Formaldehyde → HCID 118235640, compound

Participants

Reaction Steps

To a suspension of Example 325 (81%, 195 mg, 0.3 mmol) in ethanol (4 mL) was added 37% aqueous formaldehyde solution (0.1 mL, 1.33 mmol) and the resulting solution was stirred at room temperature for 20 minutes. Sodium triacetoxyborohydride (160 mg, 0.76 mmol) was added in one portion, followed by acetic acid (0.1 mL), and the whole mixture was stirred at room temperature under nitrogen for 2 h. The reaction mixture was diluted and neutralised with saturated sodium bicarbonate solution (15 mL). The crude material was then extracted into dichloromethane (2×20 mL). The combined organic extracts were dried over sodium sulphate, filtered and concentrated under vacuum. The resulting brown oil (140 mg) was purified by preparative HPLC (Method A) to afford the title compound (27 mg, 17%) as a colourless solid. δH (500 MHz, CD3OD) 9.05 (d, J 1.4 Hz, 2H), 8.38-8.35 (m, 2H), 7.41 (d, J 10.9 Hz, 1H), 7.33-7.27 (m, 1H), 7.18 (d, J 7.9 Hz, 1H), 7.14 (td, J 7.6, 0.9 Hz, 1H), 7.10 (dd, J 7.6, 1.7 Hz, 1H), 6.91 (t, J 74.0 Hz, 1H), 4.72 (d, J 11.3 Hz, 2H), 4.42 (s, 2H), 4.35 (d, J 11.4 Hz, 2H), 3.08 (s, 3H), 2.42 (s, 3H). Method D HPLC-MS: MH+ m/z 470, RT 1.09 minutes.

Provenance & Evidence