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

• ). Whilst tetrabutylammonium borohydride [22] at room temperature did not lead to a conversion of the starting material 5 either, a trace amount of desired 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine 7b was formed at elevated temperature, accompanied by disulfide 18b as the main product (Table 1, entries 5 and

• ]pyridine 7b was formed together with disulfide 18b and aminoborane 17b (Table 1, entry 11). We thus evaluated B(C6F5)3 as a nonmetallic catalyst to activate ammonia borane in the reductive hydrogenation of the C=N-bond in [1,3]thiazolo[4,5-b]pyridines 5 and 15c. In line with reports on the hydrogenation of

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

• C60 and C70 complexation, with selectivity for C70 (log KC60 = 3.3 and log KC70 = 4.7). In a follow-up of this work, they reported a similar redox-switchable biscorannulene tweezers system with a bis(arylthiol) switching unit that can be locked in the cis-conformation by forming a disulfide S–S bridge

• preferred conformation. It was achieved in tweezers 42 by the formation of an intramolecular disulfide bridge, that enables non-covalent bonds with aromatic moieties and results in a favored syn-conformation (Figure 23a) [89]. Yet, the most explored way is to use an electroactive moiety that can change its

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• in bacteria as well as the oxidative environment of the secretory pathway, as CMA1 exhibits predicted disulfide bridges. A single step of His-tag affinity chromatography was sufficient to yield protein of adequate purity and good yield (≈15 mg of eluted protein from 800 mL of cell culture, Figure 1c

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• ]. Similarly to the early transformations of thiepines, sulfur elimination was triggered by copper bronze at high temperature, thus leading to the conversion of the 6-membered cyclic disulfide into the corresponding thiophene. The 1,2-dithiin scaffold is found in natural products such as thiarubrines A and B

• , along with the 5-membered 1,8-naphthalene disulfide 49 resulting from the ring contraction of precursor 47. Such SO transfer process, favoured by the peri-interaction existing in the trisulfide-2-oxide substrate, was also successfully promoted by light and the cyclic sulfoxide 50 was obtained under

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• cyclic (alkyl)(amino) or mesoionic carbenes (CAACs or MICs) onto carbon disulfide. Nine novel compounds were isolated and fully characterized by 1H and 13C NMR, FTIR, and HRMS techniques. Moreover, the molecular structures of two CAAC·CS2 and two MIC·CS2 betaines were determined by X-ray diffraction

• applications [24][25][26][27][28]. N-Heterocyclic carbenes and their enetetramine dimers readily add to the central carbon atom of allenes and heteroallenes X=C=Y (X, Y = CR2, NR, O, S) to afford zwitterionic adducts [29]. In particular, their reaction with carbon disulfide affords stable azolium-2

• (−)-menthone was obtained in a separate step by deprotonating the corresponding aldiminium triflate with lithium diisopropylamide (LDA) at −78 °C [8]. Herein, we disclose the synthesis of three CAAC·CS2 and six MIC·CS2 inner salts from the corresponding aldiminium or 1,2,3-triazolium salts and carbon disulfide

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

• is noteworthy that the use of diphenyl disulfide as a sulfenylating agent was not effective in this protocol. N-(Aryl/alkylthio)phthalimide as an efficient sulfenylating reagent could also react with indoles to produce 3-thioindoles in the presence of 0.5 mol % of MgBr2, as a Lewis acid [68

• 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

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• -catalyzed CDC reaction of N-methylaniline with ethers. Fe-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds. Fe-catalyzed hydroalkylation of α,β-unsaturated ketones with ethers. Solvent-free Fe(NO3)3-catalyzed CDC of C(sp3)–H/C(sp2)–H bonds. Alkylation of disulfide compounds to afford tetrasubstituted alkenes. Fe

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• are being developed in non-aqueous solvents. Amines, disulfide-forming thiolates, and NADH derivatives, such as benzimidazoles and acridines, are used as sacrificial donors. Other families of compounds used in other applications such as non-aqueous RFBs, dye-sensitized solar cells, and LOHCs will also

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• electrogeneration favor a preassembly with Ar−X that i) upon photoexcitation accesses excited states higher than the first (D1) to bolster reactivity and/or ii) following PET assists in the Ar−X•− fragmentation step. The scope was expanded using triethylphosphite (P(OEt)3), dimethyl disulfide (MeSSMe) and bis

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• disulfide F3CS–SCF3 were employed (Scheme 2, 10 examples, up to 76% yield). With this approach, derivatives bearing an aromatic part substituted at the para-position with electron-donating substituents (1a,b), halogens (1c) as well as electron-withdrawing groups (1d) were difunctionalized in good yields

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• acetylacetone (19, Scheme 5c) [39]. As mentioned in the Introduction, the metalation of 1,4-dithianes is quite problematic [12][16]. In the unsaturated 1,4-dithiin series, however, the metalation of the cyclic vinyl-1,2-disulfide moiety is somewhat more feasible. Even though linear vinyl-1,2-disulfides such as

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

• reoxidized to the disulfide by (NH4)2S2O8. The disulfide (SPyf)2 is also consumed in the thiolation of C-centered radicals affording the SPyf radical and target sulfides, which are in turn useful C-centered radical precursors for photoredox-catalyzed reactions [123]. The high efficiency of the thiolation

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

• of a Cu(I) precursor, and then confined to the surface of those electrodes with the use of a solution-phase Cu(II)-mediated disulfide bond-forming reaction using excess substrate in solution. The molecules were placed by individually addressable blocks of electrodes on the array that were each

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• active site thiohemiaminal (amine to imine oxidation) or disulfide formation, respectively. Additionally, C6–Cl derivative 9 could probe cysteine alkylation. Reported herein is our exploration of this synthesis and the evaluation of GDP 6-chloro-6-deoxy-ᴅ-mannose 18 against GMD. Results and Discussion

• modifying C6 [4]. Substrate 18 was known to form a disulfide in solution [10], presumably resulting in the glycosyl-1-phosphate being unable to access the enzyme active site; unfortunately, the addition of higher concentrations of reducing agent (DTT) and solid-supported PPh3 to access the reduced form for

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• to promote the thermodynamically disfavored SN2 cleavage of an individual protein disulfide bond by poorly nucleophilic organic thiols [21]. On the other hand, as for the connection or correlation between polymer and small molecule mechanochemistry, this Perspective article discusses recent studies

• for the fullerenes to pass through. However, the capsule 5 is sensitive to mechanochemical stress due to the porosity, conformational rigidity, and due to the presence of hydrazone and/or disulfide moieties that act as mechanophores. Therefore, during ball milling, 5 gets partially disintegrated at

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

• directly. To that end, we attempted reactions from aminothiol 8a as well as from the corresponding disulfide, both at room temperature and under MWI. In these experiments, the yield of dimer 11a was in the range of 10–34%. We also tried to enhance the oxidative dimerization using a mild oxidizing agent

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

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

• respective ditellurides, a disulfide and a diselenide (Scheme 27). Recently, Ribeiro and co-workers used menadione as a nucleophile for the synthesis of 3-chloromethylated menadione 84, a key intermediate used to prepare selenium-menadione conjugates 86 [128]. In this work, compound 84 was prepared through

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

• naturally occurring HDAC inhibitors contain sulfur moieties like, e.g., disulfides or thioesters. They seem to lack a zinc-chelating group at first sight, but the disulfide or thioester acts as a prodrug and are reduced/cleaved in vivo to liberate the free thiol, a strong Zn-binding group [24][25]. Results

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• ], disulfide- [13], thioether- [14][15][16][17][18][19][20], triazole- [21][22], oxime- [23] and hydrazone formation [24] as well as multicomponent reactions such as the Ugi- or Petasis reaction [25][26][27][28][29][30][31][32]. The content of helicity can moreover be changed by the introduction of a photo

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• for accessing bis(indolyl)sulfides. To synthesize the unsymmetrical bis(indolyl)sulfide 88, Janosik reacted the indole disulfide 87 with free indole and obtained the product 88 in 81% yield, where the sulfur linkages were 2,3’- with respect to the two indole nuclei (Scheme 11a) [73][74][75][76]. Hall

• compounds having semiconductor properties [80]. The syntheses of these compounds were studied by Janosik in 2006. The N-silyl-protected 3-bromoindole 93 was subjected to strong basic medium (t-BuLi) at low temperature and then quenched with either bis(phenylsulfonyl)sulfide (83) or indole disulfide 94

• the sulfur species 102 takes place to generate copper sulfide complex 103. An oxidative homocoupling gives the bis(indol-3-yl)sulfide 101. Simultaneously, an oxidative homocoupling of the copper sulfide complex can take place to afford disulfide 104, that reacts with N-methylindole again under

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

• Jana M. Boysen,
• Nauman Saeed and
• Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

• , temperature and aeration, are known to regulate gliotoxin biosynthesis [115][119][120]. The biological activity of ETP’s like gliotoxin is mediated by the active disulfide bridge that targets vulnerable thiols or catalyses oxidative burst formation via redox cycling [78]. In previous studies, these cytotoxic

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• disulfide linkages to transportan and penetratin peptides. The PNA–peptide conjugates were effectively internalized in human Bowes melanoma cells and in vivo in rats [171]. Transportan peptide localized the PNA in membranous structures of cells, while the penetratin conjugate preferred nuclear localization

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• disulfide (97) was reported by Xu et al. The reaction has been achieved using a catalytic amount of CuI, LiOt-Bu, and 4 Å molecular sieves in THF as solvent at 40 °C under N2 atmosphere for 12 h and proceeds via a multicomponent CuAAC/persulfuration sequence. The strategy features a wide substrate scope

• ) [55]. A probable mechanism for this transformation was proposed as illustrated in Scheme 29. The cycloaddition reaction between copper(I) acetylide 99 and organic azide 95 occurs to obtain the triazole cuprate intermediate 100, which reacts as a nucleophile with the disulfide electrophile 97 to

• produce the corresponding triazole disulfide 98 [55]. A convenient route to triazole-fused sultams 104 was reported by Latyshev et al. It comprises a modified CuIAAC cycloaddition to produce intermediate sulfonamide-tethered 5-iodo-1,2,3-triazoles 103, followed by a base-mediated cyclization under

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98