A solution of the product from Step B (1.05 g, 3.52 mmol), sodium hydride (60% dispersion in mineral oil, 310 mg, 7.75 mmol) and 4-(2-chloroethyl)morpholine hydrochloride (0.721 g, 3.88 mmol) in anhydrous dimethylformamide (DMF) (20 mL) was heated at 110° C. for 2.5 h and then stirred at ambient temperature overnight. The reaction mixture was extracted with ethylacetate (3×100 mL), washed with brine, dried over molecular sieves and concentrated. The residue was chromatographed on silica, elution with 50% ethylacetate-hexane, to yield 0.32 g (22%) of the desired product.
