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

• decarboxylative transformations of NHPI esters using a phenothiazine-based organophotoredox catalyst PTH1. This type of catalyst is believed to facilitate SET to NHPI esters through the formation of EDA complexes. Interestingly, upon addition of RAE 58 to a solution of PTH1, a noticeable red shift in the UV–vis

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• successfully under the conditions applied to the preparation of 14H-quinoxaline[2,3-b]phenoxazines 5. The reaction proceeds readily with o-mercaptoaniline to produce the benzo[5,6][1,4]oxazino[2,3-b]phenothiazine derivative 10c (Scheme 6). Electronic absorption spectra of the prepared 14Н-quinoxaline[2,3-b

• ]oxazino[2,3-b]phenothiazine 10c (Figure 7) were bathochromically shifted by about 50 nm relative to those of the quinoxaline[2,3-b]phenoxazines 6. The electrochemical behavior of compounds 4a–h, 5a–c, 6a,b, and 10c was studied using cyclic voltammetry (CV). As exemplified by the CV curves (Figure S12

• Е1/2OX = 0.25 V. The irreversible two-wave reduction (Е1/2RED1 = −1.40 ± 1.60 V and Е1/2RED2 = −1.92 ± 2.45 V) is also characteristic of 14H-quinoxaline[2,3-b]phenoxazines 5a–c and 6a,b. In contrast to 5a–c and 6a,b, benzo[5,6][1,4]oxazino[2,3-b]phenothiazine 10c is reversibly reduced at Е1/2RED1

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• University, Beijing 100875, P. R. China Key Laboratory of Hainan Trauma and Disaster Rescue, The First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou 571199, P. R. China 10.3762/bjoc.19.79 Abstract A series of 1,8-naphthalimide (NI)-phenothiazine (PTZ) electron donor

• –acceptor dyads, based on naphthalimide (NI) as electron acceptor and phenothiazine (PTZ) as electron donor. The two units are connected by a C–N single bond, and they adopt orthogonal geometry due to conformational restriction. In order to tune the energy of the excited states, and to probe the effect of

• electron donor for the construction of electron donor–acceptor TADF molecules is carbazole. However, since our aim was to study the TADF photophysics with model TADF emitters, the use of phenothiazine (PTZ) instead of carbazole presents a few advantages. First, upon connection of the electron acceptor (i.e

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• good yield (80%) by heating 23 in polyphosphoric acid (Scheme 5). Independently, in an effort to synthesise phenothiazine isosteres, Craig et al. [39] prepared 1a via a Wagner–Meerwein rearrangement of 23 with P2O5 (Scheme 5) the following year. The method was used to successfully synthesise

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• both C–I bonds giving the iodinated N-arylbenzimidazoles 6a and 6b as a mixture with 54% and 25% yield [37]. A ring opening/closing cascade reaction with elemental sulfur resulted in the formation of the imidazo[4,5,1-kl]phenothiazine (7a) in 47% yield. The corresponding phenoselenazine 7b and the

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• dyads and a triad were prepared, with naphthalimide (NI) as electron acceptor and phenothiazine (PTZ) as electron donor. The NI and PTZ moieties are either directly connected at the 3-position of NI and the N-position of the PTZ moiety via a C–N single bond, or they are linked through a phenyl group

• additional investigations are required to verify the above postulate and to unravel the TADF mechanism. Recently, we and others found that the orthogonal donor–acceptor dyad derived from 1,8-naphthalimide (NI) and phenothiazine (PTZ) shows TADF in the red spectral range [20][21][22]. Our purpose of designing

• triad, naphthalimide (NI) was used as electron acceptor and phenothiazine (PTZ) as electron donor. The NI and PTZ moieties are either directly connected at the 3-position of NI and the N-position of the PTZ moiety via a C–N single bond, or connected through an intervening phenyl linker. Tuning the

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• ]. Representatives containing polycyclic aromatic systems based on phenothiazine 161 [144], carbazole 162 [145], and tetrathiofulvalenes 163 and 164 [146] and 1,1-binaphthalenes 165 and 166 [147] are known. They are shown in Figure 10. Various diaryl derivatives of C60 can also be obtained by this approach. Thus

Exploring the possibility of using fluorine-involved non-conjugated electron-withdrawing groups for thermally activated delayed fluorescence emitters by TD-DFT calculation

• Dongyang Chen and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 210–223, doi:10.3762/bjoc.17.21

• small group of structurally related N-heterocycles such as carbazole [5], dimethylacridine [13], phenoxazine [17], and phenothiazine [18]. Prior studies have shown that placing the donor groups ortho to the acceptor can lead to more limited conjugation between the two, resulting in emitters with

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• Abstract This work describes an efficient, simple, and ecofriendly sonochemical procedure for the preparation of new α-(arylamino)acetonitrile derivatives C-substituted with phenothiazine or ferrocene units. The synthetic protocol is based on the Strecker reaction of a (hetero)aryl aldimine substrate with

• that the C-(hetero)aryl-α-(arylamino)acetonitrile derivatives can be considered genotoxically safe and possibly antimutagenic. Keywords: Ames test; α-aminoacetonitriles; ferrocene; phenothiazine; SEM; single crystal XRD; sonochemistry; Introduction Sonochemistry can be considered as a major

• frequencies between 20 and 100 kHz were reported in the literature as optimal to enhance the nucleation and fragmentation rates, but the exact optimal frequency is probably reactor and system specific [8]. The exciting properties of the heterocyclic phenothiazine core displaying tunable chemical, redox

Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

• Jonas Becher,
• Daria V. Berdnikova,
• Heiko Ihmels and
• Christopher Stremmel

Beilstein J. Org. Chem. 2020, 16, 2795–2806, doi:10.3762/bjoc.16.230

• a lower affinity [38]. Along the same line, the influence of the length and substituents of the side chains at the G4-DNA ligands have been assessed for quinolinium [43], indoloquinoline [44][45], phenanthroline [46], phenothiazine [47], and thiazole orange [48] derivatives. In these studies, the

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• , bearing a quinazoline unit as the acceptor core and carbazole, dimethyldihydroacridine, or phenothiazine donor moieties, were designed and synthesized in two steps including a facile copper-catalyzed cyclization and a nucleophilic aromatic substitution reaction. The photophysical properties of the

• donor 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine. A white OLED based on these versatile exciplex systems with a relatively high maximum brightness of 3030 cd/m2 and an external quantum efficiency of 0.5% was fabricated. Keywords: carbazole; dimethyldihydroacridine; exciplex; phenothiazine

• we report on the synthesis and properties of electroactive compounds bearing a quinazoline moiety as an acceptor and the widely used carbazole, phenothiazine and dimethyldihydroacridine species as donors [11][12][13]. Results and Discussion Synthesis and thermal properties Aromatic rigid moieties

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• -free ATRP strategy [132][133][134][135][136][137]. Latter reference provided a comprehensive overview demonstrating the function of phenothiazine derivatives, perylene, diaryl dihydrophenazines, anthracene or pyrene. In addition, type II photoinitiators including benzophenone, and thioxanthones were

N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

• Fabienne Speck,
• David Rombach and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5

• after 20 h of irradiation. Keywords: addition; phenothiazine; photochemistry; photoredox catalysis; redox potential; Introduction Visible-light photoredox catalysis has become a precious tool in modern synthetic organic chemistry and experiences a continuously growing interest in industrial

• well as the first pentafluorosulfanylation method starting from sulfur hexafluoride [2]. We are convinced that the value of phenothiazine derivatives in photoredox catalysis is still underestimated. While these compounds found widespread use in ATRA (atom transfer radical addition) polymerization [15

• transfer from the N-phenylphenothiazine (1) as photocatalyst to 13a as substrate. The resulting substrate radical anion 13a−· is instantaneously protonated to radical 13a· and back-electron transfer to the intermediate phenothiazine radical cation 1+· yields the substrate cation 13a+. The latter is

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

• Abed Tarapdar,
• James K. S. Norris,
• Oliver Sampson,
• Galina Mukamolova and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

• latent TB. Herein we report the design and synthesis of the first phenothiazine–siderophore conjugate. A convergent synthetic route was developed whereby the functionalised phenothiazine component was prepared in four steps and the siderophore component also prepared in four steps. In M. smegmatis the

• functionalised phenothiazine demonstrated an equipotent MIC value in direct comparison to the parent phenothiazine from which it was derived. The final conjugate was synthesised by amide bond formation between the two components and global deprotection of the PMB protecting groups to unmask the catechol iron

• chelating groups of the siderophore. The synthesis is readily amenable to the preparation of analogues whereby the siderophore component of the conjugate can be modified. The route will be used to prepare a library of siderophore–phenothiazine conjugates for full biological evaluation of much needed new

Recent advances in materials for organic light emitting diodes

• Eli Zysman-Colman

Beilstein J. Org. Chem. 2018, 14, 1944–1945, doi:10.3762/bjoc.14.168

• molecular design approach for orange-emitting TADF molecules employing a fluorenone acceptor [5]. In the full research paper by Feng-Ming Xie et al., they disclose two bipolar, high-energy phenothiazine-5,5-dioxide-based host materials conceived to be used for deep blue OLED devices [6]. The articles in

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• , Jiangsu 215009, P.R. China Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia 10.3762/bjoc.14.73 Abstract Two novel D–A bipolar blue phosphorescent host materials based on phenothiazine-5,5-dioxide: 3-(9H-carbazol-9-yl)-10-ethyl-10H-phenothiazine-5,5

• -dioxide (CEPDO) and 10-butyl-3-(9H-carbazol-9-yl)-10H-phenothiazine-5,5-dioxide (CBPDO) were synthesized and characterized. The photophysical, electrochemical and thermal properties were systematically investigated. CEPDO and CBPDO not only have a high triplet energy but also show a bipolar behavior

• as suitable HOMO and LUMO energy levels. This preferable performance suggests that CEPDO and CBPDO are alternative bipolar host materials for the PhOLEDs. Keywords: host materials; phenothiazine; phosphorescence; synthesis; Introduction Since 1987, the Tang group [1] firstly reported double organic

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• reduced pressure. Thus, a chromatographic purification was not necessary in the improved dimerization protocol. To suppress the polymerization and to improve the yield of the dimer product, we attempted the addition of a polymerization inhibitor. As expected, the addition of 3 mol % phenothiazine

Thiophene-forming one-pot synthesis of three thienyl-bridged oligophenothiazines and their electronic properties

• Dominik Urselmann,
• Konstantin Deilhof,
• Bernhard Mayer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2016, 12, 2055–2064, doi:10.3762/bjoc.12.194

• electronics [37][38][39][40]. In comparison to thiophene, phenothiazine, a tricyclic dibenzo-1,4-thiazine, possesses a significantly lower oxidation potential, similar to aniline. However, phenothiazine derivatives form stable deeply colored radical cations with perfect Nernstian reversibility [41][42][43][44

• different bromo-substituted (oligo)phenothiazine substrates 1 had to be prepared. 3-Bromo-10-hexyl-10H-phenothiazine (1a) was synthesized according to the literature by hexylation of 3-bromo-10H-phenothiazine [45]. The 7-bromo-substituted phenothiazines 1b and 1c were prepared in good yields according to

• our one-pot bromine-lithium-exchange-borylation-Suzuki (BLEBS) sequence [78], employing an excess of 3,7-dibromo-10-hexyl-10H-phenothiazine (3) [45] as a coupling component in the Suzuki step (Scheme 1). With three bromo-substituted (oligo)phenothiazines 1 in hand the consecutive pseudo five-component

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• for acidic guests such as tartaric acid and sugar acids [62][63][64][65] (Figure 11). The best chiral discriminating d-PET system was constructed using a phenothiazine fluorophore 17 and 18 [66]. The phenothiazine fluorophore was chosen because it is a very strong electron donor. These sensors

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• nanoparticles [65], and zinc oxide nanorods directly grown on silver [66], has also been reported on. The “cholesterol self-powered biosensor” [67], in which the cathodic process is determined by cholesterol oxidase and on an anode phenothiazine-mediated oxidation of cholesterol as well as immobilization of

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• dangerous diseases. An irregular and unsanitary lifestyle adversely affects the central nervous system resulting in neuroses and psychiatric disorders. Among the antipsychotic medications phenothiazine derivatives [40][41], and especially promethazine, widely known by its brand name Phenergan®, hold well

• -phenothiazin-10-yl)propan-2-ol (±)-3 was synthesized according to the method described by Clement et al. [59], in which propylene oxide (2) was regioselectively opened by phenothiazine (1) in the presence of n-butyllithium (n-BuLi) at ambient temperature providing desired alcohol (±)-3 in 64–77% yield

• suggests that this particular process is most probably inaccessible through the sodium salt of phenothiazine (1) due to multiple substitution at aromatic ring carbon atoms and some other byproducts of the non-regioselective propylene oxide ring opening. With the hope of eliminating the unwanted side

The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

• Sarah Bay,
• Gamall Makhloufi,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 1006–1016, doi:10.3762/bjoc.10.100

• ]. This photo-induced electron transfer (PET) [30][31][32][33][34] has been investigated with donors such as porphyrines, polycyclic aromatic hydrocarbons, perylenediimides and (oligo)thiophenes [35][36], tetrathiafulvalenes [37], as well as phenothiazine and its derivatives [22][38][39][40]. The latter

• have become attractive electrophores due to their reversible and tunable oxidation potential. Interestingly quenching of the phenothiazine inherent fluorescence offers a facile evidence for the occurrence of intramolecular PET in phenothiazine-containing Do–Acc dyads [41][42]. As suitable acceptor

• moieties C60 fullerene [43][44][45], and quinones, such as 9,10-anthraquinone as a potential two electron acceptor, have been commonly used in Do–Acc arrangements [46][47][48][49][50][51]. In previous studies phenothiazine–anthraquinone couples have been introduced into peptide scaffolds [52][53][54] and

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

• Oliver Goerz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 902–909, doi:10.3762/bjoc.10.88

• -toluenesulfonic acid, phenothiazine (98%), zinc iodide (98%), and boron trifluoride diethyl etherate (46%) were purchased from Sigma-Aldrich and used as received. Isosorbide (98%) and E-benzaldoxime (97%) were purchased from Alfa Aesar, and isosorbide was recrystallized from acetone/ethyl acetate. All used

• ), crotonic acid (9.04 g, 105 mmol), p-toluenesulfonic acid (0.86 g, 5 mmol), phenothiazine (0.02 g, 0.1 mmol) and 80 mL of toluene. The flask was fitted with a Dean–Stark apparatus and the mixture was heated under reflux for 72 h. The solution was washed with 2 × 40 mL of saturated sodium hydrogen carbonate

• ), 755, 692 (ν, Aryl); ESIMS m/z: 525 [M+]. Synthesis of poly(isosorbide itaconate -co- succinate) 13: A 250 mL round bottom flask was charged with isosorbide (5.85 g, 40 mmol), itaconic acid (2.60 g, 20 mmol), succinic acid (2.36 g, 20 mmol), p-toluenesulfonic acid (0.04 g, 0.2 mmol), phenothiazine