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

• to the 13C NMR spectra, the largest downfield shift was observed for the carbonyl carbon С1, with ∆δ = 17.7–21.1 ppm, showing a substantial degree of protonation of the carbonyl group in TfOH. The tendencies are the same for the protonation of enones 2a,c,d,m leading to cations Ba,c,d,m (Table 2

• ). Thus, in the 1H NMR spectra, downfield shifts of vinyl protons H2 and H3 upon protonation were 0.50–0.61 and 0.41–0.54 ppm, respectively. In the 13C NMR spectra, ∆δ values for carbons С1 and С3 were 12.7–21.3 and 6.0–13.4 ppm, respectively. The NMR data revealed that the positive charge in the O

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• ppm) for 1H NMR and the 13C signal of C6D6 (δ = 128.06 ppm) for 13C NMR [39]. Coupling constants are given in Hz. IR spectra were recorded on a Bruker α infrared spectrometer with a diamond ATR probehead. Peak intensities are given as s (strong), m (medium), w (weak) and br (broad). Optical rotations

• ; 13C NMR (126 MHz, D2O) δ 135.80 (Cq), 133.72 (Cq), 125.03 (d, 3JC,P = 8.5, CH), 124.26 (CH), 67.10 (d, 2JC,P = 5.6, CH2), 34.11 (CH2), 25.67 (CH2), 24.83 (CH3), 17.41 (CH3), 16.86 (CH3), 15.67 (CH3) ppm; 31P NMR (202 MHz, D2O) δ −7.90 (d, 2JP,P = 21.3), −10.40 (d, 2JP,P = 21.4) ppm; HRMS–TOF (m/z

• , 3JH,H = 6.8, 1H), 4.40 (d, 3JH,P = 5.9, 2H), 1.69 (m, 3H), 1.58 (dm, 3JH,H = 7.0, 3H) ppm; 13C NMR (126 MHz, D2O) δ 132.34 (d, 3JC,P = 8.0 Hz, Cq), 124.64 (CH), 64.18 (d, 2JC,P = 5.3, CH2), 20.52 (d, 4JC,P = 1.8, CH3), 12.62 (d, 5JC,P = 2.2, CH3) ppm; 31P NMR (202 MHz, D2O) δ −7.0 (d, 2JP,P = 21.2 Hz

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• compounds 5 in yields between 11–69% after chromatographic workup. The structures of the products were unambiguously confirmed by 1H and 13C NMR spectroscopy, as well as by mass spectrometry. Assuming that four new bonds are being formed in this one-pot process, the range of yield from 11 to 69% (after

• -trisubstitued indoles 8 in good yield (Scheme 4). The 1,2,3-trisubstitued indoles 8 were unambiguously confirmed by 1H and 13C NMR spectroscopy, as well as by mass spectrometry and elemental analysis. Miura et al. could show that 1-alkyl-2,3-diarylindoles constitute a class of blue-emissive indole derivatives

• ), 7.23–7.26 (m, 1H), 7.46–7.54 (m, 5H); 13C NMR (150 MHz, CDCl3) δ 1.9 (Cquat), 32.4 (CH3), 106.7 (CH), 110.8 (CH), 111.5 (CH), 128.6 (Cquat), 129.3, 130.9, 131.5 (Cquat), 134.5 (Cquat), 143.5 (Cquat), 160.0 (Cquat); IR (cm−1) ν̃: 604 (w), 619 (w), 662 (w), 689 (s), 733 (m), 756 (s), 789 (m), 860 (w

Correction: Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 1370–1371, doi:10.3762/bjoc.19.97

• HMBC correlations of H-2/C-1, C-3, C-4, C-8a, H-4/C-3, C-4a, C-5, C-8a, C-9, H-5/C-4, C-4a, C-6, C-7, C-8a, H-9/C-2, C-3, C-4, H-10/C-7, C-8, C-8a, H-11/C-6, and H-12/C-7. Table 1 provides the revised 1D 1H and 13C NMR data of compound 1. The structural revision of 1 also required recalculation of the

• compound 1 and key HMBC correlations. Recalculated and experimental ECD spectra of compound 1. Revised 1H (600 MHz) and 13C NMR (150 MHz) data of compound 1 (δ in ppm, J in Hz, methanol-d4).

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• , and 1H/13C NMR spectroscopy. Proton NMR shows a complicated set of overlapping multiplets indicating that the reaction results in the formation of various isomers (rotamers) which are different by relative orientation of the benzoguanidine donor moieties with respect to each other (Figure 2, see

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• ) onto acyclic MBH alcohols 1a–f. Supporting Information Supporting Information File 69: Full experimental details and characterization data of all new compounds. Supporting Information File 70: 1H and 13C NMR and HRMS spectra of compounds. Acknowledgements We thank the Tunisian Chemical Society for

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• structures of the obtained dispiro compounds 3a–m were fully characterized by IR, HRMS, 1H and 13C NMR spectroscopy. Because of the three chiral carbon atoms in the product, several diastereomers might be formed in the reaction. However, TLC monitoring and 1H NMR spectra of the crude products clearly

• , 1H, CH2), 2.46 (d, J = 16.0 Hz, 1H, CH2), 2.39 (d, J = 16.0 Hz, 1H, CH2), 2.37–2.34 (m, 2H, CH2), 1.30 (s, 3H, CH3), 1.15 (s, 3H, CH3), 0.76 (t, J = 7.2 Hz, 3H, CH3) ppm; 13C NMR (101 MHz, CDCl3) δ 193.0, 173.8, 171.9, 171.2, 155.6, 142.0, 141.8, 134.8, 134.1, 131.0, 129.3, 129.1, 128.8, 128.7, 128.6

• = 4.8 Hz, 1H, CH2), 4.43 (d, J = 5.2 Hz, 1H, CH2), 2.41 (d, J = 26.8 Hz, 1H, CH2), 2.40 (s, 3H, CH3), 2.21 (d, J = 18.4 Hz, 1H, CH2), 2.10 (s, 1H, CH3), 2.05 (s, 1H, CH2), 1.87 (d, J = 16.0 Hz, 1H, CH2), 1.00 (s, 3H, CH3), 0.99 (s, 3H, CH3) ppm; 13C NMR (101 MHz, CDCl3) δ 197.5, 181.6, 177.4, 177.2

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• copper(II) porphyrins 3–8. Finally, the structures of all newly synthesized benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 3–16 and benzo[f]quinoxalinoporphyrin 17 were assigned on the basis of IR, 1H and 13C NMR, and HRMS data analysis. Photophysical characteristics The UV–vis spectra of the newly

• MHz) and 13C NMR (100 MHz) spectra were recorded in CDCl3 on a Jeol ECX-400P (400 MHz) NMR spectrometer. Chemical shifts are reported in δ scale in parts per million (ppm) relative to CDCl3 (δ = 7.26 ppm for 1H NMR and δ = 77.00 ppm for 13C NMR). The coupling constants are expressed as (J) and are

• ]chromeno[2,3-h]quinoxalinoporphyrin 3. Optimization of the reaction conditions for the synthesis of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrin 3.a Supporting Information Supporting Information File 186: Characterization data, 1H and 13C NMR spectra of newly prepared porphyrin products

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• -diaminopyrazoles 4a–c (Scheme 2). The structures of compounds 4a–c were confirmed by 1H and 13C NMR spectroscopy data, as well as high-resolution mass spectrometry (HRMS). Compound 4a was previously obtained by another method [18]. The spectral characteristics of diaminopyrazole 4a reported in [18] correspond to

• group during the reaction. The structures of compounds 5a–e were confirmed by 1H and 13C NMR spectroscopy and HRMS, as well as X-ray diffraction analysis of a single crystal of compound 5b. The involvement of arylhydrazines 3b,c in the reaction with enamines 2a–d similarly leads to the formation of 1

• upon addition of hydrochloric acid. This is probably due to the protonation of the dimethylamino moiety or/and that dimethylamine hydrochloride is a better leaving group than the free base. The structures of compounds 6a–f were confirmed by 1H and 13C NMR spectroscopy and HRMS, as well as X-ray

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• unsaturation in its structure. The 1H, 13C NMR, and HSQC spectral data of compound 1 (Table 1) revealed the presence of forty-three carbon resonances sorted into eight methyl, fourteen methylenes (one olefinic), ten methine and eleven unprotonated carbon atoms. This includes three carbonyl carbons at δC 177.4

• (C-21), 175.0 (C-5'), and 172.4 (C-1') as well as four olefinic carbon signals at δC 156.7 (C-24), 136.3 (C-9), 135.2 (C-8), and 107.4 (C-31). The 1H and 13C NMR spectral data of compound 1 (Table 1) also revealed the presence of a sugar moiety through the presence of the characteristic anomeric

• and 13C NMR data (Table 1) of the sugar moiety with that reported for a related fungal lanostanoside, ganosinoside A [26] and other glycosidic moieties [27], it was confirmed to be a β-ᴅ-glucopyranosyl residue. The HMBC spectrum of compound 1 (Figure 2) also revealed key correlations from two

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

• Vladislav Yu. Shuvalov,
• Ekaterina Yu. Vlasova,
• Tatyana Yu. Zheleznova and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

• Information Supporting Information File 124: Experimental procedures, characterization data, and 1H and 13C NMR spectra for all new compounds. Funding This work was supported by the Russian Science Foundation (grant No. 22-13-00356).

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• the addition of 1 equivalent of aromatic molecules to the standard solution using tetrahydrothiophene as the substrate. Supporting Information Supporting Information File 104: General procedures, product characterization, and copies of 1H NMR and 13C NMR spectra of compounds. Funding We are grateful

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• in the thiazine ring leads to the cleavage of the triazine C–N bond. Further proton transfer gives product 9. The structures of the synthesized compounds 3a,b,j and 5a–k,m were confirmed by IR, 1H and 13C NMR spectroscopy, and high-resolution mass spectrometry. the potassium salts 3c–i,k,m were

• characterized by their 1H and 13C NMR spectra. In the 1H NMR spectra, the doublets of the bridging hydrogen atom C(9a)H in compound 4 and C(10a)H in compound 5 are characteristic signals which allow to attribute the synthesized compounds to one of the two heterocyclic systems, i.e., imidazo[4,5-e]thiazolo[2,3-c

• closer location in structures 5 (Figure 3). In the downfield region of the 13C NMR spectra registered without proton decoupling for isomeric acids 4a and 5a, the carbon atom doublets of the carboxyl groups, carbonyl groups of thiazole (for 4a) or thiazine (for 5a) cycles, as well as multiplets of

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• by 1H NMR, 13C NMR, and HRMS spectra (Experimental section). UV–vis absorption and fluorescence emission spectra The UV–vis absorption spectra of the compounds were studied (Figure 1 and Figure S29 in Supporting Information File 1). For the compounds without an oxidized PTZ unit, there are

• , J = 7.51 Hz, 2H), 6.85–6.88 (m, 2H), 6.77–6.80 (m, 2H), 6.08 (d, J = 8.13 Hz, 2H); 13C NMR (CDCl3, 125 MHz) δ 162.9, 158.1, 151.9, 142.6, 138.2, 138.2, 130.8, 130.3, 128.0, 127.6, 124.6, 123.5, 121.1, 117.5, 116.4, 111.8; HRMS–ESI (m/z): [M + H]+ calcd for C30H17FN2O2S, 489.0995; found, 489.1072

• ) δ 8.87 (d, J = 7.63 Hz, 1H), 8.70 (d, J = 7.13 Hz, 1H), 8.59 (d, J = 8.38 Hz, 1H), 7.99 (d, J = 7.63 Hz, 1H), 7.76–7.80 (m, 1H), 7.57–7.61 (m, 2H), 7.52 (d, J = 7.38 Hz, 1H), 7.35 (d, J = 7.25 Hz, 2H), 7.11 (d, J = 7.50 Hz, 2H), 6.77–6.87 (m, 4H), 6.09 (d, J = 7.76 Hz, 2H); 13C NMR (CDCl3, 125 MHz

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• , 273.1461), 13C NMR, and DEPT spectra, indicating 5 degrees of unsaturation. The 1H NMR spectrum of 1 (Table 1) shows one methyl group at δH 1.16 (s, 3H), two olefinic protons [δH 5.05 (d, J = 1.4 Hz, 1H), δH 4.05 (d, J = 1.4 Hz, 1H)], and an oxygenated methylene at δH 4.06 (s, 2H). The 13C NMR and DEPT

• 259.1671 [M + Na]+ (calcd 259.1669). The 13C NMR and DEPT spectra (Table 1) of 2 indicate 4 degrees of unsaturation. Compound 2 is similar in structure to 1 by analysis of their NMR data. There are two differences between 2 and 1. One is that at C-4 in 2 a methyl group is attached instead of a carboxyl

• 2 was eventually clarified to be 7S,8R,10S, and it was named aquisinenoid G. Compound 3 was isolated as pale yellow gum, and its molecular formula was determined to be C15H24O3 based on its HRESIMS m/z 275.1622 [M + Na]+ (calcd for C15H24O3Na, 275.1618), 13C NMR and DEPT spectra (Table 2

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• . Reactivity of tetrahydrofuro[3,2-c]pyridine 4a. Optimization of reaction conditionsa. Supporting Information Supporting Information File 47: Experimental procedures, characterization data, copies of 1H and 13C NMR spectra, HRMS of new compounds, and X-ray crystallography data. Supporting Information File 48

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

• Xiu-Yu Chen,
• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• Hz, 1H, CH), 2.44 (s, 3H, CH3) ppm; 13C NMR (100 MHz, CDCl3) δ 168.7, 166.2, 164.9, 150.2, 146.1, 145.7, 138.7, 129.3, 128.8, 128.1, 128.0, 127.8, 127.5, 127.3, 127.0, 126.3, 126.1, 125.1, 124.7, 124.6, 106.3, 104.6, 102.8, 61.3, 57.6, 56.0, 53.0, 51.6, 50.0, 44.8, 39.5, 17.9 ppm. IR (KBr) ν: 3732

• , CH3), 0.99 (t, J = 7.2 Hz, CH3) ppm; 13C NMR (100 MHz, CDCl3) δ 172.2, 166.1, 163.5, 158.0, 149.9, 146.3, 137.8, 137.4, 135. 9, 129.2, 128.5, 128.0, 127.2, 123.0, 101.9, 75.5, 62.9, 61.1, 61.0, 58.3, 50.3, 49.2, 14.1, 13.8, 13.4 ppm; IR (KBr) ν: 3069, 2981, 1736, 1660, 1552, 1514, 1344, 1222, 1121

• ), 5a (CCDC 2260341), and 5f (CCDC 2260342) have been deposited at the Cambridge Crystallographic Data Center (https://www.ccdc.cam.ac.uk). Supporting Information File 44: Characterization data and 1H NMR, 13C NMR, HRMS spectra of the synthesized compounds. Funding This work was financially supported

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• formula of 1 was assigned to be C15H19NO3S by high-resolution (HR) ESIMS (m/z 294.1180 [M + H]+; calcd. 294.1169 for C15H20NO3S), which indicated the presence of seven double bond equivalents (DBEs). Upon analyzing the 13C NMR spectrum, the DBEs were assigned to two ring structures, two carbon–heteroatom

• conversion of a thiazoline into a thiazolidine ring. 1H and 13C NMR spectroscopic data for 1–6 in DMSO-d6. Supporting Information Supporting Information File 90: UV and total ion chromatograms of culture extracts from Massilia sp. NR 4-1. Copies of MS/MS and NMR spectra for new compounds. Acknowledgements

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• was not given for the different coupling constants between diester 1a and diketone 1b’. In the 13C NMR spectrum of diester 1a, two separate signals of carbonyl groups were observed at 163.2 and 163.3 ppm, indicating that the two ester functionalities were not equivalent. Moreover, the spectrum of

• ) in CDCl3 using TMS as an internal standard. The assignments of the 13C NMR signals were performed by DEPT experiments. IR spectra were recorded on a JASCO FT/IR-4200 spectrometer equipped with an ATR detector. High-resolution mass spectra were obtained on AB SCIEX Triplet TOF 4600 and Bruker Compact

• ), 4.17 (q, J = 1.8, 7.2 Hz, 2H), 4.48–4.37 (m, 1H), 4.81–4.72 (m, 1H), 4.97–4.88 (m, 2H), 7.09 (d, J = 8.0 Hz, 2H), 7.18 (d, J = 8.0 Hz, 2H), 7.48 (dd, J = 7.6, 7.2 Hz, 2H), 7.61 (t, J = 7.6 Hz, 1H), 8.05 (d, J = 7.2 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 13.6 (CH3), 21.1 (CH3), 42.8 (CH), 57.1 (CH), 61.9

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• 7.02 (s, 1H, H-7)], two methoxy signals [δH 3.96 (s, 3H, H3-12) and 3.73 (s, 3H, H3-11)], and two methyl signals [δH 2.51 (s, 3H, H3-10) and 1.09 (d, J = 6.8 Hz, 3H, H3-9)]. The 13C NMR and DEPT spectra of compound 1 (Table 1 and Figure S2 in Supporting Information File 1) exhibit 14 resonances

• NMR and DEPT spectra (Table 2 and Figure S9 in Supporting Information File 1) show that compound 2 is comprised of 9 carbons, including one methyl, one methoxy carbon, one sp2 methine, one ketone, and five sp2 carbons (three of them oxygenated). The 1H and 13C NMR data and the molecular formula

• -tetrasubstituted benzene substructure. The 13C NMR and DEPT spectra of 3 (Table 2 and Figure S15 in Supporting Information File 1) exhibit 15 resonances classified into two methyls, four sp2 methines, one ketone, and eight sp2 carbons (four of them oxygenated). The two methyl groups are positioned at C-3 and C-5

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• result, both products could be isolated and characterized using 1H, 13C NMR spectroscopy and mass spectrometry. Moreover, the structure of product 11a was also confirmed by single-crystal X-ray diffraction analysis. It might be noted that precipitated crystals of 11a contained two polymorph modifications

• 11g–j were confirmed by 1H, 13C NMR spectroscopy and high-resolution mass spectrometry. In the 1H NMR spectra of the products, characteristic singlets corresponding to the protons of the dihydropyranone fragment in the region δ 5.3–5.4 ppm and the protons of the hydroxy group in the region δ 5.4–5.5

• photoproducts 11 and 12.a Supporting Information Supporting Information File 42: Experimental procedures, characterization data of all products, copies of 1H, 13C NMR, HRMS spectra of all new compounds, and X-ray crystallographic data.

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• -pot synthesis of N-heterocycles. Optimization of reaction conditions.a Supporting Information Supporting Information File 112: General procedures, product characterization, and copies of 1H NMR and 13C NMR spectra of all compounds. Acknowledgements The authors acknowledge NIPER S.A.S. Nagar for

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• configurational assignment of organic compounds. The experimental NMR data (13C NMR chemical shifts) are compared with those predicted for all possible theoretical stereoisomers. The correct stereochemistry may be obtained by combining the computed and experimental data [1]. Recently, Novitskiy and Kutateladze

• ]hept-2-ene) at different temperatures and obtained mixtures of the addition products 2–6 (Scheme 1) [4]. The structures of these compounds 2–6 have been elucidated on the basis of 1H and 13C NMR spectral data, as well as a number of 2D techniques (APT, HETCOR and COSY), and extensive double resonance

• elucidated the exact configuration of compound 6. The symmetrical structure of 6 could be characterized easily because of its four-line 13C NMR spectrum. However, on the basis of 13C NMR data alone we were not able to distinguish between possible symmetrical tribromides. The configurations of the bromine

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

• Sarot Cheenpracha,
• Ratchanaporn Chokchaisiri,
• Lucksagoon Ganranoo,
• Sareeya Bureekaew,
• Thunwadee Limtharakul and
• Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

• revealed the presence of hydroxy (3429 cm−1) and carbonyl (1733 cm−1) groups. The UV absorption band maximum at λmax 283 nm and five downfield-shifted carbon signals at δC 169.8 (C-16), 163.8 (C-13), 149.3 (C-12), 111.6 (C-11), and 109.6 (C-15) in the 13C NMR data suggested the presence of the α,β

• . The 13C NMR and DEPT spectra, combined with HMQC correlations (Table 1) showed 20 resonances for carbon signals accounting for four methyls, five sp3 methylenes, five methines (two olefinics at δC 111.6, 109.6), and six quaternary carbons (one carbonyl at δC 169.8, two olefinics at δC 163.8, 149.3

• , and one oxygenated sp3 at δC 72.2). The 1H and 13C NMR spectroscopic data of 1 showed great similarity to those of 12α,14β-dihydroxycassa-13(15)-en-12,16-olide (2) isolated from Caesalpinia bonduc [18]. The difference evident was that compound 1 displayed an extended conjugate π-system with an α,β

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• reaction to generate the corresponding multiple Schiff bases and then reduced with sodium borohydride (Scheme 1a). The structure of CS-TPE was characterized by 1H NMR spectra and solid-state CP/MAS 13C NMR spectra, and the results were found to agree with the proposed structure. For instance, the products

• display distinct peaks at δ 7.50–6.70 in their 1H NMR spectra (Figure 1) and at δ 145–120 ppm in their 13C NMR spectra (Figure S1 in Supporting Information File 1), corresponding to the proton resonances of the benzene rings and the carbon resonances of the whole fluorophore, respectively. The appearance

• /MAS 13C NMR spectra of CS-TPE, optical transmittance and concentration-dependent transmittance of CS-TPE, Tyndall effect of CS-TPE and TBTQ-C6/CS-TPE and pH-responsive properties of TBTQ-C6/CS-TPE. Funding We thank the National Natural Science Foundation of China (No. 22061015) and the Hainan High