10
A. KAVITHA ET AL.
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LCMS (ES þ APCI). calcd. For C12H9NO: 183.06, found (M þ H)þ¼ 184.0; H-NMR
(400 MHz, DMSO-d6): d 8.16 (s, 1H), 6.71 (td, J ¼ 1.60, 7.40 Hz, 2H), 6.60–6.53 (m,
4H), 6.44 (dd, J ¼ 1.20, 7.60 Hz, 2H); 13C-NMR (100 MHz, DMSO-d6): d 143.23, 132.88,
124.37, 120.78, 115.52, 113.74. The analytical data are consistent with previ-
ous reports.[20].
Synthesis of 1-(10H-phenoxazin-10-yl)ethan-1-one (6aa)
A microwave tube equipped with a magnetic stir bar was charged with the N-(2-(2-bro-
mophenoxy)phenyl)acetamide 5a (0.155 g, 0.5 mmol), Na2CO3 (0.11 g, 1.0 mmol) and
DMF (20 V). The resultant reaction mixture was heated at 130 ꢁC for 30 minutes by
microwave irradiation. After completion of the reaction, water was added, extracted
with ethyl acetate. The combined organic layer was dried with anhydrous Na2SO4 and
the solvent was removed under vacuum. The residue was then purified by Biotage
Isolera silica gel (40–63 lm, 60 Å) flash column chromatography (hexane/EtOAc, 95:5)
to afford 8 mg (7% yield) of the product 6aa as a white solid; LCMS (ES þ APCI-MS)
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calcd. For C14H11NO2: 225.08, found (M þ H)þ ¼ 226.2; H-NMR (400 MHz, DMSO-
d6): d 7.62–7.60 (m, 2H), 7.28–7.16 (m, 6H), 2.27 (s, 3H); 13C-NMR (100 MHz, DMSO-
d6): d 169.27, 150.80, 129.69, 127.49, 125.88, 124.05, 117.07, 23.19. The analytical data
are consistent with previous reports.[14]
Synthesis of 6-bromo-3-chloro-10-methyl-10H-phenoxazine (7)
To a stirred solution of 6-bromo-3-chloro-10H-phenoxazine (6i) (0.10 g, 0.34 mmol) in
DMSO (10 V) was added KOH (0.64 mmol) at 0 ꢁC. The resulting solution was stirred
at RT for 15 mins. Then added MeI (0.37 mmol) in one lot. The reaction mixture was
stirred at RT for 18 h. The reaction mixture was diluted with water, extracted with ethyl
acetate. The combined organic layers were washed with water, brine, dried over anhyd-
rous Na2SO4, filtered through a cotton plug and concentrated under reduced pressure.
The resulting crude was purified by Biotage Isolera silica gel (40–63 lm, 60 Å) flash col-
umn chromatography (hexane/EtOAc, 95:5) to afford 0.085 g (81% yield) of 6-bromo-3-
chloro-10-methyl-10H-phenoxazine (7) as a off white solid. LCMS (ES þ APCI-MS)
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calcd. For C13H9BrClNO: 308.9, found (M þ H)þ ¼ 310.9; H-NMR (400 MHz, CDCl3):
d 6.91 (dd, J ¼ 1.20, 8.20 Hz, 1H), 6.84 (d, J ¼ 2.40, Hz, 1H), 6.83–6.82 (m, 1H), 6.72 (t,
J ¼ 8.00 Hz, 1H), 6.43 (dd, J ¼ 1.20, 8.00 Hz, 1H), 6.41 (d, J ¼ 8.00 Hz, 1H), 3.01 (s, 3H);
13C-NMR (100 MHz, CDCl3): d 145.49, 142.10, 135.81, 133.23, 125.88, 124.85, 124.55,
123.88, 116.17, 112.06, 110.57, 109.48, 31.25; Anal calc. for C13H9BrClNO: C, 50.27; H,
2.92; N, 4.51%; found C, 50.01; H, 3.10; N, 4.68%.
Acknowledgments
The authors are thankful to Dr. Subhendu Kumar Mohanty, Dr. Sathya Shanker and Karthik T.
Pai for their support and encouragement throughout this work. Kavitha is grateful to Syngene
International Ltd, Bangalore, India for analytical support and the permission for higher educa-
tion (Ph.D.).