Iodine → 4-(Propargyloxy)benzaldehyde

Participants

Reaction Steps

A mixture of 4-ethynylbenzaldehyde (1) (171 mg, 1.27 mmol), methyl 3-oxopentanoate (175 mg, 1.27 mmol), dimedone (181 mg, 1.27 mmol), ammonium acetate (101 mg, 1.27 mmol), I2 (97 mg, 0.38 mmol), and ethanol (10 drops) is stirred under argon for 5.5 h, quenched with 5% Na2S2O3 (30 mL), and extracted with ethyl acetate (50 mL and 30 mL). The extract is washed (5% Na2S2O3, H2O, and brine) and dried. After solvent removal at reduced pressure, the residue is purified on silica gel (33% to 60% ethyl acetate/hexane) to give 277 mg (60%) of 2 (BI-3029) as a cream solid, mp 234-236° C. IR 3332, 2933, 1704, 1610, 1482, 1214 cm−1; 1H NMR (CDCl3) δ 0.93 (s, 3H, CH3), 1.10 (s, 3H, CH3), 1.26 (t, J=7.2 Hz, 3H, CH2CH3), 2.07-2.42 (m, 4H, COCH2, CH2), 2.76-2.89 (m, 2H, CH2CH3), 3.02 (s, 1H, CH≡C), 3.63 (s, 3H, OCH3), 5.09 (s, 1H, CH), 5.90 (bs, 1H, NH), 7.27 (d, J=8.1 Hz, 2H, 3,5-ArH), 7.37 ppm (d, J=8.1 Hz, 2H, 2,6-ArH).

Provenance & Evidence