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

Extending mechanochemical porphyrin synthesis to bulkier aromatics: tetramesitylporphyrin

• Qiwen Su and
• Tamara D. Hamilton

Beilstein J. Org. Chem. 2019, 15, 1149–1153, doi:10.3762/bjoc.15.111

• milder conditions by promoting the establishment of an equilibrium for the cyclization step, then adding a gentle oxidizer (p-chloranil or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)) in a second step to obtain irreversibly the aromatized porphyrin [11]. The symmetrical tetra-meso-substituted

• particle size), ethyl acetate (anhydrous, 99.8%), hexane (mixture of isomers, 98.5%), deuterated chloroform (99.8 atom % D) were used. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 97.0%) was purchased from TCI America and used without further purification. Pyrrole (98%) was purchased from Sigma-Aldrich

Efficient synthesis of 4-substituted-ortho-phthalaldehyde analogues: toward the emergence of new building blocks

• Clémence Moitessier,
• Ahmad Rifai,
• Pierre-Edouard Danjou,
• Isabelle Mallard and
• Francine Cazier-Dennin

Beilstein J. Org. Chem. 2019, 15, 721–726, doi:10.3762/bjoc.15.67

• cyclisation in a basic medium of 2 then occurred to generate 4,5-dihydroisobenzofuran-5-ol (3) [19]. At this step, Cao et al. [17] have chosen the direct oxidation of 4,5-dihydroisobenzofuran-5-ol (3) to obtain 4-HO-OPA by using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an oxidant. However, the yield

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• . Subsequently, EtOH (20 mL) was added and the resulting mixture was cooled to −10 °C to form precipitate of Ph3PO, which was filtered as a byproduct and the filtrate was evaporated. The column chromatography (DCM/MeCN 10:1) provided the desired resulting product. 2,6-Dichloro-9-heptyl-9H-purine (1a-1): Slightly

• , CDCl3) δ 153.3, 152.9, 151.7, 145.9, 130.8, 44.7, 31.6, 29.8, 28.6, 26.6, 22.5, 14.0 ppm; HRMS–ESI (m/z): [M + H]+ calcd for C12H17Cl2N4, 287.0825; found, 287.0826. Azidation: NaN3 (5.88 g, 90.5 mmol, 3.0 equiv) was added to a solution of 9-alkyl-2,6-dichloro-9H-purine (30 mmol, 1.0 equiv) in acetone

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• formation of the gem-dichloro-α-lactam intermediate 17f which would undergo ring opening by nucleophilic addition of pyrrolidine followed by hydrolysis of the resulting α,α-dichloro-α-aminoacetamide 18f (Scheme 12). To access aminocyclopropanes, the hydrogenation of (arylmethylene)cyclopropane 13f was

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• -substituted vinylsilanes with Grubbs catalyst of first or second generation (A), the active methylene complex B and the corresponding (E)-1-phenyl-2-(silyl)ethene are formed. The methylene complex B in the presence of styrene undergoes metathetic conversion to benzylidene complex A and ethene. When dichloro

• -substituted vinylsilanes are used, the pathway shown in Scheme 1b is also possible. Metathesis of dichloro-substituted vinylsilanes with Grubbs catalyst A leads to styrene and (silyl)methylidene complex C. Formation of (silyl)methylidene complex C has not been confirmed by spectroscopic methods. The reaction

Cross metathesis-mediated synthesis of hydroxamic acid derivatives

• Shital Kumar Chattopadhyay,
• Subhankar Ghosh and
• Suman Sil

Beilstein J. Org. Chem. 2018, 14, 3070–3075, doi:10.3762/bjoc.14.285

• presence of 2nd generation catalysts. Accordingly, CM between 1-decene (4, R = C7H15) and N-benzyloxyacrylamide 5 (Scheme 1) was attempted with Grubbs’ second generation catalyst [(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene) (tricyclohexylphosphine)ruthenium, G-II]. After

• some experimentation, it was found that the reaction proceeds quickly in refluxing dichloromethane to provide the CM product 6 (R = C7H15) in 81% yield. The yield of 6 was improved to 84% when Hoveyda–Grubbs 2nd generation catalyst [1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(o

A tutorial review of stereoretentive olefin metathesis based on ruthenium dithiolate catalysts

• Daniel S. Müller,
• Olivier Baslé and
• Marc Mauduit

Beilstein J. Org. Chem. 2018, 14, 2999–3010, doi:10.3762/bjoc.14.279

• dichloro catecholthiolate (Ru-3) should render the sulfide ligand less nucleophilic and therefore less prone for nucleophilic attack. This hypothesis gained credence by increased isolated yield for the cross metathesis of allylbenzene with cis-butenediol: Ru-2 (42% yield) versus Ru-3 (61%) yield (Scheme 2c

Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum

• Jan Rinkel,
• Alexander Babczyk,
• Tao Wang,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 2974–2990, doi:10.3762/bjoc.14.277

• ). The chlorinated compound 2,5-dichloro-1,3-dimethoxybenzene (46) was also rigorously identified by comparison to all possible regioisomers that we had synthesised in a previous study [18]. Interestingly, the substitution pattern for the compound from H. macrocarpum is different to an isomer from the

• endophyte Geniculosporium sp. that was identified as 1,5-dichloro-2,3-dimethoxybenzene. Compound 46 has not been described as a natural product before. Another trace compound released by H. macrocarpum exhibited a mass spectrum that pointed to the structure of a dimethoxybenzaldehyde (Figure 8A). Comparison

• important for the fungal fragrance. Notably, fungi of the genus Hypoxylon are interesting sources of new natural products, as exemplified by the identification of 2,4,5-trimethylanisole, 2,5-dimethyl-p-anisaldehyde and its corresponding methyl ester, and 2,5-dichloro-1,3-dimethoxybenzene. Therefore, it will

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

• Pierre-Antoine Nocquet,
• Aurélie Macé,
• Frédéric Legros,
• Jacques Lebreton,
• Gilles Dujardin,
• Sylvain Collet,
• Arnaud Martel,
• Bertrand Carboni and
• François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

• strategy based on an Evans’ aldol reaction. Mildly oxidizing conditions using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) were used for the removal of the p-methoxybenzyl (PMB) group to provide alcohols 14 (Scheme 3). Several palladium(II) catalysts have been tested for the conversion of alcohols to

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• arylaldehydes including 2,4-dichloro, 2,4-dimethoxy, 3,4-dimethoxy, and 3,4,5-trimethoxy. The catalyst was used up to four cycles under the optimized conditions [70]. A new strategy was proposed for the synthesis of a novel sulfonated carbon catalyst 127 using the reaction of 5-(hydroxymethyl)furfural (123

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• −1.4 V vs Ag/AgCl in the presence of 1 in DMF/n-Bu4NClO4. The DDT was converted to 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (DDE), 1-chloro-2,2-bis(4-chlorophenyl)ethylene (DDMU), and 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro-2-butene (TTDB, E/Z

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• -dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to generate nitronaphthalene 15 (60%, Scheme 2). Due to their useful biological activity and intricate structural features of angucyclines such as 16–19 (Figure 2), several approaches have been reported for their assembly. In this context, de Koning and co

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• complexes with various aromatic guests. Results and Discussion Cryptand 2 is accessible via nucleophilic aromatic substitution in good yields (42%, Scheme 1) by treating triphenol 3 [36] with the reactive and commercially available 2,6-dichloro-3,5-dicyanopyridine following a procedure previously elaborated

• F254 TLC plates. Solvents were dried and distilled under argon using standard procedures. Procedure for the synthesis of 2 (analogous to the method described for 1 in [32]): Triphenol 3 (0.10 g, 0.28 mmol), 2,6-dichloro-3,5-dicyanopyridine (0.083 g, 0.42 mmol) and anhydrous NEt3 (0.12 mL, 0.84 mmol

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• of benzo[7]annulenylium cations 133a and 133b (Scheme 23) [49]. While the reaction of 11 with oxalyl bromide yielded bromobenzo[7]annulenenylium bromide 134a as a stable carbenium salt, the reaction of oxalyl chloride or phosgene with 11 afforded 7,7-dichloro-7H-benzo[7]annulene (135b) as a covalent

• attributed to the highest positive charge density at the benzylic position, which is the favored process under kinetic conditions. During the attempted preparation of 4,5-benzotropone diaziridine 144, the synthesis of 7,7-dichloro-7H-benzo[7]annulene (135b) was also carried out from the reaction of 4,5

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• benzylmethyl groups, and the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) [58] or catalytic tetrabutylammonium iodide with tert-butyl hydrogen peroxide for reactions with a large excess of aromatic hydrocarbons [59]. Other than these excellent examples of metal-free methods, two protocols using a

Volatiles from the xylarialean fungus Hypoxylon invadens

• Jeroen S. Dickschat,
• Tao Wang and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62

• α-cadinene (5). The same problem applies to the unambiguous identification of regioisomers of aromatic compounds. We have recently reported on the GC–MS-based identification of the fungal volatiles 1-chloro-3,4-dimethoxybenzene (6) and 1,3-dichloro-4,5-dimethoxybenzene (7) from an endophytic

• chlorinated aromatic compounds 1-chloro-3,4-dimethoxybenzene (6) and 1,3-dichloro-4,5-dimethoxybenzene (7) from Geniculosporium. Total-ion chromatogram of the bouquet from Hypoxylon invadens MUCL 54175 obtained by the CLSA headspace technique. Numbers at peaks correspond to the compounds in Table 1 and Figure

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• the platinum complexes were performed under an argon atmosphere and by exclusion of light, using flame-dried Schlenk tubes. Solvents of at least 99.0% purity were used. DMF was dried according to standard methods and stored over molecular sieve (3 Å) under argon atmosphere. Dichloro(1,5-cyclooctadiene

• temperature, then for 23 hours at 50 °C. Dichloro(1,5-cyclooctadiene)platinum(II) (300 mg, 0.8 mmol) was added at room temperature, and the mixture was stirred for two hours at 50 °C, then for 24 hours at 120 °C. Afterwards, potassium tert-butanolate (180 mg, 1.6 mmol) and 1,3-bis(2,4,6-trimethylphenyl

• ,κC2‘][bis(2,3,5,6-tetramethylphenyl) propane-1,3-dionato-κO,κO‘]platinum(II) (3) The product was obtained following the general procedure reported for 2 using 1-methyl-3-phenyl-1H-imidazol-3-ium iodide (1, 230 mg, 0.8 mmol) and silver(I) oxide (100 mg, 0.4 mmol), dichloro(1,5-cyclooctadiene)platinum