EXEMESTANE AND ITS INTERMEDIATES AND METHODS OF MAKING THE SAME

A method is provided for preparing an aromatase inhibitor of formula (I) wherein each of R1, R2, R3, R4, independently, is hydrogen, halogen or C1-C6 alkyl. In one form, the aromatase inhibitor is exemestane wherein each of R1, R2, R3, R4 is hydrogen. In the method, a compound of formula (II) wherein R1, R2, R3, R4 are as defined above and R is alkylene, is reacted with a deprotonating agent and a compound of the formula R5SO2X wherein R5 is C1-C5 alkyl and X is halogen so as to obtain a compound of formula (III) wherein R1, R2, R3, R4, R5 are as defined above. The compound of Formula (III) is then reacted with a base to form an aromatase inhibitor of formula (I).