A 0° C. solution of 14.67 g of product from Example 274 in 200 ml of 3:1 diethyl ether/water is treated with 4.99 g of sodium bicarbonate and 15.07 g of iodine. The reaction mixture is stirred vigorously for 24 hours at room temperature, quenched with 15 ml of saturated sodium sulfite, and diluted with 100 ml of water. The reaction mixture is extracted with diethyl ether, dried, concentrated in vacuo, and purified by chromatography (silica gel: 0-10% ethyl acetate/hexane) to give 15.0 g of the desired product.
