Example 3
A solution of Compound C (90 mg, 0.15 mmol), NEt3 (70 μL, 0.5 mmol) and 4-dimethylaminopyridine (DMAP) (1 crystal) in DCM (2 mL) was treated with methoxyacetyl chloride (21 μL, 0.22 mmol) and stirred at RT for 12 hr under nitrogen. The reaction mixture was diluted with MTBE and washed with water and then brine, dried over sodium sulfate and concentrated under vacuum. The residue was purified by silica gel chromatography. The THP-protected methoxyacetate was dissolved in MeOH (4 mL), treated with pyridinium para-toluene-sulfonate (PPTS) (catalytic) and stirred at 50° C. for 2 hr. The reaction mixture was concentrated, and the residue was dissolved in MTBE (20 mL) and washed with water and then brine to yield crude THP-deprotected methoxyacetate. The crude product was taken in dioxane (5 mL) along with 10% Pd/C (18 mg) and hydrogenated under a hydrogen atmosphere to yield crude Compound Ia-8 (64 mg) as an oil. MS: m/z 485 [M+Na]+
The following compounds were synthesized using similar procedures as above:
