Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• . Trimethylsilyl azide is considered as a safe replacement of metal azides. We started the solvent optimization with MeOH and H2O as solvent system at room temperature, however, it did not yield any product even after 3 days (Table 1, entry 1). The use of DMF to improve the solubility of the paraformaldehyde solid

• was also unsuccessful to increase the product yield. The increased use of microwave conditions in organic synthesis [20] and our previous promising studies on microwave-assisted MCRs [21], motivated us to use microwave conditions for further optimization. Accordingly, we investigated several sets of

• ). This method is applicable to different amines, isocyanide and acid components including Ugi-4-component and Ugi-tetrazole reactions proving the desired products with low to moderate yields. The Ugi reactions were performed in MeOH at room temperature for 24 hours and without any further optimization

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

• inhibitor (R)-rolipram (5b) [15], and the commercial drug (R)-baclofen hydrochloride (6), used to treat muscle spasticity from spinal cord injury and multiple sclerosis [16]. Results and Discussion Desymmetrization of N-protected 2,5-dihydro-1H-pyrroles Some initial results and reaction optimization Based

• before. Before exploring the reactivity of the olefin towards other aryldiazonium salts, we performed a brief optimization of the process by testing several other N,N-ligands. Therefore, five other N,N-ligands were evaluated as follows: PyraBox (L2), QuinOx (L3), PyOx L4 and L5, and PyriBOx (L6) (Figure

• –Matsuda reaction of the protected 2,5-dihydro-1H-pyrroles with aryldiazonium salts catalyzed by a (S)-PyraBox–palladium complex. Optimization of the reaction conditions with tosyl-protected pyrroline 1b.a Supporting Information Supporting Information File 4: Experimental procedures and characterization

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

• effort was then focused on the optimization of the intramolecular Heck reaction of 5a for making 1,2,3,4-tetrahydroisoquinoline 6a. A systematic evaluation of different catalysts and ligands, solvents, bases, as well as reaction temperatures and times was conducted (Table 1). The Heck reaction of 5a was

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

• carried out by application of the Suzuki–Miyaura cross-coupling. The optimization was carried out with 3a as the model compound (Table 1). The starting material 3a is a sterically hindered system in which the bromine is only partially accessible, due to the large residue. This could be the reason for the

• . Synthesis of 1,3-dimethyl-5-aryl-6-[2-(aryl)ethynyl]uracils 5a–t. Reaction conditions: 3 (1 equiv), boronic acid (1.2 equiv), Pd(PPh3)4 (5 mol %), NaOH (3 equiv), dioxane/water 5:1, 100 °C, 1 h. aYields of isolated products. Optimization of the reaction conditions for the synthesis of 5a. Photophysical data

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

• iodo(III)azolation using various azoles (a single example of iodo(III)azolation using pyrazole was reported in [28]). Table 1 summarizes the results of the optimization of the reaction conditions for the vinylation of pyrazole (2a) with 1-phenyl-1-propyne (3a) and BXT (1). Upon examination of various

• . Optimization of reaction conditions.a Supporting Information Supporting Information File 22: Experimental procedures and characterization data of new compounds. Acknowledgements We thank the Central Glass Co., Ltd. for the generous donation of 1,1,1,3,3,3-hexafluoro-2-phenylpropan-2-ol (HFAB). Funding This

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

• -oxyl; BHT = butylated hydroxytoluene. Optimization of reaction conditions.a Scope of naphthols and phenols for the synthesis of 3,4-benzocoumarins.a,b. Scope of ortho-ester-substituted diaryliodonium salts.a Supporting Information Supporting Information File 16: Experimental procedures, LC–MS spectra

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• , cycloheptene (61), when exposed to a concentrated solution of HCl in dichloromethane, did not show any reaction (Table 4, entry 1). Under the same conditions, in the presence of silica gel, they observed 97% conversion and a GC yield of 62% for chloride 62 (Table 4, entry 2). Further optimization identified

• . Bogers iron-catalyzed radical hydrochlorination. Hydrochlorination instead of hydrogenation product. Optimization of the Boger protocol by researchers from Merck [88][89]. anti-Markovnikov hydrochlorinations as reported by Nicewicz. anti-Markovnikov hydrochlorinations as reported by Nicewicz; rr

• ). Stereoselective hydrochlorination of hexahydro-1H-indene (33). Hydrochlorination of cycloheptene (61). Hydrochlorination of 1-octene (63). Influence of the HCl gas pressure on the reaction yield. Control reactions for the hydrochlorination reaction of alkene 106. Optimization reactions for the hydrochlorination

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

• details and corresponding spectra for the C60–peptide conjugates 5a–c are shown in Supporting Information File 1. The optimization of the conditions for the reaction between the peptides on resin and fulleropyrrolidine 3 are described in the Results and Discussion section above. These were used to prepare

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

• 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

• high yield (72%) of the homopropargylic azide was reached. Full insights are given about the factors that were essential for the success of the optimization process. Keywords: alkyne; azide; hypervalent iodine; photoredox; trifluoroborate salt; Introduction Homopropargylic azides are important

• [45]. Herein, we describe our initial effort towards developing an azido-alkynylation of alkenes using the SOMOphilic alkyne approach instead. Then, the optimization of the RPC strategy will be discussed in detail, giving insights into the different steps of the optimization, which were available only

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

• products 4a and 6a (Scheme 6). Both model reactions with diene 2a and allene 5a were proven to be easily scalable without further conditions optimization, delivering unsaturated γ- and ε-AA derivatives 4a and 6a in good yields. Starting from the unsaturated ε-AA derivative 4a, unsaturated ζ-amino alcohols

• Supporting Information File 1. Optimization of conditions and control experiments.a Supporting Information Supporting Information File 54: Full experimental details, analytical data and NMR spetra. Funding Financial support from the National Natural Science Foundation of China

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

• scale-up of the HPW-catalyzed GBB reaction (5.0 mmol) between 2-aminopyridine (1a), 4-nitrobenzaldehyde (2a) and cyclohexyl isocyanide (3) in EtOH under μw heating. Plausible reaction mechanism for the HPW-catalyzed GBB reaction. Optimization of the reaction conditions.a Comparison of reaction

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

• investigations, accompanied by fermentation media optimization, of a newly isolated fungus, Penicillium shentong XL-F41, led to the isolation of twelve compounds. Among these are two novel indole terpene alkaloids, shentonins A and B (1 and 2), and a new fatty acid 3. Shentonin A (1) is distinguished by an

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

• ). bsIDH (Uniprot ID P26935) was gene synthesized with codon optimization and cloned into pET28a by Twist Bioscience. pET28a-bsIDH was transformed into E. coli BL21 star (DE3) (Agilent). For overnight cultures, 5–6 colonies were inoculated into 50 mL of LB supplemented with 10 μg mL−1 ampicillin and 1.5 μg

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

• the filamentous fungus Stachbotrys bisbyi were produced in A. oryzae to synthesize grifolic acid (60) (Figure 9) [39]. In addition, the gene encoding DCAS, a prenyl group oxidase from the plant Rhododendron dauricum, was additionally expressed in A. oryzae expressing stbAC after codon-optimization to

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• previous paper [9]. After the structural optimization calculation of the (meta)stable conformations until the Hellman–Feynman force acting on each atom was less than 10−6 Ry/Bohr, the nudged elastic band method determined the minimum energy pathway. Intermediate images created by linear interpolation

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• via reduction of the thiazole moiety: optimization of the reaction conditions.a Preemergence in vivo efficacy screening of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines 7a–c and 13a–c as well as of N-acylated analogs 14a–c and 16a–f against selected monocotyledon weeds, and binding affinity to FAT A from

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• gold and HOTf, however, they are not easily explained by simple either/or mechanisms [14][32][33]. Due in part to optimization challenges and in part to remaining gaps in characterizing structure–activity relationships for alkene hydroamination, we sought to obtain additional understanding by

• characterized as general acid catalysis (without invoking gold alkyl intermediates). Although many facets of this reaction remain to be understood, there are many practical implications of our work. For example, future catalyst optimization should focus on designing ligands that create more electrophilc gold

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• selective difluorination using fluorine gas. After screening basic additives as mediating agents and subsequent optimization (see Supporting Information File 1), we found that reaction of ethyl benzoylacetate (4a), quinuclidine (1.5 equiv), and fluorine (3 equiv) in acetonitrile gave the desired

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• advantages. DBDMH is a well-known brominating and oxidizing agent that has recently gained special attention as a highly efficient, commercially available and inexpensive homogeneous catalyst [81]. After optimization, it was found that when employing a molar ratio of benzaldehyde, indole and DBDMH of 1:2

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• ). The DFT calculations [32] were performed using the Gaussian 16 program package [33] with the B3LYP functional [34] and the 6-311++G(d,p) basis set. The structures corresponding to minima on the potential energy surface and states with broken symmetry [20] were found through complete optimization of

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• was obtained from HRMS, which gave a single peak at m/z 1138.0868 corresponding to [2a + Na]+. Further optimization was then carried out to obtain the bis(fulleroid) derivative alone (Table S1 in Supporting Information File 1). On increasing the reaction temperature to 120 °C and 180 °C the results

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• atmosphere. Isolated yields. Substrate scope of amines. Reaction conditions: alkylthianthrenium salts 1 (0.3 mmol), amines 2 (0.2 mmol), DIPEA (0.4 mmol) in 2.0 mL of MeCN at 80 °C for 16 h under air atmosphere. Isolated yields. Scale-up reaction. Optimization of the thioetherification of S-(alkyl

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• have successfully optimized a modular approach for the synthesis of lipid II and its analogues, including variants with distinct prenyl-chain lengths. The key to this methodology lies in the optimization of glycosylation conditions, utilizing readily available glycosyl donors, which is a pivotal step

• lipid II-binding antimicrobials, see recent review by Buijs and co-workers [2]. List of i) glycosyl donors and ii) glycosyl acceptors used in this study. Synthesis of disaccharide pentapeptide core 7. Synthesis of lipid II (11) and its analogues 8–10. Optimization of the glycosylation conditions.a

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

• Youlong Du,
• Haibo Mei,
• Ata Makarem,
• Ramin Javahershenas,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

• bring any improvement on the reaction outcome (Table 1, entries 6 and 7). Further optimization of the reaction conditions focused on the variation of the amounts of amine 1a and tert-butyl nitrite (Table 1, entries 8–12). Considering the instability of the diazo structure generated from amine 1a, we

• . Control experiments. Proposed reaction mechanism. Scale-up synthesis. Optimization of reaction conditions.a Supporting Information Supporting Information File 8: Experimental details and spectral data. Funding We gratefully acknowledge the financial support from the National Natural Science Foundation

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• . Reaction optimization studies.a The effect of Hantzsch esters and other reaction parameters.a Supporting Information Supporting Information File 4: Full experimental details and characterization data of all compounds. Funding We are grateful for the financial support provided by the National Nature