Patent ID: 7812155

Claim:
A process for preparing a compound represented by formula (1), comprising the steps of: (a) reacting rapamycin with an alkyl triflate; (b) purifying the resulting reaction product with a normal phase chromatograph after (a); and (c) further purifying a purified product, which has been purified with the normal phase chromatograph, with a reverse phase chromatograph after (b); wherein R represents an alkyl, arylalkyl, hydroxyalkyl, alkoxyalkyl, acyloxyalkyl, aminoalkyl, alkylaminoalkyl, alkoxycarbonylaminoalkyl, acylaminoalkyl, or aryl, and wherein a stationary phase used in the reverse phase chromatograph is formed from a silica gel having a particle size in a range from 10 to 50 μm.