Pyridine → HCID 86749449, compound

Participants

Reaction Steps

A solution of pyridazino 3',4',5',6':7,8,14,15!-3β-benzoyloxy-5α-ergostane (34, 3.2 g, 6.08 mmol) in CH2Cl2 (105 mL) and pyridine (1 mL) was cooled to -78° C. in a dry ice-acetone bath and ozone gas (approximately 0.95 mmol O3/ min) was bubbled through the solution for 25 min. Then the excess O3 was removed by bubbling through argon gas. The reaction mixture was treated with methyl sulfide (3 mL) and stirred at ambient temperature for 20 min. The solvent was evaporated under reduced pressure, leaving 3.90 g of tan fluff. Purification by flash column chromatography on 77 g of Merck grade 60 silica gel using MeOH/CHCl3 (2:98) yielded 1.65 g (59%) of aldehyde (36), mp 248°-252° C. EIMS (m/z): 458 (M+). 1H NMR: δ9.72 (d, 1H, J=2.6 Hz), 8.06 (d, 2H, J=8.3 Hz), 7.57 (dd, 1H, J=7.4, 7.4 Hz), 7.45 (dd, 2H, J=7.4, 7.9 Hz), 5.05 (m, 1H), 3.23 (dd, 1H, J=4.4, 18.7 Hz), 3.22 (dd, 1H, J=7.1, 16.4 Hz), 3.09 (dd, 1H, J=11.0, 16.4 Hz), 2.76 (ddd, 1H, J=2.6, 7.0, 10.8 Hz), 2.67 (dd, 1H, J=13.0, 17.3 Hz), 1.25 (d, 3H, J=7.0 Hz ) , 1.13 (s, 3H) , 0.88 (s, 3H).

Provenance & Evidence