Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• downfield-shifted NMR resonances at H-2 [δC 4.24 for 1; δC 2.30 and 2.09 for 13] and C-2 [δC 87.8 for 1; δC 48.4 for 13] suggesting the presence of a hydroxy group at C-2 in compound 1. This initial proposal was supported by the HMBC correlations of H-4 and H-11 with C-2 and H-2 with C-3 (Figure 2A). The

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• quaternary carbon stereocenters in 86% yield. Reduction of aldehyde 119 and subsequent transesterification produced a lactone (not shown). It was exposed to SeO2 to install the allylic hydroxy group to give 120 in 65% yield. Upon catalytic hydrogenation of 120, alcohol 121 was formed. This alcohol 120 was

Fluorine effect in nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-hexopyranose

• Danny Lainé,
• Vincent Denavit,
• Olivier Lessard,
• Laurie Carrier,
• Charles-Émile Fecteau,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2020, 16, 2880–2887, doi:10.3762/bjoc.16.237

• reactive site at C4). Although rather disappointing in terms of yields, these results shed some light on the fact that both the stereochemistry of the fluorine atom at C2 and the C4 hydroxy group could influence the outcome of the fluorodeoxygenation at C4 for 1,6-anhydro-hexopyranose systems in the

• studied conditions. At this point, it became obvious to us that it would be difficult to selectively prepare 1,6-anhydro-2,3,4-trideoxy-2,3,4-trifluorohexopyranose analogues using DAST-mediated deoxyfluorination. Consequently, we turned our attention towards activation of the C4 hydroxy group as a

Changed reactivity of secondary hydroxy groups in C8-modified adenosine – lessons learned from silylation

• Jennifer Frommer and
• Sabine Müller

Beilstein J. Org. Chem. 2020, 16, 2854–2861, doi:10.3762/bjoc.16.234

• functions were removed. We used TEA·3HF in DMF for this purpose, allowing easy purification of the deprotected nucleoside derivative 5 by crystallization from DCM with a yield of 60% over two reaction steps. Next, the 5’-hydroxy group was protected with DMT, and the linker on C8 was introduced by

3-Acetoxy-fatty acid isoprenyl esters from androconia of the ithomiine butterfly Ithomia salapia

• Florian Mann,
• Daiane Szczerbowski,
• Lisa de Silva,
• Melanie McClure,
• Marianne Elias and
• Stefan Schulz

Beilstein J. Org. Chem. 2020, 16, 2776–2787, doi:10.3762/bjoc.16.228

• . Nevertheless, the transesterified sample discussed before contained methyl hydroxyalkanoates, which allowed easy location of the hydroxy-group position by GC/MS [28]. The ion m/z 103 in the spectra of the three dominating acids confirmed the location of the acetoxy group at C-3 (see Supporting Information File

Bifurcated synthesis of methylene-lactone- and methylene-lactam-fused spirolactams via electrophilic amide allylation of γ-phenylthio-functionalized γ-lactams

• Tetsuya Sengoku,
• Koki Makino,
• Ayumi Iijima,
• Toshiyasu Inuzuka and
• Hidemi Yoda

Beilstein J. Org. Chem. 2020, 16, 2769–2775, doi:10.3762/bjoc.16.227

• equivalents of NaH to give the corresponding adducts in excellent yields. The remaining phenylthio group was substituted with a hydroxy group by treatment with CuBr, and the resulting γ-hydroxyamides were cyclized under acidic conditions to afford the corresponding methylene-lactam-fused spirolactams in high

• the corresponding stabilized anion [20] and is readily transformed into a hydroxy group by treatment with copper bromide according to our previous work [21]. Allylation of 2b with 1a at room temperature proceeded in the presence of a catalytic amount of Pd(PPh3)4 by using potassium tert-butoxide or

• group of 3b with a hydroxy group was readily achieved by treatment with CuBr in aqueous media (THF/H2O) to afford the corresponding hydroxylactam in 90% yield (Scheme 2). However, the subsequent spirolactonization with p-toluenesulfonic acid (p-TsOH) was unsuccessful, leading to predominant production

Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans

• Viola Kolaříková,
• Markéta Rybáčková,
• Martin Svoboda and
• Jaroslav Kvíčala

Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226

• reactions of but-2-ynyl bromide (5b), pent-2-ynyl bromide (5c), and hex-2-ynyl bromide (5d) gave complex mixtures with significant admixtures of allenic products (Scheme 5). An alternative synthetic pathway to diynols 4b–d was hence developed consisting of the protection of the hydroxy group in diynol 4a as

A consensus-based and readable extension of Linear Code for Reaction Rules (LiCoRR)

• Benjamin P. Kellman,
• Yujie Zhang,
• Emma Logomasini,
• Eric Meinhardt,
• Karla P. Godinez-Macias,
• Austin W. T. Chiang,
• James T. Sorrentino,
• Chenguang Liang,
• Bokan Bao,
• Yusen Zhou,
• Sachiko Akase,
• Isami Sogabe,
• Thukaa Kouka,
• Elizabeth A. Winzeler,
• Iain B. H. Wilson,
• Matthew P. Campbell,
• Sriram Neelamegham,
• Frederick J. Krambeck,
• Kiyoko F. Aoki-Kinoshita and
• Nathan E. Lewis

Beilstein J. Org. Chem. 2020, 16, 2645–2662, doi:10.3762/bjoc.16.215

• facilitate the discovery of any monosaccharide–monosaccharide relation. For example, the fucose-galactose relation can be found in row 1479 of Table S6 (Supporting Information File 1). They differ by one hydroxy group therefore fucose could be represented as “A[6D]”. Similarly, abequose, a dideoxy galactose

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• of magnesium ions on metabolic transformations of nucleosides [45], in particular on the phosphorylation of the primary hydroxy group of pentoses, catalyzed by ribokinases [46], as well as on the cascade synthesis of nucleosides starting from pentoses [47][48][49][50] has been described. Based on the

Comparative ligand structural analytics illustrated on variably glycosylated MUC1 antigen–antibody binding

• Christopher B. Barnett,
• Tharindu Senapathi and
• Kevin J. Naidoo

Beilstein J. Org. Chem. 2020, 16, 2540–2550, doi:10.3762/bjoc.16.206

• %), Tyr37–Pro2 (46.73%), Arg55–Asp3 (37.77%), and Tyr54–Asp3 (31.44%). A hydrogen bond (0.15%) was observed between the hydroxy group of Tyr100 of chain B of the antibody and the 6-hydroxy group of the GalNAc. While seemingly short-lived, it occurs with some frequency throughout the simulation (see Figure

Regioselective cobalt(II)-catalyzed [2 + 3] cycloaddition reaction of fluoroalkylated alkynes with 2-formylphenylboronic acids: easy access to 2-fluoroalkylated indenols

• Tatsuya Kumon,
• Miroku Shimada,
• Jianyan Wu,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 2193–2200, doi:10.3762/bjoc.16.184

• proton Ha of Int-3b is the same as, or higher than the hydroxy group of Int-4b due to the electron-withdrawing effect of the fluoroalkyl group. It should be noted that this process is probably accelerated by 2-propanol or H2O, which is explained by the results that the most 3-fluoroalkylated indenol 4aA

Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction

• Alexander N. Reznikov,
• Dmitry S. Nikerov,
• Anastasiya E. Sibiryakova,
• Victor B. Rybakov,
• Evgeniy V. Golovin and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2020, 16, 2073–2079, doi:10.3762/bjoc.16.174

• -crystal X-ray crystallographic analysis (Figure 4) [51]. All hydrogen atoms and the hydroxy group occupy an axial position, while the remaining substituents are in equatorial positions. This is consistent with the 1H NMR data for other similar tetrahydropyranols 13b–f, therefore, their configuration was

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• produced 46. The hydrozirconation of 46 with Schwartz’s reagent under equilibrating conditions, followed by the reaction with I2 gave the vinyl iodide 47. Finally, the activation of the C-14 hydroxy group and the SN2 displacement with azide gave the C-8–C-16 fragment 48. Ghosh relied on a reductive

• ketals. The protection of the C-4 hydroxy group, hydrolysis of the acetonide, and selective tosylation of the 1° alcohol were prerequisites for the generation of the C-5–C-6 bond. To this end, the reaction of 82 with the ylide generated from trimethylsulfonium iodide gave the allylic alcohol 83. The

• cleavage of the secondary triisopropylsilyl ether were prerequisites for a vanadium-catalyzed stereoselective epoxidation of the exocyclic double bond to give 90. The C-4 hydroxy group was eventually protected as a triethylsilyl ether. Through abortive attempts, Jacobsen found that the generation of the

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

• Yuqing Wang,
• Gaigai Wang,
• Anatoly A. Peshkov,
• Ruwei Yao,
• Muhammad Hasan,
• Manzoor Zaman,
• Chao Liu,
• Stepan Kashtanov,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

• of stoichiometric amounts of the chiral promotor that was in an agreement with a two-step reaction mode requiring the initial formation of the asymmetric fluorinating agent. An attempt to use cupreine, a member of the cinchona family featuring free phenolic hydroxy group, met with failure producing

Synthesis of monophosphorylated lipid A precursors using 2-naphthylmethyl ether as a protecting group

• Jundi Xue,
• Ziyi Han,
• Gen Li,
• Khalisha A. Emmanuel,
• Cynthia L. McManus,
• Qiang Sui,
• Dongmian Ge,
• Qi Gao and
• Li Cai

Beilstein J. Org. Chem. 2020, 16, 1955–1962, doi:10.3762/bjoc.16.162

• ). The 3-hydroxy group in 5 was then protected as a Nap ether through a TMSOTf-catalyzed one-pot reductive naphthylmethylation process [17][18], by which free hydroxy groups were first trimethylsilylated in situ with hexamethyldisiloxane ((TMS)2O) before being naphthylmethylated by treatment with 2

• ) group under basic conditions followed by peracetylation afforded compound 10 on a ≈150 g scale. The regioselective anomeric deacetylation with hydrazine and reprotection of the anomeric hydroxy group as tert-butyldimethylsilyl ether (TBS) led to compound 12. Compound 12 was then treated with sodium

• compound 13. Then, (2-naphthyl)methylene acetal [21] was used to protect the C-4,6-hydroxy groups using 2-naphthaldehyde dimethyl acetal and 0.2 equiv of camphorsulfonic acid (CSA). These protecting group manipulations resulted in the exposure of the C-3 hydroxy group in compound 14 for further acylation

Selective preparation of tetrasubstituted fluoroalkenes by fluorine-directed oxetane ring-opening reactions

• Clément Q. Fontenelle,
• Thibault Thierry,
• Romain Laporte,
• Emmanuel Pfund and
• Thierry Lequeux

Beilstein J. Org. Chem. 2020, 16, 1936–1946, doi:10.3762/bjoc.16.160

• nucleotides such as the antiviral agent FPMPA (IV) [7][8][9]. Other main structural modifications of ACN relied on the introduction of a hydroxy group into the aliphatic chain to improve hydrogen bonding with enzymes [10], or of a carbon–carbon double bond to constrain the aliphatic chain and to limit

• occurring 3’-hydroxy group was achieved by allylic bromine displacement with AcOK to efficiently afford alkene 26. The phosphonate was introduced in three steps through the formation of intermediate mesylate 27. This mesylate was progressed without purification, albeit contaminated (10%) with the

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• , starting with formate. MC008 was able to fit acetate and lactate. Thus, an additional binding site was available for lactate. In the complexes of lactate with MC006–MC009, a hydrogen bond was present between the oxygen of the hydroxy group of lactate and the NH group of the macrocyclic amide. See Figure 5

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• confirmed that the reaction stopped at the bisimine I stage. This was due to the intramolecular hydrogen bonding between the hydrogen atom of the ortho-hydroxy group and the nitrogen atom of the imine group in a six-membered ring transition state [87]. Similarly, the reaction between 3-ethoxysalicylaldehyde

Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

• Xiaoyun Hu,
• Jianxin Guo,
• Cui Wang,
• Rui Zhang and
• Victor Borovkov

Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

• butanetetraol 1 is a parent compound of TADDOLs, which conventionally are obtained from enantiopure tartaric acids. The hydroxy group composition of 1 ensures its diverse reactivity. In 2010, our group established a convenient access [18] to 1 via a direct alkylation of diethyl tartrates by using PhMgBr

Synthesis, docking study and biological evaluation of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones as potential inhibitors of the mycobacterial galactan synthesis targeting the galactofuranosyltransferase GlfT2

• Marek Baráth,
• Jana Jakubčinová,
• Zuzana Konyariková,
• Stanislav Kozmon,
• Katarína Mikušová and
• Maroš Bella

Beilstein J. Org. Chem. 2020, 16, 1853–1862, doi:10.3762/bjoc.16.152

• will be discussed below. The observed binding modes of the docked molecules revealed some common interaction patterns. Interactions of the PO4 group with a metal ion and arginine R171 were observed in almost all docking poses and in some cases the C2 hydroxy group also interacted with a metal ion. The

• C5 hydroxy group very often interacts with the catalytic base aspartate D372 side chain. Moreover, in the poses where this interaction has been found, the C5 hydroxy group creates a hydrogen bond with the ammonium group of the lysine K369 residue. In many docking poses the interaction of the C3

• hydroxy group with the aspartate D256 has also been seen. The SO2 unit attached to alkyl/aryl substituents have been found in two main binding modes. In one binding mode the alkyl/aryl part is bound towards the uridine binding pocket of the UDP-Galf. The second binding mode was found in the place where

One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes

• Haruyasu Asahara,
• Minami Hiraishi and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2020, 16, 1830–1836, doi:10.3762/bjoc.16.150

• ; polysubstituted cyclohexanone; Introduction The 4-nitrophenol framework is characterized by a biased electron density in the ring and an acidic hydroxy group, which can be attributed to the electron-donating hydroxy and the electron-withdrawing nitro groups. The derivatives of 4-nitrophenol are widely used in

• trimethylsiloxy group of the diene can be converted to a phenolic hydroxy group by hydrolysis) [20], followed by the oxidation and aromatization of the obtained cyclohexanone 4 (Scheme 1). Results and Discussion Heating an acetonitrile solution of nitrostyrene 1a with Danishefsky’s diene (2) at 60 °C for 18 h

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• pure MPC-2 (see Supporting Information File 1). As shown in Figure 3, the acetylated mannose phosphoramidite β-4Ac-Man-CEP was coupled to the free hydroxy group of the citronellol derivatives containing the functional tags (Cit-BZP-yne or Cit-Dod-NBD). The reactions were performed in dichloromethane

Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71^T using linear and one-pot iterative glycosylations

• Arin Gucchait,
• Pradip Shit and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 1700–1705, doi:10.3762/bjoc.16.141

• elongation C-3 hydroxy group in the ʟ-rhamnosyl thioglycoside donor 3 allowed carrying out the stereoselective glycosylation steps followed by the removal of the PMB group [25] in one pot. This was achieved by using a combination [26][27][28][29][30] of N-iodosuccinimide (NIS) and perchloric acid supported

• treatment with HClO4-SiO2 [34]; (c) selective acetylation of the primary hydroxy group, and (d) removal of the benzyl groups by catalytic transfer hydrogenation [35] using triethylsilane in the presence of Pearlman’s catalyst [36] to furnish the desired tetrasaccharide 1 in 50% overall yield with the two O

Synthesis of Streptococcus pneumoniae serotype 9V oligosaccharide antigens

• Sharavathi G. Parameswarappa,
• Claney L. Pereira and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2020, 16, 1693–1699, doi:10.3762/bjoc.16.140

• was modified into compound 6 via benzylidene ring opening followed by benzoylation of the free C-4 secondary hydroxy group in 27. The disaccharide imidate 29 was synthesized from 6 by anomeric desilylation to afford 28 that was converted to the corresponding imidate in an excellent yield. The final [2