Process For The Preparation Of A Cyp11 A1 Inhibitor And Intermediates Thereof

The present invention relates to an improved process for the preparation of 4H-pyranone structured CYP11A1 inhibitors such as 2-(isoindolin-2-ylmethyl)-5- (( 1 -(methylsulfonyl)piperidin-4-y l)methoxy)-4H-pyran-4-one (1A) and key intermediates thereof such as 2-(chloromethyl)-5-hydroxy-4H-pyran-4-one (II), 5- hydroxy-2-(isoindolin-2-ylmcthyl)-4H-pyran-4-onc (III), (1- (methylsulfonyl)piperidin-4-yl)methyl methane sulfonate (V') and (l-(methyl- sulfonyl)piperidin-4-yl)methyl 4-methylbenzene sulfonate (V"). CYP11A1 inhibitors are useful in the treatment of hormonally regulated cancers, such as prostate cancer and breast cancer.