3-Iodobenzaldehyde (12) was synthesized as follows: pyridinium chlorochromate (2.45 g, 11.4 mmol) and dry diatomaceous earth (about 2.00 g) were suspended in anhydrous dichloromethane (20 ml) at room temperature and stirred for 15 minutes. Subsequently, a solution of 3-iodobenzyl alcohol (11) (1.02 g, 4.35 mmol) in anhydrous dichloromethane (5 ml) was added to this suspension. The reaction mixture was protected from light and stirring was continued for 2 hours at room temperature. After completion of the reaction, the reaction solution was diluted with ether and filtered through diatomaceous earth. The resulting turbid brown filtrate was concentrated to a reddish brown gelatinous paste, which was redissolved in dichloromethane and purified by short silica gel column chromatography using dichloromethane as eluent. A clarified colorless solution was finally obtained, and 3-iodobenzaldehyde (12) was concentrated to give 3-iodobenzaldehyde (12) as a white solid (0.953 g, 95% yield).1H NMR (400 MHz, CDCl3) data were as follows: δ 7.29 (t, J = 7.8 Hz, 1H, H5); 7.85 (br d, J = 7.8 Hz, 1H, H6); 7.96 (br d, J =7.8 Hz, 1H, H4); 8.21 (br s, 1H, H2); 9.93 (s, 1H, CHO).
