Preparation of N-(2-nitrophenyl)-9H-thioxanthen-9-amine from thioxanthen-9-ol and 2-nitroaniline
SyntheticPage 845
DOI:
Submitted: August 14, 2018, published: September 10, 2018
Authors
Joshua Gettins
Mariyah Sajjad
Mark Wainwright (M.Wainwright@ljmu.ac.uk)
Robert Smith (rbsmith@uclan.ac.uk)
A contribution from

Chemicals
Thioxanthen-9-ol (prepared in house from thioxanthen-9-one - see Synthetic Page 848)
2-Nitroaniline (Sigma Aldrich)
Procedure
To a round bottomed flask was added thioxanthen-9-ol (0.5 g, 2.3 mmol), 2-nitroaniline (0.4g, 2.9 mmol), acetic acid (0.25 mL) and ethanol (10 mL)*. The reaction mixture was fitted with a condenser and heated to reflux with constant stirring.** After two hours at reflux, the solution was allowed to cool to room temperature, a glass stopper fitter and orange mixture transferred to a freezer and left overnight***. The precipitate produced was isolated under vacuum filtration and washed with cold ethanol to give N-(2-nitrophenyl)-9H-thioxanthen-9-amine (0.16g, 20%) as an orange precipitate.
Author Comments
*** Leaving the reaction for an extra 24 hours in the freezer did not produce a higher yield, although a higher yield could possibly be obtained through evaporation of the reaction mixture and column chromatography.
Data
1H NMR (400 MHz, DMSO-d6) δ 8.76 (d, J = 8.9 Hz, 1H), 8.06 (dd, J = 8.6, 1.6 Hz, 1H), 7.71 – 7.61 (m, 4H), 7.58 – 7.52 (m, 1H), 7.45 (dd, J = 8.9, 1.3 Hz, 1H), 7.37 – 7.32 (m, 4H), 6.74 (ddd, J = 8.4, 6.8, 1.2 Hz, 1H), 6.21 (d, J = 8.8 Hz, 1H). 13C NMR (101 MHz, DMSO) δ 143.40, 136.51, 134.84, 132.03, 131.71, 127.84, 127.68, 127.47, 127.03, 126.44, 116.35, 115.58, 54.87. LC-MS 335 [M+1].
Lead Reference
Hori, M., Kataoka, T., Ohno, K., Toyoda, T.; Reactivities of 9-phenylxanthylium and 9-phenylthioxanthylium salts in electrophilic and nucleophilic reactions. I. Nitration Chemical & Pharmaceutical Bulletin (1973), 21(6), 1272-1281.
Keywords
alcohols, amines, heterocyclic compounds