Isolation and biosynthesis of daturamycins from Streptomyces sp. KIB-H1544

• Yin Chen,
• Jinqiu Ren,
• Ruimin Yang,
• Jie Li,
• Sheng-Xiong Huang and
• Yijun Yan

Beilstein J. Org. Chem. 2022, 18, 1009–1016, doi:10.3762/bjoc.18.101

• COSY correlation of H-3/H-4 and the HMBC correlations (H-3 to C-1, C-4, C-1’’; H-4 to C-1, C-2, C-1’; 4-OH to C-3, C-5; 5-OH to C-1, C-4, C-1’; H-2’ to C-5; H-3’ to C-1’; H-4’ to C-2’, C-6’; H-2’’ to C-2, C-3, C-4’’; H-3’’ to C-1’’; H-4’’ to C-2’’). The NOESY correlation (Figure 2) between H-4 and 5-OH

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• -dependent density functional theory/electronic circular dichroism (TDDFT-ECD) calculations or X-ray diffraction analysis. A plausible biosynthetic pathway of these sesquiterpenoids and their internal correlation were proposed and discussed. In an in vitro bioassay, (+)-aristolone (3) exhibited promising

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• , dimer 2 and trimer 3 showed similar correlation patterns to those observed in the monomer involving two and three trans-amide bonds, respectively, for the predominant rotamers (Figure 4 and Supporting Information File 1). We could also show that the two amides of dimer 2 have approximately the same cis

Synthesis of bis-spirocyclic derivatives of 3-azabicyclo[3.1.0]hexane via cyclopropene cycloadditions to the stable azomethine ylide derived from Ruhemann's purple

• Alexander S. Filatov,
• Olesya V. Khoroshilova,
• Anna G. Larina,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2022, 18, 769–780, doi:10.3762/bjoc.18.77

• reactivity descriptors, we have found a correlation between the structure of cyclopropene substrates 2 and their reactivity towards PRP (1). In the next step, we concentrated on studying the mechanism of the 1,3-DC reactions between PRP (1) and cyclopropenes 2. At first, it was planned to explore the

Cholyl 1,3,4-oxadiazole hybrid compounds: design, synthesis and antimicrobial assessment

• Anas J. Rasras,
• Mohamed El-Naggar,
• Nesreen A. Safwat and
• Raed A. Al-Qawasmeh

Beilstein J. Org. Chem. 2022, 18, 631–638, doi:10.3762/bjoc.18.63

• HMQC experiment revealed a correlation between the CH–O protons at 3.37, 3.79, and 3.91 ppm, and the carbon atoms at 72.0, 68.6, and 73.2 ppm, respectively. Moreover, the CH2S proton at 3.99 ppm correlated with carbon at 21.7 ppm. The methylene protons in -CH2-N-pyrrolidine at 3.51 ppm correlated with

• carbon at 42.7 ppm (see Supporting Information File 1). A COSY experiment for compound 4p showed long correlation between the two singlet methylene CH2S at 4.00 ppm and -CH2-N-pyrrolidine at 3.51 ppm (Supporting Information File 1). Antimicrobial activity The newly synthesized compounds were evaluated

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• geometrical or constitutional situation at the binding sites [92]. In a detailed recent study, the finding of a Hammett correlation in such nanorotors corroborated that a rate-determining dissociation at the rotator–metal binding interaction dictated the rotational speed [93]. Reducing Product Inhibition (RPI

• ) through nanomechanical motion. Recently, the suitability of the four-component rotors to act as catalysts in various click reactions was investigated having a look at nanorotors [Cu2(55)(60)(X)]2+ (with X = 62, 63 or 64), revealing an unexpected correlation between their rotational speed and catalytic

• catalytic yield increased in a linear fashion. Such a clear correlation asks for a convincing theory. A straightforward explanation is that higher rotational speed should lead to a reduction of product inhibition by kicking out the product bound at the catalytic copper center. As shown experimentally, only

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

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

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

• . Due to the wide variety of this products and their synthetic availability, terarylenes are convenient models for a detailed study of the correlation between the structure of such objects and their photochemical properties [18][19][20][21]. As a rule, the phototransformation of terarylenes proceeds in

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• 1000 rpm. During the storage period the activity was measured under standard activity conditions. By calculating of the residual activity, the stability was calculated by exponential fitting [32]. Due to inadequate correlation of the exponential fit to determine the deactivation, a half-life time could

Terpenoids from Glechoma hederacea var. longituba and their biological activities

• Dong Hyun Kim,
• Song Lim Ham,
• Zahra Khan,
• Sun Yeou Kim,
• Sang Un Choi,
• Chung Sub Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58

• of 2 were similar to those of substolide A except for signals of the methoxy group attached to C-8 and of a monosaccharide at C-6 in 2 [12]. The planar structure of 2 was established based on 2D NMR spectroscopic data (COSY, HSQC, and HMBC). The HMBC correlation from H-1' (δH 4.42) to C-6 (δC 76.6

• [14]. The COSY correlation between H-5 (δH 3.67) and H-6 (δH 4.62) and the HMBC cross peak of H-1' (δH 4.23) to C-6 (δC 74.5) and between H-6 and C-7 (δC 119.6) confirmed the location of the glucopyranosyl group at C-6 (Figure 4A). The anomeric carbon configuration for a glucopyranosyl unit was

• , 72.0, 78.5, and 62.9), and an acetyl group carbon (δC 172.0 and 21.2) (Table 3). The 1H and 13C NMR spectra of compound 5 were similar to those of compound 4 except for the presence of acetyl group signals. The HMBC correlation from H-2' (δH 4.69) to the carbonyl carbon at δC 172.0 (C-2'') located the

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• correlation of H-6 with the carboxyl carbonyl carbon (C-14, δC 179.6). The HMBC correlations of the geminal olefinic protons (Hab-3, δH 5.93 and 5.52) to the remaining carboxyl carbonyl carbon (C-1, δC 174.5), C-2 (δC 150.2) and C-4 (δC 84.6) and H-4 (δH 4.72) to C-2 and C-3 (δC 118.7) and the chemical shift

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• (Supporting Information File 1). The correlation between two syn-Hs of C4-OH/C2-H and another two syn-Hs of C4-OH/α C5-H were well visualized in the NOESY spectra. In order to explain the formation of dispirocyclopentanebisoxindole after studying some related literatures [23][24][25][29] a plausible reaction

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• interaction between m-TPEWP5 and G (1 equiv of each) in D2O. A strong cross-correlation peak was perceived between the m-TPEWP5 aromatic protons and the Hc proton of G. The above results evidenced that the alanine pendant of the guest unit stayed in the m-TPEWP5 cavity. Besides, in order to confirm the host

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea

• Di Zhang,
• Zhe Wang,
• Xiao Han,
• Xiao-Lei Li,
• Zhong-Yu Lu,
• Bei-Bei Dou,
• Wen-Ze Zhang,
• Xu-Li Tang,
• Ping-Lin Li and
• Guo-Qiang Li

Beilstein J. Org. Chem. 2022, 18, 374–380, doi:10.3762/bjoc.18.42

• 1.94) with H-14 (δH 1.50) indicated the β-orientation of H-8/H3-18/H3-19, while α-orientation of H-9/H-14. Furthermore, the NOESY correlation of H3-21 with H3-18 suggests the E geometry of ∆17(20). The absolute configuration of 2 was established by single-crystal X-ray diffraction analysis (Figure 4

• correlations (Figure 2) found from H3-21 to C-17/C-20/C-22, from H3-26 to C-25/C-27/C-24, and from H3-28 to C-24/C-25, together with the 1H,1H-COSY correlation (Figure 2) from H-22 to H-24 confirmed the side chain of compound 3. Thus, the planar structure of compound 3 was established, which was the same as

• proton–proton correlation of H-17/H-20/H-21/H-22/H-23/H2-29. These data, together with the key HMBC correlations from H3-28 to C-23/C-24/C-25 and from H3-26/H3-27 to C-24/C-25, confirmed the structure of the side chain of compound 4. The NOESY correlations (Figure 3) from H-1a (δH 1.22) to H-3 and H-9, H

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• ppm). Therefore, compound 1 must feature three ring structures in order to comply with the required degrees of unsaturation. Proton–proton correlation spectroscopy (COSY) revealed four spin systems, which could be connected through 1H,13C long-range correlations (Figure 2) determined in a

• heteronuclear multiple bond correlation (HMBC) experiment. The first spin system comprises the proton signals at δH 4.46 (dd, J = 11.3, 1.6 Hz, H-2), 3.22 (m, H2-6), 1.90 (m, H-4a), 1.77 (m, H-4b), 1.89 (m, H-3a), 1.45 (m, H-3b), and 1.30 ppm (m, H2-5). HMBC correlations from H-2 and H-6 to the carbonyl carbon

• C-1 in combination with the observed chemical shifts reinforced the assumption of an α-amino-ε-caprolactam structure. An HMBC correlation from H-2 to a carbonyl carbon at 176.5 ppm (C-7) allowed the linkage of this moiety with a 2,2-dimethyl-3-hydroxydecanoic acid residue, which was identified on

Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities

• Meifang Wu,
• Xiangdong Su,
• Yichuang Wu,
• Yuanjing Luo,
• Ying Guo and
• Yongbo Xue

Beilstein J. Org. Chem. 2022, 18, 200–207, doi:10.3762/bjoc.18.23

• based on the HMBC correlations from H-4 (δH 7.70) to C-2 (δC 161.3), C-5 (δC 121.4), and C-6 (δC 153.5), together with a 1H-1H COSY correlation between H-3 and H-4 (substructure A), while the HMBC cross-peaks from H-4' (δH 7.67) to C-2' (δC 161.1), C-5' (δC 130.3), and C-8a (δC 141.5), along with the

• two spin-spin systems of H-3'/H-4' and H-5'/H-6' (substructure B) depicted in the 1H-1H COSY of 1. Although the direct evidence between substructures A and B was missing, to our delighted, the key ROESY correlation of H-5/H-8' (Figure 3 and Supporting Information File 1, Figure S34, recorded in DMSO

• -configuration (Figure 3). The key HMBC correlations of δH 4.35 and 4.75 (Glc H-6'') with δC 106.8 (Xyl C-1''') and the reverse correlation of δH 4.94 (Xyl H-1''') with δC 170.6 (Glc C-6'') suggested the linkage of the xylopyranosyl moiety at C-6 of the glucopyranosyl unit. This deduction was further confirmed

Mechanistic studies of the solvolysis of alkanesulfonyl and arenesulfonyl halides

• Malcolm J. D’Souza and
• Dennis N. Kevill

Beilstein J. Org. Chem. 2022, 18, 120–132, doi:10.3762/bjoc.18.13

• . The solvolyses of these additional types of sulfur(VI) substrates will be the topics of a future review. Keywords: correlation; Grunwald–Winstein equation; Hammett equation; mechanism; solvolysis; sulfonyl halides; Review 1. Introduction to solvolyses of sulfonyl halides In medicinal chemistry

• the unimolecular (low l value and high m value), as in the solvolyses of tert-butyl chloride [25][35], or a tendency to bimolecular solvolyses (high l value and intermediate m value, as is very well illustrated in a correlation of the rates of solvolyses of phenyl chloroformate [42]. When applying to

• this review which involve the application of the extended Grunwald–Winstein equation should, through a consideration of goodness-of-fit parameters, such as correlation coefficient and F-test value, allow this question to be answered. 3. Studies by Bentley and co-workers Koo, Bentley, Kang, and Lee [43

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• . The methylene carbon C35 adjacent to the hydroxamic acid group showed a smaller chemical shift (δC 28.0). The positional assignment of C34 and C35 was made by a ROESY correlation observed between H34 and 32-NH (Figure 2). To verify the structure deduced from the NMR analysis, an MS/MS analysis was

Regioselective synthesis of methyl 5-(N-Boc-cycloaminyl)-1,2-oxazole-4-carboxylates as new amino acid-like building blocks

• Jolita Bruzgulienė,
• Greta Račkauskienė,
• Aurimas Bieliauskas,
• Vaida Milišiūnaitė,
• Miglė Dagilienė,
• Gita Matulevičiūtė,
• Vytas Martynaitis,
• Sonata Krikštolaitytė,
• Frank A. Sløk and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2022, 18, 102–109, doi:10.3762/bjoc.18.11

• -HMBC spectra. The aforementioned enamine proton and protons 2’(4’)-H (δ 4.00-4.09 ppm) from the azetidine ring system shared the HMBC cross-peak with the ketone carbonyl carbon (δ 195.4 ppm). Finally, in the 1H,15N-HMBC spectrum of 3a, an expected long-range correlation between the enamine proton (δ

• -ADEQUATE spectrum thus allowing to assign a neighboring quaternary carbons C-4 (δ 109.9 ppm) and C-5 (δ 175.4 ppm), H–C(3)–C(4) and H–C(3’)–C(5), respectively. The 1H,15N-HMBC experiment revealed an expected long-range correlation between the 1,2-oxazole methine H-3 proton (δ 8.50 ppm) and nitrogen N-2

• which resonated at δ −0.6 ppm, while the azetidine ring protons showed a sole correlation with the azetidine nitrogen N-1’ (δ −311.7 ppm) [29][39]. Furthermore, 15N-labeled methyl 5-(N-Boc-azetidin-3-yl)-1,2-oxazole-4-carboxylate (5) was synthesized by analogy to 4a, by the reaction of β-enamino

Efficient and regioselective synthesis of dihydroxy-substituted 2-aminocyclooctane-1-carboxylic acid and its bicyclic derivatives

• İlknur Polat,
• Selçuk Eşsiz,
• Uğur Bozkaya and
• Emine Salamci

Beilstein J. Org. Chem. 2022, 18, 77–85, doi:10.3762/bjoc.18.7

• data (COSY and HMQC). The diagonal peak at 4.62 ppm has cross peaks with the protons resonating at 4.26 and 4.39 ppm, respectively, in the COSY spectra of 8. The cross peak between H-7 and H-6 showed strong correlation, which clearly supports the trans relation of the proton H-6. The cross peak between

• H-7 and H-10 also showed weak correlation, which clearly supports the cis relation of the proton H-10. In this reaction, lactonization and hydrolysis of the Boc group to the corresponding amine were observed. The formation of lactone 8 as the major product can be explained by nucleophilic attack of

• resonating at 4.49, 1.53, and 2.02 ppm, respectively, in the COSY spectra of 10. The cross peak (δ 4.49 ppm) between H-6 and H-7 showed a strong correlation, which clearly supports the trans relation of the proton H-7. Furthermore, its structure was unambiguously confirmed by single crystal X-ray analysis

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• . The 1H NMR spectrum of 2 was similar to those of 1 in overall (Table 1 and Table 2). One major difference was a replacement of the triplet methyl peak in 1 by a six proton-equivalent doublet methyl peak, which suggested an isopropyl-terminated structure. This was proven by a COSY correlation between

• unused carbon (δH 177.1, C-1) and the molecular formula. A NOESY correlation between H-11 and H-12 supported an E-configuration for the C-4/C-5 double bond. The established planar structure was identical to that of a fungal metabolite phialomustin B [26], for which specific rotation, enumerated 1H and

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• product selectivity in the irradiation of alkenyl amide 1 across a range of pH and found a significant correlation (Figure 3b–d). The formyl product 8 predominated at acidic and neutral pH. The amount of 8 decreased with increasing pH, and above pH 10 the C–X cleavage product 2 became the major product

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• excellent enantioselectivity when either CAT 1 (93–97% ee) or CPA 7 (93–96% ee) was used as catalyst (Scheme 21). The authors described that, BINOL-derived CPAs and pThr-type CPA scaffolds were found to be effective for atroposelective cyclodehydrations. Both the DFT and catalyst correlation studies showed

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• tetrazole formation. In support of this was the fact that no lactam byproduct was detected in reactions carried out with TMSN3. As it was confirmed by detailed NMR analysis (see Supporting Information File 1), only homoregioisomeric 12a-azatetrazoles were obtained. This is in good correlation with earlier

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

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

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

• geometry was inferred from its NOESY spectrum, which showed a weak but distinct correlation between the vinyl proton singlet (δ 5.66) and the methylene group flanked by nitrogen and the ester (δ 4.06). The E-geometry was also suggested by the chemical shift of the hydrogen atoms at C-3 of the pyrrolidine

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• scratches [18]. However, little is known about the exact healing mechanism on the molecular scale and the correlation to the macroscopic properties of such polymers. For this purpose, the current study will focus on the design of polymers containing π–π interactions and the quantification of the healing

• ionomers revealed a strong correlation of the bond lifetime with the healing behavior [27]. A similar behavior was also observed for metallopolymers [13]. Consequently, the polymers P1 and P2 were also studied by frequency sweeps at certain temperatures (see Figure 3). At temperatures below the endothermic

• and presumably associated with the elastic recovery of the material. Consequently, for the first time, a correlation between the structure behavior of polymers featuring reversible π–π interactions and the healing behavior could be obtained. Conclusion Supramolecular polymers based on π–π interactions