Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• , we published a series of ‘bent’ diindenodithienothiophene derivatives (2–4, Figure 2) [16]. It was observed that oxidising the central sulfur atom significantly increased the solution photoluminescence quantum yield (PLQY) from 0.004 (3) to 0.72 (4). The diketo derivative 5 of compound 2 has been

• all the sulfur atoms of the DTT core and the electron-withdrawing [20] keto groups. The LUMO is presented strongly in the seven fused rings, but is poorly represented in the outer ethylhexylthiophenes, which are electron-rich and twisted out of plane. The LUMO is strongly localised at the electron

• -deficient keto groups. Interestingly, neither the HOMO, nor the LUMO, is present at the central sulfur atom of the DTT motif. Organic field-effect transistors To estimate the charge carrier mobility from the saturation regime of the current–voltage plot, bottom gate/bottom contact (BG/BC) OFETs [76][77

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• )(phenyl)phosphinate (53) was reduced with lithium aluminum hydride to 2-aminobenzyl(phenyl)phosphine (57). It was oxidized with sulfur to give zwitterionic 2-aminobenzyl(phenyl)dithiophosphinic acid (58), which underwent thermal elimination of hydrogen sulfide to yield 2-phenyl-1,3-dihydrobenzo[d][1,2

• )phosphine (57) with two atom-equivalents of sulfur in refluxing benzene, affording the zwitterionic 2-aminobenzyl(phenyl)dithiophosphinic acid 58 in 80% yield. It was converted to 2-phenyl-1,3-dihydrobenzo[d][1,2]azaphosphole 2-sulfide (59) in 91% yield by heating at 100–120 °C under vacuum (Scheme 10) [30

• peroxide and sulfurization with sulfur, respectively (Scheme 16) [37][38]. Synthesis via formation of the C–C bond neighboring at the ring phosphorus atom In 1984, Collins and co-workers attempted the synthesis of benzo-γ-phosphonolactams 56a and 93 from (chloromethyl)(phenyl)-N-methyl-N

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• , regioselective double oxidative photocyclization was observed during the construction of three S-shaped double helicenes DH-1–3 based on thiophene/selenophene. From DH-1 to DH-3, sulfur atoms in the molecular framework were gradually replaced by selenium atoms. The crystal structures of DH-1 and DH-2 and

• )2-bb-DSS, the notation bb means that the positions of the heteroatoms of the outer two heterocycles are on the same side as those of the middle heterocycle. Taking dithienothiophene as example, according to the positions of sulfur atoms, there are six isomers of dithienothiophene, in which the

• sulfur atoms on the same side is defined as bb by us. The double Wittig reaction of 4a and 4b with 1,3-phenyldimethyltriphenylphosphonium bromide afforded compounds 5a and 5b with yields of 46% and 64%, respectively. After the double Wittig reaction of 4c we obtained a mixture of cis and trans isomers of

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• , while other synthetic approaches were explored to obtain these reagents, the SN2 strategy described in this work was the most efficient. Such synthetic alternatives included: first, a sulfur(VI) fluoride exchange (SuFEx) between perfluoroalkylsulfonyl fluorides and the corresponding silyl enol ether

Synthesis of sulfur karrikin bioisosteres as potential neuroprotectives

• Martin Pošta,
• Václav Zima,
• Lenka Poštová Slavětínská,
• Marika Matoušová and
• Petr Beier

Beilstein J. Org. Chem. 2022, 18, 549–554, doi:10.3762/bjoc.18.57

• Martin Posta Vaclav Zima Lenka Postova Slavetinska Marika Matousova Petr Beier Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic 10.3762/bjoc.18.57 Abstract The only known sulfur-containing karrikin, 3-methyl-2H-thiopyrano[3,4

• oxygen with sulfur. In particular, we present synthetic procedures toward bioisosteres of karrikins with one or two sulfur heteroatoms incorporated into the core backbone together with evaluation of their biological activity in inhibition of acetylcholinesterase. Keywords: acetylcholinesterase

• ; butenolides; karrikin; sulfur; Introduction Neurological disorders, especially the Alzheimer’s and the Parkinson’s diseases represent a serious problem for elderly populations worldwide. Studies of these neurodegenerative diseases led to the discovery of a deficit of acetylcholine and dopamine levels in the

Chemistry of polyhalogenated nitrobutadienes, 17: Efficient synthesis of persubstituted chloroquinolinyl-1H-pyrazoles and evaluation of their antimalarial, anti-SARS-CoV-2, antibacterial, and cytotoxic activities

• Viktor A. Zapol’skii,
• Isabell Berneburg,
• Ursula Bilitewski,
• Melissa Dillenberger,
• Katja Becker,
• Stefan Jungwirth,
• Aditya Shekhar,
• Bastian Krueger and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2022, 18, 524–532, doi:10.3762/bjoc.18.54

• . Interestingly, the oxidation of the sulfur atom in pyrazole 9d (EC50 = 1.1 ± 0.04 µM) improved the antimalarial activity by a factor of more than three (sulfoxide 10d, EC50 = 0.3 ± 0.01 µM). In our experiments we used the established antimalarial drug amodiaquine as control. As shown in Table 1, the EC50 of

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

• -bonded phenyl substituents (compounds 2a–d) are almost coplanar with the pyrimidine core (dihedral angle 0.5–1.5°), while a phenyl group connected with the pyrimidine ring via a sulfur atom (compounds 5 and 6) is twisted out of the pyrimidine plane and is not conjugated with the pyrimidine ring. Despite

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

• featuring ligand groups with nitrogen or sulfur as donor atoms [4]. The siderophore–iron complexes are recognized by highly selective microbial transporters. Following their translocation into the cell, the bound iron is released via a reductive or hydrolytic mechanism [2] Members of the genus Nocardia are

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

• space group P212121. The presence of sulfur anomalous scatters allowed to unequivocally establish the absolute configurations, which reads S at the chiral center C2 and R at the C10 (C numbering as in Figure 1). The absolute configuration of the two sulfur stereogenic centers is confirmed to be R

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• spectroscopy (Scheme 3h). Formation of 4a could have occurred from the direct reaction of the N–H nitrogen of 3a with NFSI, which would agree with the propensity for NFSI to react with some hard oxygen and nitrogen nucleophiles at the sulfur atom instead of at the fluorine atom [39][40]. Similarly, NFSI has

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

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

• to synchronous bond-making and bond-breaking, with a small negative charge development on the sulfur at the transition state, for the solvolytic process. Subsequent to this 1927 study, Hammett reported [5][6] in 1937, the development of the Hammett equation, involving the consideration of a scale

• changes observed as the water content increased were consistent with an SN2 reaction becoming a mixed SN2–SN1 situation and then, eventually, an essentially SN1 pathway was followed. It was concluded that nucleophilic attack at sulfur has many of the characteristics of attack at carbon, including the

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

• Yuki Yamamoto,
• Akihiro Tabuchi,
• Kazumi Hosono,
• Takanori Ochi,
• Kento Yamazaki,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

• methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• ligands that could coordinate several metal centers with the aid of sulfur, nitrogen or oxygen donor atoms that allow multiple bindings [13]. Moreover, compounds bearing a –C(O)NHC(S)– moiety and their metal complexes have assorted biological and pharmacological properties such as anti(myco)bacterial

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• sulfur atom at the 3’-position, these compounds have proved to be structurally potent nucleoside analogues, and the best example is BCH-189. The majority of methods traditionally involves the chemical modification of nucleoside structures. It requires the creation of artificial sugars, which is

• sulfur atom instead of C-3', and an unnatural ʟ-configured sugar [20]. The presence of oxygen as a second heteroatom in the sugar ring was also found to result in anti-HIV activity in 1,3-dioxolane nucleosides [21]. A good example for the preparation of 2’,3’-dideoxy-3’-oxacytidine in a stereospecific

• reverse transcriptase [25]. Nucleosides with sulfur atom-containing heterocyclic sugar rings at the 3’-position are important pharmaceutical substances. Two well-known important molecules in this category are lamivudine (1) and emtricitabine (2), as shown in Figure 1. It was found that there is a

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• Michael additions of aldehydes to nitroalkenes both under solvent-free conditions and in solution. The N-sulfinylurea catalyst was more efficient than the corresponding thiourea. For some substrates, enantioselectivities reached 98% ee. The stereogenic center on the sulfur did not have a considerable

• acidity of the hydrogen-bond donating unit. This notion has often been realized with substituted aryls such as 3,5-bis(trifluoromethyl)phenyl. Ellman introduced a different approach and developed N-sulfinylureas. An additional potentially useful feature is the stereogenic center on sulfur. tert

• unit, which should engage in enamine activation of enolizable carbonyl compounds. The urea or thiourea moiety shall provide hydrogen-bond donating ability. Furthermore, these compounds possess a sulfinyl group with an additional stereogenic center on the sulfur. To verify the influence of a matched

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

• [57][58][59][60][61][62][63][64][65]. Results are summarized in Table 2. Triphenylphosphine and triethyl phosphite could be used interchangeably in the sulfur extrusion step. However, in most cases the co-elution of enaminones 15 with phosphorus-derived byproducts during chromatographic purification

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• nucleophile and the alkyl or aryl radicals. From 2013 to 2019, the authors disclosed a series of nitrogen, sulfur, oxygen, and carbon nucleophiles for photoinduced, copper-catalyzed cross-couplings with organic halides. The copper–nucleophile complexes that were generated in situ as photoredox catalysts

Strategies for the synthesis of brevipolides

• Yudhi D. Kurniawan and
• A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

• -promoted double bond migration. The cyclopropyl functionality in 46 can be assembled from the reaction of sulfur ylide and the α,β-unsaturated ketone 47, which in turn can be realized from the cross metathesis between commercially available ethyl vinyl ketone (48) and the C2-symmetrical diene-diol 49. The

Halides as versatile anions in asymmetric anion-binding organocatalysis

• Lukas Schifferer,
• Martin Stinglhamer,
• Kirandeep Kaur and
• Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

• frameworks 57 were accessed in excellent yields up to 93% and enantioselectivities up to 94% ee. Increased aromaticity proved again to be essential for achieving high enantioselectivities. Additionally, Lewis base activation of the allylsilane substrates through the thiourea sulfur atom is proposed to be

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• discovered the synergistic combination of nickel catalysis and benzaldehyde for the arylation of C(sp3)–H bonds adjacent to nitrogen or sulfur in amides 6 and thioethers 28, respectively, under UVA light irradiation [68]. As shown in Scheme 16, both primary and secondary C(sp3)–H bonds of amides were

• irradiation with UVA light enabled the cross-coupling of α-oxy C–H bonds of acyclic/cyclic ethers 9 with alkyl bromides 40 (Scheme 24) [86]. The catalytic system was not limited to α-oxy C–H bonds of cyclic ethers, substrates having other heteroatoms such as nitrogen and sulfur that can imbue a hydridic

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

• , nitrogen, oxygen, silicon, phosphorus, sulfur, selenium, and tellurium. This review will skip the reports on the corresponding carbon-centered analogs. Boranes First discovered in 1894 [34], 2,2’-bisarylborinates are used for treating prostate cancers utilizing their property of inhibiting the transient

• -atom (80, Scheme 9b) [66]. A similar protocol was adopted by van de Watering in their recent syntheses [67][68]. Sulfides The C2 tethering of indoles with sulfur can be achieved in neutral medium by treatment with various SL2 (L is a leaving group) moieties [69][70]. This is a common method for the

• synthesis of bis(indol-2-yl)sulfides which are the precursors of potent bioactive molecules [71][72][73]. The simple synthetic strategies for the molecular units 82 were first reported by Barbier in 1989. The condensation of tryptamine monoacetate (81a) or indole oxime (81b) with sulfur dichloride in a

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• direct access to several sulfur-containing pharmacological compounds that present valuable biological activities, such as anti-HIV (9) [51], inhibition of snake venom enzymes (10) [52], or even anti-estrogenic effects (11) [53] (Scheme 4A). Recently, Hou and co-workers also explored the utility of a

Cerium-photocatalyzed aerobic oxidation of benzylic alcohols to aldehydes and ketones

• Girish Suresh Yedase,
• Sumit Kumar,
• Jessica Stahl,
• Burkhard König and
• Veera Reddy Yatham

Beilstein J. Org. Chem. 2021, 17, 1727–1732, doi:10.3762/bjoc.17.121

• -dichlorobenzaldehyde (2w) in 70% yield. The sulfur-containing compounds 4-(phenylthio)benzyl alcohol (1r) and the heterocyclic compound thiophene-2-ylmethanol (1x) gave the corresponding aldehydes 2r and 2x in 61 and 80% yield, respectively. Finally, 2-naphthylmethanol (1y) was subjected to the reaction conditions and

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

• recent studies show that J can be further optimized. Chen and co-workers reported that substitution of oxygen-4 of J with sulfur improved the Hoogsteen binding properties of 4-thiopseudoisocytosine (L, Figure 6) [98]. UV thermal melting and gel electrophoresis studies showed that L formed more stable L•G

• sulfur modification removed the undesired ability of J to form a Watson–Crick base pair with G in single-stranded nucleic acids. This is important for avoiding off-target binding to single-stranded RNA and DNA in biological systems. L appears to be a promising improvement of J as a neutral analogue of