Diisopropylethylamine → (2S,5R)-tert-butyl 5-(N-(allyloxy)-2-nitrophenylsulfonamido)-2-carbamoyl-3-methyl-5,6-dihydropyridine-1(2H)-carboxylate

Participants

Reaction Steps

To a solution of (2S,5R)-5-(N-(allyloxy)-2-nitrophenylsulfonamido)-1-(tert-butoxycarbonyl)-3-methyl-1,2,5,6-tetrahydropyridine-2-carboxylic acid (Intermediate 82, 3.98 g, 8.00 mmol) in DMF (20 mL) at room temperature was added ammonia hydrochloride (0.856 g, 16.00 mmol), 2-(3H-[1,2,3]triazolo[4,5-b]pyridin-3-yl)-1,1,3,3-tetramethylisouronium hexafluorophosphate(V) (4.56 g, 12.00 mmol) and N-ethyl-N-isopropylpropan-2-amine (5.57 mL, 32.00 mmol). The reaction mixture was stirred at room temperature for 2 h. The reaction mixture was diluted with ethyl acetate and washed with saturated sodium bicarbonate and three times with 1:1 brine:water. The organics were dried over magnesium sulfate, filtered and concentrated. The crude product was purified with silica gel chromatography (220 g, 10%-80% ethyl acetate/hexanes) to yield the desired product (2.79 g, 70.2%) as an yellow foam.

Provenance & Evidence