24,31-Epoxy-24-methyl-elemo-lanost-8,9-ene-3-ol

To a solution of 1g (2.27 mmol) of 1 in 40ml of chloroform at room temperature was added 0.55g (2.27 mmol) of meta-chloroperbenzoic acid (mCPBA). The solution was stirred for 3 hours and then it was washed with 10% aqueous sodium bisulphite and saturated sodium bicarbonate, dried over sodium sulphate and concentrated under reduced pressure to give 0.89g (85.85%) of the epoxide 2 after purification by flash chromatography (10% ethyl acetate in hexane).

Mp: 139-140 (hexane).

MS: 442 ([M]⁺).

IR (KBr): 3400 (OH); 1638 (C=C); 1287 (C-O epoxide).

¹H NMR (200 MHz, CDCl3): 3.2 (dd, J₁=12 Hz, J₂=4 Hz, C3-H); 2.55 (m, C31-H₂); 0.74 (s, C18-H₃);

0.87 (s, C19-H₃); 0.79 (s, C28-H₃); 0.97 (d , J=2 Hz, C26-H₃); 0.99 (d, J=2Hz, C27-H₃); 0.93 (d, J=6Hz, C21-H₃); 0.94 (s, C29-H₃); 0.95 (s, C30-H₃).

13C NMR (100 MHz, CDCl3) (ppm): 78.48 (C3); 133.62 (C8); 133.0 (C9); 68 (C24); 62.3 (C31).