1-Hydroxybenzotriazole → tert-butyl [(4'R)-6'-{[(5-methoxypyrazin-2-yl)carbonyl]amino}-2',2'-dimethyldispiro[cyclopropane-1,3'-chromene-4',4''-[1,3]oxazol]-2''-yl]carbamate

Participants

Reaction Steps

To a mixture of tert-butyl[(4′R)-6′-amino-2′,2′-dimethyldispiro[cyclopropane-1,3′-chromene-4′,4″-[1,3]oxazol]-2″-yl]carbamate (100 mg, 0.268 mmol), 5-methoxypyrazine-2-carboxylic acid (45 mg, 0.30 mmol) and 1H-benzotriazol-1-ol (40 mg, 0.29 mmol) in dichloromethane (2 mL) was added N-[3-(dimethylamino)propyl]-N′-ethylcarbodiimide hydrochloride (57 mg, 0.30 mmol). The mixture was stirred at room temperature for 3 hours and directly purified by silica gel column chromatography (precolumn: NH-silica gel, main column: neutral silica gel, hexane/ethyl acetate=2:1-1:1-0:1) to afford tert-butyl[(4′R)-6′-{[(5-methoxypyrazin-2-yl)carbonyl]amino}-2′,2′-dimethyldispiro[cyclopropane-1,3′-chromene-4′,4″-[1,3]oxazol]-2″-yl]carbamate (108 mg).

Provenance & Evidence