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

• MCF7) [13]. In 2008, Muhi-eldeen et al, synthesized a hybrid compound with 1,3,4-oxadiazole moiety and pyrrolidine connected with propargylic moiety showed antibacterial activity against Staphylococcus aureus and E. coli [14]. On the other hand, the coupling of piperazine with heterocyclic compounds

• observed in most of the compounds except for derivatives 4b, 4d, 4p, and 4u. All aromatic compounds showed resonances at δ = 6.50–8.00 ppm. Compounds 4b and 4c indicated the fluorine coupling effect on the aromatic protons. The carbaldehyde proton in compound 4h resonates at δ = 8.00 ppm, while compound 4k

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

• + 26), respectively, were successfully employed as visible-light photocatalysts for a cross-coupling cyclization of N,N-dimethylaniline (27) and N-alkyl/aryl maleimides 28 (Figure 6). Notably, the systems showed much higher catalytic activity compared to similar reactions with the dye or cages alone

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

• introduced by the coupling of pyruvate to the enzyme was calculated by using the exponential fit. The calculated value is −12.9 ± 5.5 mL/mol (the values at 50 MPa and 89 MPa were considered as outliers and not included in the calculation). Kinetic studies of the immobilized aldolase show an increase in

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

• 3.24; 8β, δH 2.69), H-13 (8α, δH 1.90; 8β, δH 2.05), and coupling constants of H-1 (8α, 3JH-1/H-2 = 10, 1.5 Hz; 8β, 3JH-1/H-2 = 4, 1 Hz). The 1H NMR chemical shifts and coupling constants of compound 1 (δH 3.45 and 1.89, 3JH-1/H-2 = 10.1, 1.1 Hz) is similar to that of 8α-DIG, suggesting that 1 could be

• ) (Supporting Information File 1, Figure S8), and the coupling constant of the anomeric proton (J = 7.8 Hz), confirmed it as being in the β-configuration [11]. Thus, the structure of 1 was determined as (1S,4S,5R,8S,10R)-1,10;4,5-diepoxy-8-O-β-ᴅ-glucopyranosyl-glechoman-8,12-olide. Compound 2 was obtained as a

• defined as β-configuration from the coupling constant of 7.8 Hz [11]. The relative configuration of 3 was established using the NOESY spectrum (Figure 4A). The NOE correlations of H3-14, H-3b/H-2b; H-6/H-3b/H3-15 suggested that H-6, H3-14, and H3-15 were positioned in the same orientation. The absolute

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• treated with copper iodide to obtain the phenanthroline–Cu(I) complex (R)-8. A Glaser-type coupling with the terminal alkynes 9, followed by demetalation, proceeds smoothly in 78% yield. This furnishes the desired chiral rotaxane (R)-10, consisting of a BINOL-based macrocycle and a diyne thread. The CD

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• of aryl moieties into methylthio-substituted nitrogen heterocycles such as tCBz-mPYR are a Ni(0)-catalyzed cross-coupling reaction with Grignard reagents [34][36] or the Liebeskind–Srogl reaction employing arylboronic acids [37][38][39]. Taking into account a large assortment of arylboronic acids and

• the simplicity of the method, we chose the Liebeskind–Srogl cross-coupling reaction for the synthesis of the target 2-arylpyrimidine derivatives. Thus, heating tCbz-mPYR with phenyl-, 4-cyanophenyl-, 3-cyanophenyl-, or 3-bromophenylboronic acid at 130 °C in dioxane in the presence of Pd(PPh3)4, copper

• modified with various phenyl-like fragments, increasing the flexibility of the molecular structure, probably altering the electron–vibronic coupling. A similar behavior was observed for similar pyrimidine TADF compounds [42]. Moreover, fluorescence line shapes of compounds 2a and 2d were different from the

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

• Hao Guo,
• Yu-Fei Ao,
• De-Xian Wang and
• Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

• 10.3762/bjoc.18.51 Abstract A series of tetraamino-bisthiourea chiral macrocycles containing two diarylthiourea and two chiral diamine units were synthesized by a fragment-coupling approach in high yields. Different chiral diamine units, including cyclohexanediamines and diphenylethanediamines were

• fragment-coupling approach, different chiral diamine units, including the homo- and hetero-combination, can be easily incorporated. This provides a very rich structural diversity of the macrocycles and allows for fine tuning of the chiral cavity environments. With the short and high-yielding synthesis

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

• , 3o, 3q, 3s, 3t and 3x) gave a good yield of the corresponding product, respectively. Here also, the halo-substituted aryl ring on 1 can be further used for transition-metal-catalyzed cross coupling reactions, thus providing a very good application. Then the effect of N-protecting groups on the

• . Chemical shifts are reported in parts per million (ppm) downfield from an internal TMS (tetramethylsilane) reference. Coupling constants (J) are reported in hertz (Hz), and spin multiplicities are represented by the symbols s (singlet), brs (broad singlet), d (doublet), t (triplet), q (quartet) and m

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• understanding of the TADF mechanism are highly important tasks in this research field. The singlet–triplet energy splitting between the S1 and T1 states (ΔEST) and spin–orbit coupling (SOC) play key roles in manifesting the TADF character of an organic compound. To boost the rISC process, ideally, the ΔEST is

• ) occurs in the singlet excited state (1CT). An efficient rISC can be mediated by mixing the 1CT state with a locally excited triplet state on the donor (3LED) or the acceptor (3LEA) through spin–vibronic coupling [14] or non-Condon effects [15][16]. In 2016, we developed a twisted D–A–D compound POZ-DBPHZ

• D–A–D compound. This is indeed the case, as the average spin–orbit coupling for the T1 to S1 transition in the D–A compound 1 is 0.462 meV, whereas for the D–A–D compound POZ-DBPHZ it is 0.177 meV. However, the average energy gap taken from all geometries in the nuclear ensemble for this transition

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

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

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

• expected 3,4,5-trisubstituted isoxazole 3a and 55% of a compound that we identified as furoxan 4 (a 1,2,5-oxadiazole 2-oxide) which formed through homo-coupling of substrate 1a (Table 1, entry 3). Na2CO3 in 98% water, 2% methanol produced 52% of the isoxazole 3a and 33% of compound 4 after 3 hours (Table 1

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

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• involved in various transformations including homo- and cross-coupling [1][2][3][4][5][6][7], addition [1][8][9], cycloaddition [1][10][11] and other reactions. Of particular synthetic value is the addition to the triple bond of bromoacetylenes to provide vinyl adducts, which can undergo numerous

• reductive coupling of acid halides with ketones [36][37] and acetolyses of α-phenoxy-α-diazoketones [38] were also employed. Recently, F. P. Cossío et al. [39] have described a method for the preparation of benzo[b]furans by thermal heating of a dispersion of α-phenoxyketones in Al2O3. We involved the

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• generated from the carboxylic acid through decarboxylation mediated by [Ag+]-peroxydisulfate, followed by their coupling with the quinone, providing the respective alkylated product. One of the first practical applications of this methodology to produce menadione (10) was described by Ashnagar and co

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

• addition, compound 1 exhibited a moderate anti-inflammatory effect in zebrafish. Experimental General experimental procedures NMR spectra were measured via an Agilent DD2-500 spectrometer (500 MHz for 1H NMR and 125 MHz for 13C NMR). Chemical shifts are reported in parts per million (ppm) with coupling

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

• Robin Schulte and
• Heiko Ihmels

Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41

• -dioxaborolane was prepared and shown to be a suitable substrate for Pd-catalyzed Suzuki–Miyaura coupling reactions with selected haloarenes. It was demonstrated exemplarily that the novel monosubstituted 2-(1-naphthyl)norbornadiene, that is accessible through this route, is transformed to the corresponding

• derivatives may be metalated in a Li–halogen exchange reaction [27]. In another versatile approach, arylation and alkenylation reactions of the norbornadiene may be accomplished with a Suzuki–Miyaura coupling reaction. In this case, halogenated norbornadienes react with arylboronic acids or their esters to

• the corresponding aryl-substituted norbornadienes under optimized conditions [28][29][30][31]. To the best of our knowledge, however, no borylated norbornadiene derivatives have been employed in Suzuki–Miyaura coupling reactions so far, although this synthetic route appears to be a useful

Synthesis of 5-unsubstituted dihydropyrimidinone-4-carboxylates from deep eutectic mixtures

• Sangram Gore,
• Sundarababu Baskaran and
• Burkhard König

Beilstein J. Org. Chem. 2022, 18, 331–336, doi:10.3762/bjoc.18.37

• replacement of organic solvents. The melts are stable against air and have very low vapor pressures resembling the properties of ionic liquids. In addition, the polarity of these melts is very high [33]. Recently, we have explored several organic transformations such as coupling reaction, cycloaddition

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• irradiation, biradical species 12 was generated and immediately abstracted a hydrogen atom from the methyl group of 11. Site-selective radical coupling at the oxygen atom between 13 and 14 produced the 1,4-adduct 15. The unusual site-selectivity of this reaction was also traced from the restricted geometry

• and fixed orientation of the guests inside the cage A. One of the carbonyl groups of 10 was in close proximity to the methyl group of 11, which was determined by X-ray crystallography. The possible C-coupled 1,2-adduct and other coupling products were not detected. However, in the absence of host A, a

• mixture was formed without the O-coupled 1,4-adduct 15. This indicated that the molecular container A favored the O-coupling pathway while suppressed others. This work showed the powerful site-selective control ability of molecular containers, which was normally only observed in natural enzymes. Reduction

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• intermediate spontaneously turns into the carbanion C, thus realizing the imine umpolung and allowing the cross-coupling reaction with the remaining electrophilic ketimine 1. The complete diastereoselectivity would arise from the mutual approach of the two oxindole nuclei from the less hindered side, that is

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

• Long Zhao,
• Mao-Lin Yang,
• Min Liu and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

• –Spengler-like cyclization processes [12]. Some 4-substituted 3,4-dihydroquinazolines were prepared by copper-catalyzed oxidative cross coupling of hydroxy intermediates with various nucleophiles [13]. Other 3,4-dihydroquinazolines were also obtained efficiently by intramolecular aza-Wittig reactions [14

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• , Kottayam, Kerala, 686560, India 10.3762/bjoc.18.31 Abstract Iron- and cobalt-catalyzed Sonogashira coupling reactions are becoming central areas of research in organic synthesis. Owing to their significant importance in the formation of carbon–carbon bonds, numerous green and nanoparticle protocols have

• emerged during the past decades. The non-toxic and inexpensive nature of catalysts gained much attention in recent times. In this context, their catalytic nature and activity in Sonogashira coupling reactions were well explored and compared. Most importantly, one of the highlights of this review is the

• emphasis given to green strategies. This is the first review on iron- and cobalt-catalyzed Sonogashira coupling reactions which comprehends literature up to 2020. Keywords: C–C bond formation; cobalt; green reaction; iron; nanoparticles; Sonogashira; Introduction The palladium-catalyzed cross-coupling

Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• the art and science of selective molecular engineering [1]. To date, organic synthesis has largely been governed by the interconversion of pre-existing functional groups through the use of more traditional transition-metal-catalyzed cross-coupling reactions [2][3][4][5]. Although these reactions have

• carbo- and heterobicyclic alkenes was investigated, the study was limited by the number of unsymmetrical coupling partners. In their seminal report, the authors were able to produce hydroacylated adducts 15a and 15b in good yield. On the basis of the aforementioned literature, several different products

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• anomeric configuration of 1 was based on the chemical shift of H3eq, which is located in lower magnetic field (over 2.5 ppm) when compared to a β-glycoside (under 2.5 ppm) [27]. Additionally, the anomeric configuration can be determined through the coupling pattern of C-1 in a selective proton decoupled

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

• 1 (Table 1) exhibited downfield chemical shifts corresponding to two pairs of olefinic protons with the AB coupling patterns at δH 7.70 (d, J = 9.5 Hz, H-4), 7.67 (d, J = 9.5 Hz, H-4'), 6.40 (d, J = 9.5 Hz, H-3), and 6.34 (d, J = 9.5 Hz, H-3'), a typical ABX coupling system at δH 7.46 (d, J = 8.5 Hz

• , H-5'), 7.01 (dd, J = 8.5, 2.4 Hz, H-6'), 7.02 (d, J = 2.4 Hz, H-8'), suggesting the presence of a 1,2,3-trisubstituted benzene ring, and two meta-coupling protons at δH 7.81 (s, H-8) and 7.40 (s, H-5), indicating a 1,3,4,6-tetrasubstituted benzene ring. Additionally, the 1H NMR spectrum revealed

• were confirmed by the interpretation of key signals observed in the 1H-1H COSY, HSQC, HMBC, and NOSEY spectra of 1. The β-configurations of the glucopyranosyl and xylopyranosyl units were determined by the relatively large coupling constants (J = 7.8 and 7.1 Hz) of their anomeric protons, respectively

Diametric calix[6]arene-based phosphine gold(I) cavitands

• Gabriele Giovanardi,
• Andrea Secchi,
• Arturo Arduini and
• Gianpiero Cera

Beilstein J. Org. Chem. 2022, 18, 190–196, doi:10.3762/bjoc.18.21

• acid derivative through a user-friendly amide coupling in the presence of EDC·HCl and catalytic amounts of DMAP in CH2Cl2. Under these conditions, the corresponding diphosphine intermediates A (para), B (meta), and C (ortho) were isolated in moderate yields. Finally, gold(I) catalysts could be obtained

• integration ratio (Figure 2). These include: i) two doublets at 4.2 and 3.6 ppm with a geminal coupling of 2J = 14.2 Hz for the a/a' couple and ii) a singlet at 3.92 ppm for the b/b' couple, typical of an anti-orientation [35]. This situation suggests a single inversion point which confers to the macrocycle a

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• hydrochloride salt, using a protocol developed by Nudelman et al. [51]. Coupling with the protected tripeptides using TBTU occurred without epimerization [52]. The two tetrapeptide allyl esters were subjected to the peptide Claisen rearrangement, the key step of the synthesis. Subjecting allyl ester 8a to the

Asymmetric organocatalytic Michael addition of cyclopentane-1,2-dione to alkylidene oxindole

• Estelle Silm,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2022, 18, 167–173, doi:10.3762/bjoc.18.18

• compounds with non-aromatic substituents at the double bond (3i and 3o). The relative anti-configuration of the vicinal diastereotopic hydrogens was determined by comparing the 3JHH coupling constants of the major diastereomer with those of the minor diastereomer. The constants were larger for the major