Synthesis
General procedure for the synthesis of 6-fluoro-1-tetralone from 4-(3-fluorophenyl)butyric acid: a mixture of 4-(3-fluorophenyl)butyric acid (1.92 g, 10.5 mmol) and polyphosphoric acid (2 g) was heated under nitrogen protection at 110°C for 2 hours. After completion of the reaction, it was cooled to room temperature, the reaction was quenched with water and the reaction mixture was diluted with ether. Subsequently, it was washed with saturated aqueous sodium bicarbonate (2 times), the organic phase was dried with anhydrous sodium sulfate and concentrated to give 6-fluoro-1-tetralone (1.51 g, 87% yield). The product was characterized by NMR (400 MHz, CDCl3): δ 2.16 (m, 2H), 2.64 (t, 2H), 2.97 (t, 2H), 6.92 (dd, 1H), 6.99 (dt, 1H), 8.04 (dd, 1H).
References
[1] Patent: WO2005/92854, 2005, A1. Location in patent: Page/Page column 2
[2] Synthetic Communications, 1991, vol. 21, # 8-9, p. 981 - 987
[3] Patent: WO2006/66790, 2006, A1. Location in patent: Page/Page column 71-73
[4] Patent: WO2006/66745, 2006, A1. Location in patent: Page/Page column 21-22
[5] Patent: US2007/293526, 2007, A1. Location in patent: Page/Page column 29
