Chemoselective N-acylation of indoles using thioesters as acyl source

• Tianri Du,
• Xiangmu Wei,
• Honghong Xu,
• Xin Zhang,
• Ruiru Fang,
• Zheng Yuan,
• Zhi Liang and
• Yahui Li

Beilstein J. Org. Chem. 2022, 18, 89–94, doi:10.3762/bjoc.18.9

• equiv to 2.0 equiv, 85% of the desired product could be obtained (Table 1, entry 10). Subsequently, we conducted a temperature optimization and 73% of the product was observed at 100 °C (Table 1, entry 11). Under the optimized reaction conditions, the scope of the reaction by variation of indoles and

• thioesters and indoles. Reaction conditions: 1 (0.2 mmol, 1.0 equiv), 2 (0.6 mmol, 3.0 equiv), Cs2CO3 (0.6 mmol, 3.0 equiv), xylene (2.0 mL), 140 °C, 12 h. Isolated yields are shown. Gram-scale experiment. Control experiments. Proposed mechanism. Optimization of the reaction conditionsa. Supporting

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

• Yelong Lei and
• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6

• gel column chromatography (PE/EA 2:1, v/v) to give product 3. Oxazoline-containing bioactive natural products. Synthetic methods of oxazoline derivatives. Scopes of aziridines and diazo esters. Proposed reaction mechanism. Direction of tautomerization. Optimization of reaction conditionsa. Supporting

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• cyanoformate as the cyanide source. They carried out the optimization studies using N,N-dimethylaniline (1.0 mmol) and ethyl cyanoformate (2.0 mmol) as the model substrates and the optimized conditions include 5 wt % Ru/C (20 mg) as catalyst and 2.5 equiv of TBHP (in decane) as oxidant in methanol at 60 °C for

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

• chromatography. The diastereoisomeric ratios (dr values) were determined by 1H NMR spectroscopy and the enantiomeric excess (ee) values were determined by HPLC analysis. Gram-scale synthesis of 3ah. Further transformation of 3ah. One-pot three-component reaction. Proposed reaction mechanism. Optimization of the

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• IC50 values (2.8 and 2.0 µM against HCT-116 and T98G cells, respectively). Additionally, the C2 phenyl ring in compound 10b may be subjected to future replacements for optimization as less bulky groups at this position seem to be of great interest for gain in activity (e.g., 2-methyl group in verubulin

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• (CF3)ppy]2(dtbbpy)PF6. SET = single-electron transfer event. Optimization of reaction conditionsa. Supporting Information Supporting Information File 324: General information, synthetic procedures, additional optimization and mechanistic results, NMR spectra and characterization of compounds and

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

• Chuanhua Qu,
• Run Huang,
• Yong Li,
• Tong Liu,
• Yuan Chen and
• Guiting Song

Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193

• mmol), MeCN (1.0 mL), 80 °C, under air atmosphere for 10 h; yields are reported for the isolated products. Synthetic applications of the synthesized compound 3b. Mechanistic studies and proposed mechanism. Optimization of the reaction conditions for the sulfonylation and isonitrilation of p-quinone

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• ligand rotamers were considered during the optimization process. Only one enantiomer was selected for running the calculations for simplicity. The obtained results are gathered in Figure 1 and Figure 2. These calculations show that for ligands L1 and L3, conformer A and conformer B, resulting from a free

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• ). Based on these results, we selected acetonitrile as the best solvent for further optimization. When changing the molar ratio of the reactants to a 1:2 molar ratio of quinoline 1b and salicylaldehyde (2a), the yield of the desired product 3ba increased to 90%. The best result was obtained when quinoline

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

• heterocyclization, optimization of the reaction conditions was performed. The solvent, reaction temperature and time, as well as the reagent ratio were varied. Since CH2Cl2, CH2Cl2–TFA, and 2,2,2-trifluoroethanol (CF3CH2OH, TFE) are used most often for the reactions with PIFA, these solvents were evaluated in the

• of 2-(buten-3-yl)quinazolin-4(3H)-ones 7. Optimization of the reaction conditionsa. Synthesis of 1-(hydroxymethyl)-2,3-dihydropyrroloquinazolin-5(1H)-ones 6. Supporting Information Supporting Information File 376: Detailed experimental procedures for all compounds and precursors, X-ray structure

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

• . Optimization of the reaction conditions for the synthesis of 1-aminoisoquinolines.a Supporting Information Supporting Information File 338: Experimental and analytical data.

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

• (1). Specifically, this approach used enzyme optimization techniques to efficiently synthesize highly enantiopure nucleoside analogues. The group found that the stereochemistry of the target molecules was selectively obtained using different enzymes. Importantly, the stereochemistry of the 1,3

• ). Enantioselectivity for a wide range of substrates was achieved in good yield with rigorous optimization of the reaction conditions by utilization of wild-type CAL-B. Synthetic N-glycosylation strategies for glycosidic C–N bond formation in 1,3-oxathiolane nucleosides This section will discuss the methods for

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

• fluorenone (59%) is only slightly lower compared to the standard reaction while the yield of the aldehyde has increased notably (23%). Unable to improve the initial reactions conditions within the framework of this optimization study, we continued our studies with the standard conditions described in entry 1

• fluorenone (3). Optimization study for the oxidative cyclization of primary amine 2a with aqueous TBHP. Supporting Information Supporting Information File 252: Additional experimental details (synthesis of the intermediates) and copies of NMR spectra. Acknowledgements We thank Marie-Luise Behrens, Büsra

Ligand-dependent stereoselective Suzuki–Miyaura cross-coupling reactions of β-enamido triflates

• Tomáš Chvojka,
• Athanasios Markos,
• Svatava Voltrová,
• Radek Pohl and
• Petr Beier

Beilstein J. Org. Chem. 2021, 17, 2657–2662, doi:10.3762/bjoc.17.179

• products 2 and inversion products 3. The effect of different catalysts on product yields and ratios. Supporting Information Supporting Information File 250: Experimental part, optimization, compound characterization, and copies of NMR spectra. Funding This work was financially supported by the Czech

Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• scale-up. Proposed mechanism. Optimization of reaction conditions.a Supporting Information Supporting Information File 372: General procedure, characterization data for electrolysis products and NMR spectra. Funding Financial support of this research from NSFC (21971213) and the Fundamental Research

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

• Akhil K. Dubey and
• Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

• the best of our knowledge, organocatalyzed or metal-catalyzed enantioselective conjugate additions of nitroalkanes to β-silyl enones are not yet known. Results and Discussion The optimization study began with the conjugate addition reaction between β-TMS enone 1a and nitromethane (2) as the model

• while keeping other parameters fixed (Table 1, entry 13). Performing the reaction with catalyst VIII, the pseudoenantiomeric catalyst of VII, furnished ent-3a in 80% yield and 94% ee (Table 1, entry 14). From the aforementioned studies, compromising slight lower yield of 3a, we set up the optimization

• reaction mixture. cDetermined by HPLC using chiral stationary phase. Organocatalytic 1,4-conjuagte addition of nitromethane (2) to enone 3o. Preparative scale synthesis of 3c and ent-3d. Catalysts screening and optimization of reaction conditions.a Supporting Information Supporting Information File 366

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

• nitroalkene 9 using catalyst (S,R)-C2. Synthesis of isothiocyanate 3a and isocyanate 3b. Synthesis of sulfinylthioureas C1 and ureas C2. Synthesis of adducts 8a,d,f in solution. Michael additions of aldehydes 6b–d with nitroalkene 9. Michael addition of 3-phenylpropanal (6c) to nitroalkene 11. Optimization of

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

• noticeably, while the yield was preserved. Ketone 3 and enone 4 were used for the optimization of reaction conditions. Firstly, the ketone 3 was reacted with hydrazoic acid in the presence of boron trifluoride etherate as a Lewis acid (Table 1, entry 1). The desired tetrazole 13 was obtained after

• %) and b) K2Cr2O7, H3O+, H2O/Et2O, rt, 3 h (84%). Optimization of reaction conditions for the transformation of ketones. Optimization of reaction conditions for the transformation of enones. Synthesis of different B-ring-fused and C-ring-fused bile acid tetrazoles.a Results of antiproliferative activity

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• to 30, confirming the importance of Au(I) in catalyzing both steps in the tandem reaction. Notably, this is the first time in the literature that α-ketol rearrangements have been initiated by a gold catalyst. Optimization revealed that the tandem reaction is best performed with Au(JohnPhos)SbF6 in

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• , 100 °C), 1–3 h. Further functionalization of dihydropyrrolizine 19a. Reagents and conditions: (i) NBS, DMF, 0 °C, 1 h, then rt, 18 h; (ii) PhB(OH)2, Pd(PPh3)4 (cat.), Na2CO3, DMF, reflux, 20 h. Optimization of the cyclization of enaminone 15a to pyrrolizine 19a. Preparation of enaminones 15a–ya, and

Direct C(sp³)–H allylation of 2-alkylpyridines with Morita–Baylis–Hillman carbonates via a tandem nucleophilic substitution/aza-Cope rearrangement

• Siyu Wang,
• Lianyou Zheng,
• Shutao Wang,
• Shulin Ning,
• Zhuoqi Zhang and
• Jinbao Xiang

Beilstein J. Org. Chem. 2021, 17, 2505–2510, doi:10.3762/bjoc.17.167

• column chromatography. Optimization of the reaction conditions for the allylic alkylation of 1a.a Supporting Information Supporting Information File 306: Experimental details, characterization data and copies of NMR spectra of new compounds. Funding We would like to thank the Sci-Tech Development

Copper-catalyzed monoselective C–H amination of ferrocenes with alkylamines

• Zhen-Sheng Jia,
• Qiang Yue,
• Ya Li,
• Xue-Tao Xu,
• Kun Zhang and
• Bing-Feng Shi

Beilstein J. Org. Chem. 2021, 17, 2488–2495, doi:10.3762/bjoc.17.165

• . Synthetic applications. Mechanistic experiments. Optimization of reaction conditions.a Supporting Information Supporting Information File 254: Full experimental details, compound characterization, and copies of NMR spectra. Funding Financial support from the National Natural Science Foundation of China

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• reaction [63][64]. As a model reaction, we studied the coupling between 2,4-dibromo-9-chloro-5,6,7,8-tetrahydroacridine (2) and phenylboronic acid (3a). After a thorough optimization using Pd(PPh3)4 as catalyst, toluene as solvent, and K3PO4 as base, the desired bis-arylated product 4a was isolated in up

• a PGSTAT30 Autolab potentiostat. Theoretical calculations The theoretical studies were realized in vacuum with the Gaussian 09 program [70]. The geometry of the equilibrium conformer at the ground state was first found at AM1 level. Then, further optimization through density functional theory (DFT

• at a scan rate of 50 mV/s. Synthesis of 2. Synthesis of compounds 4a–g. Optimization of the Suzuki–Miyaura coupling between 2 and 3a.a Photophysical properties of tetrahydroacridines 4a–d in dichloromethane solution. Selected bonding and non-bonding distances (Ǻ) for compounds 4a–d. Supporting

Enantioselective PCCP Brønsted acid-catalyzed aminalization of aldehydes

• Martin Kamlar,
• Robert Reiberger,
• Martin Nigríni,
• Ivana Císařová and
• Jan Veselý

Beilstein J. Org. Chem. 2021, 17, 2433–2440, doi:10.3762/bjoc.17.160

• substrate scope of the intermolecular aminalization reaction for anthranilamide derivatives. aAfter recrystallization; bTHF used as a reaction solvent. Optimization of reaction conditions for the aminalization reaction between 1a and 2a. Catalyst screening of the aminalization reaction between 1a and 2a