Patent ID: 8722880

Claim:
A method for preparing 42-(dimethylphosphinate) Rapamycin (Ridaforolimus) of the following formula I, comprising the following steps: (a) reacting Rapamycin of the following formula II with a silane compound in a first basic condition to obtain a compound of the following formula IV: (b) deprotecting the compound of the formula IV in a first acid condition to obtain a compound of the following formula V: (c) reacting the compound of the formula V with Dimethylphosphinic chloride in a second basic condition to perform a phosphorylation reaction to obtain a compound of the following formula VI: (d) hydrolyzing the compound of the formula VI in a second acid condition to obtain Ridaforolimus of the formula I, wherein each R 1 , R 2 and R 3 is independently H, C 1-6 linear alkyl, benzyl, phenyl, or p-methylbenzyl, with the proviso that all R 1 , R 2 and R 3 are not H.