Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• the lactam ring of 3a. Gratifyingly, we obtained scaffold C in 71% yield by refluxing 3a with aluminum chloride in benzene (Scheme 6) [43]. For comparison, debenzylation of paullone with sodium in liquid ammonia gave A in 40% yield [23]. In addition, the generality of synthetic pathway (c) (Scheme 1

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

• Jiang-Song Zhai and
• Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

•  3, in addition to substrates 3ae and 3al, it appeared that the reaction could well tolerated the presence of electron-donating and electron-withdrawing groups on the benzene ring of substrates 2, and afforded most of the products 3 in excellent chemical yields (90 to >99%) and stereoselectivities

• (>20:1 dr, 84–>99% ee). Possibly due to the influence of steric hindrance, reactions involving substrate 2 with ortho-substitution on the benzene ring has lower yields and worse enantioselectivities than those with meta-substitution and para-substitution. Meanwhile, the enantioselectivities of the

The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• natural product 17 [HRMS–ESI (m/z): 221.1904 [M + H]+, calculated for C15H25O+ 221.1900 and [α]D25 = −7.7, (c 0.26, benzene)] whose structure was elucidated by NMR spectroscopy (Table 1 and Figures S29–S35 in Supporting Information File 1). The 13C NMR spectrum showed signals for 15 carbons, including

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• TBT through outer-surface interaction than the host–guest interaction between the benzene ring or the melamine group of TBT. The host–guest interaction of Q[7]-TBT Using the same method of 1H NMR titration as above. The interaction between Q[7] and TBT is studied and is proved to be different from

• coordination ability of Schiff base, providing a theoretical study for the Q[n]-Schiff base complex. Experimental The synthesis of 1: Compound 1 is synthesized according to the literature (Scheme 2) [34]. Melamine (10 mmol, 1.26 g) was suspended in benzene (20 mL) and a suspension of 4-hydroxybenzaldehyde (30

• mmol, 3.66 g) in benzene (30 mL) was added under stirring, then reflux overnight. The pink powder was formed and washed with warm water to get the pure compound 1. 1H NMR (DMSO-d6) δ 12.1 (s, 3H), 9.76 (s, 3H), 7.80 (d, 6H), 7.08 (d, 6H), 4.06 (t, 6H), 2.40 (t, 6H), 1.93 (m, 6H) ppm. The synthesis of 2

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• )) (10 nm)/X wt % DICzTRZ or ICzTRZ: CzSi (20 nm)/PPF (2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan) (5 nm)/TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene) (50 nm)/Liq (lithium quinolin-8-olate) (1 nm)/Al (80 nm), where X is 20 or 30. The PVK layer is applied to facilitate hole injection from

Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol

• Lin Zhang,
• Jun Zheng,
• Guangyan Luo,
• Xiaoyue Li,
• Yunqian Zhang,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194

• superposition of the spectra recorded for Q[8] (a) and CPE (b), and there was no interaction. When comparing (c) and (d), the C–H stretching vibration peak was observed at 3100 cm−1 and the C=C skeleton vibration peaks of the benzene ring of CPE were observed at 1603, 1520 and 1413 cm−1; the bending vibration

• peaks of the O–H bonds were observed at 1106 and 1066 cm−1. The nitro-symmetric tensile vibration peak observed at 1503 cm−1 and the nitro-asymmetric tensile vibration peak at 1320 cm−1 disappeared in the spectrum (d). At the same time, the fingerprint region peak of the benzene ring observed from 500

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

• Alla I. Vaskevych,
• Nataliia O. Savinchuk,
• Ruslan I. Vaskevych,
• Eduard B. Rusanov,
• Oleksandr O. Grygorenko and
• Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

• of natural product-like compound libraries. Keywords: [bis(trifluoroacetoxy)iodo]benzene PIFA; nitrogen heterocycles; oxidative cyclization; pyrrolo[1,2-a]quinazolines; Introduction An important design concept in current drug discovery includes structural modifications of naturally occurring

Me₃Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

• Krishna M. S. Adusumalli,
• Lakshmi N. S. Konidena,
• Hima B. Gandham,
• Krishnaiah Kumari,
• Krishna R. Valluru,
• Satya K. R. Nidasanametla,
• Venkateswara R. Battula and
• Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

• -oxo-2-phenylethyl)benzonitriles substituted with various groups (Br, Cl and methyl) on both the benzene rings were treated with different anilines to yield respective products (5a–m) in good yields (Scheme 3). Examination of the effect of the substituents on the reaction revealed that the substituents

• on both the benzene rings of 2-(2-oxo-2-phenylethyl)benzonitriles have no significant impact on the yields of the reaction delivering the corresponding products in almost similar yields (3b–e, Scheme 3). Interestingly, different alkylamines such as methylamine, ethylamine and piperazines were also

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• chiral N-arylbenzimidazoles involving a carbon–carbon bond cleavage under optimal reaction conditions. In the presence of CPA 2, N1-(aryl)benzene-1,2-diamines 66 were used in the reaction with multicarbonyl compounds 67 and 68 and afforded the corresponding products, axially chiral N-arylbenzimidazoles

• 69 and 70 in high yields (up to 89%) with excellent enantioselectivity (up to 98% ee, Scheme 22) [78]. The primary amino group in the N1-(aryl)benzene-1,2-diamines reacts with the carbonyl group in 67 to give imine intermediate I-15 mediated by the chiral phosphoric acid. Meanwhile, isomerization of

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• , cyclocondensation of 47 with 2-mercaptoacetaldehyde diethyl acetal (3nb) in the presence of p-TSA in benzene solvent afforded 1,3-oxathiolane intermediate (±)-2,2-bis(acetoxymethyl)-5-ethoxy-1,3-thioxalane (48). More recently, an approach developed by Snead et al. [53] at the Medicines for All Institute used lactic

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• radical cyclizations [22], Pschorr reactions [23], and diverse cycloaddition protocols [24][25]. Especially transition-metal-catalyzed cross-coupling reactions starting from benzophenones, benzoic acids, dihalogenated benzene building blocks and others have emerged as new approaches in recent years [26

AlBr₃-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: synthesis of 3,3-diarylpropenenitriles

• Yelizaveta Gorbunova,
• Dmitry S. Ryabukhin and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2021, 17, 2663–2667, doi:10.3762/bjoc.17.180

• , benzene and its polymethylated derivatives) under the action of aluminum bromide (AlBr3, 6 equiv) at room temperature for 0.5–2 h result in the stereoselective formation of 3,3-diarylpropenenitriles (Ar(Ar′)C=CHCN) in yields of 20–64%, as products of mainly anti-hydroarylation of the acetylene bond. The

• -3,3-diarylpropenenitriles 2a–o as products of the regioselective hydroarylation of the acetylene bond (Scheme 1). These reactions proceeded only with an excess of AlBr3 (6 equiv). Thus, running the reaction of nitrile 1a with benzene under the action of less amount AlBr3 (1–4 equiv) resulted in an

• NOESY correlations between the vinyl proton and the aromatic protons or methyl groups in neighboring aryl substituents (see Supporting Information File 1). However, the configuration of nitrile 2o was unclear. Benzene, o-, m-, p-xylenes, and 1,2,4-trimethylbenzene (mesitylene) were included in the

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• )benzene (7b). Hexanal (6b) reacted successfully with 4-fluoro-β-nitrostyrene (7c) and gave product 8d under all conditions tested (in solution, solvent-free, and ball-milling conditions, vide infra). Again, small amounts of catalyst (S,R)-C2 gave the best chemical yield. Catalyst (S,R)-C2 (3 mol %) in

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• Lewis acid concentration, or by the decrease of temperature. The use of TMSN3 enabled a more efficient exclusion of water from the reaction mixture in comparison to a HN3 solution in benzene, which is difficult to dry thoroughly. This, in turn, was helpful in shifting the Schmidt reaction towards

• for the preparation of tetrazoles with hydrazoic acid Caution: Hydrazoic acid should be handled with care in an efficient fume hood since it is toxic and explosive. In a two-neck round-bottom flask equipped with an addition funnel and argon inlet, a benzene solution of hydrazoic acid (18 mL) and boron

• trifluoride etherate (1.15 mL) were placed. The mixture was cooled with an ice water bath, and a benzene solution of the carbonyl compound (1.50 mmol in 15 mL of benzene) was added dropwise over 40 minutes with stirring and cooling. After the addition was completed, the reaction mixture was left at room

Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4-c]carbazoles via domino Diels–Alder reaction

• Ren-Jie Fang,
• Chen Yan,
• Jing Sun,
• Ying Han and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2021, 17, 2425–2432, doi:10.3762/bjoc.17.159

• crystal structure of compound 4g was determined by X-ray diffraction (Figure 4). It can be seen that the ring of pyrrolo[3,4-c]carbazole exists in a slightly twisted plane. The dihedral angles of the phenyl and the benzoyl group to the central benzene ring are 72.018° and 88.402°. To further expand the

• with benzylideneacetone gave the desired carbazoles 6m and 6n albeit in significantly lower yields. Thus, this one-pot domino reaction successfully constructed carbazoles with four substituents on the benzene ring from the corresponding indole derivatives with two molecules of chalcones. It should be

Synthesis of 5-arylacetylenyl-1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions

• Andrey I. Puzanov,
• Dmitry S. Ryabukhin,
• Anna S. Zalivatskaya,
• Dmitriy N. Zakusilo,
• Darya S. Mikson,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2021, 17, 2417–2424, doi:10.3762/bjoc.17.158

• ), oxadiazole 3a gave the product of hydration of the acetylene bond (4d, yield of 65%) existing in solution as equilibrium between ketone and enol forms in a ratio of 1.2:1 according to NMR data (see Supporting Information File 1). Then, reactions of 5-acetylenyl-1,2,4-oxadiazole 3a–d with arenes (benzene and

• proton and aromatic protons (see Supporting Information File 1). In the case of the reaction with o-xylene, pairs of E/Z-isomers of two regioisomers, (E/Z)-5b and (E/Z)-5b1, were obtained. We also checked the reaction of oxadiazole 3a with benzene under the action of Lewis acids AlCl3, AlBr3 and acidic

• in the same reaction in TfOH (compare entry 3 in Table 2 with data shown in Scheme 5). Thus, among the tested acidic reagents, TfOH showed better results for the hydroarylation of compounds 3. Additionally, the reaction of oxadiazole 3a with benzene in TfOH (rt, 1 h) in the presence of cyclohexane

Strategies for the synthesis of brevipolides

• Yudhi D. Kurniawan and
• A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

• isolated in 80% yield over two steps. Reduction of the ester provided allylic alcohol 29 (92%) ready for later epoxidation. After considerable optimizations, the authors found that the dropwise addition of TBHP to 29 in refluxing benzene solution containing a catalytic amount of VO(acac)2 afforded the

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B

• Emmanuel T. Oluwabusola,
• Olusoji O. Adebisi,
• Fernando Reyes,
• Kojo S. Acquah,
• Mercedes De La Cruz,
• Larry L. Mweetwa,
• Joy E. Rajakulendran,
• Digby F. Warner,
• Deng Hai,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156

• ), δC 170.0.0 (C-7), and δC 169.4 (C-10). The downfield methine proton signals at δH 6.96 (d, J = 8.7, 1.8 Hz, H-2), 7.52 (td, J = 8.7, 7.2, 1.8 Hz, H-3), 6.94 (td, J = 8.7, 1.8 Hz, H-4), and δH 7.99 (dd, J = 8.1, 1.8 Hz, H-5) were consistent with a 1,2-disubstituted aromatic benzene ring of a salicylic

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• proceeding by means of the initial generation of an iminyl radical that cyclizes onto the electron-rich aromatic ring or through the formation of a radical cation on the electron-rich benzene ring. Finally, the methodology has successfully been applied to synthesizing the natural product trisphaeridine

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• (Table 1) of compound 1 displayed characteristic resonances for a 1,3,4-trisubstituted benzene ring [δH 7.00 (d, J = 1.9 Hz, H-2), 6.87 (dd, J = 8.1, 1.9 Hz, H-6), and 6.78 (d, J = 8.1 Hz, H-5)], a 1,3,4,5-tetrasubsituted benzene ring [δH 6.62 (brs, H-2′) and 6.65 (brs, H-6′)], an oxygenated methine [δH

• (Table 1) showed a 1,3,4-trisubstituted benzene ring [δH 6.58 (d, J = 2.3 Hz, H-2), 6.57 (d, J = 8.0 Hz, H-5), and 6.49 (dd, J = 8.0, 2.3 Hz, H-6); δC 146.9 (C-3), 143.9 (C-4), 131.9 (C-1), 121.2 (C-6), 114.2 (C-5), and 112.2 (C-2)], a 1,3,4,5-tetrasubstituted benzene ring [δH 6.73 (s, H-2′, 6′); δC

A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids

• Li Liu,
• Yue Li,
• Tiao Huang,
• Dulin Kong and
• Mingshu Wu

Beilstein J. Org. Chem. 2021, 17, 2321–2328, doi:10.3762/bjoc.17.150

• -withdrawing motifs, and thus gave a better result. For example, the (2-oxoindolin-3-yl) phosphate substrates with a methyl or methoxy group at the 5-position of the benzene ring could all react with hydrobromic acid in good yield, giving 4b, 4c, and 4g in 72–76% yield. The position of the residue R1 on the

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• substituted diaryl ketone, 4-(4-methoxybenzoyl)benzonitrile (96) serves as the HAT photocatalyst to activate the C(sp3)–H bonds for olefin functionalization. It was identified that the use of nonpolar, aprotic solvents, such as benzene and α,α,α-trifluorotoluene (TFT) is critical for the formation of the

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• benzene which resulted in low yields of the products 134 (Scheme 18a) [44]. Using different N-protected substituted indoles 135, Naidu observed improved yields of 136 when catalytic oxidant I2 was added in 1,4-dioxane as solvent (Scheme 18b) [96]. Using aerial oxygen as the oxidant, Yang used Se0 in the

Enantioenriched α-substituted glutamates/pyroglutamates via enantioselective cyclopropenimine-catalyzed Michael addition of amino ester imines

• Zara M. Seibel,
• Jeffrey S. Bandar and
• Tristan H. Lambert

Beilstein J. Org. Chem. 2021, 17, 2077–2084, doi:10.3762/bjoc.17.134

• active (Table 1, entry 6). With the identification of cyclopropenimine 5 as our optimal catalyst [44], we examined the effect of the reaction medium. Solvents such as benzene (Table 1, entry 7), TBME (Table 1, entry 8), and toluene (Table 1, entry 10) produced reactivities on par with ethyl acetate and

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• three linearly fused benzene rings. Because of their extended aromatic and conjugated π-system, anthracene derivatives possess interesting photochemical and photophysical properties [1][2][3], as well as gelling ability [4]. These important properties make them relevant for the development and

• sequential modifications [30], photocyclization of divinylterphenyl derivatives [31], tandem radical cyclization of (Z,Z)-1,4-bis(2-iodostyryl)benzene derivatives [32], and ring-closing olefin metathesis of tetravinylterphenyls [33] as the best-known synthetic routes. Herein, we have classified the synthetic

• with internal alkynes 11 bearing an electron-donating or electron-withdrawing group on the benzene ring resulted in the corresponding substituted anthracenes 12 in moderate to good yields (see the representative examples 12a–g). The same authors also investigated the applicability of reacting internal