List of used abbreviations - RosDok - Universität Rostock

948 (w) 853 (m), 803 (m), 751 (m), 626(m) 554 (m) cm −1 . GC-MS (EI, 70 eV): m/z
(%): 304 (M + , 100), 266 (12), 262 (43), 226 (14), 225 (20), 211 (13), 192 (4), 91 (9),
63 (4). HRMS (EI): calcd for C16H15O2ClS [M + ]:304.04523, found 304.045603.
General procedure for the synthesis of thioxanthones 6a-g: To 5 (1.0 mmol) was
added concentrated sulfuric acid (98%, 12 mL / mmol of 5) at 20 °C and the solution
was stirred for 2 h. To the solution was added ice water (50 mL). The organic and the
aqueous layer were separated and the latter was extracted with dichloromethane (3 x
15 mL). The combined organic layers were dried (Na2SO4), filtered, and the filtrate
was concentrated in vacuo. The residue was purified by chromatography (silica gel,
heptanes / EtOAc).
S
Me Me
Me
O
1,2,3-Trimethylthioxanthone (6a): Starting with 5b (114 mg,
1.0 mmol) and conc. sulfuric acid, 6a was isolated as a highly
viscous oil (270 mg, 98%). 1 H NMR (250 MHz, CDCl3): δ = 2.21
(s, 3 H, CH3), 2.30 (s, 3 H, CH3), 2.68 (s, 3 H, CH3), 7.31 (m, 1
H, ArH), 7.40 (m, 3 H, ArH), 8.30 (dd, 1 H, 3 J = 7.4, 4 J = 2.1 Hz,
ArH). 13 C NMR (62 MHz, CDCl3): δ = 15.9, 19.1, 21.4 (CH3), 124.2, 125.0, 125.7
(ArCH), 127.0 (C), 129.4, 131.0 (ArCH), 132.4, 134.9, 135.4, 135.7, 141.0, 141.1,
183.3 (C). IR (neat): ν̃ = 3023 (w), 2918 (w), 1712 (m), 1671 (s), 1530 (m), 1493 (s),
1329 (m), 1216 (s), 1166 (m), 1019 (m), 7546 (w) 645 (m) cm −1 . GC-MS (EI, 70 eV):
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