively [12]. The differences in the structural bases of Trt1, AusL, and AdrI are quite intriguing, in that
  • was created, and produced the new compound 11, as expected. In this mutant, deprotonation occurs from the OH-3 of the folded intermediate, and the altered cyclization mode produces 11 (Figure 2). Reconstitution based on the several meroterpenoid pathways in heterologous expression systems Recently
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Published 13 Mar 2024
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