Synthesis
The general procedure for the synthesis of 4-fluoro-1-naphthalenecarboxaldehyde from 1,1-dichlorodimethyl ether and 1-fluoronaphthalene was as follows: a solution of 1,1-dichlorodimethyl ether (5.9 mL, 65 mmol) in methylene chloride (30 mL) was cooled in an ice bath, followed by the addition of stannum tetrachloride (7.6 mL, 65 mmol) drop-wise over a period of 15 min. After stirring for 45 minutes, a dichloromethane (30 mL) solution of 1-fluoronaphthalene (5.5 mL, 50 mmol) was added. The reaction mixture was allowed to warm slowly to room temperature and stirred overnight. The reaction mixture was poured into ice water (100 mL) and diluted with dichloromethane (50 mL). The organic layer was separated and further diluted with dichloromethane (100 mL) followed by washing with water (3 x 50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and the solvent was removed in vacuum to give 4-fluoro-1-naphthaldehyde (7.62 g, 87% yield) as a pale yellow solid. Mass spectrum (ESI) m/z 175 (M + H)+.
References
[1] Journal of Organic Chemistry, 1995, vol. 60, # 20, p. 6592 - 6594
[2] Patent: WO2004/52890, 2004, A1. Location in patent: Page 78
[3] Patent: CN105566284, 2016, A. Location in patent: Paragraph 0267; 0268
[4] Bioorganic and Medicinal Chemistry Letters, 2004, vol. 14, # 13, p. 3481 - 3486
[5] Patent: WO2008/407, 2008, A1. Location in patent: Page/Page column 57
