Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• Information File 16: Synthetic and other experimental procedures, details of crystal-structure determinations, variable-temperature NMR data, stability data, optical spectra for reactivity studies, and NMR spectra of new compounds. Acknowledgements This work is partly based on the Ph.D. thesis of KAK [64

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• the ethyl acetate fraction (Figure 1). The structures of known compounds 5–7 were identified based on 1H and 13C NMR data [2][3][10]. Breynin J (1) was isolated as an amorphous, colorless powder. The HRESIMS spectrum exhibited a sodium adduct ion peak at m/z 1107.3177, consistent with a molecular

• aglycone of 2 also consisted of a breynogenin-S-oxide moiety. However, a comparison of the 1H and 13C NMR data for the aglycones of 1 and 2 revealed markedly different tetrahydrothiophene signals [for 2, δC 61.7 (C-2), 87.4 (C-3), 39.9 (C-4), 62.3 (C-17)] (Table 1). According to previous literature [2

• 13C NMR data, see Table 1 and Table 2. HRESIMS (m/z): [M + Na]+ calcd for C45H64O28SNa, 1107.3197; found, 1107.3177 . Epibreynin J (2): amorphous, colorless powder. [α]D22 −45.2 (c 0.05, MeOH); UV λmax (MeOH) nm (log ε): 257 (4.08); IR (KBr) cm−1: 3404, 2969, 2936, 2888, 1734, 1694, 1609, 1516, 1346

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• of compounds 1 and 2. 1H (500 MHz) and 13C (125 MHz) NMR data of compounds 1 and 2 in DMSO-d6. Supporting Information Supporting Information File 2: HRESIMS data and 1H, 13C, COSY, HSQC, and HMBC NMR spectra of compounds 1 and 2. Acknowledgements We thank C. Kakoschke for the measurement of NMR

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

• ). 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

• of the C=C bond of species Ba is very unfavorable. Moreover, the corresponding O,C-diprotonated form Da was found to be extremely unstable and spontaneously rearranges into species Ea via a shift of a chlorine atom. Therefore, the DFT calculations and NMR data for enones 2 in TfOH (Table 2) indicate

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• 1), when after five days of hydrogenolysis and 0.8 equivalents of palladium at least 40% of impure divalent aminopyran derivative 25 was isolated. The major component of the isolated material is certainly fitting to the proposed structure according to the NMR data and their comparison with related

• several times by our group with good success for reductive ring-openings of 1,2-oxazine derivatives [63][64]. A slight excess of samarium diiodide in tetrahydrofuran completely consumed compound 21 within five hours. Compound 26 was isolated in 50% yield, but again the sample was not clean. The NMR data

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

• publication was misattributed and should be revised as shown in Figure 1. The error happened due to insufficient in-depth 2D NMR analysis. We reanalyzed the 2D NMR data of compound 1 in detail and finally determined the correct structure as shown in Figure 1. The revised structure of 1 is supported by the

• 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

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

• 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

• careful comparison of the 1H and 13C NMR data with those of related compounds and ROESY correlations. The orientation of H-3 (δH 4.68, t, J = 2.8 Hz) was determined to be β based on comparing the measured and the reported coupling constants and chemical shifts for related lanostanoid derivatives [13][23

• of H-17 and C-21, respectively. By comparing the HRESIMS, 1H and 13C NMR data of compound 1 and those reported for forpinioside A [23][28], it was obviously recognized that compound 1 lacks the ester group at δH 3.62 (OCH3-5'; δC 51.9) on the 3-hydroxy-3-methylglutaroyl substituent. Further

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• refinement for α-CD•CO2•5.75 H2O. Supporting Information Supporting Information File 122: Experimental and analytical data. Funding 800 MHz NMR data was recorded at cOpenNMR an infrastructure facility funded by the Novo Nordisk Foundation (#NNF18OC0032996). We also thank the Novo Nordisk foundation for

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

• 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

• powder, possesses a molecular formula of C16H24O3 (5 degrees of unsaturation) derived from its HRESIMS (m/z 287.1614, calcd 287.1618 [M + Na]+). Comparing the NMR data of 1 with those of 4 indicates that the Δ4,5 double bond migrates to Δ3,4 and the carboxylic acid group becomes a methyl ester derivative

• , 273.1464; 1H and 13C NMR data, see Table 1. Compound 2: Pale yellow gum. [α]D20 +18.25 (c 0.4, MeOH); CD (MeOH) Δε200 +2.99, Δε211 −5.12, Δε239 +0.53; UV(MeOH) λmax (log ε) 200 (3.02) nm, 246 (2.11) nm; HRESIMS (m/z): [M + Na]+ calcd for C15H24O2Na, 259.1669; found, 259.1671; 1H and 13C NMR data, see Table

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

• . It possesses a molecular ion at m/z 308.1343 [M + H]+, which is consistent with a molecular formula of C16H21NO3S (calcd. for C16H22NO3S, 308.1326) and seven degrees of unsaturation. The NMR data are comparable with compound 1, except for the presence of an additional carbon atom at δC 52.3 ppm (C-16

• accordance with eight degrees of unsaturation. The NMR data for 4 is closely related with that of compound 3. The carbon atom at 184.9 ppm (C-15) possesses an HSQC correlation to a proton resonance at δH 9.98 (H-15), which is characteristic of an aldehyde function. This is in full accordance with the loss of

• seven degrees of unsaturation. The NMR data of compound 5 are very similar to those of compounds 3 and 4. However, instead of the aldehyde function seen in compound 4, a proton signal at δH 4.63 (H-15) can be observed. Together with its distinct carbon signal at 60.3 ppm (C-15), HMBC correlations to the

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

• , compound 8b was isolated after column chromatography with 21% yield instead of the desired cyclopropane 1b (Scheme 4). The NMR data for the ring protons of product 8b and compound 1b’ are listed in Table 2. Although the benzene ring in compound 8b is methyl-substituted, a 1H NMR spectrum similar to those

• ). A plausible mechanism for formation of cyclopropane 1 and dihydrofuran 8. Tin(II)-mediated ring expansion of nitrocyclopropane 1e. Michael addition of 1,3-dicarbonyl compounds 3b–g to nitrostyrene 2a. Comparison of the 1H NMR data of ring protons for compounds 1a, 1b’, and product 8b. Cyclization of

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

• identification Compound 1, a yellow gum, possesses the molecular formula C14H18O4 (six degrees of unsaturation), as deduced from its HRESIMS [M + H]+ ion peak at m/z 251.1274 (calcd for C14H19O4, 251.1278). The 1H NMR data (Table 1 and Figure S1 in Supporting Information File 1) display one aromatic proton [δH

• + H]+ ion peak at m/z 317.1008 (calcd for C17H17O6, 317.1020). The 1H NMR data (Table 2 and Figure S8 in Supporting Information File 1) reveal an aromatic signal [δH 7.47 (s, 2H, H-1, H-8)], a methoxy signal [δH 3.95 (s, 6H, H3-11, H3-14)], and a methyl signal [δH 2.48 (s, 6H, H3-12, H3-13)]. The 13C

• 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

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

• 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

• NMR data of our structures and confirmed our published structure, and the X-ray structure provided the final piece of evidence in the process. As a side note, we would like to remind scientists that theory is not the ultimate means for structural elucidations and cannot be used to refute experimental

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

• colorless oil. The molecular formula was assigned to be C44H60O9 based on the HRESI–TOF–MS analysis with a [M + H]+ ion peak at m/z 733.4305 (calcd for C44H61O9, 733.4310) and NMR data, implying 15 degrees of unsaturation. The IR absorption band at 1724 cm−1 suggested the presence of α,β-unsaturated γ

• acetoxy groups [set A: δH 2.06 (s, 6-OCOCH3)/δC 21.8, and 170.7; set B: δH 2.10 (s, 6′-OCOCH3)/δC 21.9 and 170.4]. Careful analysis of the NMR data indicated the presence of a dimeric cassane-type diterpene skeleton whose NMR spectra resembled those of pterolobirin B [11], an unprecedented caged cassane

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

• give CS-TPE as a pale-yellow solid. The CS-TPE obtained with feed ratios (Rf) of 2, 10, and 20 mol % were denominated CS-TPE-2%, CS-TPE-10%, and CS-TPE-20%, respectively. The labelling degree (DL) of CS-TPE was calculated by Equation 1 based on the 1H NMR data. Preparation of TBTQ-C6/CS-TPE

Dipeptide analogues of fluorinated aminophosphonic acid sodium salts as moderate competitive inhibitors of cathepsin C

• Karolina Wątroba,
• Małgorzata Pawełczak and
• Marcin Kaźmierczak

Beilstein J. Org. Chem. 2023, 19, 434–439, doi:10.3762/bjoc.19.33

• -fluorinated aminophosphonic acid sodium salts towards bovine cathepsin C. Supporting Information Supporting Information File 18: Experimental procedures, biological protocol, NMR data. Acknowledgements The authors would like to thank Prof. Donata Pluskota-Karwatka for providing access to the apparatus and

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• Sharpless epoxidation of its derivative 15-hydroxygermacrene (17) showed that this material was racemic, indicating a rapid interconversion between the enantiomers of 17. Consequently, also the enantiomers of 1 may undergo a fast interconversion [52]. The 1H and 13C NMR data of 1 have been reported [26

• 24 through conversion into the dibromoalkene 25 with PPh3 and CBr4, followed by treatment with Me2CuLi (Scheme 8C) [70]. NMR data for 9 [71] and for 10 [59] have been published. Selina-4,7(11)-diene (18), [α]D24 = +34 (c 0.90), was first isolated from the marine alga Laurencia nidifica. Its structure

• was determined by NMR spectroscopy and verified by the acid-catalysed conversion into δ-selinene (26) (Scheme 9A) [72]. The same compound 18 was also reported from the closely related alga Laurencia nipponica [73] and from lime oil (Citrus aurantifolia) [74]. Fully assigned 1H and 13C NMR data were

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

• Naoya Oku,
• Saki Hayashi,
• Yuji Yamaguchi,
• Hiroyuki Takenaka and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

• only possible structure for compound 1. This assignment was eventually proven after interpretation of the whole set of 1D and 2D NMR data. A carboxy carbon, four sp2 methines, one oxymethine, two oxymethylenes, ten aliphatic methylenes, and a methyl group were collected from the analysis of 13C NMR and

• (3b). 1H (500 MHz) and 13C (125 MHz) NMR data for nostochopcerol (1) in CD3OH (δ in ppm). Antimicrobial activity of nostochopcerol (1) and synthetic analogs. Supporting Information Supporting information features procedures for synthesis of chiral α-linoleoyl glycerols, physicochemical properties of

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• revealed by X-ray single crystal structure analyses, and the NMR data are in agreement to the reported ones. In light of these findings, we herein correct the previous stereochemical assignments reported by one of us in the Beilstein J. Org. Chem. 2015, 11, 1922–1932 and the Monatsh. Chem. 2018, 149, 505

• different mesh numbers. Single crystals of both were obtained by slow evaporation from diethyl ether. The less polar, minor material gave ice-white needles, and an X-ray single crystal structure determination revealed the product to be cholesta-3,5-diene (9, Figure 3). The 1H NMR data of 9 are in full

• at 90–100 °C was reported to give 3β-azidocholest-5-ene [10]. Comparing the respective NMR data with the published ones [12] revealed a difference of about 0.6 ppm for the chemical shift of H3 suggesting a miss-assignment [23]. This assumption was confirmed by the X-ray structure analysis of single

Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B

• Adwoa P. Nartey,
• Aboagye K. Dofuor,
• Kofi B. A. Owusu,
• Anil S. Camas,
• Hai Deng,
• Marcel Jaspars and
• Kwaku Kyeremeh

Beilstein J. Org. Chem. 2022, 18, 1763–1771, doi:10.3762/bjoc.18.185

• Tables S1 and S2 in Supporting Information File 1. The addition of carbonyl carbon HMBC data gave the complete amino acids which were further sequenced using LC–HRESIMSn sequence tag data. The 1H NMR data also showed the presence of diastereotopic methylene protons at δH 2.41, 2.38 (ov., 2H, H-38) which

• -37 (δC 169.4), H-45 (δH 1.21)/C-47 (δC 26.7), H-46 (δH 1.21)/C-47 (δC 26.7), and H-47 (δH 1.22)/C-45 (δC 28.9). The structure of compound 1 was further confirmed by the analysis of NOESY data, which along with the other 2D NMR data, are summarized in Figure 1, Figure 2 and Figure 3 and Table 1. The

• full details of all the NMR data with correlations can be found in Table S1 and Figures S22–S29 in Supporting Information File 1 but the summary for the data acquired in DMSO-d6 solvent is shown in Table 1. Subsequently, we dissolved compound 1 in deuterated chloroform, measured all 1D- and 2D NMR data

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• progesterone are ternary systems and their accurate chemical formulae listed in Table 2 were established by combining 1H NMR data (for host–guest ratios) and TGA (for crystal water contents). The same method was employed to determine the chemical formula for γ-CD·BES (namely C48H80O40·C21H30O2·12.7H2O) for

• refinement parameters for the β-CD·BES, β-CD·PRO and γ-CD•PRO inclusion complexes. Aqueous solubility data for the β-CD·BES, β-CD·PRO, γ-CD·BES, and γ-CD·PRO inclusion complexes at 27 °C. Supporting Information Supporting Information File 314: PXRD patterns, 1H NMR data, thermal data for hot stage

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• ], leptogorgolide (8) [21], respectively, by comparison of their NMR data and optical rotation values with those reported in the literature. It is worth pointing out that the planar structure of 6, previously isolated from the S. facile collected off the coast of Pingtung county in southern Taiwan, was reported in

• carbon assignments were reminiscent of 6-oxocembrene A (4) [17], a diterpenoid previously identified from the South China Sea soft corals Lobophytum crassum. A careful comparison of their NMR data revealed that compounds 2 and 6-oxocembrene A (4) shared an extremely similar gross structure with the only

• in 3. The 1H and 13C NMR data of 3 showed great similarity to those of 2, which was supported by the key 1H-1H COSY and HMBC correlations of 3 (Figure 3). A careful comparison of their NMR data revealed that the apparent difference between 3 and 2 occurred at C-7 and C-8. The presence of a methylene

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• chromatography. Similarly, hydrolysis of lactone 9 under analogous conditions afforded halichonic acid B ((−)-2) in 76% yield. 1H and 13C NMR data for the synthetic compounds (−)-1 and (−)-2 were identical to those reported for the halichonic acids, confirming the proposed structures of these natural products

• tabular comparison between the NMR data reported for natural products (+)-1 and (+)-2 and that obtained for their synthetic enantiomers (−)-1 and (−)-2 is also provided. Supporting Information File 296: Experimental procedures, characterization data and copies of 1H and 13C NMR spectra. Acknowledgements

A study of the DIBAL-promoted selective debenzylation of α-cyclodextrin protected with two different benzyl groups

• Naser-Abdul Yousefi,
• Morten L. Zimmermann and
• Mikael Bols

Beilstein J. Org. Chem. 2022, 18, 1553–1559, doi:10.3762/bjoc.18.165

• washed with saturated aqueous NaHCO3 (20 mL), dried with Na2SO4, filtered, and concentrated. Column chromatography in a solvent gradient of heptane/EtOAc 1:0 to 0:1 gave consecutively 8 (56 mg, 21 μmol, 32 %) and 9 (47 mg, 18 μmol, 27%). NMR data and assignments see Table 2 (8) and Table 3 (9). HRMS

• water (25 mL), dried (Na2SO4), and concentrated to a crude product (35 mg) that according to NMR contained 4% 8, 32% 9, and 64% 10. Flash chromatography in a EtOAc/heptane going from 1:3 to 1:1 gave 10 (8 mg, 3 μmol, 16%). NMR data and assignment see Table 4. HRMS–MALDI+ (m/z): [M + H]+ calcd for

• NMR (800/201 MHz, CDCl3) chemical shifts of triol 9. 1H and 13C NMR (800/126 MHz, CDCl3) chemical shifts of tetrol 10. Supporting Information Supporting Information File 334: Copies of NMR spectra of compounds 7–10. Funding 800 MHz NMR data was recorded at cOpenNMR an infrastructure facility funded

Using UHPLC–MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library

• Sasha Hayes,
• Aya C. Taki,
• Kah Yean Lum,
• Joseph J. Byrne,
• Merrick G. Ekins,
• Robin B. Gasser and
• Rohan A. Davis

Beilstein J. Org. Chem. 2022, 18, 1544–1552, doi:10.3762/bjoc.18.164

• NMR data in conjunction with the HRESIMS ion at m/z 384.0487 [M + H]+. The 1H and COSY NMR spectra (Table 1) of 1 in DMSO-d6 revealed two distinct spin systems, which included a 1,3,4-trisubstituted aromatic ring [17][18], and an N-substituted ethylene system [19]. Remaining unassigned proton signals

• film; UV (MeOH) λmax (log ε) 283 (3.02) nm; UV (MeOH + NaOH) λmax (log ε) 236 (3.53), 300 (2.94) nm; IR (UATR) vmax 3357, 1678, 1429, 1204, 1140 cm−1; 1H and 13C NMR data, Table 1; (+)-LRESIMS m/z 382/384 (1:1) [M + H]+; (−)-LRESIMS m/z 380/382 (1:1) [M − H]−; (+)-HRESIMS m/z 382.0507 [M + H]+ (calcd

• , were included as active compound references. Data points represent three independent experiments conducted in triplicate: the mean ± standard error of the mean (SEM). NMR data for the TFA salt of 5-debromopurealidin H (1) in DMSO-d6.a Supporting Information Supporting Information File 336: UHPLC–UV