1,10-phenanthroline-5,6-dione was prepared by a previously published method []. A mixture of 2-hydroxy- 5-methyl-isophthalic aldehyde (0.25 g, 1.5 mmol), 1,10-phenanthroline-5,6-dione (0.32 g, 1.5 mmol), ammonium acetate (2.31 g, 30 mmol) and glacial acetic acid (30 cm3) was refluxed for about 2 h, then cooled to room temperature and diluted with water (ca, 60 cm3). Dropwise addition of concentrated aqueous ammonia gave a yellow precipitate, which was collected and washed with water. The crude product in ethanol was purified by silica gel filtration (60-100 mesh, ethanol). The principal yellow band was collected. A yellow crystalline solid was obtained by slow evaporation of the solution, which was then dried in vacuo. Yield 0.35 g, 65%.
1H NMR (500 MHz, d6-DMSO): d13.85 (s, 1H), 10.51 (s, 1H), 9.14 (s, 1H), 8.99 (d, 2H, J = 8), 8.87 (d, 2H, J = 8), 8.29 (s, 1H), 7.78 (t, 2H, J = 7), 7.48 (s, 1H). 2.36 (s, 3H).
13C NMR (125 MHz, d6-DMSO): 192.2, 158.9, 150.8, 148.1, 143.6, 134.9, 131.8, 131.3, 129.8, 128.1, 127.6, 126.3, 123.6, 123.3, 120.5, 22.3.
IR (KBr. cm-1): 3416s, 3036m, 1693s, 1609m, 1560m, 1482m, 1356m, 1250s, 1131m, 1075s, 969s, 807s, 737s and 646s.
FAB-MS ([M+1]+): 355.
Supplementary materials
Supplementary File 1Supplementary File 2Supplementary File 3Acknowledgement
Support for this research provided by the National Natural Science Foundation of China, the National Science Foundation of Guangdong Province and Research Fund of Royal Society of Chemistry U.K. is gratefully acknowledged.
References
- Yamada, M.; Tanaka, Y.; Yoshimato, Y.; Kuroda, S.; Shimao, I. Bull. Chem. Soc. Jpn. 1992, 65, 1006. [CrossRef]
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