MDP2P from Isosafrole via Epoxide Intermediateby OsmiumSee CA 107:39790k. Isosafrole in acetonitrile + H2O2 in methanol + Na carbonate (pH 8-10.5), temperature 10-45°C, 20h. 94% epoxide. This can be rearranged to MDP2P in about 90% overall yield. Possibly this could also work with straight safrole. I don't have more info than this CA ref, but I'd try the following:
I have never done that, it's just what I would do if I had a lab and the intent to produce MDP2P via this route. Don't blame me if this doesn't work or explodes into your face. Ketone from Acetonitrile Epoxidation? I have no idea if this will work for isosafrole. For all I know it could react with the ring instead of the side chain. If it did for the desired epoxide then it would still need to be refluxed in dilute H2SO4 to form the ketone (as with the performic methods). "In an alkaline solution hydrogen peroxide reduces the intermediate to the amide with the liberation of oxygen, but at pH 8 no oxygen is evolved and the solution of peroxycarboximidic acid can be used to oxidize an olefin to its epoxide, pyridine to its N-oxide, and aniline to azoxybenzene." "A low-cost method for epoxidation of cyclohexene is by dropwise addition of 30% H2O2 and NaOH to a stirred mixture of cyclohexene, methanol, and acetonitrile at 60°C, the yield of cyclohexene oxide is 85%" Radziszewski reaction: CH3CN + H2O2 ---[NaOH]--> CH3C(NH)OOH ---[H2O2]--> CH3C(O)NH2 + H20 + O2I guess that the intermediate acid, CH3C(NH)OOH, would need to do a better job than regular peracetic CH3CHOOH in order for this to be sucessful with
our favorite olefin. |