Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• ). In the 13C NMR spectrum, a total of 43 signals were observed in the low-field region (approximately 160–120 ppm), of which 29 signals are attributed to the C60 carbon cage and 14 signals are attributed to the aromatic ring carbon nuclei of the Dip groups (Figure 4). In addition, three sp3 carbon

• . Reagents were used as purchased unless otherwise specified. The 1H and 13C NMR measurements were conducted on a JEOL ECA-500 spectrometer (JEOL Ltd.). Absorption spectra were measured using a UV-3150 spectrophotometer (Shimadzu Corp.). Cyclic voltammograms and differential pulse voltammograms were recorded

• Hz, 6H), 1.371 (d, J = 7.0 Hz, 6H), 1.365 (d, J = 7.0 Hz, 6H), 1.31 (d, J = 7.0 Hz, 6H), 1.29 (d, J = 7.0 Hz, 6H), 1.17 (d, J = 7.0 Hz, 6H), 1.06 (d, J = 7.0 Hz, 6H); 13C NMR (CDCl3/CS2 3:1) δ 160.16 (s, 2C), 158.38 (s, 2C), 158.33 (s, 2C), 158.29 (s, 2C), 158.18 (s, 2C), 157.12 (s, 2C), 155.78 (s

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• reactivity of 9dc,dl. Supporting Information Supporting Information File 26: Experimental section and copies of 1H and 13C NMR spectra of all new compounds. Funding The authors thank the São Paulo Foundation Science (FAPESP, #2018/02611-0, #2013/07600-3 and #2023/18007-3, to FC) for financial support. F. C

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• spectroscopy. After 51 hours of reaction in boiling CH2Cl2, Diels–Alder adduct 27 was observed in 22% yield. Compound 27 was identified by 1H NMR and 13C NMR spectroscopies as well as high-resolution ESI mass spectrometry. Although the lack of reactivity observed for 3 and 23 limited our kinetic analysis, we

• modified cardboard box were utilized for detection of TLC spots. Melting points were determined in open capillary tubes using a Mel-Temp apparatus, and are uncorrected. Proton nuclear magnetic resonance (1H NMR) spectra and carbon nuclear magnetic resonance (13C NMR) spectra were recorded on either a

• , washed with 5 mL water, and then air dried to give 3 as a white solid (57 mg, 60%, Scheme 3). Mp 169–170 °C (from [13], 188–189 °C); 1H NMR (500 MHz, CDCl3) δ 7.15–7.08 (m, 2H), 6.98 (s, 4H), 6.86–6.79 (m, 2H), 2.35 (s, 6H), 2.12 (s, 12H); 13C NMR (126 MHz, CDCl3) δ 143.54, 139.17, 138.71, 128.23, 127.43

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• anomers with a α/β ratio of 2:1, as determined by 1H and 13C NMR. Deprotected nucleosides Va and Vb but not Vc exhibited absorbance in the UV region with ε258 = 4230 L⋅mol−1⋅cm−1 and ε262 = 4730 L⋅mol−1⋅cm−1, respectively. This was most likely a result of the presence of a double bond next to the P=O unit

• the enzymatic assays and the synthesis of nucleosides and modified ODNs, assignment of 1H, 13C, 31P NMR and IR spectra and results of HRESIMS experiments for new compounds synthesised as well as RP-HPLC profiles and HRESIMS spectra of ODNs. Acknowledgements NMR and mass spectrometry facilities at

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• inhibitor of homeodomain-interacting protein kinases (HIPKs) [32], and combretastatin A-4 analogs evaluated for their anticancer properties against a panel of 60 human cancer cell lines [33] (Figure 2). The structures of all new compounds were confirmed by 1H and 13C NMR and HRMS. X-ray diffraction studies

• were performed for compounds 12c and 13c,d (Figure 3; see Supporting Information File 1 for details) that allowed us to unambiguously establish the structures of both the starting hydrazones and rearrangement products. Conclusion In summary, we have developed an efficient method for the synthesis of

• molecule is not shown), 13c (top right), and 13d (bottom) with thermal ellipsoids set at a 50% probability level. Intermolecular hydrogen bonds are drawn with dashed lines. Methods for the synthesis of isoxazolo[4,5-b]pyridines: (A) annulation of an isoxazole fragment to a pyridine ring; (B) annulation of

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• , 230−400 mesh from Whatman. Routine 300(75) MHz 1H(13C) NMR spectra were recorded on Varian Mercury 300 or Gemini 300 spectrometers. Routine 500(125) MHz 1H(13C) NMR were recorded on an INOVA 500 spectrometer. 2D NMR spectra were recorded using a 600 MHz Varian instrument. Chemical shifts (δ) are given

• amounts of CH2Cl2 and THF (10 mL), and dried in vacuo to afford a bright orange solid of 1a (0.264 g, 1.14 mmol, 89%). 1H NMR (600 MHz, DMSO-d6) δ 8.30–8.31 (dd, J = 3 Hz, J = 6.6 Hz, 2H), 8.49–8.51 (dd, J = 3 Hz, J = 6.6 Hz, 2H); 13C NMR (150 MHz, DMSO-d6) δ 114.5, 130.4, 136.1, 136.2, 142.7, 147.4; HRMS

• (s, 6H), 8.27 (s, 2H); 13C NMR (125 MHz, DMSO-d6) δ 20.1, 114.2, 127.8, 134.6, 142.3, 146.6, 148.7. The proton NMR in chloroform matches the literature value [25]; HRMS (DART): [M + H]+ calcd for C14H8N6, 261.0883; found, 261.0889; [M + NH4]+, 278.1149; found, 278.1154. Aceanthryleno[1,2-b]pyrazino

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• details and copies of 1H, 13C, and 19F NMR spectra. Acknowledgements T.D. thanks for the generous gift of fluoroalcohols from Central Glass Co., Ltd. Funding N.T. and T.D. acknowledge support from JSPS KAKENHI Grant Number 20K06980 (N.T.) and 19K05466 (T.D.), JST CREST grant number JPMJCR20R1 (T.D.), and

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• and 13C NMR, and HRMS analysis. In addition, single crystals of compound 6d and 8c were obtained for X-ray analysis to confirm the structures (Figure 2). Conclusion In conclusion, we have developed a one-pot synthesis with two or three steps for making tetrazolo-pyrazino[2,1-a]isoquinolin-6(5H)-ones

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

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• separated by 0.21 ppm. In the 13C NMR spectrum of 11a–f, a ≈10 ppm upfield shift for the chloroacetal was seen to δ ≈92 ppm from the C5 acetal present in the starting materials. Only a single diastereomer was formed for all 3,3-disubstituted rearrangement products due to the hindrance on the endo-face, with

• open chain aldehydes present in solution (≈5%) with a doublet at δ 9.6 ppm, with the configuration of the hemiacetal centre confirmed in the solid state by X-ray crystallography on 12a and 12d. The 1H and 13C NMR spectra for 13b,d,e were similar to the starting materials, except that the resonances

• and X-ray structure for 24. Supporting Information Supporting information includes detailed experimental details and characterisation data, X-ray crystallography, and copies of 1H and 13C spectra for new compounds. Supporting Information File 11: Experimental details, X-ray crystallography and

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

• Dongxu Zhang,
• Wenyu Du,
• Xingming Pan,
• Xiaoxu Lin,
• Fang-Ru Li,
• Qingling Wang,
• Qian Yang,
• Hui-Min Xu and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73

• mainly elucidated through comparative 1H and 13C NMR spectra and by comparing analytical data with existing literature reports [28][29] (see Supporting Information File 1, Figures S1–S7). The 1H NMR spectrum of compound 2 exhibited characteristic signals for one olefinic proton at δH (5.48) and four

• methyl groups at δH (0.83, 0.87, 0.98 and 1.77). Its 13C and DEPT NMR spectra showed 15 carbon resonances, including four methyl groups, four methylenes, four methines, and three quaternary carbon atoms. This information suggests that it may be a drimenol congener and the structure was further supported

• comparing the 1H and 13C NMR data with the literature (Figures S11 and S12 in Supporting Information File 1) [41]. Although the chemical structure of compound 8 has been documented, its 1H and 13C NMR data were not fully reported [42]. Therefore, we conducted comprehensive 1D and 2D NMR experiments on it

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• most other solvents. C60–oligo-Lys and C60–oligo-Glu were characterized by 1H and 13C NMR. Photoinduced 1O2 generation was observed in the most soluble C60–oligo-Lys conjugate under visible light irradiation (527 nm) to show the potential of this highly water-soluble molecule in biological systems, for

• part (α, β, γ, δ, and ε). The observed splitting of the protons a and b was presumably due to a diastereotopic effect of the methine proton c, similar to the spectrum of the monoadduct. Figure 6a shows the 13C NMR spectra of 5a in D2O and of the monoadduct in CDCl3. Together with the 1H NMR, COSY, HSQC

• –peptide conjugate 5a in D2O (above) and of the precursor monoadduct in CDCl3 (bottom) at 600 MHz. 13C NMR spectrum of C60–peptide conjugate 5a in D2O and of the precursor monoadduct in CDCl3 at 150 MHz (a) and expansion of the sp2 carbon region (b). The asterisks in (a) correspond to a TFA impurity

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• second ketosynthase of the polyketide synthase BaeJ involved in bacillaene biosynthesis (BaeJ-KS2). For this purpose, both enantiomers of a 13C-labelled N-acetylcysteamine thioester (SNAC ester) surrogate of the proposed natural intermediate of BaeJ-KS2 were synthesised, including an enzymatic step with

• glutamate decarboxylase, and incubated with BaeJ-KS2. Substrate binding was demonstrated through 13C NMR analysis of the products against the background of various control experiments. Keywords: bacillaene; biosynthesis; enzyme mechanisms; isotopes; trans-AT polyketide synthases; Introduction Polyketides

• is still important. Previous approaches to determine KS domain specificities have involved mass spectrometry (MS)-based methods [22][23], MS analysis of trypsin-digested proteins [24], and radiochemical assays [25]. Here, we report on a new method using 13C-labelled substrate surrogates in

Genome mining of labdane-related diterpenoids: Discovery of the two-enzyme pathway leading to (−)-sandaracopimaradiene in the fungus Arthrinium sacchari

• Fumito Sato,
• Terutaka Sonohara,
• Shunta Fujiki,
• Akihiro Sugawara,
• Yohei Morishita,
• Taro Ozaki and
• Teigo Asai

Beilstein J. Org. Chem. 2024, 20, 714–720, doi:10.3762/bjoc.20.65

• HREIMS spectrum. The 1H and 13C NMR spectra of 1 were identical to those of sandaracopimaradiene [30][31]. As the specific rotation of compound 1 was in good agreement with the reported data ([α]D24 −14.3 (c 0.97, CHCl3) in this study; [α]D25 −10.29 (c 0.65, CHCl3) in the literature [31]), compound 1 was

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• from 1. The 1H NMR spectrum showed additional olefinic proton signals at δH 5.35, as compared with that of 1. In line with this, two sp2 carbon signals at δC 130.6 and 131.0 were detected in the 13C NMR spectrum, demonstrating the presence of an olefin in 4. The comparative analysis of the MS/MS

• ][18]. The absolute configurations of the amino acid constituents, Pro, Ser and two modified ornithine residues, in 3–5 were assigned as ʟ, ᴅ, and ʟ, respectively (Figures S25, S33, and S41, Supporting Information File 1). The geometry of the olefins in 4 and 5 was determined to be Z based on the 13C

• phase for 30 minutes to yield variochelins A (1, 10.0 mg), B (2, 20.1 mg), C (3, 3.0 mg), D (4, 2.1 mg), and E (5, 5.3 mg). Variochelin A (1) HRESIMS m/z: [M − 2H]2−, calcd for C47H83O17N11, 535.7911; found, 535.7912, Δ 0.2 ppm for C47H83O17N11; −7.5, (c 1.78, MeOH), 1H and 13C NMR chemical shifts see

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• catalysed by copper(II) complex of ligand IV. Asymmetric aldol reactions of various aldehydes with ketones catalysed by compound IV. Supporting Information Supporting Information File 62: General information and experimental data of prepared compounds, copies of 1H and 13C NMR spectra and DFT calculations

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• by the higher HOMO level of 3 compared to that of 4. The products were characterized by spectroscopic and spectrometric analyses (Figures S3–S11 in Supporting Information File 1). 1H, and 13C NMR spectra clearly indicated the formation of [2 + 2] monoadducts. 7Li NMR spectra showed a sharp singlet

• : 155 MHz, 13C: 100 MHz), a Bruker ADVANCE III (1H: 600 MHz) and a Bruker ADVANCE III 700 (1H: 700 MHz, 7Li: 272 MHz, 13C: 176 MHz) spectrometer. Chemical shifts (δ) were reported in parts per million (ppm) relative to residual proton of solvent for 1H (5.32 ppm, CDHCl2), LiCl in D2O for 7Li (0 ppm

• , external standard), and carbon of the solvent for 13C (53.84 ppm, CD2Cl2). High-resolution matrix-assisted laser desorption ionization (HR-MALDI) mass spectra were obtained on a Bruker solariX 12T mass spectrometer with dithranol as a matrix. UV–vis absorption spectra were measured on a JASCO V-670 and a

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

• geometry of the remaining double bond at C-18 was established to be trans by comparing the 13C NMR chemical shifts at C-16 and C-21 between 1 and polycavernoside D (5) (Table S1 in Supporting Information File 1) [5]. In addition, a 4J long-range coupling between δH 1.95 (H-26) and δH 2.18 (H-24) and three

• procedures Optical rotations were measured with a JASCO DIP-1000 polarimeter. UV spectra were recorded on a UV-3600. ECD spectra were measured with JASCO J-1100. IR spectra were recorded on a Bruker ALPHA instrument. All NMR data were recorded on a JEOL ECX-400/ECS-400 spectrometer for 1H (400 MHz) and 13C

• (100 MHz). 1H NMR chemical shifts (referenced to the residual solvent signal of CHD2OD: δ 3.31, CHCl3: δ 7.26) were assigned using a combination of data from COSY and HMQC experiments. Similarly, 13C NMR chemical shifts (referenced to the solvent signal CD3OD: δ 49.0, CDCl3: δ 77.16) were assigned

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• ). After large-scale cultivation, 3 was isolated and subjected to nuclear magnetic resonance (NMR) analysis, which suggested that 3 is the C-5′ desmethyl form of preterretonin A [17]. However, several missing signals in the 13C NMR spectrum, likely due to keto–enol tautomerization in the D-ring, hindered

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• reproducible. Unsuccessful substrates for these reactions were also detected (Scheme 4). The use of 2-amino-3-hydroxypyridine provided a complex mixture of products (1H and 13C NMR analysis). When 6-amino-2-thiouracil was used, only the starting materials were recovered. Regarding the aldehyde component, the

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• m/z 341.1862 [M − H]− (calcd for C20H25N2O3, 341.1870). Spectroscopic analysis, including 1H NMR, 13C NMR (Table 1), and DEPT, revealed that compound 1 contains three methyl groups, one of which is oxygenated, four methines, three saturated non-protonated carbons, and two ketone carbonyl carbons (δC

• substructure at C-14 with a methine at C-16, indicated by the methoxy group. The position of the methoxy substituent was established by HMBC correlations, and the 13C NMR data suggested that compound 1 includes a 4-oxo-2,3-dihydro-(1H)-quinolin-3-yl fragment. The planar structure was established from HMBC

• 335.1719 [M + Na]+ (calcd for C19H24N2O2Na+, 335.1730) and m/z 311.1755 [M − H]− (calcd for C19H23N2O2, 311.1765). Spectroscopic analysis using 1H NMR, 13C NMR, and DEPT (Table 2) indicated that compound 2 comprises two methyl groups, five methines, five saturated non-protonated carbons, and one ketone

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• were isolated preparatively and fully characterized by IR, 1H, and 13C NMR spectroscopy as well as HRMS and XRD methods. The reverse thermal reaction was catalyzed by protonic acids. N-Acylated compounds exclusively with Fe2+ formed nonfluorescent complexes with a contrast naked-eye effect: a color

• products 3a–c were comprehensively characterized by IR, 1Н and 13C NMR spectroscopy, HRMS (Supporting Information File 2) as well as by X-ray diffraction analysis. The molecular structure of 3b is shown in Figure 3. The crystal data, details of the data collection and refinements for 3b as well as complete

• reaction occurred catalytically in the presence of HClO4. A special technique for the preparative synthesis of photoproducts was developed. For the first time in the course of studying N→O acylotropic migrations, O-acylated photoproducts were comprehensively characterized by IR, 1H and 13C NMR spectroscopy

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• ]pyridine (13c, 54% combined isolated yield). As shown for N-acylated target compounds 16a–f, the acylation of 6-bromo-2,3-dihydro[1,3]thiazolo[4,5-b]pyridines 13a–c, affording target compounds 14a–c, proceeded under mild conditions with a suitable acyl chloride reagent and triethylamine as base in DCM. It

• ]pyridine 7b had a higher water solubility of 173 mg/L and a lower LogP of 1.59 (pH 2.3). However, the lipophilicity of the new 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines was highly dependent on the substituents. For example, the brominated analogs 13b and 13c showed considerably higher LogP values of 2.88

• (i.e., 13b) and 3.17 (i.e., 13c). We were thus curious to see how the structural change from a heteroaromatic thiazole unit to a partially saturated thiazoline moiety affected the in vitro and in vivo efficacy of the target compounds. All compounds that were prepared to explore the SAR of substituted

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• determined as C12H13NO7S (requiring seven degrees of unsaturation) from the [M + H]+ ion at m/z 316.0484 (calcd. for C12H14NO7S, 316.0485) by HRESIMS. The 1H and 13C NMR spectral data of 1 are listed in Table 1. The 1H NMR and heteronuclear single quantum coherence (HSQC) data indicated the presence of two

• sp2 methines, one sp3 methine, one sp3 methylene, and one methyl group. The 13C NMR data showed the resonances of twelve carbons, which were classified into six olefinic carbons (including two oxygenated carbons: δC 151.0 and 145.2), three carbonyl carbons, one sp3 methine carbon, one sp3 methylene

• of 0.5 mL·min−1 and gradient elution with MeOH/H2O with 0.1% FA. Structure elucidation Spectra from 1H NMR at 500 MHz and 13C NMR at 125 MHz were measured in CD3OD using a JNM-ECA500 (JEOL Ltd., Tokyo Japan). Chemical shifts were referenced to CD3OD (3.31 ppm) in the 1H NMR spectra and CD3OD (49.0