Diisopropylethylamine → [(S)-1-Methyl-2-(7-{[(pyridine-3-carbonyl)-amino]-methyl}-furo[2,3-g]indazol-1-yl)-ethyl]-carbamic acid benzyl ester

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Reaction Steps

To a solution of the product from Step B (0.32 g, 0.847 mmol) in THF (20 mL) was added polymer supported di-isopropyl ethyl amine (3.86 mmol/g, 0.44 g, 1.69 mmol, 2 eq); this suspension was cooled (ice bath) and nicotinoyl chloride (0.15 g, 0.847 mmol) was added. The ice bath was removed and mixture was stirred for one hour, additional nicotinoyl chloride (50 mg) was added and the mixture was stirred at room temperature overnight. Triethylamine was added and after stirring for 10 min saturated aqueous sodium bicarbonate (150 mL) was added. This mixture was extracted with ethyl acetate (2×100 mL). The combined extracts were dried (MgSO4) and evaporated to an oil which was purified by chromatography (silica gel, hexane/ethyl acetate gradient) to give a solid (0.16 g, 39%): LC/MS m/z 484 [M+H]+.

Provenance & Evidence