To 4-{[3-methyl-6-(methyloxy)-2-phenyl-1-naphthalenyl]oxy}benzaldehyde (8) (0.565 g, 1.53 mmol) was added a 2:1 acetone:H2O solution (21 mL). The turbid solution was cooled in an ice-water bath and sulfamic acid (0.158 g, 1.63 mmol, 1.06 eq) was added portionwise over several minutes. The reaction mixture was stirred for 5 min and sodium chlorite (80% tech. Grade) (0.185 g, 1.64 mmol, 1.07 eq) was added portionwise. The reaction mixture was stirred for 30 min. The acetone was removed in vacuo and the reaction mixture was partitioned between H2O and CH2Cl2. The organic phase was separated and the aqueous phase was extracted with CH2Cl2. The organic extracts were combined, dried over MgSO4, filtered, and the filtrate was concentrated to give the crude product. The crude product was purified by flash chromatography over SiO2 with CH2Cl2:MeOH (94:6) to give 0.47 g (80%) of the compound 16 as a gold-yellow amorphous solid. 1H NMR (400 MHz; DMSO-d6): δ 2.17 (s, 3H), 3.86 (s, 3H), 6.64 (d, J=8.7 Hz, 2H), 7.07 (dd, J=2.6 Hz, 9.2 Hz, 1H), 7.16 (m, 2H), 7.21-7.30 (m, 3H), 7.35 (d, J=2.4 Hz, 1H), 7.52 (d, J=9.1 Hz, 1H), 7.70 (m, 3H), 12.63 (br s, 1H). AP LRMS m/z 385 (M+H)+.
