Directed Synthesis of 1-Substituted Phenoxazines

Katritzky, Alan R.; Miguel, Luis; Rewcastle, Gordon W.

doi:10.3987/r-1987-12-3135

Cited by 16 publications

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“…While compound 1a was easily made from phenoxazine 3 as described in the literature, the synthesis of 1b shown in Scheme required a more complex methodology. There is currently only one reported route to 1-alkylphenoxazine derivatives without other substituents on the ring system . Katritzky and coworkers reported that the C(1) of intermediate 4 could be deprotonated with assistance from the adjacent −CO 2 Li group.…”

Section: Resultsmentioning

confidence: 99%

“…There is currently only one reported route to 1-alkylphenoxazine derivatives without other substituents on the ring system. 35 Katritzky and coworkers reported that the C(1) of intermediate 4 could be deprotonated with assistance from the adjacent −CO 2 Li group. This gives access to the dilithiated species 5 that upon reaction with electrophiles gave a range of 1-substituted phenoxazines, although 1-methylphenoxazine 6 was not reported.…”

Section: ■ Introductionmentioning

confidence: 99%

“…This gives access to the dilithiated species 5 that upon reaction with electrophiles gave a range of 1-substituted phenoxazines, although 1-methylphenoxazine 6 was not reported. 35 The lithiation and methylation of the 1-position of phenoxazine 3 are very sensitive to the reaction conditions and required the sequential use of 1.0 equiv of t BuLi and MeI. A small amount (≈5%) of unreacted 3 could not be separated from 6.…”

Section: ■ Introductionmentioning

confidence: 99%

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Bond Rotations and Heteroatom Effects in Donor–Acceptor–Donor Molecules: Implications for Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence

et al. 2018

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New thermally activated delayed fluorescence (TADF) blue emitter molecules based on the known donor−acceptor−donor (D−A−D)type TADF molecule, 2,7-bis(9,9-dimethylacridin-10-yl)-9,9-dimethylthioxanthene-S,S-dioxide (DDMA-TXO2), are reported. The motivation for the present investigation is via the use of rational molecular design, based on DDMA-TXO2, to elevate the organic light emitting diode (OLED) performance and obtain deeper blue color coordinates. To achieve this goal, the strength of the donor (D) unit and acceptor (A) units have been tuned with methyl substituents. The methyl functionality on the acceptor was also expected to modulate the D−A torsion angle in order to obtain a blue shift in the electroluminescence. The effect of regioisomeric structures has also been investigated. Herein, we report the photophysical, electrochemical, and single-crystal X-ray crystallography data to assist with the successful OLED design. The methyl substituents on the DDMA-TXO2 framework have profound effects on the photophysics and color coordinates of the emitters. The weak electron-donating methyl groups alter the redox properties of the D and A units and consequently affect the singlet and triplet levels but not the energy gap (ΔE ST ). By systematically manipulating all of the aforementioned factors, devices have been obtained with acceptor-substituted III with a maximum external quantum efficiency of 22.6% and Commission Internationale de l'Ećlairage coordinates of (0.15, 0.18) at 1000 cd m −2 .

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Bond Rotations and Heteroatom Effects in Donor–Acceptor–Donor Molecules: Implications for Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence

et al. 2018

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“…Such a structural motive is found in disilaphenothiazine 17 that can be accessed easily following a comparable strategy (Scheme ). After protection of the nitrogen of phenothiazine with CO 2 , leading to a lithio carbamate used as ortho ‐director group, 15 was selectively deprotonated, then silylated by chloropentadi‐silane, giving 16 in 76 % yield after deprotection. Introduction of the propargyl chain onto the deprotected nitrogen was performed using NaH and propargyl bromide 3 a .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of N‐Heterocycles‐Fused Azasilines by Palladium‐Catalyzed Si‐Si Bond Activation

2019

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Azasilines fused nitrogen heterocycles are prepared in excellent yields (from 74 to 98 % according to the structures) for the first time in one operation with high regio‐ and stereoselectivities. The key step consists of an intramolecular palladium‐catalyzed cyclisation reaction of heteroaryl disilane cores, bearing double or triple bond. We first studied the reactivity of pyridyl heterocycles, using xylenes as solvent and Pd(dba)2‐P(OEt)3 as catalyst at 130 °C. The Z configuration of the adducts suggested that the reaction proceeds following a syn addition on the alkyne. This strategy has then been illustrated by the synthesis of complex polyheterocyclic scaffolds (phenothiazine, indole, carbazole, quinoline and tetrahydroquinoline) starting from other nitrogen heteroaryl compounds, to demonstrate the potential of the process, in order to obtain promising biological scaffolds.

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“…A C-1 anion of phenothiazine can be generated by in situ protection of the N-10 position followed by deprotonation with t -BuLi. 6 Reaction of phenothiazine with 2 equivalents of BuLi gives access to a C-1 and N-10 doubly lithiated species. [7][8][9] 10-Alkylphenothiazines can be lithiated at C-4 with BuLi 8,10 or preferably with s -BuLi/ TMEDA.…”

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confidence: 99%

Synthesis of 3,7-Disubstituted 10-Methylphenothiazines

Ebdrup¹

1998

Synthesis

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Lithiation at the C-3 and C-7 positions of N -methylphenothiazine ( 1) can be achieved by halogen metal exchange reaction starting from 3,7-dibromo-10-methylphenothiazine (2) . Reaction of the lithiated species with carbon, sulfur and silicon electrophiles results in new 3,7-disubstituted 10-methylphenothiazines 4a-g . The described procedure gives high yield and an easy excess to important enzyme mediators. 4a 6.80 (d, 2H, 7.15 (m, 2H, 7.14 (m, 2H) 3.34 (s, 3H) J = 8.0) J = 8.0) 4b 6.67 (d, 2H, 6.94 (dd, 2H, 6.95 (m, 2H) 3.31 (s, 3H) J = 8.5) J = 2.0, 8.5) 4c 6.70 (d, 2H, 7.10 (dd, 2H, 7.08 (d, 2H, 3.31 (s, 3H) J = 8.5) J = 8.0, 2.0) J = 2.5) 4d 6.92 (d, 2H, 7.68 (dd, 2H, 7.60 (d, 2H, 3.49 (s, 3H) J = 8.5) J = 8.5, 2.0) J = 2.0) 4e 7.06 (d, 2H, 7.79 (d, 2H, 7.63 (s, 2H) 3.41 (s, 3H) J = 8.5) J = 8.5) 4f 6.74 (d, 2H, 7.07-7.10 (m, 4H) 3.35 (s, 3H) J = 8.5) 4g 6.79 (d, 2H, 7.28 (dd, 2H, 7.25 (d, 2H, 3.36 (s, 3H) J = 8.0) J = 8.0, 0.5) J = 1.0) a Recorded in CDCl 3 except for 4e which was recorded in DMSO-d 6 . Assignment based on HSQC, HMBC and NOE spectra recorded for 4f, 11,18 and the observed coupling constants. b Additional peaks not listed in Table 3 are as follows. 4b: 2.23 (s, 6H, ArCH 3 ); 4c: 2.42 (s, 6H, SCH 3 ); 4d: 9.83 (s, 2H, CHO); 4e: 12.81 (br s, 1H, CO 2 H); 4f: 0.90 [s, 18H, C(CH 3 ) 3 ], 1.82 (br s, 2H, CHOH), 4.29 (s, 2H, ArCH); 4g: 0.22 [s, 18H, Si(CH 3 ) 3 ].

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Directed Synthesis of 1-Substituted Phenoxazines

Cited by 16 publications

References 0 publications

Bond Rotations and Heteroatom Effects in Donor–Acceptor–Donor Molecules: Implications for Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence

Bond Rotations and Heteroatom Effects in Donor–Acceptor–Donor Molecules: Implications for Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence

Synthesis of N‐Heterocycles‐Fused Azasilines by Palladium‐Catalyzed Si‐Si Bond Activation

Synthesis of 3,7-Disubstituted 10-Methylphenothiazines

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