Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• equiv of NaH in DCM under conditions similar to our previous reports on the deoxygenative trifluoromethylthiolation of carboxylic acids [31]. 19F NMR analysis of the crude reaction mixture after 2 h at rt revealed no conversion towards the desired acyl fluoride product 2a, however, 30% of thioester 3a

• was formed (internal standard: PhCF3, Table 1, entry 1). Pleasingly, changing the base to K2CO3 led to the formation of 2a in 7% 19F NMR yield (Table 1, entry 2), while the selectivity of the reaction could be switched significantly upon employing organic amine bases (Table 1, entries 3 and 4). Using

• 2.0 equiv of diisopropylethylamine (DIPEA), 2a could be obtained in quantitative 19F NMR yield although a reduction to 1.5 equiv led to a significant drop in efficiency, delivering the acyl fluoride in only 30% 19F NMR yield together with 45% of thioester 3a (Table 1, entries 4 and 5). At this stage

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• gives first insights into the optical properties. It was observed that the photophysical properties could be partially modulated by the chosen substituents. Experimental General information Nuclear magnetic resonance spectra (1H/13C/19F NMR) were recorded on a Bruker AVANCE 300 III, 250II, or 500. The

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• and characterization data of all products, copies of 1H, 13C, 19F NMR spectra of all compounds. Acknowledgements The authors thank the Research Center of Analysis and Test of the East China University of Science and Technology for the help on the characterization and Professor Zhen-Jiang Xu from SIOC

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• substituent of porphyrins 3, 5, 11, 12, 14, 18–20, 23, 24, and 26 were also observed supporting the structures of these compounds (see Supporting Information File 1, experimental and Figures S1–S14 for details). The 19F NMR spectra were also in good agreement with the structures of the synthesized compounds

• aminoporphyrin 5. Synthesis of carboranyl-substituted porphyrins 5–7. Synthesis of acylated carboranylporphyrins 11, 12, and 14. Synthesis of thio-substituted carboranylporphyrins 18–20. Synthesis of amino-substituted carboranylporphyrins 23, 24, and 26. Chemical shifts (ppm) and multiplicities (J, Hz) in 19F

• NMR spectra for all synthesized compounds. Supporting Information Supporting Information File 2: Experimental details and characterization data. Acknowledgments This work was performed employing the equipment of Center for molecular composition studies of INEOS RAS. Funding This work was supported

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• reaction of compound 1a with Selectfluor in acetonitrile (MeCN) gave high yields of the monofluorinated product 2a with no difluorinated product being observed by 19F NMR analysis of the product mixture after 5 h (Scheme 1). In contrast, attempts to fluorinate 1a with one equivalent of fluorine gas in MeCN

• gave no noticeable conversion on analysis by 19F NMR spectroscopy, and a large excess of fluorine led to formation of a dark brown tar from which no useful product could be isolated. On the bases of these failed attempts, coupled with our previous experiences with the DBM scaffold [16][17][36], we used

• the crude yields of fluorinated products were estimated by 19F NMR integration (monofluoro product 2a, δF −189.9 ppm; difluoro product 3a, δF −102.7 ppm) (Table 1, entry 3). Using excess fluorine or DABCO (entries 5 and 6 in Table 1) led to the formation of tars, while 0.1 equiv of DABCO (entry 7

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• completion of the reaction the mixture of isomers 3a,b was separated from the water phase and distilled at 55 °C. Further increase in the amount of KOH led to the elimination of the second mole of HBr with the formation of hexafluorobut-2-yne (4). By controlling the course of the reaction by the 19F NMR

• obtained by us fully correspond to the literature data [19][20]. The 1H and 19F NMR spectra of compounds 7a,b also corresponded to the data given in the literature [21][22]. We present here the spectral data for isomer 6a, as well as the missing data of 13C NMR spectra for iodoolefins 7a,b. It should be

• excess of anhydrous KF (Scheme 6). The mixture was stirred at 30 °C for several days until none of the starting 8 was detected in 19F NMR spectra. The desired iodoolefin 7a together with byproduct triethylfluorosilane (Et3SiF) were removed from sulfolane under vacuum and after double distillation with

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• and the reaction mixture was stirred at room temperature for 3 h. After concentrating the mixture, the residue was purified by column chromatography on silica gel using a mixture of petroleum ether/ethyl acetate 30:1 (v/v) as the eluent to afford products 2. The yields were determined by 19F NMR

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• after immersion in a 1:10 (v/v) mixture of 85% aq H3PO4 and 95% aq EtOH. 1H, 13C, and 19F NMR spectra of solutions in CDCl3 and acetone-d6 were recorded on a Bruker AVANCE-600 instrument at 600 MHz for 1H and 151 MHz for 13C or on a Bruker AM-300 instrument at 300 MHz for 1H, 75 MHz for 13C, and 282 MHz

• for 19F NMR. The 1H chemical shifts are given relative to the signal of the residual CHCl3 (δH 7.27) or acetone-d5 (δH 2.05), the 13C chemical shifts were measured relative to the signal of CDCl3 (δC 77.0) or acetone-d6 (δC 29.92). The 19F chemical shifts are given relative to the external signal of

• (q, JC,F = 285, CF3), 115.2 (q, JC,F = 288, CF3), 127.6, 129.6, 130.6, 136.0 (Ph), 156.4 (q, JC,F = 45, COCF3), 156.9 (q, JC,F = 44, COCF3), 158.0 (q, JC,F = 39, COCF3), 166.2, 167.5, 168.4 (COCH2Cl, CO2Me); 19F NMR (282 MHz, CDCl3, δ, ppm) −76.8 (NHCOCF3), −75.7, −75.2 (OCOCF3); HRESIMS (m/z): [M

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• . The addition of a typical radical scavenger – TEMPO (2,2,6,6-tetramethylpiperidin-1-yloxyl) significantly inhibited the reaction (as shown in Scheme 3), suggesting the involvement of radical species during the reaction process. Moreover, the radical trapping product was detected and confirmed via 19F

• NMR (Figure S3 in Supporting Information File 1) [30] and high-resolution mass spectrometry. You and co-workers proposed a reaction pathway involving the combination of the indole substrate and Umemoto’s reagent to form an electron donor–acceptor (EDA) complex [31]. We excluded the possibility of an

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• and anion of the IL as the length of the side alkyl chain increases, which makes the BF4‒/water interaction more effective. Although Saihara and co-workers demonstrated that BF4‒ hydrolysis generates HF, which reacts with the surrounding glass container yielding SiF62‒ (signal at −130 ppm in 19F NMR

• spectrum) [106], we never detected such a peak in 19F NMR spectra of the neat IL, analysed after reaction work-up, keeping it under vacuum to completely eliminate diethyl ether traces before NMR analysis. It should be mentioned that the solution was kept in the NMR tubes only for the time necessary to

• -chelate. In fact, the following convincing peaks were found in the NMR spectra: a singlet at 6.11 ppm, along with a quartet at 4.68 ppm (1H NMR spectrum), a peak at 83.3 ppm (13C NMR spectrum) and a singlet at −139.1 ppm (19F NMR spectrum) [109]. A simple washing with distilled water gave the

Substituent-controlled construction of A₄B₂-hexaphyrins and A₃B-porphyrins: a mechanistic evaluation

• Seda Cinar,
• Dilek Isik Tasgin and
• Canan Unaleroglu

Beilstein J. Org. Chem. 2023, 19, 1832–1840, doi:10.3762/bjoc.19.135

• -tosylimines. Experimental General method: All reagents and solvents were purchased from Sigma-Aldrich, Fisher Scientific, or Acros Organics and were used without further purification. 1H NMR (400 MHz), 13C NMR (100 MHz), and 19F NMR (376 MHz) spectra were recorded on a Bruker 400, Ultra Shield high

• -performance digital FT-NMR spectrometer. Data for 1H NMR, 13C NMR, and 19F NMR are reported as follows: chemical shift (δ, ppm), multiplicity (s = singlet, d = doublet, t = triplet, m = multiplet, q= quartet, bs = broad singlet, dd = doublet of doublets, td = triplet of doublets, qd = quartet of doublets

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• 22.8, 14.2 ppm; 19F NMR −63.1 ppm; HRESI(+)-MS (m/z): [M + H+] calcd for C94H144F6N5O7, 1569.0970; found, 1569.957. General procedure for the solvent screening of stereoselective Michael addition of acetylacetone to trans-β-nitrostyrene First, trans-β-nitrostyrene (12, 11.9 mg, 0.08 mmol) and the

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• 19F NMR spectroscopy to monitor the consumption of the gem-difluoro starting material 1, which was completely consumed within 16 h (Figure 3). However, a 48 h time course gave a superior yield (Table 1, entry 13 vs entry 20). We hypothesize this might be due to the volatile nature of the gem

• . Additionally, 30% of the aniline byproduct was also isolated, which explains the modest yields of this reaction and the sluggish nature. To investigate the mechanism of the current transformation, we conducted a series of experiments including a time course of the reaction using 19F NMR spectroscopy (Figure 3

• and beyond. The Z-geometry of INT-1 was determined from its 3JH−F coupling constant of 35.7 Hz in the 1H NMR with a matching J value in the 19F NMR. This is in agreement with Cao’s report on the geometry of N-(α-fluorovinyl)azoles [33]. The configurations of the E- and Z-isomers were determined by

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• of enones 2a,e,n with an excess (5 equiv) of AlBr3 or AlCl3 in CH2Cl2 solution at room temperature for 3 days afforded complex mixtures of compounds. Then, the protonation of compounds 1 and 2 in TfOH was investigated by means of NMR spectroscopy. According to the 1H, 13C, and 19F NMR data, hydroxy

• -protonated forms B is substantially delocalized from the carbonyl group to vinyl carbon C3. For fluorophenyl-substituted compounds and cations 1d and Ad, 2d and Bd, also a large downfield shift of the corresponding fluorine signals is observed in the 19F NMR spectra (∆δ = 25.3–25.7 ppm), which shows a

• ketones 1a,c,f,i into the corresponding enones 2 and indanones 3 in TfOH at 80 °C for shorter reaction time under the conditions of incomplete conversion of the starting compounds.a 1H, 13C, and 19F NMR data of compounds 1, and 2 in CDCl3 and their O-protonated forms A, and B, respectively, in TfOH

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• NEt3·3HF, AgHF2 could also be used. The complexes were found to be air-stable in the solid state and moderately stable in solution. They were unambiguously characterized on the basis of NMR studies including 19F NMR and X-ray crystal analysis. With the IMes ligand, an air-stable bis(NHC)Cu(I) complex

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• found to shift to lower ppm values because the Hα nuclei have been affected by higher electron density caused by the formation of the halogen-bonded complex between 2a and DABCO. To confirm that the shift of Hα was indeed produced by a halogen-bonding interaction, 19F NMR analysis of compound 2d, which

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• Pr2 and Pr4 (ΔG = −42.5 and −43.3 kcal·mol−1; cis-6c), respectively. This is consistent with the experimental results, since two sets of signals corresponding to the diastereoisomers trans-6c and cis-6c are always observed in the 19F NMR spectrum of the crude mixture, with a slight preference for the

• cyclopropanation. Reaction conditions: alkene (0.15 mmol), diazo compound 5 (0.1 mmol), CuI (1 mol %), dry toluene, 111 °C, Ar atmosphere. aYields refer to isolated products; bdr ratio determined by 19F NMR spectroscopy. Scope of the cyclopropanation. Reaction conditions: alkene (0.15 mmol), diazo compound 5 (0.1

• mmol), CuI (1 mol %), dry toluene, 111 °C, Ar atmosphere. aYields refer to isolated products; bdr ratio determined by 19F NMR spectroscopy. Addition of CuI to the diazo compound 5. Possible addition of styrene to Int2 yielding Int4_1 and Int4_2 through Int3_1 and Int3_2. Possible addition of styrene to

Simple synthesis of multi-halogenated alkenes from 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane)

• Yukiko Karuo,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2022, 18, 1567–1574, doi:10.3762/bjoc.18.167

• experiments with the aim of identifying further applications of 2 will be reported in due course. Experimental General information 1H NMR, 19F NMR and 13C NMR spectra were recorded on JEOL ECZ 400S spectrometers. Chemical shifts of 1H NMR are reported in ppm from tetramethylsilane (TMS) as an internal

• standard. Chemical shifts of 13C NMR are reported in ppm from the center line of a triplet at 77.16 ppm for deuteriochloroform. Chemical shifts of 19F NMR are reported in ppm from CFCl3 as an internal standard. All data are reported as follows: chemical shifts, relative integration value, multiplicity (s

• ), 153.9; 19F NMR (376 MHz, CDCl3) δ −80.5 (s, 1F), −80.6 (s, 1F); EIMS m/z: 250, 252 [M]+; HREIMS: [M]+ calcd for C8H5BrClFO, 249.9196, 251.9176; found, 249.9202, 251.9172. (3-Chloro-4-fluoro-4-phenoxybut-3-en-1-yn-1-yl)trimethylsilane (7): To a solution of 2a (0.5 mmol), bis(triphenylphosphine)palladium

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• enabled straightforward reaction monitoring via 19F NMR. To this end, a 1 T benchtop NMR equipped with a flow cell was connected to the reactor outlet and used to acquire a series of spectra. In particular, a series of 128 repetitions with a 90° pulse width and a relatively long repetition time of 5.2 s

• outlet. First, we verified that the NMR yield calculated directly from the benchtop 19F NMR spectrum was in good agreement with the high-field NMR yields calculated with an internal standard (see Supporting Information File 1, Table S1). Then, a program was developed to monitor the reaction yield over

• time by automatically acquiring, processing and integrating the 19F NMR spectrum of the reaction mixture flowing in the spectrometer (see relevant code in Supporting Information File 3). In particular, the python packages flowchem [35] and nmrglue [36] were used to control the spectrometer and process

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• reaction. In order to clarify the coordination reaction of nitrogen atoms, Bazan’s group designed a conjugated polymer containing pyridine and thiazole groups and small molecule 15 (Figure 8) and compared the 1H NMR spectra and 19F NMR spectra after the addition of 1 equivalent B(C6F5)3 at various

• temperatures from 230 to 300 K (see Figure 9) [43]. As shown in Figure 9a, when the temperature reached 280 K, the aromatic resonances became intense, implying the appearance of a new species, which was assigned to the Lewis acid–base adduct. Fifteen new resonance peaks were also observed in the 19F NMR

• small molecule 15 containing pyridine and thiazole groups reported by Bazan et al. and pyridine groups-containing diketopyrrolopyrroles (DPP) 16–18 investigated by Huang et al. (a) 1H NMR spectra in the aromatic region and (b) 19F NMR spectra of compound 15 (top) and the mixture with 1 equivalent B(C6F5

Direct C–H amination reactions of arenes with N-hydroxyphthalimides catalyzed by cuprous bromide

• Dongming Zhang,
• Bin Lv,
• Pan Gao,
• Xiaodong Jia and
• Yu Yuan

Beilstein J. Org. Chem. 2022, 18, 647–652, doi:10.3762/bjoc.18.65

• . A plausible reaction mechanism. Optimization of the reaction conditions.a Supporting Information Supporting Information File 48: Synthetic schemes for products, characterization data, and copies of 1H, 13C, and 19F NMR spectra. Funding We gratefully acknowledge funding from Jiangsu Provincial

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• NMR). 19F NMR spectra were recorded on a Bruker-400 spectrometer. Coupling constants (J) are given in Hz. The following abbreviations were used to designate the multiplicities: s = singlet, d = doublet, t = triplet, q = quartet, quint = quintet, m = multiplet, br = broad. Melting points were measured

• copies of 1H, 13C, and 19F NMR spectra. Funding This work was supported by the American Association of Colleges of Pharmacy (2018 New Investigator Award to H. V. L.), the National Institute of General Medical Sciences (P30GM122733 pilot project award to H. V. L.), and funds from the Department of

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• monofluorinated product 2c in 51% yield. Analysis of the milled mixture by 1H and 19F NMR spectroscopy also revealed the presence of difluorinated products 2c' and 2c''. The product composition of the reaction of 1c with NFSI (1.0 equiv) remained unchanged at lower milling speeds (25 Hz vs 30 Hz), but the use of

• , we reacted a mixture of NFSI and imidazole (3a) by ball milling. Analysis by NMR spectroscopy of the crude reaction mixture showed that 1-(benzenesulfonyl)imidazole (4a) had been formed in 41% yield (Scheme 3a). Complementarily, 19F NMR spectroscopy of the crude reaction mixture evidenced a

• distinctive peak at 65.8 ppm in the 19F NMR spectrum (Scheme 3g), which was assigned to phenylsulfonyl fluoride (PhSO2F) [35], a byproduct often obtained in reactions with NFSI [36][37]. Trying to improve the rheology of the reaction mixture and to increase the basicity of the medium, we milled 3a and NFSI in

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

• yield obtained for the synthesis of 3bc (R1 = 5-OMe, 75%), the aromatic aldehyde 2c substituted with a similar electron-rich group (R1 = 5-NEt2) gave only a regular 40% yield for 3bb. The structures of the new Schiff bases 3 were characterized by 1H, 13C, and 19F NMR spectroscopy and HRMS techniques

• . The structural assignments for the synthesized quinolines 1a–f were consistent with the 1H, 13C, and 19F NMR spectra described in the literature [14]. When the 1H NMR spectral data were recorded in CDCl3 as a solvent for the 3aa–be series and compared with the NMR spectral data of the 1a–f series, the

• similar structures described in the literature [7][14][22]. The CF3 group bonded at C-4 was assigned as a quartet with 1JCF ≈ 274.6 Hz, with chemical shifts of 123.52 ppm, on average. The 19F NMR spectra in CDCl3 showed a singlet at −61.70 ppm, on average, in relation to the CF3 group. Furthermore, there

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

• determination, 1H/13C/19F NMR spectra for all compounds.