Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• nucleosides 2,6-dichloro-9-(2,3,5-tri-O-acetyl-5-C-(3-mesitylisoxazol-5-yl)-α-ʟ-idopentofuranosyl)-9H-purine (91) and 2,6-dichloro-9-(2,3,5-tri-O-acetyl-5-C-(1-phenyl-1,2,3-triazol-4-yl)-β-ᴅ-glucopentofuranosyl)-9H-purine (92) starting from 3,5-di-O-acetyl-6,7-dideoxy-1,2-O-isopropylidene-ʟ-ido/α-ᴅ-gluco-hept

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

• Rashmi Singh,
• Tomas Horsten,
• Rashmi Prakash,
• Swapan Dey and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79

• converted to novel oxazole-fused derivatives 19 and 20, respectively, by condensation with benzaldehyde and subsequent 2,3-dichloro-5.6-dicyano-p-benzoquinone (DDQ)-mediated oxidation (Scheme 3). Aldehyde building block 16 was a versatile starting material for further cyclization reactions. Synthesis of

Unexpected rearrangements and a novel synthesis of 1,1-dichloro-1-alkenones from 1,1,1-trifluoroalkanones with aluminium trichloride

• Beatrice Lansbergen,
• Catherine S. Meister and
• Michael C. McLeod

Beilstein J. Org. Chem. 2021, 17, 404–409, doi:10.3762/bjoc.17.36

• of 1,1-dichloro-1-alkenones. The reaction scope was found to be broad, with various chain lengths and aryl substituents tolerated. For substrates containing an electron-rich aromatic ring, further reactions take place, resulting in bicyclic and/or rearrangement products. Keywords: aluminium

• trichloride; dichloroalkenes; Friedel–Crafts alkylation; rearrangement; trifluoroalkanes; Introduction 1,1-Dichloro-1-alkenes are valuable synthetic intermediates and have been employed in Pd-mediated cross couplings of one or both chlorine atoms [1][2][3][4][5][6][7], carbonylation reactions [8], and C–H

• bond alkynylations of heteroarenes [9]. The 1,1-dichloro-1-alkenyl moiety is found in a number of pyrethroid insecticides including permethrin and marine natural products such as caracolamide A [10] (Figure 1). 1,1-Dichloro-1-alkenes 2 are commonly prepared from the corresponding aldehydes 1 in one

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

• reaction of 4,5-dichloro-3,6-di-tert-butyl-o-benzoquinone (4) [19] with alkali metal gem-dithiolates. This synthetic procedure allows us to significantly extend the range of substituents which could be potentially introduced to the final product. Gem-dithiolates are comparatively less studied than related

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• isomerization of trans-1,2-dichloro-3,3-difluorocyclopropane (84) (Scheme 37) [82]. Further research in this area was performed by the groups of Jefford [83] and Dolbier [84], who studied the 1,1-difluoro-2,3-dimethylcyclopropanes 86 and 87 (Scheme 38). Dolbier found that geminal fluorine substituents lowered

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• procedure for the SNAr–Arbuzov reaction: synthesis of 9-alkyl-2-chloro-9H-purine C6-phosphonates 2 Diethyl (2-chloro-9-heptyl-9H-purin-6-yl)phosphonate (2a): 2,6-Dichloro-9-heptyl-9H-purine (1, 1.03 g, 3.59 mmol, 1.0 equiv) was dissolved in P(OEt)3 (12 mL) and stirred for 3 h at 160 °C (HPLC control). Then

Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles

• Wenbo Huang,
• Kaimei Wang,
• Ping Liu,
• Minghao Li,
• Shaoyong Ke and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2920–2928, doi:10.3762/bjoc.16.241

• obtained for 4o and 4p were slightly inferior. Gratifyingly, a 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)aniline also participated smoothly in this reaction, and the expected product 4q can be obtained in 75% yield. This fluorinated substituent on the aniline ring has been identified as the key precursor

A new method for the synthesis of diamantane by hydroisomerization of binor-S on treatment with sulfuric acid

• Rishat I. Aminov and
• Ravil I. Khusnutdinov

Beilstein J. Org. Chem. 2020, 16, 2534–2539, doi:10.3762/bjoc.16.205

• starting binor-S (2) being recovered unchanged. The reaction of hydrocarbon 2 with hydrochloric acid proceeds with the addition of HCl to the cyclopropane ring and results in the formation of a mixture of mono- and dichloro derivatives, the synthesis of which has been reported [13][14]. When sulfuric acid

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• mitochondrial activity was determined by the following formula: (Absorbance of treated cells/ Absorbance of control cells) × 100 (%). Synthesis of 3,5-dichloro-4,4-difluoro-8-(4-boronophenyl)-4-bora-3a,4a-diaza-s-indacene (PBA-BODIPY, 1) PBA-BODIPY (1) was prepared following the synthetic strategy reported in

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• ′-tetramethylethylenediamine (TMEDA) as shown in the Scheme 1. Having the compound 4 in hand, it was subjected to the cyclization in the presence of boron trifluoride to provide the tricyclohexyl-fused benzene derivative which on further dehydrogenation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) afforded 1,5,9

• achieve this goal, they commenced with the two-fold Friedel–Crafts alkylation reaction of sumanene (2) with 2,5-dichloro-2,5-dimethylhexane (50) involving AlCl3 to generate compound 51 which on subsequent oxidation provided triketosumanene 52 (Scheme 11). Finally, compound 52 was reacted with ethylene

• effective strategy for scalable synthesis of pristine sulfur, selenium and tellurium-doped sumanenes starting from 1,2-dichloro-3-nitrobenzene 200 by employing the Ullmann coupling and Sandmeyer reaction as key transformations (Scheme 49) [18][87][88]. The target was achieved starting from a three-fold

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• -cyanonaphthalene, 9,10-phenanthrenequinone, xanthone, 2,7-dichloro-9-fluorenone, 9-fluorenone, benzophenone, 2-bromo-9-fluorenone and 2-chlorothioxanthone, 5-debenzosuberenone afforded the best yield of 69 (73%, Scheme 28). In the presence of protected basic, acidic and nonpolar side chains, benzylic fluorination

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• , starting from the literature-known dichloro NDI 1 having two 3-dimethylaminopropyl groups attached to the imide nitrogens [31]. This compound was first methylated at the nitrogen atoms by the reaction with iodomethane in refluxing toluene, giving the diammonium NDI 2 in a very good yield of 89%. In the

• )-2,6-dichloro-1,4,5,8-naphthalenetetracarboxylic acid diimide diiodide (2): To a solution of N,N'-bis((3-(dimethylamino)propyl)amino)-2,6-dichloro-1,4,5,8-naphthalenetetracarboxylic acid diimide (1, 1.00 g, 1.98 mmol) in toluene (90 mL) was added iodomethane (2.27 g, 1.00 mL, 16.0 mmol). The reaction

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• 2.19 M solution (≈10 mL). Knochel–Hauser base: lithium dichloro(2,2,6,6-tetramethylpiperidinato)magnesate (TMPMgCl⋅LiCl): 2-Chloropropane (4.284 mg, 4.99 mL, 54.0 mmol, 1.2 equiv) and 2,2,6,6-tetramethylpiperidine (TMPH, 6.420 g, 7.67 mL, 45.0 mmol, 1.0 equiv) were dissolved in THF (16.2 mL) and

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• ). However, the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) at 25 °C for 48 h led to the aromatized compound 21a in high yield (Table 4, entry 3). Under similar reaction conditions, the series of pyrrolo[3,4-e]indole-1,3-diones 21b–g was resulted in high yields (Table 4, entries 4 and 6–10

Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment

• Jan Geldsetzer and
• Markus Kalesse

Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64

• -dichloro-1,1,3,3-tetraisopropyldisiloxane, TBSOTf = tert-butyldimethylsilyl trifluoromethanesulfonate, proton sponge = 1,8-bis(N,N-dimethylamino)naphthalene. Synthesis of (Z)-bromide 4 using a palladium-catalyzed, stereoselective dehalogenation [21][22][23][24]. TBSOTf = tert-butyldimethylsilyl

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• with AlCl3 reproducibly provided a pure terrylene [8]. Scholl reaction using a superacid catalyst in combination with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as oxidant provides a scalable preparation of quaterrylene [9], but unfortunately the low solubility prevents 1H NMR characterization

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• mixture was treated with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to give the α,α'-diethynyl-substituted dipyrrin 7a. Subsequent boron complexation in the presence of trimethylsilyl chloride (TMSCl) as a fluoride scavenger afforded 4a in 16% yield over three steps. Separately, α-ethynyl

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• which is more than one order of magnitude greater than the effect of the sulfur atom. This was established based on the determination of the absolute and relative rates of nucleophilic substitution of chlorine in 2,6-dichloro-9-selenabicyclo[3.3.1]nonane and 2,6-dichloro-9-thiabicyclo[3.3.1]nonane [36

Convenient synthesis of the pentasaccharide repeating unit corresponding to the cell wall O-antigen of Escherichia albertii O4

• Tapasi Manna,
• Arin Gucchait and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 106–110, doi:10.3762/bjoc.16.12

• presence of tetrabutylammonium bromide (TBAB) followed by oxidative removal [33] of the PMB group using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to give trisaccharide acceptor 13 in 72% yield. Trisaccharide acceptor 13 was then allowed to couple with ʟ-rhamnosyl trichloroacetimidate donor 5 in the

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• the Schlenk tube was sealed and the reaction mixture stirred for 66 h at 100 °C. The crude mixture was concentrated under reduced pressure, dissolved in toluene (20 mL), and treated with 2,3-dichloro-5,6-dicyano-p-benzoquinone (427 mg, 1.88 mmol, 2 equiv) for 30 min at rt with stirring. The reaction

α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA

• Shital K. Chattopadhyay,
• Subhankar Ghosh,
• Sarita Sarkar and
• Kakali Bhadra

Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245

• derivative [21]. Thus, anilide 7a was prepared by straightforward amide bond formation between aniline and 6-heptenoic acid (5) to study its cross metathesis with the hydroxamate 8. Pleasingly, use of Grubbs’ second generation catalyst [(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro

Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• be formed. However, the 1H NMR spectroscopic evidence for this was speculative at best and would suggest a very small quantity of the desired product (see Supporting Information File 1, Figure S34). Another main contaminant was the dichloro(p-cymene)ruthenium(II) dimer, which we could not eliminate

• dichloro(p-cymene)ruthenium(II) dimer or the triazolium chloride salt already observed. As a last attempt to find evidence for the ruthenacycle, a high-resolution mass spectrum was acquired directly after the reaction was completed. The most important isotopic distribution detected was at 984.4283 Da

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• were prepared by Stille coupling of stannyl compound 1 [3] with 3,5-dibromopyridine, 2,6-diiodopyrazine, and 2,4-dichloro-1,3,5-triazine, respectively (Scheme 1; see Experimental section for the synthetic procedure of OUJ-2). Optical properties The photoabsorption and fluorescence spectra of OUY-2, OUK

• -7000 (Hokuto Denko). Synthesis General synthetic procedure of (D–π–)2A fluorescent dyes OUY-2, OUK-2 and OUJ-2 OUY-2 [2], OUK-2 [3] and OUJ-2 were prepared by Stille coupling of stannyl compound 1 [3] with 3,5-dibromopyridine, 2,6-diiodopyrazine, and 2,4-dichloro-1,3,5-triazine, respectively, by using

• Pd(PPh3)4 as a catalyst in toluene at 110 °C under an argon atmosphere (Scheme 1). Synthesis of OYJ-2: A solution of 1 [3] (0.60 g, 0.95 mmol), 2,4-dichloro-1,3,5-triazine (0.071 g, 0.48 mmol), and Pd(PPh3)4 (0.18 g, 0.16 mmol) in toluene (10 mL) was stirred for 48 h at 110 °C under an argon

Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• -1,2-oxaphosphol-2-ium ions. The progenitor of the oxaphospholium ion family, 2,2-dichloro-5,5-dimethyl-1,2-oxaphosphol-2-ium, was postulated for the first time in 1978 [12]. We have recently reported on the generation, NMR characterization and reactions of oxaphospholium ions bearing phenyl or phenoxy

• –8.07 ppm, the signal of vinyl carbon C4 at 166.8–171.9 ppm, and the signal of quaternary carbon C5 at 96.0–116.3 ppm. It is worth noting that 2,2-dichloro (A, B) and 2,2-diarylsulfanyl (F, G)-substituted cations exhibit down field shifted signals in the 31P NMR (δ 87.82–115.37 ppm) in comparison with

Synthesis of pyrrolo[1,2-a]quinolines by formal 1,3-dipolar cycloaddition reactions of quinolinium salts

• Anthony Choi,
• Rebecca M. Morley and
• Iain Coldham

Beilstein J. Org. Chem. 2019, 15, 1480–1484, doi:10.3762/bjoc.15.149

• adduct 10 was performed using the oxidant 2,3-dichloro-5,6-dicyanoquinone (DDQ) to give the fully unsaturated product 13. To expand the range of products and explore the scope of the reaction further, we prepared the salts 14a and 14b (from 6-chloroquinoline and 6-bromoquinoline) and these were heated