Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• the homobenzylic position, engaging in an anti-Markovnikov manner with a formal chloride nucleophile. The ultimate step involves hydrogen atom transfer (HAT) with thiol 148, culminating in the formation of the desired product 147. Therefore, the generation of the vinyl radical cation plays a pivotal

• combination with a chloride anion, regenerates the initial acridinium catalyst 161. The thiyl radical is formed through hydrogen atom transfer (HAT) with thiol 150, thus completing the second catalytic cycle. Hence, the key distinction from Nicewicz's work is that in the Ritter protocol, chloride undergoes

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• the p-fluorine atom in the pentafluorophenyl substituent with an azide functionality which upon reduction with SnCl2 resulted in the formation of the corresponding porphyrin with an amino group. Pentafluorophenyl-substituted A3B-porphyrins were studied and transformed to thiol and amino-substituted

• has become one of the most popular route for the site-selective modification of cysteine residues in bioconjugation technology. We suppose that the maleimide group in porphyrin 11 is a useful target for thiol conjugation via Michael addition reactions [44]. This also concerns biotin-conjugated organic

• studied the nucleophilic substitution reactions of the p-fluorine atom in the pentafluorophenyl-containing porphyrin 6 with thiol-substituted compounds such as 2-mercaptoethanol (15), cysteamine hydrochloride (16), and 3-chloro-1-propanethiol (17) as shown in Scheme 5. The reactions proceeded readily in

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• % purity) [26] provided a more selective reaction, no water-based work-up was needed and the pure product was obtained by simple recrystallization from ethanol in yields up to 88%. The oxidation step thiol → sulfoxide was fast and full conversion to the intermediate was achieved in one hour for most

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

• quantities of the most active compounds for advanced biological testing. Pleasingly, our four-step approach using a potassium O-ethyl dithiocarbonate-mediated formation of thio intermediates 11a–c (thiol–thione tautomers) with subsequent sulfur removal using iron powder in acetic acid [19] proceeded smoothly

• 11b as thiol–thione tautomer consisting of 6-bromo-5-(2-fluorophenyl)[1,3]thiazolo[4,5-b]pyridine-2-thiol and 6-bromo-5-(2-fluorophenyl)[1,3]thiazolo[4,5-b]pyridine-2(3H)thione (17.20 g, 97%). 1H NMR (400 MHz, CDCl3, δ) 9.96 (br s, 1H), 8.01 (s, 1H), 7.50–7.44 (m, 1H), 7.41–7.38 (m, 1H), 7.29–7.25 (m

• , 1H), 7.19–7.15 (m, 1H). The thiol–thione tautomer 11b (14.55 g, 42.64 mmol, 1.0 equiv) was dissolved in acetic acid (200 mL), and iron powder (35.71 g, 639.61 mmol, 15 equiv) was carefully added in portions. The resulting reaction mixture was stirred at 100 °C for 10 h. After full conversion

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• II, which could be transferred to III by cyclization and epoxidation. Oxidation and methylation of intermediate III would produce IV. Compounds 1–4 could be obtained by nucleophilic attack at C-8 with the hydroxy or thiol group from IV via intermediate V, followed by oxidation and cyclization

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• (Figure 1) [3]. The adenylation (A) domain in NRPSs is responsible for the selection and activation of amino acids, hydroxy acids, and aryl acids upon ATP consumption (Figure 2a) [4]. The activated aminoacyladenosine monophosphate (AMP) is transferred to the thiol group of a phosphopantetheine prosthetic

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• ester 98 and Cs2CO3 in DMF resulted in the generation of the excited charge transfer complex 99. Subsequent SET mediated by the thiol catalyst followed by fragmentation afforded α-amino radical 100, which was then oxidized by the resulting thiol-radical species, regenerating the thiol catalyst while

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• . synthesized a tetrapodal scaffold using diazatriptycene with thiol anchors (Qx57) to demonstrate electrostatic dipole engineering in n-type OFETs. The scaffold was designed to enforce upright functional groups, particularly quinoxaline subunits, and utilized OFETs as prototypes to showcase the potential of

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• catalyst to produce radicals at the 2- and 5-positions of thiophene and synthesized four types of poly(3-alkylthiophene)s (PATs) with different linking ways (Scheme 10). 2.2 Polymerization by thiol–ene chemistry The thiol–ene reaction (also called alkene hydrothiolation) is the anti-Markovnikov addition of

• a thiol to a C–C double bond and was first reported in 1905 [80]. It is considered as a click chemistry reaction due to its high yield, stereoselectivity, rate, and thermodynamic driving force. Generally, the thiol–ene reaction is conducted under radical conditions, often photochemically induced [81

• ]. In a typical thiol–ene system, the polymerization undergoes a free-radical chain mechanism, involving an initiation step from a thiol group via radical transfer or homolysis (Scheme 11, initiation), radical addition of the thiyl radical to the ene functionality (propagation 1), transfer from the

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• usually a two-step procedure, involving a treatment of the thiol with sulfuryl chloride in the presence of Et3N and the addition of the resulting solution to a mixture of succinimide/phthalimide and Et3N in the next step [39][40]. According to the irreplaceable role of sulfur-based frameworks in materials

• form intermediate I with the assistance of the Lewis acid. Intermediate I reduced by Et3SiH 139 to give thiol. Through the reaction of thiol with I, disulfide as a byproduct was formed, and intermediate II was generated by the reaction of I with 138. Product 140 was obtained via direct hydride

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• presence of dimethylaminopyridine (DMAP). Then, 27.2 reacted with potassium thioacetate to produce the thioester 27.3. Its reduction with lithium aluminium hydride produced the free thiol 27.4 that was used as nucleophile on octadecyl iodide to install the C18 lipid chain. The deprotection of the primary

• Markowska et al. in 1993 [134]. As detailed in Figure 28, the synthesis starts with a Mitsunobu esterification of 28.1 with thioacetic acid to produce the thioester 28.2. Then, the reduction with lithium aluminium hydride produced the thiol 28.3. Finally, the phosphocholine moiety was introduced by using

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• with a α-haloketone or α-haloester II. The initially formed α-thioiminium salt III can undergo either a base-catalyzed elimination to give nitrile X and thiol IX [10][11][12] or cyclization to give a thiazole XIII or thiazolone XI depending on the substituent at the carbonyl group Y. Both side

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• to the plausible pathway shown in Scheme 6. As we expected, the nucleophile 2a attacked on the position C4 of the substrate 1a, which resulted in the cleavage of the S5–C4 bond and the formation of a thiol intermediate A (1-(2-thiophenyl)pyrrole derivative generated in situ as a precursor analog for

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

• ]. Based on its structure, many other inhibitors have been developed, such as vinyl sulfones, fluoromethyl ketones, and semicarbazides [8][9]. These inhibitors covalently bind to the nucleophilic thiol group of Cys234 in the active site of cathepsin C via a thioether bond. Phosphonates have been identified

Group 13 exchange and transborylation in catalysis

• Dominic R. Willcox and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

• borylation of thiols with HBpin (Scheme 17) [79]. Through computational analysis, a mechanism was proposed whereby the ambiphilic amine-borane 73 underwent concerted addition to the thiol 74 S–H bond, to give a zwitterion 75. After loss of H2, a neutral thioborane 76 was generated, which underwent B‒S/B‒H

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• the stereogenic centers formed during the cascade cyclization was secured by the use of benzothiophene-based TADDOL thiol 166 as chiral catalyst. They obtained in one single step a 5.3:1 and 3.4:1 diastereomeric ratio for C14 and C15, respectively, while forming the desired trans [5-8] ring junction

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• radical (SPyf, Scheme 24) was proposed as a hydrogen atom abstracting agent for unactivated C–H bonds of alkanes and other CH-reagents [123] (Scheme 24). It was generated by the irradiation of the corresponding disulfide with 400 nm LEDs. In the proposed catalytic cycle tetrafluoropyridinyl thiol HSPyf is

Cyclometalated iridium complexes-catalyzed acceptorless dehydrogenative coupling reaction: construction of quinoline derivatives and evaluation of their antimicrobial activities

• Hongling Shui,
• Yuhong Zhong,
• Renshi Luo,
• Zhanyi Zhang,
• Jiuzhong Huang,
• Ping Yang and
• Nianhua Luo

Beilstein J. Org. Chem. 2022, 18, 1507–1517, doi:10.3762/bjoc.18.159

• . In addition, Aravinda's group [11] prepared 3-(1,3-dioxolan-2-yl)benzo[h]quinolines containing thiol and selenol groups in one pot by microwave irradiation, and tested the antibacterial activity of the compounds. The results showed that the antibacterial effect of some compounds was better than

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

• Kendra Drayton-White,
• Siyue Liu,
• Yu-Chia Chang,
• Sakashi Uppal and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• peptide so that the thiol group in the sidechain could be used to place the molecule the array with the use of an electrochemically initiated Cu(I)-catalyzed cross-coupling reaction (Scheme 1) [9]. To this end, the Cu(I) catalyst needed for the reaction was generated at the electrodes by the reduction of

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• cycloisomerization of the α-ketoester 22, which can be described as a Friedel–Crafts-type reaction or an aldol reaction of an S,O-ketene acetal (Scheme 4). The required ketoester 22 was synthesized from sulfonylchromenone 20, accessible from dihydroxyacetophenone 19 and thiol 18 derived from known alcohol 17 [11][12

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• . Results and Discussion We began our work with the condensation reactions of 2-aminothiophenols 8 and bromopyruvic acid and esters 9 to form 4H-benzo-1,4-thiazines 10, having a carboxylic acid or an ester function at the C-3 position (Scheme 1). The reaction of thiol 8a with bromo-substituted acid 9a in

• classical conditions as well as under MWI. The acid 10aa could not be formed even when 2,2'-disulfanediyldianiline was used as the starting material in DMF or ethanol at room temperature or under reflux. Thiol 8a reacted with the keto ester 9c in ethanol to form the ester 10ac with a yield of 51% and 29

• formed in 50% yield in ethanol and 30% in diethyl ether (Table 1, entries 10 and 11). Reactions with thiol 8c, having an electron-donating methoxy group, and acid 9a or esters 9b,c only gave unidentifiable decomposition products in various solvents (ethanol, diethyl ether, methanol, and CH2Cl2) at

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• % isolated yield, along with some amount of the alkene complex (see Scheme 4). In an attempt to increase the yield of the cysteine derivatives, the amount of the thiol was doubled. Unexpectedly, this resulted in the inversion of the diastereomeric ratio (entry 2 in Table 2). To find a reason, the experiment

• , the (R,S):(R,R) diastereomeric ratio was changed from 1:1 to 13:1 in favor of the thermodynamically more stable (R,S) diastereomer. The experiment with thiophenol performed under the same reaction conditions (a two-fold excess of thiol and the Et3N additive) gave the cysteine derivatives in 88% yield

• and with 12:1 diastereoselectivity; again, the (R,S) diastereomer was the dominant (entry 4, Table 2), in line with the previous results with tolylthiol. In case of an aliphatic thiol (benzylthiol), the results were qualitatively similar. The diastereomeric ratio is inverted in favor of the

Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

• Houchao Xu,
• Anne Wochele,
• Minghe Luo,
• Gregor Schnakenburg,
• Yuhui Sun,
• Heike Brötz-Oesterhelt and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

• later revised as that of (Z)-4. The same compound is also observed in S. olivaceus [10] and was reported to function as a competitive inhibitor of glutathione S-transferase [11], which may be a result of a thiol addition of glutathione to the Michael acceptor in 4. While the relative and absolute

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

• available cholic acid, which was converted to its cholyl hydrazide (1) as previously reported by us [21]. The produced cholyl hydrazide 1 was heterocyclized to 1,3,4-oxadiazole-2-thiol 2 in excellent yield (93%), via the treatment with carbon disulfide and trimethylamine in refluxing ethanol (Scheme 1) [33

• ]. Having oxadiazole-2-thiol 2 at hands, the reactive thiol was subjected to the reaction with propargyl bromide and sodium carbonate as a base to afford the thiopropargylated derivative 3 in 82% yield after 24 h (Scheme 2) [33]. Compound 3 was the starting point for a Mannich reaction to generate a library

• of this library will be reported in due course. Biologically active cholic acid hybridized with different heterocyclic scaffolds. Structures of target compounds 4a–v. Synthesis of cholyl 1,3,4-oxadiazole-2-thiol 2. Synthesis of cholyl 2-(propargylthio)-1,3,4-oxadiazole 3. Synthesis of target